lecture 2

Biomedicine: Human Sciences

Lecture 2:

Terminology, Landmarks

and Skeletal System

Learning Outcomes

In today’s topic you will learn:

⮚ Key anatomical terminology to

describe directions, movements,

regions and planes of the body.

⮚ The major bones of the body.

⮚ The structure and functions of the

skeletal system.

⮚ Joints.

⮚ The signs, symptoms, investigation

procedures and some orthodox treatments

of skeletal system pathologies.

Anatomical Position

The anatomical position describes the body position from which

directional terms always refer to: • Person stands erect, palms forward. • Feet parallel, flat on the floor.

• Arms are at the sides of the body.

Individuals can lie in a supine, prone or side-lying position:

• Supine describes the body lying face up.

The anatomical position:

• Prone describes the body lying face down.

Directional Terms

Anatomical Term:	Definition:
Medial	Nearer to the midline
Lateral	Away from the midline
Bilateral	Both sides
Unilateral	One side
Ipsilateral	On the same side
Contralateral	On the opposite side
Proximal	Nearer to the trunk
Distal	Further from the trunk
Anterior (ventral)	Nearer the front
Posterior (dorsal)	Nearer the back
Superior	Towards the top
Inferior	Towards the bottom

Body Planes

In human anatomy, the following

three planes are used:

Coronal / frontal plane:

• Separating the body front and back.

Sagittal plane:

• Separating the body left and right.

Horizontal / transverse plane:

• Separating the body top and bottom.

The Human Skeleton

There are 206 bones in the human body.

• The skeleton accounts for 18% of body weight.

FUNCTIONS:

• Supports framework for the body.

• Forms boundaries (skull).

• Attachment for muscles and tendons.

• Permits movement (joints).

• Haematopoiesis — formation and development

of blood cells from the red bone marrow.

• Mineral homeostasis (mostly calcium and phosphate).

• Triglyceride storage (yellow bone marrow).

Bone Cells ^osteo-^{= bone}

1. Osteogenic cells:

• Bone stem cells. They are the only bone cell

to undergo division (producing osteoblasts).

2. Osteoblasts:

• These are bone-building cells.

B = build

• They synthesise and secrete collagen

and other components of bony matrix.

• They are trapped and become osteocytes.

3. Osteocytes:

• Osteocytes are mature bone cells. They maintain the daily metabolism of bone, such as nutrient exchange. © CNM: Human Sciences – The Skeletal System. BQ.

Bone Cells

4. Osteoclasts:

• Osteoclasts are huge cells derived from the fusion of as many as 50 monocytes (WBCs).

• On the side facing the bone surface, the cell membrane is folded into a ruffled border where the cell releases powerful lysosomal enzymes and acids which digest bone matrix.

• Resorption is the breakdown of bone matrix.

• Osteoblasts and osteoclasts work together to remodel bone throughout life. Excess osteoclast activity leads to a loss of bone density.

osteo- = bone

-cyte = cell

-clast = broken

An osteoclast:8

^peri-^{= layer surrounding}Compact Bone diaphysis = shaft

The skeleton is formed from two

types of bone: Compact and spongy.

• 80% of the skeleton is compact bone.

• Contains few spaces and is strong.

• Compact bone is found beneath the

periosteum of all bones and makes up the

bulk of the diaphysis of long bones.

• A structural unit of compact bone is an osteon.

These are aligned in the same lines as stress.

Compact Bone

An osteon contains these four parts:

1. Haversian canal:

Contains blood vessels and nerves.

2. Lamellae:

Concentric rings of calcified extracellular

matrix containing minerals and collagen.

3. Canaliculi:

A mini system of interconnected canals

that provides a route for nutrients / waste.

4. Lacunae:

Small spaces called lacunae with osteocytes.

Spongy Bone

Spongy bone does not contain osteons.

Instead it consists of an irregular lattice of

thin columns called trabeculae that are

arranged along lines of stress.

• Microscopic spaces between trabeculae help make bone lighter and can be filled with bone marrow. They also contain blood vessels that nourish the bone.

• Spongy bone makes up the interior of short, flat and irregularly-shaped bones and the ends of long bones. Spongy bone is always covered with compact bone.

Bone Matrix

Like other connective tissues, bone

contains an extracellular matrix that

surrounds separated cells.

• The most abundant mineral in bone is

calcium phosphate. This combines with

other mineral salts such as magnesium,

sulphate, potassium.

• These minerals are deposited and crystallise

(harden) in the framework formed by

collagen fibres of the matrix (imagine

collagen as the scaffolding). Together, these

minerals contribute to the hardness of bone.

Long Bones

Long bones are defined as ‘bones that have

a greater length than width’.

• Long bones contain a shaft (diaphysis)

and two heads (epiphyses).

• Long bones are slightly curved for strength

(allowing better force distribution).

• Long bones contain mostly compact bone

in the diaphysis and spongy bone in the

epiphyses.

• Examples include the femur, tibia and humerus.

Long Bones: Epiphysis

EPIPHYSIS:

• The epiphysis forms the proximal

and distal ends of long bones.

• Epiphyses are separated from

the diaphysis by the epiphyseal

plate (a layer of hyaline

cartilage that allows the

diaphysis to grow in length).

• The epiphysis contains a thin

outer region of compact bone

covered by articular / hyaline cartilage and inner spongy bone with red bone marrow.

Distal epiphysis

Long Bones: Diaphysis

DIAPHYSIS:

• The diaphysis describes the tubular shaft of

long bones.

• Outer compact bone covered by ‘periosteum’.

• Contains a central

medullary cavity that

contains red / yellow

bone marrow. ALL

marrow starts off as

red marrow.

Periosteum

The periosteum surrounds the

external surface of bone when

it is not covered by cartilage.

• Hyaline cartilage replaces

periosteum on joint surfaces.

• The periosteum is a pain-sensitive, highly-vascular membrane that

protects bone and serves as an

attachment for ligaments and tendons.

• The periosteal arteries enter the

diaphysis through many perforating

canals, delivering oxygenated blood.

peri- = surrounding osteo- = bone

Periosteum

The periosteum is a double-layered membrane, containing:

• A tough outer fibrous layer that protects bone.

• An inner osteogenic layer that contains osteoblasts and

peri- = surrounding osteo- = bone

osteoclasts, assisting in bone

growth and repair.

Types of Bone

Bone type:	Examples:
Short bones (cubed shaped):	Carpals, tarsals
Irregular bones (complex shapes):	Vertebrae
Flat bone (two plates of compact bone):	Skull, scapula
Sesamoid bone:	Patella
Long bones:	Femur, tibia, etc.

Bone Formation

Bone formation begins during foetal development, before continuing into childhood and then into adult life.

• There are two ossification pathways used to produce bone; these are:

1. Intramembranous ossification:

— Bone develops from connective tissue sheets. — All flat bones (i.e. skull) and the clavicles .. develop this way.

2. Endochondral ossification:

— Bone develops by replacing hyaline cartilage. © CNM: Human Sciences – The Skeletal System. BQ.

endo = within

chondral = cartilage19

Bone Growth

Long bones elongate from the epiphyseal growth

plate. This plate is a layer of hyaline cartilage in

the epiphyses where osteoblasts

are produced, ossifying the bone matrix.

• In the early twenties, the epiphyseal growth plate

ossifies so that only a thin epiphyseal line remains.

• If a bone fracture damages the epiphyseal plate

during childhood, the bone may grow shorter.

• Bones can also grow in thickness using osteoblasts

in the periosteum. This continues throughout life

due to physical stress, muscle activity and weight.

Epiphyseal Growth Plate

This image illustrates the activity

within the growth plate:

Cartilage cells (chondrocytes)

undergo mitosis here.

At this stage, chondrocytes stop

dividing.

At this point, minerals start to

deposit, capillaries invade and

deliver osteoblasts / osteoclasts 🡪 new bone is formed.

Growth plate in distal tibia

Bone Hormones

Many hormones affect bone growth and

remodelling (density) by altering the ratio of

osteoblast to osteoclast activity.

Promote osteoblast activity (and so bone

formation):

• Growth hormone and thyroid hormone.

• Oestrogen and testosterone.

• Calcitonin.

Promote osteoclast activity (and so bone loss):

• Parathyroid hormone.

• Cortisol (and steroid medications).

Bone Homeostasis

Bones are an important mineral reservoir —

mostly calcium.

• Blood calcium levels have to be tightly controlled

to ensure proper blood clotting, nerve and muscle function.

If blood calcium levels are low: Hypocalcaemia

• Osteoclasts break down bone and release calcium into the blood.

If blood calcium levels are high: Hypercalcaemia

• Increased osteoblast activity (takes calcium back into bone). • Calcium exchange is regulated by the parathyroid glands and the thyroid gland.

Parathyroid Hormone

Parathyroid hormone increases blood

calcium.

1. Increases the activity of osteoclasts

(resorption).

2. Stimulates the kidneys to reabsorb

and retain calcium in the blood.

3. Increases formation of calcitriol which promotes calcium uptake from food in the intestines.

Parathyroid hormones are secreted from the parathyroid glands, which are located in the anterior neck.

calcitriol = active form of vitamin D

Calcitonin

Calcitonin is a hormone that lowers

blood calcium levels.

• Secreted by para-follicular cells

of the thyroid gland.

• It inhibits osteoclasts and

promotes osteoblast deposition

of calcium in the bones.

• The overall result is increased bone

formation and decreased blood

calcium.

Vitamin D

Vitamin D facilitates calcium

absorption in the intestines

and is directly involved in bone

turnover.

• Vitamin D₃works closely with

vitamin K₂. D₃assists the

absorption of calcium into the

blood, whilst K₂activates a protein

called osteocalcin which controls

utilisation of the calcium in the

body (depositing it in bones).

Vitamin D

• Vitamin D levels in the body decrease with

age. This is broadly associated with a

combination of factors including:

⮚ Low sun exposure, reduced dietary

absorption, reduced ability to produce

an active form of vitamin D through its

processes in the skin, liver and kidneys.

• High alcohol intake reduces vitamin D

conversion into its active form.

• Magnesium is a co-factor needed for the

conversion of vitamin D in the body. Many

osteoporotic women are deficient in magnesium.

Exercise

Within limits, bone can become stronger in response to mechanical stress, e.g. pull of skeletal muscle and gravity.

• Mechanical stress leads to increased mineral deposition and increased collagen production.

• Mechanical stress is important for ensuring bone formation occurs more quickly than bone resorption.

Hence weight bearing exercise builds bone.

• Lack of stress on bones can cause bone mass loss of up to 1% per week, e.g. bedridden patients, astronauts.

^Source:^{www.osteoporosis.newlifeoutlook.com/weight-bearing-exercise/}ortho- = correct or straighten dontist = teeth specialist

Summary Quiz:

1. What is meant by the following: Superior; medial; distal; supine? 2. Name the cell that builds bone.

3. Name the bone cell that has a ruffled border and secretes enzymes. 4. Name the structural unit of compact bone.

5. In what direction are the trabeculae of spongy bone positioned / directed?

6. What is the role of the Haversian canal? 7. Explain the role of the periosteum.

Video: Bone remodelling: www.youtube.com/watch?v=0dV1Bwe2v6c

8. Give ONE example of a short and sesamoid bone.

9. Does parathyroid hormone increase or decrease blood calcium? 10. Explain why a patient might be deficient in vitamin D. 29

Axial Skeleton

The skeleton is divided into the axial and

appendicular sections.

• The axial skeleton is the central skeleton

and contains 80 bones.

• The appendicular skeleton consists of the

bones supporting the extremities / limbs.

• The axial skeleton serves to protect the

body's most vital organs.

• The axial skeleton contains the: Skull, inner ear

bones, hyoid, thoracic cage and vertebral column.

Skull

Forms the cranium (upper head) and face

and encapsulates the brain.

• The skull bones are joined with fibrous joints (sutures).

• Sinuses are air-filled cavities in the skull that:

• Give resonance to the voice.

• Lighten bones of face and cranium.

• Fontanelles:

• Fibrous sutures (soft spots) on a baby’s head joining

the skull bones together. Ossify at 12–18 months.

• Allow the baby’s head through the birth canal.

Vertebral Column

The vertebral column consists

of 24 movable vertebrae:

• Cervical (7) C1–C7.

• Thoracic (12) T1–T12.

• Lumbar (5) L1–L5.

• Sacrum and coccyx (fused bones).

• Vertebrae are named by region and number.

E.g. C3 articulates with C2 above and C4 below.

Neighbouring vertebrae connect via intervertebral discs.

• Functions: Protection for spinal cord; movement

(e.g. side bending); support of skull; forms axis of the trunk.

Intervertebral Discs

• Discs are shock-absorbing structures. 23 discs

are present in the spine (none in sacrum).

These get progressively thicker lower down.

• They bind vertebral bodies and separate

individual vertebrae.

• Discs are most hydrated in the morning and in

those aged between 30–40 years. They make

up one-third of the length of the spinal column.

• Two parts: Annulus fibrosus, nucleus pulposus.

• The nucleus pulposus is a gel-like pad.

Thoracic Cage and Ribs

Consists of the:

• Sternum

• Ribs (12 pairs):

- The first rib sits behind the clavicle

in the anterior chest. Just superior to

the clavicle is the apex of the lung.

- The ribs attach to the sternum via

costal cartilage.

- Ribs 11 + 12 are floating ribs as they have no anterior bony attachments (they attach posteriorly to vertebrae T11 + T12). 34

Appendicular Skeleton

The appendicular skeleton is the distal

skeleton — consisting of the limbs.

• The appendicular skeleton consists

of 126 bones.

• Functions include movement and

organ protection.

• Consists of the following key areas:

– Shoulder girdle, arm and hand.

– Pelvic girdle, leg and foot.

Arms and Shoulder

Shoulder girdle:

• Clavicle (anteriorly).

• Scapula (posteriorly).

• Humerus (upper arm).

• Ulna (medial forearm bone).

• Radius (lateral elbow bone).

• Carpals (wrist bones).

• Metacarpals (bones in between

carpals and digits / fingers).

• Phalanges (fingers, divided into:

Proximal, intermediate and distal).

Pelvic Girdle

• Pelvis = Hip bones + sacrum

Right sacro-iliac joint

Leg

The lower limb contains these bones:

• Femur (the longest and strongest bone

in the body).

• Tibia (shin bone).

• Fibula (bone in lateral lower leg).

• Patella (sesamoid bone, anterior knee).

• Tarsals (ankle bones).

• Metatarsal bones (bones

connecting middle section of foot).

• Phalanges (toes).

Muscle Attachments

Muscles that attach to bone and move

joints are called skeletal muscles.

• Skeletal muscles attach to sites of the

human skeleton, and their subsequent

contracture (shortening) generates

movement.

• Generally, skeletal muscles are attached

to bone via tough fibrous structures called

tendons (for example, feel your calf

muscle and then the Achilles tendon as it

attaches to your ankle).

Joints

Joints connect two bony structures and

permit varying degrees of movement.

• There are 187 joints in the human body.

There are three types of joints:

1. Fibrous joints:

• Bones are held tightly together, permitting

limited movement; e.g. sutures in the skull.

2. Cartilaginous joints:

• Articulating bones tightly connected by

cartilage; permit little or no movement.

• Examples: Epiphyseal growth plate, intervertebral discs. © CNM: Human Sciences – The Skeletal System. BQ.

Synovial Joints

Synovial joints permit the most movement. • Bones at the joints are covered by a layer of hyaline cartilage called articular cartilage that reduces friction and acts as shock absorber. • Synovial joints contain synovial fluid, which consists mostly of hyaluronic acid and interstitial fluid filtered from blood. Synovial joints have no direct blood supply. They obtain nutrients by diffusion (joint

movement is essential for this to happen).

synovial = moveable joint containing fluid

• Examples of synovial joints include ball and socket (shoulder and hip) and hinge (elbow and knee).

Bursae

Bursae are closed, fluid filled sac-like structures that are strategically located to reduce friction.

• The inside of a bursa contains connective tissue fluid similar to synovial fluid.

• These sacs cushion areas where bone would otherwise rub on muscle, tendons or skin.

• Located between: Skin and bone, tendon and bone, muscle and bone or ligament and bone.

Bursa = Latin for

purse or pouch

Angular Movements

• Flexion— decrease in joint angle.

• Extension— increase in joint angle.

• Rotation — movement around its

longitudinal axis. In the limbs it can be

medial or lateral (away from the midline).

• Lateral flexion — movement of trunk away

from the midline.

• Abduction — movement away from midline.

• Adduction— movement towards midline.

• Circumduction— circular (flexion, abduction,

extension, hyperextension, adduction in

succession).

Special Movements

• Elevation — superior movement (up).

• Depression — inferior movement (down).

• Protraction — anterior movement (forward).

• Retraction — posterior movement (backward).

• Inversion — medial movement of sole (turn in).

• Eversion — lateral movement of sole (turn out).

• Dorsiflexion — bending foot up.

• Plantar flexion — bending foot down.

• Supination — movement of forearm to turn palm up.

• Pronation — movement of forearm to turn palm posteriorly. • Opposition — movement of thumb across palm to touch fingertips.

Summary Quiz:

1. Name the thigh bone.

2. Name the TWO bones of the forearm.

3. Is the vertebral column part of the axial or appendicular skeleton?

4. Describe the role of intervertebral discs.

5. Indicate the number of vertebrae found in the lumbar spine. 6. Describe the function of a bursa.

7. Give ONE example of a fibrous joint in the body.

8. Describe the structure of a synovial joint.

9. Define what is meant by the movement flexion.

10.Describe what happens to the foot during plantar flexion. 45

Skeletal System Pathologies:

Fractures

A fracture describes any break

in a bone.

• Causes include trauma, low bone

density (associated with

osteoporosis), vitamin D deficiency.

• Can damage blood vessels that

supply bone and surrounding nerves.

Fracture Classification

▪ Complete — bone is broken into two or more

fragments. Can be either open (perforated skin)

or closed (soft tissues not compromised).

▪ Incomplete — bone is fractured but not into

fragments.

• Fractures can be linear (along the bone length)

or transverse — dissect across the bone).

• Another type is an avulsion fracture, which

occurs when a tendon or ligament pulls off a

piece of bone.

Fracture Repair

1. Haematoma (and inflammation):

callus = mass of tissue

Blood vessels at fracture line are broken and blood

leaks into site. Causes death of local cells and swelling. 2. Fibrocartilaginous callus formation:

Phagocytes clean up the debris. Fibroblasts invade and lay down collagen forming a soft callus (two–three weeks). 3. Bony callus formation:

Osteoblasts replace soft callus with new bone (< three months). 4. Bone remodelling:

The callus is mineralised and compact bone laid down. Then osteoclasts reshape the new bone. Remodelling

occurs over months to years.

Fractures: Treatment

• Address potential causes of fracture (i.e. underlying nutritional deficiencies, osteoporosis, etc). Improve

circulation and nutrients to the bone to aid repair.

• Creams and ointments can be very

effective — they get absorbed into the area.

• Herbs — comfrey, gotu kola.

• Nutrients — calcium, vitamin D, vitamin C.

• Homeopathic — arnica for bruising, ruta for injured nerves. Calc phos 4c should be given for two weeks to help fuse bones together.

Arnica

Sprains

A sprain involves a trauma that forces a joint

beyond its normal range, over-straining /

tearing ligaments. This often leads to joint

instability.

TREATMENT:

• First aid — RICE (Rest, Ice, Compression,

Elevation).

• Herbs locally and internally — tissue repair,

e.g. comfrey. Manual therapy and rehab.

• Nutrients — glucosamine, vit. C, zinc, vit. E

• Homeopathy (e.g. arnica, ruta) and acupuncture.₅₀ Ligaments are tough bands of connective tissue that attach bone to bone.

Subluxation and Dislocation

SUBLUXATION:

• Incomplete or partial joint dislocation.

DISLOCATION:

• Complete separation of two bones at a joint.

• A dislocation leads to reduced strength and

compromised joint function (movement).

Associated with a high risk of reoccurrence

unless sufficiently strengthened.

• Commonly occurs in the shoulder and knee (patella). May be accompanied by damage to soft tissues, nerves and blood vessels.

Should the

patella be there?51

X-rays

X-rays are commonly used to visualise the skeletal

system, lungs, heart and teeth.

• X-rays pass through less dense matter (air, fat, muscle, and other tissues) but are absorbed or scattered by

denser materials (bones, tumours, lungs affected by

severe pneumonia), appearing white.

• Blood clots (thromboses) can also be detected by x

ray, due to the accumulation of RBCs (and hence iron).

• Adverse effects: Cancer (induces DNA damage /

genetic mutations) — discussed further in oncology.

Kyphosis

A healthy spine will include a thoracic spine

kyphosis. This is important as it can help

distribute forces through the spine.

• However, some individuals can become hyper

kyphotic. This may be a result of poor posture

(due to occupation, stress, body language, etc).

• A hyper-kyphosis can also occur secondary to

a disease (e.g. osteoporotic spinal fractures).

• May cause muscular fatigue around the

scapula (shoulder blade) or even irritation of

the rib joints. May also interfere with breathing.

Lordosis

A lordosis describes an increased concavity, as

seen in the lumbar and cervical spine.

• A healthy spinal curve will include a cervical spine

and a lumbar spine lordosis. However, individuals

can become hyper-lordotic, which can cause pain.

• May be a genetic / ethnic cause (i.e. Afro-Caribbean

women) or secondary to other musculoskeletal

changes. More common in obese individuals. It is

also a normal adaptation for pregnancy.

• A hyper-lordotic posture can cause muscular fatigue

and also encourage the vertebral joints to move

closer, causing inflammation.

Scoliosis

A scoliosis describes a lateral ‘S’ shaped

curve in the spine.

• Generally, the more pronounced the abnormal

curve, the more clinically relevant. People often

live with scoliosis and are asymptomatic.

• People can be born with scoliosis or develop

it throughout their life (often adolescent onset).

• Scoliosis can develop as a result of everyday

imbalances, e.g. carrying rucksack on one

shoulder. Also common with leg length discrepancies.

• Severe scoliosis can cause spinal nerve compression.

Osteoporosis

Osteoporosis describes chronic, progressive thinning of the bone (porous bone).

• Characterised by decreased bone mineral density (BMD), leading to bone fragility and an increased risk of fracture.

• Diagnosed conventionally by dual x-ray absorptiometry (a DXA scan).

osteo- = bone -porosis = porous

On this test, a T-Score lower than -2.5 indicates osteoporosis.

Osteoporosis animation: www.youtube.com/watch?v=c5tc01WFYks

Osteoporosis Risk Factors

• Increasing age — over 30 years of age, ability

to retain calcium lowers.

• Female and post-menopausal — oestrogen

would normally suppress osteoclast activity.

• Poor diet — high acid-forming diet (high in sugars

and proteins), low in minerals, malnourished,

excess sodium, caffeine, fizzy drinks.

• Drugs — long-term corticosteroid therapy

(> six months).

• GIT diseases — liver disease, malabsorption

syndromes, low stomach acidity (gastric acid is

needed to ionise calcium and assist absorption).

Osteoporosis Risk Factors

• Genetics — family history.

• Sedentary lifestyle.

• Endocrine pathologies, e.g. Cushing’s

Syndrome, hyperparathyroidism,

hyperthyroidism, inability to produce

oestrogen.

• Low body weight.

• High alcohol consumption and smoking.

• Toxins (heavy metals).

Osteoporosis

SIGNS AND SYMPTOMS:

• Asymptomatic until the bone has reached critical thinness whereby fractures occur spontaneously with minor trauma. Commonly affecting spine and hips.

• Focal pain and kyphotic posture with loss of height.

• Pain is aggravated by prolonged sitting, standing or bending. It is relieved by lying on side with hips and knees flexed.

TREATMENT:

• Allopathic: Bisphosphonates (alendronic acid) - can cause muscle & joint pains, fractures, oesophagitis and gastritis. HRT. • Natural: Healthy alkaline diet and no caffeine / alcohol. Calcium, magnesium, increase vitamin D₃and K₂^{, weight}bearing exercise, herbs (hormone balancing), avoid toxins. 59

Osteomalacia and Rickets

Osteomalacia and rickets describe inadequate mineralisation of the bone matrix in spongy and compact bone.

• Characterised by decalcification and hence softening of bone. It is seen

especially in the spine, pelvis and legs.

• Rickets: Prior to epiphyseal plate

closure (< 18yrs).

• Osteomalacia: As an adolescent or adult. © CNM: Human Sciences – The Skeletal System. BQ.

osteo- = bone

-malacia = 'softening'

Osteomalacia and Rickets

CAUSES:

• Vitamin D deficiency, possibly due to:

• Insufficient sunlight.

• Insufficient dietary vitamin D.

• Secondary deficiency: Malabsorption disorders.

• Reduced receptor sites for vitamin D in tissues.

SIGNS AND SYMPTOMS:

• Deformed bones (bowed legs) and possible fractures.

• Severe back pain and muscle weakness.

• In rickets: Delayed closure of fontanelles and skull softening.

osteo- = bone

Osteomyelitis

myelo- = marrow -itis = inflammation

A bacterial infection of the bone marrow, resulting in necrosis and hence bone weakness.

• Presents as severe bone pain (often worse at night), with swelling, redness and warmth.

CAUSES:

• Bacterial infection (Staphylococcus aureus)

through the blood supply or post-fracture.

• Immunosuppression, diabetes, IV drug users.

INVESTIGATIONS:

• Bloods: Elevated inflammatory markers (ESR / CRP) and WBCs. • X-ray, MRI.

Osteoarthritis

arthritis = disease causing painful joints

A degenerative wear-and-tear arthritis of the articular cartilage, typically affecting weight-bearing (larger) joints in individuals typically over 50 years of age.

SIGNS AND SYMPTOMS:

• Onset is gradual, pain increasing

(months / years).

• Joint pain and stiffness.

• Not associated with systemic

symptoms.

Osteoarthritis

CAUSES:

• Primary: Associated with ageing. 80% of 65- year olds have radiological signs of OA.

• Secondary: Associated with predisposing factors:

⮚ Congenital ill-development.

⮚ Trauma — e.g. fractures, surgery,

meniscal injury, obesity.

DIAGNOSIS:

• X-ray — revealing joint space narrowing, osteophyte (bone spur) formation,

squaring of rounded joint surfaces.

arthritis = disease causing painful joints

Consider

the side

effects.

Does your

patient

really

need an

x-ray?

Osteoarthritis

PATHOPHYSIOLOGY:

1. Articular cartilage wears away; underlying bone is exposed. 2. Subchondral bone becomes hard and glossy (eburnation). 3. Remodelling of underlying bone (i.e. thickening) occurs. 4. Compensatory bone overgrowth in an

attempt to stabilise joint = osteophytes (spurs).

TREATMENT:

• Allopathic: NSAIDs, joint replacement.

• Natural: Nutrition (glucosamine and chondroitin to

improve cartilage and synovial fluid health / vitamin C / MSM), Herbs (comfrey, turmeric), Acupuncture, manual therapy (e.g. osteopathic / chiropractic), homeopathy, weight loss.

Rheumatoid Arthritis

Autoimmune inflammation of the synovium,

potentially affecting ALL organs except the

brain (systemic inflammation).

• Affects 1% of people worldwide, ↑ in women.

• Peak occurrence between 30–50 years of age.

AETIOLOGY:

• Genetic markers (HLA-DR4 and DR1).

• Infectious agents, e.g. EBV, rubella.

• Abnormal intestinal permeability, small

intestinal bacterial overgrowth (SIBO), smoking.

Rheumatoid Arthritis

SIGNS AND SYMPTOMS:

• Symmetrical / bilateral arthritis of

small joints (hands and feet mostly).

• Gradually spreads through more

proximal structures.

• Progressive morning stiffness (> one hour).

• Deformity of joints, e.g. swan neck, ulnar deviation.

• General malaise and fatigue.

• Subcutaneous nodules (around fingers and elbows).

• C1/C2 subluxation and compression of the spinal cord leading to paralysis and neurological complications.

• Kidney problems.

Rheumatoid Arthritis

ALLOPATHIC TREATMENT:

• Anti-inflammatories and immunosuppressants

(significant implications of immune suppression).

• Surgery.

NATURAL TREATMENT:

• Nutrition: Anti-inflammatory and reducing

intestinal permeability: Increasing antioxidants,

Mediterranean diet / increase omega-3, vit. D₃.

• Herbs for pain, inflammation and immune

modulation: Turmeric, boswellia, devil’s claw

• Homeopathy (e.g. rhus tox) and acupuncture.

Rheumatoid v. Osteoarthritis

	OA:	RA:
Type of disease: (cause)	Degenerative wear and tear.	Autoimmune.
Tissue(s) affected:	Articular cartilage.	Synovial membrane.
Type of joint affected:	Mostly hips and knees (weight-bearing joints).	Any synovial joints (tends to be systemic).
Age of onset:	50 years +.	30–50 years.
Symmetrical:	Asymmetrical.	Symmetrical / bilateral.
Radiology findings:	Osteophytes, narrowed joint space.	Bone erosions on x ray.
Blood tests:	No abnormal findings.	Raised ESR, CRP, rheumatoid factor.

Rheumatoid v. Osteoarthritis

	OA:	RA:
Signs and symptoms:	Gradual onset with increasing pain months / yrs. Weight-bearing joints.	Bilateral joint pain affecting small joints (hands and feet mostly).
	Morning stiffness < 30 mins. Often worse in the evening.	Morning stiffness > one hour.
	Eventually the joints become deformed. Enlarged joint in distal finger.	Deformities occur. Ulnar deviation of digits. Swan neck fingers.
	No systemic symptoms.	Systemic symptoms, e.g. fatigue, weight loss.
	Osteophyte / bone spurs.	Subcutaneous nodules.

Ankylosing Spondylitis (AS)

AS is a systemic autoimmune disease associated with chronic inflammation of the spine and sacroiliac joints, often leading to spinal fusion (ankylosis) and stiffness. • Age of onset is typically between 15–30 years

of age, more commonly affecting males. • Strong genetic association with HLA-B27 (present in 95% of AS patients).

• Links with inflammatory bowel diseases (and leaky gut), as well as urogenital or intestinal infections such as salmonella and shigella, cross-reacting with HLA-B27. © CNM: Human Sciences – The Skeletal System. BQ.

ankylosis = fusion spondylo- = spine -itis = inflammation

Ankylosing Spondylitis (AS)

SIGNS AND SYMPTOMS:

• Typically begins with sacroiliac and lower lumbar

spine pain, before progressing up the spine.

Associated with worsening morning stiffness.

• Lower back symptoms often improve with activity.

• The lumber lordosis flattens and patients often

become kyphotic.

• Hip and heel (Achilles) pain are common.

• 20% suffer acute iritis — (HLA-B27 diseases)

• Systemic symptoms: Fever, fatigue and malaise.

Ankylosing Spondylitis (AS)

DIAGNOSIS:

• Elevated blood inflammatory markers

(ESR/CRP), HLA-B27 positive.

• X-ray / MRI — identifies characteristic

bamboo spine.

TREATMENT:

• Allopathic: Surgery, anti-inflammatories

(including non-steroidal and steroids).

• Natural: Nutrition (remove pathogenic

organisms / elimination diet / increase

vitamin D₃and antioxidants) and herbs

(anti-inflammatory), homeopathy, acupuncture.

Gout

Gout is a type of monoarthritis, characterised by uric acid crystal deposition in synovial joints.

• One of the most common forms of arthritis in men (10:1 women), over 40 years of age.

• Excess uric acid forms solid crystals

(monosodium urate) on cartilage surfaces.

• This causes white blood cells to infiltrate activating an acute inflammatory response.

• Hyperuricaemia = elevated blood uric acid levels, due to overproduction or underexcretion.

• Uric acid is derived from the breakdown of purines. © CNM: Human Sciences – The Skeletal System. BQ.

mono = one

arthro- = joint

Gout

CAUSES:

• Increased intake of purine-rich foods (red

meat, organ meats, shellfish, etc).

• Dehydration, kidney disease, medications,

obesity, excessive alcohol consumption

(competes with uric acid for elimination by the

kidneys and accelerates purine breakdown), hypertension, Type II diabetes.

DIAGNOSIS:

• Blood serum for uric acid (not definitive 🡪

Uric acid crystals:

fluctuates) but can be useful to monitor treatment.

• Analysis of synovial fluid (needle aspiration).

Gout

SIGNS AND SYMPTOMS:

• Most often affects the big toe. Can affect the

mid-feet, ankles, knees, elbows, hands.

• Usually monoarticular (one joint).

• Sudden onset of intensely painful, red, hot

and swollen joints, often lasting 12–24

hours. Shiny skin over joint.

• Urate crystals can deposit under the skin

and produce tophi.

Gout

ALLOPATHIC TREATMENT:

• Allopurinol to prevent episodes (hepatotoxic).

• Corticosteroid injections (adverse effects:

indigestion, rapid heartbeat, nausea, insomnia,

mood changes, diabetes, glaucoma, osteoporosis).

NATURAL TREATMENT:

• Nutrition (anti-inflammatory / alkaline,

folate inhibits the production of uric acid,

quercetin), weight loss, increase of water

intake, natural diuretics.

• Herbs (for inflammation), homeopathy, acupuncture.

Folate-rich foods

Disc Herniation

The nucleus pulposus of the intervertebral disc

leaks out through the annulus fibrosus.

• This tends to affect discs with the highest fluid

content, most commonly lumbar spine (L5 /

S1), then cervical spine. (Age 30–40 years).

• The classic injury mechanism is combined:

Lumbar spine flexion (bending) and rotation.

• A herniated disc can compress spinal nerves.

• Treatment: Manual therapy and exercise,

homeopathy (arnica); anti-inflammatory nutrients

and herbs (e.g. devil’s claw, ginger, boswellia).

Bursitis

Bursitis describes inflammation of a bursa.

• Bursae are located around many joints in

the body. Commonly affects the shoulder

(sub-acromial) and hip (trochanteric).

CAUSES:

• Repetitive use (for example: Sub-acromial

bursitis might occur following lots of

overhead work (e.g. decorating).

• Sudden trauma, infection, wear and tear.

Summary Quiz!

1. Compare the causes of osteoarthritis and rheumatoid arthritis. 2. What tissue is likely to be damaged in an ankle sprain? 3. List TWO symptoms of ankylosing spondylitis.

4. List FOUR risk factors of osteoporosis.

5. What is the difference between rickets and osteomalacia? 6. Who is most at risk of developing gout?

7. Compare the joints involved in osteoarthritis and rheumatoid arthritis.

8. Why is vitamin D important for bone health?

9. Why might somebody develop bursitis?

10. Define the condition osteomyelitis.

lecture 2

Biomedicine: Human Sciences

Lecture 2:

Terminology, Landmarks

and Skeletal System

Learning Outcomes

In today’s topic you will learn:

⮚ Key anatomical terminology to

describe directions, movements,

regions and planes of the body.

⮚ The major bones of the body.

⮚ The structure and functions of the

skeletal system.

⮚ Joints.

⮚ The signs, symptoms, investigation

procedures and some orthodox treatments

of skeletal system pathologies.

Anatomical Position

The anatomical position describes the body position from which

directional terms always refer to: • Person stands erect, palms forward. • Feet parallel, flat on the floor.

• Arms are at the sides of the body.

Individuals can lie in a supine, prone or side-lying position:

• Supine describes the body lying face up.

The anatomical position:

• Prone describes the body lying face down.

Directional Terms

Anatomical Term:	Definition:
Medial	Nearer to the midline
Lateral	Away from the midline
Bilateral	Both sides
Unilateral	One side
Ipsilateral	On the same side
Contralateral	On the opposite side
Proximal	Nearer to the trunk
Distal	Further from the trunk
Anterior (ventral)	Nearer the front
Posterior (dorsal)	Nearer the back
Superior	Towards the top
Inferior	Towards the bottom

Body Planes

In human anatomy, the following

three planes are used:

Coronal / frontal plane:

• Separating the body front and back.

Sagittal plane:

• Separating the body left and right.

Horizontal / transverse plane:

• Separating the body top and bottom.

The Human Skeleton

There are 206 bones in the human body.

• The skeleton accounts for 18% of body weight.

FUNCTIONS:

• Supports framework for the body.

• Forms boundaries (skull).

• Attachment for muscles and tendons.

• Permits movement (joints).

• Haematopoiesis — formation and development

of blood cells from the red bone marrow.

• Mineral homeostasis (mostly calcium and phosphate).

• Triglyceride storage (yellow bone marrow).

Bone Cells ^osteo-^{= bone}

1. Osteogenic cells:

• Bone stem cells. They are the only bone cell

to undergo division (producing osteoblasts).

2. Osteoblasts:

• These are bone-building cells.

B = build

• They synthesise and secrete collagen

and other components of bony matrix.

• They are trapped and become osteocytes.

3. Osteocytes:

• Osteocytes are mature bone cells. They maintain the daily metabolism of bone, such as nutrient exchange. © CNM: Human Sciences – The Skeletal System. BQ.

Bone Cells

4. Osteoclasts:

• Osteoclasts are huge cells derived from the fusion of as many as 50 monocytes (WBCs).

• On the side facing the bone surface, the cell membrane is folded into a ruffled border where the cell releases powerful lysosomal enzymes and acids which digest bone matrix.

• Resorption is the breakdown of bone matrix.

• Osteoblasts and osteoclasts work together to remodel bone throughout life. Excess osteoclast activity leads to a loss of bone density.

osteo- = bone

-cyte = cell

-clast = broken

An osteoclast:8

^peri-^{= layer surrounding}Compact Bone diaphysis = shaft

The skeleton is formed from two

types of bone: Compact and spongy.

• 80% of the skeleton is compact bone.

• Contains few spaces and is strong.

• Compact bone is found beneath the

periosteum of all bones and makes up the

bulk of the diaphysis of long bones.

• A structural unit of compact bone is an osteon.

These are aligned in the same lines as stress.

Compact Bone

An osteon contains these four parts:

1. Haversian canal:

Contains blood vessels and nerves.

2. Lamellae:

Concentric rings of calcified extracellular

matrix containing minerals and collagen.

3. Canaliculi:

A mini system of interconnected canals

that provides a route for nutrients / waste.

4. Lacunae:

Small spaces called lacunae with osteocytes.

Spongy Bone

Spongy bone does not contain osteons.

Instead it consists of an irregular lattice of

thin columns called trabeculae that are

arranged along lines of stress.

• Microscopic spaces between trabeculae help make bone lighter and can be filled with bone marrow. They also contain blood vessels that nourish the bone.

• Spongy bone makes up the interior of short, flat and irregularly-shaped bones and the ends of long bones. Spongy bone is always covered with compact bone.

Bone Matrix

Like other connective tissues, bone

contains an extracellular matrix that

surrounds separated cells.

• The most abundant mineral in bone is

calcium phosphate. This combines with

other mineral salts such as magnesium,

sulphate, potassium.

• These minerals are deposited and crystallise

(harden) in the framework formed by

collagen fibres of the matrix (imagine

collagen as the scaffolding). Together, these

minerals contribute to the hardness of bone.

Long Bones

Long bones are defined as ‘bones that have

a greater length than width’.

• Long bones contain a shaft (diaphysis)

and two heads (epiphyses).

• Long bones are slightly curved for strength

(allowing better force distribution).

• Long bones contain mostly compact bone

in the diaphysis and spongy bone in the

epiphyses.

• Examples include the femur, tibia and humerus.

Long Bones: Epiphysis

EPIPHYSIS:

• The epiphysis forms the proximal

and distal ends of long bones.

• Epiphyses are separated from

the diaphysis by the epiphyseal

plate (a layer of hyaline

cartilage that allows the

diaphysis to grow in length).

• The epiphysis contains a thin

outer region of compact bone

covered by articular / hyaline cartilage and inner spongy bone with red bone marrow.

Distal epiphysis

Long Bones: Diaphysis

DIAPHYSIS:

• The diaphysis describes the tubular shaft of

long bones.

• Outer compact bone covered by ‘periosteum’.

• Contains a central

medullary cavity that

contains red / yellow

bone marrow. ALL

marrow starts off as

red marrow.

Periosteum

The periosteum surrounds the

external surface of bone when

it is not covered by cartilage.

• Hyaline cartilage replaces

periosteum on joint surfaces.

• The periosteum is a pain-sensitive, highly-vascular membrane that

protects bone and serves as an

attachment for ligaments and tendons.

• The periosteal arteries enter the

diaphysis through many perforating

canals, delivering oxygenated blood.

peri- = surrounding osteo- = bone

Periosteum

The periosteum is a double-layered membrane, containing:

• A tough outer fibrous layer that protects bone.

• An inner osteogenic layer that contains osteoblasts and

peri- = surrounding osteo- = bone

osteoclasts, assisting in bone

growth and repair.

Types of Bone

Bone type:	Examples:
Short bones (cubed shaped):	Carpals, tarsals
Irregular bones (complex shapes):	Vertebrae
Flat bone (two plates of compact bone):	Skull, scapula
Sesamoid bone:	Patella
Long bones:	Femur, tibia, etc.

Bone Formation

Bone formation begins during foetal development, before continuing into childhood and then into adult life.

• There are two ossification pathways used to produce bone; these are:

1. Intramembranous ossification:

— Bone develops from connective tissue sheets. — All flat bones (i.e. skull) and the clavicles .. develop this way.

2. Endochondral ossification:

— Bone develops by replacing hyaline cartilage. © CNM: Human Sciences – The Skeletal System. BQ.

endo = within

chondral = cartilage19

Bone Growth

Long bones elongate from the epiphyseal growth

plate. This plate is a layer of hyaline cartilage in

the epiphyses where osteoblasts

are produced, ossifying the bone matrix.

• In the early twenties, the epiphyseal growth plate

ossifies so that only a thin epiphyseal line remains.

• If a bone fracture damages the epiphyseal plate

during childhood, the bone may grow shorter.

• Bones can also grow in thickness using osteoblasts

in the periosteum. This continues throughout life

due to physical stress, muscle activity and weight.

Epiphyseal Growth Plate

This image illustrates the activity

within the growth plate:

Cartilage cells (chondrocytes)

undergo mitosis here.

At this stage, chondrocytes stop

dividing.

At this point, minerals start to

deposit, capillaries invade and

deliver osteoblasts / osteoclasts 🡪 new bone is formed.

Growth plate in distal tibia

Bone Hormones

Many hormones affect bone growth and

remodelling (density) by altering the ratio of

osteoblast to osteoclast activity.

Promote osteoblast activity (and so bone

formation):

• Growth hormone and thyroid hormone.

• Oestrogen and testosterone.

• Calcitonin.

Promote osteoclast activity (and so bone loss):

• Parathyroid hormone.

• Cortisol (and steroid medications).

Bone Homeostasis

Bones are an important mineral reservoir —

mostly calcium.

• Blood calcium levels have to be tightly controlled

to ensure proper blood clotting, nerve and muscle function.

If blood calcium levels are low: Hypocalcaemia

• Osteoclasts break down bone and release calcium into the blood.

If blood calcium levels are high: Hypercalcaemia

• Increased osteoblast activity (takes calcium back into bone). • Calcium exchange is regulated by the parathyroid glands and the thyroid gland.

Parathyroid Hormone

Parathyroid hormone increases blood

calcium.

1. Increases the activity of osteoclasts

(resorption).

2. Stimulates the kidneys to reabsorb

and retain calcium in the blood.

3. Increases formation of calcitriol which promotes calcium uptake from food in the intestines.

Parathyroid hormones are secreted from the parathyroid glands, which are located in the anterior neck.

calcitriol = active form of vitamin D

Calcitonin

Calcitonin is a hormone that lowers

blood calcium levels.

• Secreted by para-follicular cells

of the thyroid gland.

• It inhibits osteoclasts and

promotes osteoblast deposition

of calcium in the bones.

• The overall result is increased bone

formation and decreased blood

calcium.

Vitamin D

Vitamin D facilitates calcium

absorption in the intestines

and is directly involved in bone

turnover.

• Vitamin D₃works closely with

vitamin K₂. D₃assists the

absorption of calcium into the

blood, whilst K₂activates a protein

called osteocalcin which controls

utilisation of the calcium in the

body (depositing it in bones).

Vitamin D

• Vitamin D levels in the body decrease with

age. This is broadly associated with a

combination of factors including:

⮚ Low sun exposure, reduced dietary

absorption, reduced ability to produce

an active form of vitamin D through its

processes in the skin, liver and kidneys.

• High alcohol intake reduces vitamin D

conversion into its active form.

• Magnesium is a co-factor needed for the

conversion of vitamin D in the body. Many

osteoporotic women are deficient in magnesium.

Exercise

Within limits, bone can become stronger in response to mechanical stress, e.g. pull of skeletal muscle and gravity.

• Mechanical stress leads to increased mineral deposition and increased collagen production.

• Mechanical stress is important for ensuring bone formation occurs more quickly than bone resorption.

Hence weight bearing exercise builds bone.

• Lack of stress on bones can cause bone mass loss of up to 1% per week, e.g. bedridden patients, astronauts.

^Source:^{www.osteoporosis.newlifeoutlook.com/weight-bearing-exercise/}ortho- = correct or straighten dontist = teeth specialist

Summary Quiz:

1. What is meant by the following: Superior; medial; distal; supine? 2. Name the cell that builds bone.

3. Name the bone cell that has a ruffled border and secretes enzymes. 4. Name the structural unit of compact bone.

5. In what direction are the trabeculae of spongy bone positioned / directed?

6. What is the role of the Haversian canal? 7. Explain the role of the periosteum.

Video: Bone remodelling: www.youtube.com/watch?v=0dV1Bwe2v6c

8. Give ONE example of a short and sesamoid bone.

9. Does parathyroid hormone increase or decrease blood calcium? 10. Explain why a patient might be deficient in vitamin D. 29

Axial Skeleton

The skeleton is divided into the axial and

appendicular sections.

• The axial skeleton is the central skeleton

and contains 80 bones.

• The appendicular skeleton consists of the

bones supporting the extremities / limbs.

• The axial skeleton serves to protect the

body's most vital organs.

• The axial skeleton contains the: Skull, inner ear

bones, hyoid, thoracic cage and vertebral column.

Skull

Forms the cranium (upper head) and face

and encapsulates the brain.

• The skull bones are joined with fibrous joints (sutures).

• Sinuses are air-filled cavities in the skull that:

• Give resonance to the voice.

• Lighten bones of face and cranium.

• Fontanelles:

• Fibrous sutures (soft spots) on a baby’s head joining

the skull bones together. Ossify at 12–18 months.

• Allow the baby’s head through the birth canal.

Vertebral Column

The vertebral column consists

of 24 movable vertebrae:

• Cervical (7) C1–C7.

• Thoracic (12) T1–T12.

• Lumbar (5) L1–L5.

• Sacrum and coccyx (fused bones).

• Vertebrae are named by region and number.

E.g. C3 articulates with C2 above and C4 below.

Neighbouring vertebrae connect via intervertebral discs.

• Functions: Protection for spinal cord; movement

(e.g. side bending); support of skull; forms axis of the trunk.

Intervertebral Discs

• Discs are shock-absorbing structures. 23 discs

are present in the spine (none in sacrum).

These get progressively thicker lower down.

• They bind vertebral bodies and separate

individual vertebrae.

• Discs are most hydrated in the morning and in

those aged between 30–40 years. They make

up one-third of the length of the spinal column.

• Two parts: Annulus fibrosus, nucleus pulposus.

• The nucleus pulposus is a gel-like pad.

Thoracic Cage and Ribs

Consists of the:

• Sternum

• Ribs (12 pairs):

- The first rib sits behind the clavicle

in the anterior chest. Just superior to

the clavicle is the apex of the lung.

- The ribs attach to the sternum via

costal cartilage.

- Ribs 11 + 12 are floating ribs as they have no anterior bony attachments (they attach posteriorly to vertebrae T11 + T12). 34

Appendicular Skeleton

The appendicular skeleton is the distal

skeleton — consisting of the limbs.

• The appendicular skeleton consists

of 126 bones.

• Functions include movement and

organ protection.

• Consists of the following key areas:

– Shoulder girdle, arm and hand.

– Pelvic girdle, leg and foot.

Arms and Shoulder

Shoulder girdle:

• Clavicle (anteriorly).

• Scapula (posteriorly).

• Humerus (upper arm).

• Ulna (medial forearm bone).

• Radius (lateral elbow bone).

• Carpals (wrist bones).

• Metacarpals (bones in between

carpals and digits / fingers).

• Phalanges (fingers, divided into:

Proximal, intermediate and distal).

Pelvic Girdle

• Pelvis = Hip bones + sacrum

Right sacro-iliac joint

Leg

The lower limb contains these bones:

• Femur (the longest and strongest bone

in the body).

• Tibia (shin bone).

• Fibula (bone in lateral lower leg).

• Patella (sesamoid bone, anterior knee).

• Tarsals (ankle bones).

• Metatarsal bones (bones

connecting middle section of foot).

• Phalanges (toes).

Muscle Attachments

Muscles that attach to bone and move

joints are called skeletal muscles.

• Skeletal muscles attach to sites of the

human skeleton, and their subsequent

contracture (shortening) generates

movement.

• Generally, skeletal muscles are attached

to bone via tough fibrous structures called

tendons (for example, feel your calf

muscle and then the Achilles tendon as it

attaches to your ankle).

Joints

Joints connect two bony structures and

permit varying degrees of movement.

• There are 187 joints in the human body.

There are three types of joints:

1. Fibrous joints:

• Bones are held tightly together, permitting

limited movement; e.g. sutures in the skull.

2. Cartilaginous joints:

• Articulating bones tightly connected by

cartilage; permit little or no movement.

Synovial Joints

movement is essential for this to happen).

synovial = moveable joint containing fluid

• Examples of synovial joints include ball and socket (shoulder and hip) and hinge (elbow and knee).

Bursae

Bursae are closed, fluid filled sac-like structures that are strategically located to reduce friction.

• The inside of a bursa contains connective tissue fluid similar to synovial fluid.

• These sacs cushion areas where bone would otherwise rub on muscle, tendons or skin.

• Located between: Skin and bone, tendon and bone, muscle and bone or ligament and bone.

Bursa = Latin for

purse or pouch

Angular Movements

• Flexion— decrease in joint angle.

• Extension— increase in joint angle.

• Rotation — movement around its

longitudinal axis. In the limbs it can be

medial or lateral (away from the midline).

• Lateral flexion — movement of trunk away

from the midline.

• Abduction — movement away from midline.

• Adduction— movement towards midline.

• Circumduction— circular (flexion, abduction,

extension, hyperextension, adduction in

succession).

Special Movements

• Elevation — superior movement (up).

• Depression — inferior movement (down).

• Protraction — anterior movement (forward).

• Retraction — posterior movement (backward).

• Inversion — medial movement of sole (turn in).

• Eversion — lateral movement of sole (turn out).

• Dorsiflexion — bending foot up.

• Plantar flexion — bending foot down.

• Supination — movement of forearm to turn palm up.

• Pronation — movement of forearm to turn palm posteriorly. • Opposition — movement of thumb across palm to touch fingertips.

Summary Quiz:

1. Name the thigh bone.

2. Name the TWO bones of the forearm.

3. Is the vertebral column part of the axial or appendicular skeleton?

4. Describe the role of intervertebral discs.

5. Indicate the number of vertebrae found in the lumbar spine. 6. Describe the function of a bursa.

7. Give ONE example of a fibrous joint in the body.

8. Describe the structure of a synovial joint.

9. Define what is meant by the movement flexion.

10.Describe what happens to the foot during plantar flexion. 45

Skeletal System Pathologies:

Fractures

A fracture describes any break

in a bone.

• Causes include trauma, low bone

density (associated with

osteoporosis), vitamin D deficiency.

• Can damage blood vessels that

supply bone and surrounding nerves.

Fracture Classification

▪ Complete — bone is broken into two or more

fragments. Can be either open (perforated skin)

or closed (soft tissues not compromised).

▪ Incomplete — bone is fractured but not into

fragments.

• Fractures can be linear (along the bone length)

or transverse — dissect across the bone).

• Another type is an avulsion fracture, which

occurs when a tendon or ligament pulls off a

piece of bone.

Fracture Repair

1. Haematoma (and inflammation):

callus = mass of tissue

Blood vessels at fracture line are broken and blood

leaks into site. Causes death of local cells and swelling. 2. Fibrocartilaginous callus formation:

Phagocytes clean up the debris. Fibroblasts invade and lay down collagen forming a soft callus (two–three weeks). 3. Bony callus formation:

Osteoblasts replace soft callus with new bone (< three months). 4. Bone remodelling:

The callus is mineralised and compact bone laid down. Then osteoclasts reshape the new bone. Remodelling

occurs over months to years.

Fractures: Treatment

• Address potential causes of fracture (i.e. underlying nutritional deficiencies, osteoporosis, etc). Improve

circulation and nutrients to the bone to aid repair.

• Creams and ointments can be very

effective — they get absorbed into the area.

• Herbs — comfrey, gotu kola.

• Nutrients — calcium, vitamin D, vitamin C.

• Homeopathic — arnica for bruising, ruta for injured nerves. Calc phos 4c should be given for two weeks to help fuse bones together.

Arnica

Sprains

A sprain involves a trauma that forces a joint

beyond its normal range, over-straining /

tearing ligaments. This often leads to joint

instability.

TREATMENT:

• First aid — RICE (Rest, Ice, Compression,

Elevation).

• Herbs locally and internally — tissue repair,

e.g. comfrey. Manual therapy and rehab.

• Nutrients — glucosamine, vit. C, zinc, vit. E

• Homeopathy (e.g. arnica, ruta) and acupuncture.₅₀ Ligaments are tough bands of connective tissue that attach bone to bone.

Subluxation and Dislocation

SUBLUXATION:

• Incomplete or partial joint dislocation.

DISLOCATION:

• Complete separation of two bones at a joint.

• A dislocation leads to reduced strength and

compromised joint function (movement).

Associated with a high risk of reoccurrence

unless sufficiently strengthened.

• Commonly occurs in the shoulder and knee (patella). May be accompanied by damage to soft tissues, nerves and blood vessels.

Should the

patella be there?51

X-rays

X-rays are commonly used to visualise the skeletal

system, lungs, heart and teeth.

• X-rays pass through less dense matter (air, fat, muscle, and other tissues) but are absorbed or scattered by

denser materials (bones, tumours, lungs affected by

severe pneumonia), appearing white.

• Blood clots (thromboses) can also be detected by x

ray, due to the accumulation of RBCs (and hence iron).

• Adverse effects: Cancer (induces DNA damage /

genetic mutations) — discussed further in oncology.

Kyphosis

A healthy spine will include a thoracic spine

kyphosis. This is important as it can help

distribute forces through the spine.

• However, some individuals can become hyper

kyphotic. This may be a result of poor posture

(due to occupation, stress, body language, etc).

• A hyper-kyphosis can also occur secondary to

a disease (e.g. osteoporotic spinal fractures).

• May cause muscular fatigue around the

scapula (shoulder blade) or even irritation of

the rib joints. May also interfere with breathing.

Lordosis

A lordosis describes an increased concavity, as

seen in the lumbar and cervical spine.

• A healthy spinal curve will include a cervical spine

and a lumbar spine lordosis. However, individuals

can become hyper-lordotic, which can cause pain.

• May be a genetic / ethnic cause (i.e. Afro-Caribbean

women) or secondary to other musculoskeletal

changes. More common in obese individuals. It is

also a normal adaptation for pregnancy.

• A hyper-lordotic posture can cause muscular fatigue

and also encourage the vertebral joints to move

closer, causing inflammation.

Scoliosis

A scoliosis describes a lateral ‘S’ shaped

curve in the spine.

• Generally, the more pronounced the abnormal

curve, the more clinically relevant. People often

live with scoliosis and are asymptomatic.

• People can be born with scoliosis or develop

it throughout their life (often adolescent onset).

• Scoliosis can develop as a result of everyday

imbalances, e.g. carrying rucksack on one

shoulder. Also common with leg length discrepancies.

• Severe scoliosis can cause spinal nerve compression.

Osteoporosis

Osteoporosis describes chronic, progressive thinning of the bone (porous bone).

• Characterised by decreased bone mineral density (BMD), leading to bone fragility and an increased risk of fracture.

• Diagnosed conventionally by dual x-ray absorptiometry (a DXA scan).

osteo- = bone -porosis = porous

On this test, a T-Score lower than -2.5 indicates osteoporosis.

Osteoporosis animation: www.youtube.com/watch?v=c5tc01WFYks

Osteoporosis Risk Factors

• Increasing age — over 30 years of age, ability

to retain calcium lowers.

• Female and post-menopausal — oestrogen

would normally suppress osteoclast activity.

• Poor diet — high acid-forming diet (high in sugars

and proteins), low in minerals, malnourished,

excess sodium, caffeine, fizzy drinks.

• Drugs — long-term corticosteroid therapy

(> six months).

• GIT diseases — liver disease, malabsorption

syndromes, low stomach acidity (gastric acid is

needed to ionise calcium and assist absorption).

Osteoporosis Risk Factors

• Genetics — family history.

• Sedentary lifestyle.

• Endocrine pathologies, e.g. Cushing’s

Syndrome, hyperparathyroidism,

hyperthyroidism, inability to produce

oestrogen.

• Low body weight.

• High alcohol consumption and smoking.

• Toxins (heavy metals).

Osteoporosis

SIGNS AND SYMPTOMS:

• Asymptomatic until the bone has reached critical thinness whereby fractures occur spontaneously with minor trauma. Commonly affecting spine and hips.

• Focal pain and kyphotic posture with loss of height.

• Pain is aggravated by prolonged sitting, standing or bending. It is relieved by lying on side with hips and knees flexed.

TREATMENT:

Osteomalacia and Rickets

Osteomalacia and rickets describe inadequate mineralisation of the bone matrix in spongy and compact bone.

• Characterised by decalcification and hence softening of bone. It is seen

especially in the spine, pelvis and legs.

• Rickets: Prior to epiphyseal plate

closure (< 18yrs).

osteo- = bone

-malacia = 'softening'

Osteomalacia and Rickets

CAUSES:

• Vitamin D deficiency, possibly due to:

• Insufficient sunlight.

• Insufficient dietary vitamin D.

• Secondary deficiency: Malabsorption disorders.

• Reduced receptor sites for vitamin D in tissues.

SIGNS AND SYMPTOMS:

• Deformed bones (bowed legs) and possible fractures.

• Severe back pain and muscle weakness.

• In rickets: Delayed closure of fontanelles and skull softening.

osteo- = bone

Osteomyelitis

myelo- = marrow -itis = inflammation

A bacterial infection of the bone marrow, resulting in necrosis and hence bone weakness.

• Presents as severe bone pain (often worse at night), with swelling, redness and warmth.

CAUSES:

• Bacterial infection (Staphylococcus aureus)

through the blood supply or post-fracture.

• Immunosuppression, diabetes, IV drug users.

INVESTIGATIONS:

• Bloods: Elevated inflammatory markers (ESR / CRP) and WBCs. • X-ray, MRI.

Osteoarthritis

arthritis = disease causing painful joints

A degenerative wear-and-tear arthritis of the articular cartilage, typically affecting weight-bearing (larger) joints in individuals typically over 50 years of age.

SIGNS AND SYMPTOMS:

• Onset is gradual, pain increasing

(months / years).

• Joint pain and stiffness.

• Not associated with systemic

symptoms.

Osteoarthritis

CAUSES:

• Primary: Associated with ageing. 80% of 65- year olds have radiological signs of OA.

• Secondary: Associated with predisposing factors:

⮚ Congenital ill-development.

⮚ Trauma — e.g. fractures, surgery,

meniscal injury, obesity.

DIAGNOSIS:

• X-ray — revealing joint space narrowing, osteophyte (bone spur) formation,

squaring of rounded joint surfaces.

arthritis = disease causing painful joints

Consider

the side

effects.

Does your

patient

really

need an

x-ray?

Osteoarthritis

PATHOPHYSIOLOGY:

attempt to stabilise joint = osteophytes (spurs).

TREATMENT:

• Allopathic: NSAIDs, joint replacement.

• Natural: Nutrition (glucosamine and chondroitin to

improve cartilage and synovial fluid health / vitamin C / MSM), Herbs (comfrey, turmeric), Acupuncture, manual therapy (e.g. osteopathic / chiropractic), homeopathy, weight loss.

Rheumatoid Arthritis

Autoimmune inflammation of the synovium,

potentially affecting ALL organs except the

brain (systemic inflammation).

• Affects 1% of people worldwide, ↑ in women.

• Peak occurrence between 30–50 years of age.

AETIOLOGY:

• Genetic markers (HLA-DR4 and DR1).

• Infectious agents, e.g. EBV, rubella.

• Abnormal intestinal permeability, small

intestinal bacterial overgrowth (SIBO), smoking.

Rheumatoid Arthritis

SIGNS AND SYMPTOMS:

• Symmetrical / bilateral arthritis of

small joints (hands and feet mostly).

• Gradually spreads through more

proximal structures.

• Progressive morning stiffness (> one hour).

• Deformity of joints, e.g. swan neck, ulnar deviation.

• General malaise and fatigue.

• Subcutaneous nodules (around fingers and elbows).

• C1/C2 subluxation and compression of the spinal cord leading to paralysis and neurological complications.

• Kidney problems.

Rheumatoid Arthritis

ALLOPATHIC TREATMENT:

• Anti-inflammatories and immunosuppressants

(significant implications of immune suppression).

• Surgery.

NATURAL TREATMENT:

• Nutrition: Anti-inflammatory and reducing

intestinal permeability: Increasing antioxidants,

Mediterranean diet / increase omega-3, vit. D₃.

• Herbs for pain, inflammation and immune

modulation: Turmeric, boswellia, devil’s claw

• Homeopathy (e.g. rhus tox) and acupuncture.

Rheumatoid v. Osteoarthritis

	OA:	RA:
Type of disease: (cause)	Degenerative wear and tear.	Autoimmune.
Tissue(s) affected:	Articular cartilage.	Synovial membrane.
Type of joint affected:	Mostly hips and knees (weight-bearing joints).	Any synovial joints (tends to be systemic).
Age of onset:	50 years +.	30–50 years.
Symmetrical:	Asymmetrical.	Symmetrical / bilateral.
Radiology findings:	Osteophytes, narrowed joint space.	Bone erosions on x ray.
Blood tests:	No abnormal findings.	Raised ESR, CRP, rheumatoid factor.

Rheumatoid v. Osteoarthritis

	OA:	RA:
Signs and symptoms:	Gradual onset with increasing pain months / yrs. Weight-bearing joints.	Bilateral joint pain affecting small joints (hands and feet mostly).
	Morning stiffness < 30 mins. Often worse in the evening.	Morning stiffness > one hour.
	Eventually the joints become deformed. Enlarged joint in distal finger.	Deformities occur. Ulnar deviation of digits. Swan neck fingers.
	No systemic symptoms.	Systemic symptoms, e.g. fatigue, weight loss.
	Osteophyte / bone spurs.	Subcutaneous nodules.

Ankylosing Spondylitis (AS)

of age, more commonly affecting males. • Strong genetic association with HLA-B27 (present in 95% of AS patients).

ankylosis = fusion spondylo- = spine -itis = inflammation

Ankylosing Spondylitis (AS)

SIGNS AND SYMPTOMS:

• Typically begins with sacroiliac and lower lumbar

spine pain, before progressing up the spine.

Associated with worsening morning stiffness.

• Lower back symptoms often improve with activity.

• The lumber lordosis flattens and patients often

become kyphotic.

• Hip and heel (Achilles) pain are common.

• 20% suffer acute iritis — (HLA-B27 diseases)

• Systemic symptoms: Fever, fatigue and malaise.

Ankylosing Spondylitis (AS)

DIAGNOSIS:

• Elevated blood inflammatory markers

(ESR/CRP), HLA-B27 positive.

• X-ray / MRI — identifies characteristic

bamboo spine.

TREATMENT:

• Allopathic: Surgery, anti-inflammatories

(including non-steroidal and steroids).

• Natural: Nutrition (remove pathogenic

organisms / elimination diet / increase

vitamin D₃and antioxidants) and herbs

(anti-inflammatory), homeopathy, acupuncture.

Gout

Gout is a type of monoarthritis, characterised by uric acid crystal deposition in synovial joints.

• One of the most common forms of arthritis in men (10:1 women), over 40 years of age.

• Excess uric acid forms solid crystals

(monosodium urate) on cartilage surfaces.

• This causes white blood cells to infiltrate activating an acute inflammatory response.

• Hyperuricaemia = elevated blood uric acid levels, due to overproduction or underexcretion.

mono = one

arthro- = joint

Gout

CAUSES:

• Increased intake of purine-rich foods (red

meat, organ meats, shellfish, etc).

• Dehydration, kidney disease, medications,

obesity, excessive alcohol consumption

(competes with uric acid for elimination by the

kidneys and accelerates purine breakdown), hypertension, Type II diabetes.

DIAGNOSIS:

• Blood serum for uric acid (not definitive 🡪

Uric acid crystals:

fluctuates) but can be useful to monitor treatment.

• Analysis of synovial fluid (needle aspiration).

Gout

SIGNS AND SYMPTOMS:

• Most often affects the big toe. Can affect the

mid-feet, ankles, knees, elbows, hands.

• Usually monoarticular (one joint).

• Sudden onset of intensely painful, red, hot

and swollen joints, often lasting 12–24

hours. Shiny skin over joint.

• Urate crystals can deposit under the skin

and produce tophi.

Gout

ALLOPATHIC TREATMENT:

• Allopurinol to prevent episodes (hepatotoxic).

• Corticosteroid injections (adverse effects:

indigestion, rapid heartbeat, nausea, insomnia,

mood changes, diabetes, glaucoma, osteoporosis).

NATURAL TREATMENT:

• Nutrition (anti-inflammatory / alkaline,

folate inhibits the production of uric acid,

quercetin), weight loss, increase of water

intake, natural diuretics.

• Herbs (for inflammation), homeopathy, acupuncture.

Folate-rich foods

Disc Herniation

The nucleus pulposus of the intervertebral disc

leaks out through the annulus fibrosus.

• This tends to affect discs with the highest fluid

content, most commonly lumbar spine (L5 /

S1), then cervical spine. (Age 30–40 years).

• The classic injury mechanism is combined:

Lumbar spine flexion (bending) and rotation.

• A herniated disc can compress spinal nerves.

• Treatment: Manual therapy and exercise,

homeopathy (arnica); anti-inflammatory nutrients

and herbs (e.g. devil’s claw, ginger, boswellia).

Bursitis

Bursitis describes inflammation of a bursa.

• Bursae are located around many joints in

the body. Commonly affects the shoulder

(sub-acromial) and hip (trochanteric).

CAUSES:

• Repetitive use (for example: Sub-acromial

bursitis might occur following lots of

overhead work (e.g. decorating).

• Sudden trauma, infection, wear and tear.

Summary Quiz!

1. Compare the causes of osteoarthritis and rheumatoid arthritis. 2. What tissue is likely to be damaged in an ankle sprain? 3. List TWO symptoms of ankylosing spondylitis.

4. List FOUR risk factors of osteoporosis.

5. What is the difference between rickets and osteomalacia? 6. Who is most at risk of developing gout?

7. Compare the joints involved in osteoarthritis and rheumatoid arthritis.

8. Why is vitamin D important for bone health?

9. Why might somebody develop bursitis?

10. Define the condition osteomyelitis.