Anatomy Notes

Topic 1.1a: Bones, Tissues and Development

content:

• an overview of terminology, orientation and the anatomical position

• bone development and growth and the change over time

learning outcomes:

• 4 main types of tissue

• function of the skeletal system

• identify specific bone markings

structural hierarchy:

atoms → molecules → organelles → cells → tissues → organ → organ system → organism

tissue types:

1. nervous tissue

2. muscle tissue

3. epithelial tissue

4. connective tissue

nervous tissue:

• transmits electrical impulses for rapid communication between organ systems

• e.g. brain, spinal cord, nerves

muscle tissue:

• allows movement to occur throughout the body

• types: skeletal, smooth, cardiac

• e.g. muscles of heart (cardiac), muscles of walls of hollow organs (smooth)

epithelial tissue:

• covers the body’s surfaces and also lines its cavities

• e.g. skin surface (epidermis), glands (e.g. pancreas), lining of digestive tract organs and other hollow organs

connective tissue:

• provides support and protection for the body organs

• made of living cells in a non-living matrix

• e.g. bones, tendons, fat and other soft padding tissue

anatomical position:

• standard body position used as a reference point

• feet are placed slightly apart, person stands tall and upright, arms are slightly abducted, palms facing forward

planes: In anatomical studies, the body is often cut or sectioned along a flat surface

sagittal plane: divides the body into left and right portions

midsagittal or median plane: when the sagittal plane is directly in the midline, thus dividing the body evenly

frontal or coronal plane: vertical plane that divides the body into anterior and posterior sections

transverse or horizontal or axial plane: divides the body into superior and inferior sections

directional terminology:

• language that describes the position of body parts with reference to another body part

superior: above (e.g. the head is superior to the abdomen)

inferior: below (e.g. the umbilicus is inferior to the chin)

anterior: towards the front (e.g. the heart is anterior to the vertebral column) - ventral

posterior: towards the back (e.g. the heart is posterior to the sternum) - dorsal

medial: toward the midline, or on the inner side (e.g. the heart is medial to the arm)

lateral: further away from the midline (e.g the arms are lateral to the chest)

proximal: closer to the point of attachment of a limb to the body trunk (e.g. the humerus is proximal to the radius)

distal: farther from the point of attachment of a limb to the body trunk (e.g. the radius is distal to the thigh)

superficial: external; toward or at the body surface (e.g. the skin is superficial to the skeletal muscles)

deep: internal; away from the body surface (e.g. the lungs are deep to the skin

body cavities:

these cavities are closed to the outside and provide protection to the organs within them

• dorsal body cavity

• ventral body cavity

dorsal body cavity:

protects the nervous system organs and has two subdivisions

• cranial cavity - the skull protects the brain

• vertebral cavity - encloses the spinal cord, runs within the bony vertebral column

ventral body cavity:

more anterior and larger of the two body cavities, 2 major subdivisions

• thoracic cavity - contains the lungs and heart

• abdominopelvic cavity - subdivided into 2 parts, separated from the thoracic cavity by the diaphragm

  • abdominal cavity - the superior portion

    • contains - stomach, intestine, spleen, liver and other organs

  • pelvic cavity - the inferior portion

    • contains - urinary bladder, some reproductive organs and the rectum

abdominopelvic cavity:

Due to its size, it is separated into 4 quadrants

• right upper quadrant

• left upper quadrant

• right lower quadrant

• left lower quadrant

these are made by dividing the cavity into a sagittal section and a transverse section through the umbilicus at right angles

skeleton:

tissue type: connective tissue (bones and cartilage) as these are living cells in a non-living matrix

• humans have an endoskeleton - more practical and allows for agility and speed of movement

• some animals have an exoskeleton - more useful for protection from predators however, it is limiting in terms of mobility

function:

• protection - of the organs within the body’s cavities

• support - for the muscles to attach to

• storage - a site for minerals such as calcium and phosphate as well as a fat storage in the yellow bone marrow

• haemopoiesis - a process that occurs in the red bone marrow that is responsible for red blood cell production

bone classification:

• the 206 human bones are divided into 2 groups

  • axial skeleton

  • appendicular skeleton

• these are classified based on shape NOT their size

appendicular skeleton:

• bones of the upper and lower limbs and the pectoral and pelvic girdles

• primarily find long bones (e.g. humerus) - help manipulate our environment, provide a site for mineral storage or attachment points for muscles

axial skeleton:

• contains the bones of the skull, vertebral column and rib cage

• primarily flat bones and irregular bones (e.g. vertebral bones) or short bones (e.g. bones in the foot, talus)

• these generally protect and support other body parts

compact vs spongy bone:

• compact - it is the dense outer layer and is smooth and solid

  • built for protection

• spongy bone - contains a honeycomb mesh of bony spikes (these are called trabeculae

  • filled with red bone marrow

  • sometimes called diploë

all bones contain a layer of spongy bone which is then surrounded by compact bone

structure of long bones:

all long bones have the same general structure: a shaft, 2 bone ends and membranes

diaphysis: the shaft

• thick compact bone surrounding a central medullary cavity that contains yellow bone marrow

epiphyses (pl.)/ epiphysis (sg.): the bone ends

• contain an outer shell of compact bone and an interior of spongy bone

• the joint surface of the ends is covered in articular cartilage

  • this helps to cushion the bone ends during movement

specialised membranes cover the bony surfaces

endosteum: delicate connective tissue covering the internal bone surfaces

• it lines canals passing through the compact bone and covers the trabeculae of the spongy bone

periosteum: dense connective tissue covering the external bone surface (except joints)

• this outer periosteal layer is continuous with tendons

• this provides a very strong bond between the muscle and bone itself

• the inner layer of the periosteum is innervated with nerves and blood vessels

structure of flat, irregular and short bones:

• two thin layers of compact bone which is separated by a layer of spongy bone

• the spongy bone or diploë or trabeculae is filled with red bone marrow

• these bones do not have a marrow cavity

• contain the periosteum on the outside and the endosteum on the inside

function of flat bones:

bones found in the cranium, sternum, scapula and rib

• designed for protection

function of long bones:

bones found in the limbs

• designed for movement or locomotion as the result of muscle attachment

bone formation and remodelling:

4 cell types:

1. stem cell or osteogenic cell - this cell is found in bone marrow and later differentiates into an osteoblast

2. osteoblast - responsible for bone growth (the bone builder)

3. osteocyte - a mature bone cell that monitors and maintains the mineralised bone matrix

4. osteoclast - this cell is responsible for bone-resorbing

compact bone:

this is the layer of bone found on the outside of both long and flat bones, it is highly structured to take support in the long axis of the bone

• it has passageways that act as conduits for nerves and blood vessels

• central canal - hollow canals that are filled with neurovascular bundles - these are the nerves and blood vessels that pass through the compact bone

• lamella - the layer of bony matrix that surrounds each central canal

  • the collagen fibres of each lamella run in a particular direction

  • collagen in a neighbouring lamella run at a different angle

  • this creates a stronger bond which is capable of resisting torsion forces

• osteon - group of circumferential lamellae

  • the structural unit of compact bone

  • it functionally acts as a weight bearing pillar

• perforating canal - joins one central canal to another

  • these lie at right angles to the long axis of the bone

  • connect the blood and nerve supply of the medullary cavity to the central canals

• osteocytes - these mature bone cells lie in the lacunae (little islands or space) at the junction of the lamalle

  • they monitor and maintain the bone matrix

  • act as stress and strain sensors which respond to the mechanical loading of the bone

  • important for bone mass and remodelling

skeletal development:

ossification (the process of bone formation) begins during embryonic development and occurs according to a relatively predictable timetable allowing fetal age to be determined by ultrasound

• most questions about structure, function and dysfunction are found during embryonic development

in utero -

• the bony skeleton starts to form

  • the connective tissue layer arises from the mesoderm layer in the fetus

  • this mesoderm layer produces the embryonic mesenchymal cells

  • these mesenchymal cells produce the membranes and cartilages

  • these membranes and cartilage then produce the embryonic skeleton

• before 8 weeks of fetal development, the embryonic skeleton is made of hyaline cartilage and fibrous membranes

at 8 weeks of fetal age -

• primary ossification centres are formed

• bones start to ossify

by 12 weeks -

• most long bones have well-defined primary ossification centres

at birth -

• most long bones are well ossified

• except for the epiphyses where length development continues long after birth

postnatally (after birth) -

• bones grow in length and size

• then they remodel

• secondary ossification centres appear at the time of birth

  • these then develop in a predictable sequence at the epiphyseal growth plate

  • this provides for long bone growth throughout childhood and adolescence

by 25 years old -

• nearly all growth plates are completely ossified

• skeletal growth ceases

Summary of 1.1.a:

the skeletal system consists of -

• bones

• cartilage

• ligaments

these form a strong and flexible framework

bone development occurs in utero and during childhood

there are 4 cells involved in bone formation -

1. osteogenic or stem cells

2. osteoblasts

3. osteocytes

4. osteoclasts

osseous tissue is a type of connective tissue

bones can be considered an organ -

• it is made of osseous tissue (type of connective tissue)

• cartilage

• blood

• bone marrow

• adipose

• nervous and connective tissue

an organ is defined by the existence of 2 more tissue types

compact bone (smooth and solid) surrounds spongy bone (trabeculae)

bones are classified based on shape not size

• they can be long, flat, irregular or short

Topic 1.1.b: Bones, Tissues and Development

content:

• bone development and growth and the change over time

• cells and hormones involved in bone remodelling

learning outcomes:

• describe the differences between intramembranous and endochondral ossification

• describe the clinical conditions

  • Dwarfism

  • Marfan’s Syndrome

• describe the clinical conditions

  • Rickets

  • Osteomalacia

  • Osteoporosis

types of ossification:

• intramembranous - occurs inside the membrane

  • in the cranial bones and sternum

• endochondral - occurs inside the cartilage

  • in the long bones of the leg and arm (e.g. the femur and humerus)

intramembranous ossification:

begins within fibrous connective tissue membranes formed by mesenchymal cells

there are 4 steps -

1. stem cells or osteogenic cells migrate to the fibrous membranes

   1. these then differentiate into osteoblasts which then forms an ossification centre that produces the initial trabeculae in the spongy bone

2. the osteoblasts secrete osteoid which then calcifies, thus trapping the osteoblasts

   1. the trapped osteoblasts now surrounded by new bone become mineralised which transforms them into osteocytes (mature bone cells) (osteocytes are living bone cells that are trapped in tiny islands called lacunae)

   2. other inactive osteoblasts remain on the edge of the new bone matrix

3. accumulated osteoid is laid down and blood supply infiltrates the bone forming a network of trabeculae - the formation of woven bone

   1. the periosteum which is rich with blood supply forms on the external surface of the woven bone

4. lamellar bone replaces the woven bone just deep to the periosteum

   1. this forms the compact bone plates

   2. the blood supply within the trabeculae of the spongy bone becomes the red bone marrow

simplified intramembranous ossification:

1. ossification centres develop in the fibrous connective tissue membrane due to osteogenic cell migration. Mesenchymal cells cluster and differentiate into osteoblasts which forms an ossification centre

2. osteoblasts secrete osteoid which then calcifies, these trapped osteoblast become osteocytes

3. immature spongy bone and periosteum form due to accumulated osteoid being laid down and forming a honeycomb of immature spongy bone. this honeycomb is then infiltrated with blood supply. in addition, the vascularised mesenchyme condenses on the external surface of the bone and becomes the periosteum

4. compact bone replaces immature spongy bone just deep to the periosteum due to the trabeculae being remodelled and replaced with the compact bone. the immature spongy bone in the centre is also remodelled to form mature spongy bone and is eventually filled with red bone marrow.

skull of a newborn - example of intramembranous ossification:

at birth, the skull bones are still incomplete, they are connected by ossified remnants of fibrous membranes. these fibrous membranes are called fontanelles

fontanelles:

• soft fibrous membranes of the skull that ossify after birth

• the fontanelles allow an infants head to be compressed slightly during birth to accomodate the birth canal as well as brain growth in the foetus and infant

• the largest fontanelle is the anterior fontanelle

  • diamond shaped

  • still palpable for 1.5 - 2 years after birth

• the majority of other fontanelles are replaced by the end of the first year of life

hydrocephalus:

• condition known as ‘water on the brain’

• occurs due to a blockage in the ventricular system within the brain which is normally responsible for draining the cerebrospinal fluid

in a newborn:

• the fontanelles allow for expansion of the skull to relieve some of the pressure on the brain while treatment is planned or awaited

in an adult:

• this condition signifies a medical emergency as the cranium which is now ossified cannot expand thus the volume of cerebrospinal fluid continues to increase and cause pressure on the brain as well as compression of nervous tissue

endochondral ossification:

this process uses hyaline cartilage patterns for bone construction, this is the more complex of the two as the hyaline cartilage simultaneously breaks down as ossification proceeds

1. a bone collar forms around the hyaline cartilage model

2. the hyaline cartilage becomes calcified in the centre of the diaphysis, this then cavitates and the bone matrix begins to break down and mineralise

3. the periosteal bud invades these internal cavities and spongy bone begins to form

4. the diaphysis elongates and a medullary cavity forms, secondary ossification centres appear in the epiphyses of the long bones at birth

5. the epiphyses ossify in adolescence due to a surge in sex hormones, the epiphyseal plate starts to close over. when ossification is complete, hyaline cartilage remains only in the epiphyseal plates and articular cartilages

the epiphyseal line is a remnant of the ossified epiphyseal growth plate

epiphyseal plate:

• longitudinal bone growth mimics many of the events of endochondral ossification and depends on the presence of epiphyseal cartilage

• in the epiphyseal plate there are zones of cartilage cells that cause elongation of long bones

  • this is up until the pubertal hormones, testosterone and oestrogen stop the cells from proliferating and halt bone growth

• the cartilage on the epiphyseal plate that is closest to the epiphysis is inactive

  • this is called the resting zone

• epiphyseal plate cartilage that is next to the diaphysis organises in a specific pattern

  • allows for fast and efficient growth in the length of the bone

zones of cartilage cells:

1. proliferation zone - cartilage cells (chondrocytes) multiply quickly and push the epiphysis away from the diaphysis which lengthens the entire bone

2. hypertrophic zone - older chondrocytes hypertrophy (they grow bigger)

3. calcification zone - surrounding cartilage calcifies then the chondrocytes die and deteriorate

4. ossification zone - cartilage is invaded by marrow from the medullary cavity, osteoclasts erode the spicules and osteoblasts cover them with new bone which is now ossified

long bone growth:

during infancy and youth - long bone growth occurs via interstitial growth of the epiphyseal plate cartilage and its replacement by bone

• long bones grow in length by a cycle of cartilage growing and then replaced by bone

  • cartilage then continues to grow and is further replaced by bone

  • cartilage is constantly chased by bone

• growing bones widen as well as lengthen

• bone remodels as it grows by appositional growth

appositional growth:

• osteoblasts beneath the periosteum secrete bone matrix on the external bone surface - this builds thicker and wider bones

• osteoclasts on the endosteum or surface of the diaphysis resorb or remove bone

• bone remodelling or reshaping involves bone resorption then followed by appositional growth then repeats

why add and remove bone?:

• this process is required to increase strength and thickness of the bone

• at the same time it reduces the weight and heaviness of the bone

• both osteoblasts and osteoclasts are central to bone remodelling activity

• they are located within the periosteum and the endosteum

  • convenient as this is next to the connective tissue layers within the bone

bone as a dynamic tissue:

• it is constantly being reshaped by osteoblasts adding new bone and osteoclasts removing (resorbing) old bone

  • osteoblasts - builders

  • osteoclasts - crushers

• when young - the osteoblasts out-do the osteoclasts - the net result is building bigger and stronger bones

• approach middle age - osteoblasts and osteoclasts activity is approximately even

• over the age of 50 - osteoclastic activity outweighs the osteoblastic activity

  • this makes bones much thinner and lighter

altered bone growth:

• some conditions cause altered bone growth

  • marfans syndrome

  • achondroplastic dwarfism

  • pituitary dwarfism

bone remodelling:

• growth and remodelling within the skeleton - regulated by 2 control loops

  • hormonal - maintains calcium homeostasis in the blood

  • response to mechanical and gravitational forces acting on the skeleton

hormonal control loop:

• determines whether and when remodelling occurs

• this is in response to changing blood calcium levels

mechanical stress on the bone:

• determines where the remodelling occurs

mechanical stress:

bone fractures and healing:

bone markings:

summary of 1.1b:

2 processes for ossification:

• intramembranous

• endochondral ossification

long bone growth is coordinated by hormones

• growth hormones

• sex hormones

bone remodelling is controlled by -

• hormone activity - parathyroid hormone

  • this regulates the release of calcium into blood by stimulating osteoclast activity

• mechanical stress - osteocytes monitor and maintain bone matrix

  • release biochemical signals in response to physical stress

  • this alters action of osteoclasts and osteoblasts

bone markings are classified into 3 categories -

• projections that form attachment sites for tendons and ligaments

• projections that form joints

• depressions or openings to allow passage of neurovascular bundles

Topic 1.2a: Axial Skeleton: The Skull

learning outcomes:

• components of the axial skeleton

• 22 bones in the human skull - 8 cranial, 14 facial

• key features of the human skull - anterior, posterior, lateral, superior and inferior aspects

• paranasal sinuses

summary:

axial skeleton:

• contains the skull, spinal column and thoracic cage

human skull:

• has 22 bone, 14 of which are facial and 8 are cranial

• the cranial bones protect the brain and special senses - they are joined by sutures

• the facial bones surround the oral and nasal cavities

• 3 paired cranial fossae form the base of the skull - this is called the cranial vault - this fits the contours of the lobes of the brain

• the sphenoid and ethmoid bones are located deep inside the skull

  • they have specialised structures to suit their function

• the maxillae and the mandible form the upper and lower jaw bones

• the paranasal sinuses lighten the skull

  • they help humidify inspired air

Topic 1.2b:

learning outcomes:

• components of a typical vertebra

• structural and functional differences of the 3 categories of vertebrae

  • specialised vertebrae C1 and C2 and the sacrum

• features and functions of the ribcage

summary:

• vertebral column contains -

  • 7 cervical

  • 12 thoracic

  • 5 lumbar

  • 5 fused sacral vertebrae

  • 4 fused coccygeal vertebrae

• curvatures of the vertebral column

  • primary

  • secondary

  • concave

  • convex

• intervertebral discs and the curvatures of the vertebral column

• provides the spine with flexibility

• a typical vertebra is made up of a body and vertebral arch which form the vertebral foramen to house and protect the spinal cord

• specialised cervical vertebra C1 atlas and C2 axis

• thoracic cage contains the sternum and 12 pairs of ribs

• sternum is made up of 3 segments: manubrium, body, xiphoid process

• ribs -

  • 1-7 true

  • 8-12 false

  • 11-12 floating

Topic 1.3a:

learning intentions:

• composition of the pectoral girdle and its attachment to the axial skeleton

• structural features of the scapula and the clavicle

• structural features of the humerus, radius, ulna and bones of the wrist and hand

summary:

• the upper limb is attached to the axial skeleton by the pectoral girdle

• the pectoral girdle is composed of the scapula and the clavicle

• the humerus articulates with the shallow glenoid cavity of the scapula

• forearm - composed of the radius (located more laterally and the ulna which is located more medially

• the radius articulates with the carpals

• the carpals form the wrist

• the metacarpals form the bones in the palm

• the phalanges are the bones located in the fingers

Topic 1.3b:

learning intentions:

• composition of the pectoral girdle and its attachment to the axial skeleton

• structural features of the coxal bones

• structural features of the femur, tibia, fibula, key tarsal bones and phalanges of the foot

summary:

• the lower limb articulates with the axial skeleton via the pelvic girdle

• coxal bones articulate with the axial skeleton via the sacroiliac joint

• coxal bones are comprised of 3 fused bones - ilium, ischium and pubis

• the head of femur articulates with the acetabulum

• the lower leg is comprised of the tibia and fibula

• the tibia articulates with the second largest tarsal bone = talus

• the heel is formed by the largest tarsal bone = calcaneus

• metatarsals form the forefoot

• phalanges form the toes

Topic 1.4: Joints

learning intentions:

• 2 different classification systems for joints

• give an example of the different types of joints

• identify different types and structure of joints and how it governs movement

• key features of the knee joint and common injuries

summary:

• joints - classified structurally and functionally

• fibrous joints - generally immobile depending on the length of the fibres in the joint - synarthrotic, amphiarthrotic

  • e.g. sutures, syndesmosis

• cartilaginous joints - immobile or slightly moveable - synarthrotic, amphiarthrotic

  • e.g. intervertebral disc, pubis symphysis

• synovial joints - freely moveable - diarthrotic

  • e.g. knee joint, glenohumeral joint

  • non-axial, uniaxial, multiaxial

  • joint cavity with capsule filled with synovial fluid

  • most structurally complex and most commonly dysfunctional

• the knee joint is the large and complex tibiofemoral joint

• the knee joint capsule encloses the lateral and posterior aspects of the knee

• ligaments enclose the anterior aspect of the knee joint

• the knee has capsular, intracapsular and extracapsular ligaments

• when the knee is locked straight, the femur rotates medially on the tibia

• the unhappy triad involves injury to the

  • anterior cruciate ligament ‘medial (tibial) collateral ligament

  • medial meniscus

joints or articulations: point where two or more bones meet

they have 2 functions -

1. permit mobility

2. offer stability

considered the weakest part of the skeleton -

• they represent a break in the continuum of bones

• prone to wearing out

• however, connective tissue surrounding the joints is strong

• classification of joints is based on structure and function

  • the structure of the articulation determines the function

joint classification:

structural classification: based on the physical structure of the joint

• fibrous joint - where two bones are joined by fibrous connective tissue

  • there is no joint cavity

• cartilaginous joint - two bones are joined by cartilage

  • no joint cavity

  • e.g. in the intervertebral discs in the spine

  • e.g. in the pubis symphysis in the pelvis

• synovial joint - these joints have a joint cavity, a joint capsule and filled with synovial fluid

  • e.g. most of the joints in the limbs throughout the body

functional classification: based on the range of movement that occurs at those joints

• synarthrotic joint (together) - the joint is immovable

  • e.g. sutures between the cranial bones

• amphiarthrotic joint (both ways) - the joint is slightly moveable

  • e.g. intervertebral discs, pubis symphysis

• diarthrotic joint (through) - freely moveable joints

  • most of the joints in the limbs

  • the knee joint, shoulder joint, hip joint

fibrous joints:

• bones are joined by connective tissue

• don’t contain a joint cavity

• most are immovable

  • however, the length of the connective tissue fibres dictates how much movement might occur

examples:

• e.g. the sutures join the cranial bones together and allow them to interlock

  • as the fibres are short, it results in a nearly rigid space

• in syndesmosis - bones are connected by ligaments that vary in length

• distal tibiofibular joint (between tibia and fibula) - fibres are short

  • little or no movement is allowed

• interosseous membrane between radius and ulna - fibres are much longer

  • allow considerable movement

• gomphoses - peg-in-socket joint that ‘nails’ the tooth in the bony alveolar socket

cartilaginous joints:

• bones are united by cartilage

• lack a joint cavity

• not very moveable

examples:

• synchondrosis - joints where the bones are connected by hyaline cartilage

  • such as the epiphyseal growth plates in long bones of children

  • or joint between the 1st rib and the sternum

  • these are synarthrotic joints or immovable joints

• symphyses - joints where fibrocartilage connects the bones

  • compressible

  • acts as a shock absorber

  • these are amphiarthrotic joints - designed for flexibility and stability

    • e.g. intervertebral discs in the spine

    • pubic symphysis of the pelvis

synovial joints:

• possess fluid-filled joint cavity - this is what separates the bones in the joint

  • have a joint cavity, capsule and are filled with synovial fluid

• freely movable or diarthrotic

• degree of movement → depends on the structure of the articulating bones

• contains articular (hyaline) cartilage is glassy and smooth

  • it acts like a cushion to withstand compression of the bone ends

• joint cavity is enclosed by two layered articular capsule

  • composed of tough outer fibrous layer that is continuous with the periosteum of the bone - helps to strengthen the joint

  • inner layer - synovial membrane - made of loose connective tissue and produces synovial fluid

• the synovial fluid fills all the ‘free space’ within the joint capsule

  Synovial fluid

  • viscous egg-white consistency

  • however, it thins during joint activity

  • derived from filtration from the blood flowing from the capillaries in the synovial membrane

  • located within the articular cartilage

  • seeps out of the cartilage when a joint is compressed

  • function - to reduce friction between cartilages and minimise wearing of the joint surfaces

  • when pressure is relieved fluid seeps back into the cartilage

    • similar to a sponge

• these joints are also reinforced by ligaments

• capsular ligaments - expansion of the fibrous layer of the capsule

• some ligaments - extracapsular

  • located outside the joint capsule

  • these are covered with synovial membrane but not ‘within’ the joint capsule

movements at synovial joints:

dictated by the structure of the joint surfaces

gliding movement - occurs when nearly flat bones slip and glide over one another

• e.g. intercarpal joints in the wrist (between the carpals) and intertarsal joints in the foot

  • non-axial movements

  • do not include any angular movement about an axis

angular movement: increase or decrease the angle between 2 bones

• flexion - occurs in a sagittal plane

  • angle between bones is reduced - more acute angle

  • e.g. neck flexion - bend the neck forward, chin to chest

• extension - occurs in the sagittal plane

  • angle between bones increases

  • e.g. neck extension - straighten the neck back toward the anatomical position

  • e.g. neck hyperextension - extending the neck beyond the anatomical position

• abduction - movement away from the midline or the midsagittal plane of the body

  • e.g. shoulder abduction - lifting the arm laterally away from the side of the body

• adduction - movement in the opposite direction, back toward the midline

• circumduction - if the distal part of the limb moves in circles, while the proximal part of the limb remains relatively stationary

  • multiaxial movement

    • e.g. at the shoulder joint

rotation: turning movement of a bone around its long axis

• commonly occurs at the hip and shoulder joints

• only movement occurring between the first two cervical vertebrae

• e.g. the ‘no’ movement of our heads

• when rotating the shoulder or the hip joint,

  • lateral rotation - turning the limb outwards

  • medial rotation - turing the limb inwards

opposition: of the thumb

• occurs at the first metacarpophalangeal joint

  • a saddle joint that allows the thumb tip to touch each of the other fingers

• provides humans the ability to grasp and manipulate fine objects

dorsiflexion and plantarflexion:

• special movements that occur at the ankle joint

• dorsiflexion - pulling the toes and the top of the foot upwards (equivalent of wrist extension)

  • dorsi - top of the foot

  • dorsal - towards the back

• plantarflexion - pointing the toes downwards (like wrist flexion)

  • plantar - sole of the foot

inversion and eversion:

• special movement occuring in the foot

• inversion - sole of the foot is turned medially

• eversion - sole of the foot is turned laterally

protraction and retraction:

• non angular movements forwards and backwards

• e.g. protraction of the mandible - push the lower jaw forward

• e.g. retraction of the mandible - pulling it back toward the vertebral column

pronation and supination:

• special rotation of the radius around the ulna

• in the anatomical position - the forearm is supinated

  • radius and ulna lie parallel to each other

• if the palm is face down - the distal end of the radius rotates across the ulna

  • forming an X shape

  • the forearm is pronated

6 types of synovial joint shapes:

plane joint -

• allows nonaxial movement between flat joint surfaces

• e.g. gliding

hinge joint -

• allows uniaxial movement such as flexion and extension

• this occurs around a medial to lateral joint axis

pivot joint -

• allows uniaxial movement such as rotation

• this occurs around a vertical a vertical axis

condylar -

• this joint allows biaxial movement to occur between 2 oval shaped articular

movements:

knee joint: