Session 1: Introduction to the Musculoskeletal System

What is the function of bursa?

Reduce friction

What is an example of an irregular bone?

Vertebrae

Muscles which assist with the prime movers are known as...

Synergists

The muscle compartments are separated by...

Deep fascia

Flexion

Decreases the angle of a joint (bending)

Extension

Increases the angle of a joint (straightening)

Abduction

Movement away from the midline of the body

Adduction

Movement toward (add) the midline of the body

Pronation of forearm

Movement that turns the palm down (towards posterior)

Supination of forearm

Movement that turns the palm up (towards superior)

Inversion of foot

Turning the sole of the foot inward (interior)

Eversion of foot

Turning the sole of the foot outward (exterior)

Protraction of scapula

Moving a part forward

Retraction of scapula

Moving a part backward

Adult skeleton is made up of ___ bones

206

Functions of the skeletal system

1) Protection

2) Support

3) Movement/leverage

4) Storing minerals

5) Haemopoiesis

Function of bone

1) Support = rigid framework

2) Protection = encloses vital structures (viscera)

3) Body movement = anchoring attachment for muscles (levers/pivot)

4) Haemapoiesis = in red marrow

5) Mineral storage = in bone matrix

6) Lipid storage in emergencies = in yellow marrow

Inorganic matter of bone

Hydroxyapatite = calcium, phosphorus

Inorganic minerals give bones their hardness, and resistance to compression

Organic matter of bone

Collagen, glycosaminoglycans, proteoglycans and glycoprotein

Organic collagens give bones their flexibility, resistance to tension and pulling

Inorganic component of bone (calcium hydroxyapatite crystals) give ___

Strength

Organic component of bone (type I collagen) confers ___ and resistance to ___

Organic component of bone (type I collagen) confers flexibility and resistance to stress

The axial skeleton is mainly for ___

Protection

- Skull protects brain

- Vertebral column protect spinal cord

- Ribs protect heart and lungs

The TWO main divisions of the skeleton

Axial and appendicular skeleton

Axial skeleton

The portion of the skeleton that supports and protects the organs of the head, neck, and trunk (central)

- Skull = protects brain

- Vertebral column = protects spinal cord

- Ribs = protects heart/lungs

- Sternum = protects heart/lungs

- Hyoid

Appendicular skeleton

Everything else - provide motility

- Hip bones

- Shoulder blades

Five major shapes of bones and example of each

1) Long e.g., humerus

2) Short (cuboidal) e.g., carpal

3) Flat e.g., skull parietal

4) Irregular e.g., vertebra

5) Sesamoid e.g., patella

The appendicular skeleton is mainly for ___

Motility

- Includes upper and lower limbs & girdles attaching limbs to axial skeleton

- Includes the scapulae (shoulder blades) and pelvis structures between limbs and axial skeleton

List some examples of surface markings of bones

Tuberosity = roughened, rounded elevation

Tubercle = smaller elevation

Fossa = depression

Foramen = hole/opening

The surface markings of bone are found where ___, ___, ___ or ___ are attached to bone

The surface markings of bone are found where fascia, ligaments, tendons or aponeuroses are attached to bone

Joints classification is via two measures...

1) Classification by degree of movement

2) Classification by type of tissue

What is a joint?

Place where two bones meet

Classification of joint by degree of movement

Synarthrosis = meaning and example

Synarthrosis = immovable e.g., skull suture (in a baby, skull sutures are slightly moveable)

Classification of joint by degree of movement

Amphiarthrosis = meaning and example

Amphiarthrosis = slightly moveable e.g., joints between vertebral bodies (spine)

Classification of joint by degree of movement

Diarthrosis = meaning and example

Diarthrosis = freely moveable e.g., synovial joint (shoulders, knees)

Classification of joint by type of tissue

Cartilaginous = meaning and example

Cartilaginous = e.g., IV disc, pubic symphysis (no/minimal movement)

Classification of joint by type of tissue

Fibrous = meaning and example

Fibrous = e.g., skull (virtually no movement)

Classification of joint by type of tissue

Synovial = meaning and example

Synovial = e.g., knee (variety of movements)

Hinge synovial joint example

Elbow and knee

Saddle synovial joint example

Thumb

Condyloid synovial joint example

Jaw and finger joints

Plane synovial joint example

Bones of foot

Ball & socket synovial joint example

Hip and shoulder

Pivot synovial joint example

Base of skull, atlas and axis

Example of fibrous joint

Skull sutures

Gomphosis

Syndesmosis

Example of cartilaginous joint

Synchondrosis

Symphysis

Typical features of a synovial joint

- Hyaline cartilage

- Articular cavity with synovial fluid = lubrication

- Joint capsule = made of outer (fibrous) and inner (synovial) membranes

Three factors help to maintain the stability of joints (prevent dislocation of joints) - what are they?

1) Shape, size and arrangement of articular surfaces

2) Ligaments

3) Muscle tone

Types of synovial joints

Hinge

Saddle

Plane

Pivot

Condyloid

Ball & socket

Three main structures found around joints - name them

1) Ligaments

2) Tendons

3) Bursa

Ligaments join ___ to ___

Ligaments join bone to bone

Tendons join ___ to ___

Tendons join muscle to bone

Bursa

Fluid-filled sac lined by synovial membrane that cushions at points of friction between bone and surrounding tissue (reduce friction)

Found in patella and elbow

Hilton's law

The sensory nerve supplying a joint also supplies the muscles moving the joint and the skin overlying the insertions of the muscle

Types of skeletal muscle and examples

A) Circular

B) Convergent

C) Parallel

D) Unipennate

E) Multipennate

F) Fusiform

G) Bipennate

Example of a fusiform skeletal muscle

Biceps brachii found in upper arm

Example of bipennate skeletal muscle

Rectus femoris found in thigh

Example of unipennate skeletal muscle

Extensor digitorum longus found in lateral part of leg

Example of parallel skeletal muscle

Sartorius found in thigh

Example of convergent skeletal muscle

Pectoralis major found in chest

When bursa become inflamed, ___ occurs

Bursitis

Function of skeletal muscle

1) Movement

2) Stability of joints

3) Posture

4) Heat generation

5) Convert chemical energy to power mechanical work

Three factors that increase stability of joints

1) Shape, size & arrangement of articular surfaces

2) Ligaments

3) Muscle tone e.g., rotator cuff muscle (shoulder)

A lever consists of...

1) Rigid structure (bone)

2) Force acting upon it (muscle)

3) Fulcrum fixed point (joint)

4) Load/resistance placed on structure (weight)

THREE TYPES OF LEVER CLASSES (FLE)

What is a first class lever?

Fulcrum is in the middle

THREE TYPES OF LEVER CLASSES (FLE)

What is a second class lever?

Load is in the middle

THREE TYPES OF LEVER CLASSES (FEL)

What is a third class lever?

Effort is in the middle

What are the four main muscle groups?

1) Agonists

2) Antagonists

3) Synergists

4) Fixators

Agonist muscles

Prime movers

Antagonist muscles

Oppose prime movers

Synergist muscles

Assist the prime movers

Fixator muscles

Stabilize action of prime movers

What is a muscle compartment?

A group of functionally related muscles enclosed by fascia

Each muscle compartment is separated by what?

Deep fascia

Muscles within each compartment share three similar factors - what are these?

Muscles within each compartment share similar...

1) Nerve supply

2) Blood supply

3) Function

How many muscles are in each muscle compartment?

3-4 muscles per muscle compartment

Describe the 5-phase repair of a fracture of a long bone.

1) Clot formation

2) Organisation of cartilage and cartilage cells = new chondroblasts

3) Soft callus formation = made of osteoid and woven bone matrix

4) Hard callus formation = with mineralisation

5) Modelling and remodelling of new bone by osteoblasts and osteoclasts to form lamellar bone

In a striated muscle cell where is calcium stored and what stimulates it to be released?

Calcium is stored in sarcoplasmic (endoplasmic) reticulum and the release is stimulated by action potential

List and name the three types of muscle fibre and briefly describe the role of each type

Type 1 (slow oxidative) = Endurance

Type 2a (fast oxidative) = Walking and sprinting

Type 2b (fast glycolytic) = Short intense movements

Long bones enable body movement by acting as a ___

Lever

Most of the bones of the arms and hands are long bones; however, the bones in the wrist are categorised as ___ bones

Short bones

The part of a long bone where growth in diameter primarily occurs during development is known as the...

Diaphysis

The terms here are paired with their opposites.

Which is incorrect?

Caudal/Ventral

3 multiple choice options

Which of the following bones is NOT part of the axial skeleton?

Scapula

3 multiple choice options

The bone shown in green is an example of what type of bone?

Irregular

In this long bone the area marked by the arrow is a site of active bone growth in children called the...

Epiphyseal plate

What type of joint is formed at the site indicated by the arrow?

Fibrous

How do you classify the synovial joint shown in image A?

Ball & socket e.g., hip

Based on axis of movements; how will you classify the synovial joint shown in image B.

Hinge joint e.g., elbow

Name the type of joint formed at site indicated by the arrow in image A.

Cartilaginous joint

How do you classify this bone shown in this image?

Flat bone

Architecturally; how do you classify the synovial joint shown in image A.

Saddle joint e.g., between trapezium carpal bone and 1st metacarpal bone

In skeletal muscle we have specialized fibres known as ___ which sense the degree of stretch and tension in the muscle.

Muscle spindles

3 multiple choice options

Bones of the hand

Phalanges

Metacarpals

Carpals

Bones of the hand (detail)

Vertebral column

Femur

Thigh bone of the leg; the longest and strongest bone in the body

Synovial joints can produce multiple movements because they are an example of a diarthrosis

List some of the movements they can produce

o Flexion

o Extension

o Abduction

o Adduction

o Internal rotation

o External rotation

o Circumduction

o Gliding

Architecturally; how do you classify the synovial joint shown in this image

Pivot joint e.g., between C1 and C2 vertebrae

Architecturally; how do you classify the synvoial joint shown in this image

Condyloid joint e.g., between radius and carpal bones of wrist

Architecturally; how do you classify the synvoial joint shown in this image

Plane joint e.g., between tarsal bones