General Musculoskeletal System

Question 1

Long Bone

Answer 1

• Resists gravity so we can stand
• Middle section = diaphysis
• End section = epithysis
• epithysis - diaphysis - epithysis

Question 2

Flat Bone

Answer 2

• Protects vital organs to maintain life
• Large SA for site of muscle attachment
• Source of red bone marrow (usually from hip - safest & most accessible)
• The whole bone isn’t completely flat - just the majority

Question 3

Short Bone

Answer 3

• Equal width & length
• For stability but has limited movement

Question 4

Irregular Bone

Answer 4

• Doesn’t fit into other bone classifications

Question 5

Sesamoid Bone

Answer 5

• Seed shape
• Forms within tendons

Question 6

Fibrous Joint

Answer 6

• Dense, fibrous connective tissue between bones - rich in collegen
• Found in teeth, syndemosis (fib+tib joint) & sutures (front skull)
• Synarthrosis - gives limited/no movement

Question 7

Primary Cartilaginous Joint

Answer 7

• Hyaline cartilage
• Bone - hyaline cartilage - bone
• Example - first sternocostal rib
• Amphiathrosis - permits slight mobility

Question 8

Secondary Cartilaginous Joint

Answer 8

• Thin layer of hyaline cartilage & fibrocartilage
• Bone - hyaline - fibrocartilage - hyaline - bone
• Example - intervertebral disc
• Amphiathrosis - permits slight mobility

Question 9

Synovial Joints

Answer 9

• Ends of bone lined with cartilage to resist compression
• Space between = synovial cavity filled with synovial fluid
• Diathrosis - freely moveable

Question 10

Clinical Relevance - Synovial Joints

Answer 10

• Osteoarthritis - space breaks down & joints rub (painful)
• Rheumatoid arthritis - inflamation

Question 11

Ligaments

Answer 11

A fibrous, connective tissue that connects two bones

• mechanical stability of bones
• guides joint motion
• prevents excess movement

Question 12

Ligament Types

Answer 12

• Capsular - direct connection to the bone/joint
• Extracapsular - lie outside the capsule
• Intracapsular - lie within the capsule

Question 13

Bursae

Answer 13

​Synovial fluid-filled sacs (lubricated cushions) that reduce friction when muscles & tendons rub over skin & bone, to ensure they can glide easily.

• Synovial - between bones & muscles, tendons & ligaments
• Superficial - located just underneath the skin, between skin & bone
• Adventitious/accidental - caused by repeat irritation (e.g big toe when shoe rubs)

Question 14

Bursae Composition

Answer 14

• Sac is made from synovial membrane - typically thin, one cell thick
• Synovial fluid is secreted from the inner membrane of synovial joint into the synovial cavity
• Synovial fluid is ultrafiltrate from blood plasma & cells from joint tissue

Question 15

Clinical Relevance - Bursitis

Answer 15

• A painful condition where the bursa become inflammed
• Appears red & tender, sore to touch and warm
• Can be treated by rest, elevatation & cold compress (minor) or antibiotics, steroid injections & removal (severe)

Question 16

Skeleton

Answer 16

Axil Skeleton

• skull, vertabral column, ribs & sternum
• midline of body: protection & muscle attachment

Appendicular

• upper limbs: dexterity
• lower limbs: support & movement (locomotion - getting to to a destination)
• Arms & legs follow a similar pattern, evolutionary development as we used to be quadrapeds girdle > long proximal > two parallel long > short > long

Question 17

Muscles

Answer 17

Muscle belly: contains contractile muscle fibres that generate force

• Usually run from one bone to another, across a joint
• During contraction, the muscle moves one bone to another

Stationary bone - origin

Mobile bone - insertion

• Muscles work in groups & have identifiable functions in generating movement (common action)

Agonist/prime mover - generates basic movement

Antagonist - controls movement

• Common innervation - group of muscles are usually supplied by the same nerve
• Creates ‘muscle memory’

Question 18

Clinical Relevance - Neurological Examination (muscles & nerves)

Answer 18

​Movement tests (neurological examinations) can tell if muscles & nerves are working simultaneously and that the spinal chord is intact

Question 19

Tendons

Answer 19

• Tough bands of fibrous, connect tissue that usually connects muscle to bone (found at the end of muscles)
• Function: transfer muscle force to bone to facilitate joint movement
• Can be broad & flat (back) aka aponeuroses or rounded (ankle)

Question 20

Clinical Relevance - Tendon Reflex

Answer 20

A clinical examination testing the stretch reflex of a tendon (shows intactness of the nervous system). The stretch is created by a blow apon a muscle tendon (e.g knee).

Question 21

Clinical Relevance - Presentation of a Clavical Fracture

Answer 21

• Arm is adducted
• Lateral end depressed
• Tenting of the skin - medial end pulling

(presentation of fractures always depend on the pull of muscles attached)

Question 22

Muscle Contractions

Answer 22

• Concentric contractions - get smaller
• Eccentric contractions - get longer
• Isotonic contractions - stay the same

A combination of contractions gives smooth/controlled movement, often against gravity

Question 23

Superficial Fascia

Answer 23

Fasciae - layers of tissue made from collegen (connective tissue), lying deep to the skin. Found all over body but varies in people & parts - anatomical variation.

• Superficial fascia - outermost layer, a mixture of loose connective tissue & fat
• Thick layer for support & insulation

Question 24

Deep Fascia

Answer 24

• Inner to superficial fascia, membraneous layer of connective tissue
• Seperates & surrounds groups of muscle - forms layers that may direct infection via specific parts
• Divides the body into compartments - fascial septa (usually containing muscle, nerves & vessels)
• Compartments show innervation (nerve supply) to muscles within them - usually common innervation

Question 25

Clinical Relevance - Deep Fascia

Answer 25

• Tough & fibrous so cannot stretch. If there is swelling in a compartment (usually due to a fracture/muscle strain), pressure can build up and compress nerves & blood vessels - cause circulatory problems/nerve damage
• ‘Fasciotomy’ - making an incision through the skin, superficial & deep fascia to relieve pressure & restore blood and nerve supply to the limbs

Question 26

Clinical Relevance - Cross Sections

Answer 26

• On a specimen, veins usually still have blood remaining in them (way the fluid is pumped upwards in arteries)
• Arteries have thicker walls (lumen) and will bounce back when compressed or touched
• To tell side of body - the basilic vein runs down the medial side of the arm
• To tell anterior/posterior compartment, determine side of body, basilic (medial) & cephalic vein (lateral)