Movement And Support Of The Shoulder Joint

Question 1

What does the CNS and the peripheral nervous system consist of?

Answer 1

CNS-brain(skull) and the spinal cord (vertebral column)

PERIPHERAL NERVOUS SYSTEM- cranial nerves, spinal nerves

Question 2

What are somites in embryos?

Answer 2

They are blocks of muscle tissue that develop in pairs alongside spinal cord
Group combines to form each forelimb. Drags nerves as well and therefore the nerve supply reflects the origin

Question 3

Describe the structure of the spinal nerves

Answer 3

Leave the spinal cord though the intervertebral foramen

They are paired left and right and branch- the dorsal branches supply dorsal structures

Question 4

From what vertebrae do the brachial plexus form and where are they located?

What nerves supply the forelimb?

Answer 4

Ventral branches off C6,C7,C8,T1 and T2 form the brachial plexus. It is located in the axillary region

Emerging nerves supply the forelimb

Question 5

What are afferent and efferent supplies?

Answer 5

Afferent-carry impulses from structures to brain (sensory nerve fibres)

Efferent-carry impulses from brain to structure (muscle or organ), (motor nerve fibres)

Question 6

What are mixed nerves?

Answer 6

Consist of both motor and sensory fibres, and transmit messages in both directions at once (spinal reflexes)

Question 7

What does and doesn’t the brachial plexus supply?

Answer 7

Supplies all intrinsic muscles
Supplies some extrinsic muscles:
-latissimus dorsi (retractor)
-serratus ventralis (protractor and retractor) 
-pectoral (adductor) 

Doesn’t supply:
Brachiocephalicus (protractor)
Trapezius and rhombiodeus (abductors)

Question 8

What are the 3 different types of joints and what types of movement do they allow?

Answer 8

Fibrous-little movement
Cartilagenous-little movement
Synovial- allow a large range of movement between bones

Question 9

What are the typical features of a synovial joint”

Answer 9

Hyaline cartilage covers articular surfaces to reduce friction and aid flexibility. It is avascular (no nerve supply) and has no nerve endings

Synovial fluid:

• sticky
• nourishes cartilage
• lubricates

Synovial membrane:

• produces synovial fluid
• physical barrier to contain fluid

Joint capsule:

• fibrous layer
• incorporates synovial membrane
• attaches around osteochondral junction

Question 10

What were ligaments?

Answer 10

Fibrous tissue that condenses to form ligaments (DENSE FIBROUS CONNECTIVE TISSUE)
Ligaments run from bone to bone
Collateral ligaments support joints (medial and lateral)

Question 11

What are the function of ligaments in relation to joints?

Answer 11

Support the joint and hold the bones together by restricting bone movement

Question 12

Describe what flexion and extension of joints are.

Answer 12

Flexion- decreased angle, folded limb, non weight bearing position

Extension- increased angle, stretched limb and associated with weight bearing

Question 13

What are the components of the shoulder joint?

Answer 13

• scapula (glenoid cavity-concave)

- humerus (head-convex)

Question 14

What are the palpable landmarks of the shoulder joint

Answer 14

Acromion process (scapula) 
Greater tubercle (humerus)

Question 15

What features does the shoulder joint have?

Answer 15

All synovial joint features except it has glunohumeral ligaments at the lateral aspect and has poorly developed collateral ligaments

Question 16

What is the bicipital bursa of the shoulder joint?

Answer 16

• joint capsule extends into inter-tubercular groove, between greater and lesser tubercles
• wraps around tendon of origin of biceps branchii
• held in place by the transverse ligament

Question 17

What lateral support does the shoulder joint have?

Answer 17

Supraspinatus muscle-originates at the supraspinous fossa and inserts at the greater tubercle
Infraspinatus muscle- originates at the infraspinous foss, inserts distal to the greater tubercle and abducts the shoulder . Supplied by the suprascapular nerve (MOTOR FIBRES ONLY)

Question 18

What medial support does the shoulder have?

Answer 18

Supscapulris muscle: originates at the subscapular fossa. Inserts on the lesser tubercle, adducts the shoulder joint. Supplied by the subscapular nerve (MOTOR FIBRES ONLY)

Question 19

What are shoulder extensors.

Answer 19

Cross cranial to shoulder joint

Question 20

What type of muscle is the brachiocephalicus and what is its nerve supply like?

Answer 20

Brachiocephalicus-extrinsic muscle, not supplied by the brachial plexus

Question 21

Describe where the biceps branchii muscle originates and inserts. What type of muscle is it and what is its nerve supply like?

Answer 21

Originates at the supraglenoid tubercle
Inserts at the ulnar and radial tuberosities
It’s a intrinsic muscle which is a elbow flexor and shoulder extensor

It has a motor nerve supply via the musculocutaneous nerve

Question 22

What are shoulder flexors?

Answer 22

Cross caudal to the shoulder joint

Question 23

What is the nerve supply of the latissimus dorsi nerve supply like?

Answer 23

From bronchial plexus

Question 24

Where does the teres major originate and insert itself. Describe its nerve supply.

Where is the teres minor located?

Answer 24

Originates at the caudal border of the scapula
Inserts at the medial humerus
Nerve supply via the axillary nerve, motor and sensory fibres

The teres minor overlies the lateral aspect of the joint space

Question 25

Where does the deltoideus muscle originate and insert? Describe its nerve supply

Answer 25

It has 2 heads which originate at the scapular spine and acromion process. It inserts at the lateral aspect of the humerus. It’s a intrinsic muscle

It’s nerve supply:

• axillary nerve
• mixed type (motor and sensory nerve fibres)

Question 26

Describe where the triceps muscle originates and inserts and its function, as well as its nerve supply.

Answer 26

It has 4 heads
Has a long head and is split into 2 parts
Originates at the caudal border of the scapula and inserts on the olecranon of ulna.
It’s functions as a elbow extensor

Nerve supply:

• radial nerve
• motor and sensory fibres