The shoulder and elbow joints

Question 1

What is the function of the glenoid labrum

Answer 1

It softens and slightly deepens the outer edge of the socket

Question 2

Where do most fractures occur?

Answer 2

The surgical neck (around the inferior end of the head of the humerus/around the intertubercular groove)

Question 3

What makes up the articular capsule?

Answer 3

The fibrous capsule and synovial membrane

Question 4

Describe the synovial capsule

Answer 4

It is attached around the labrum, lines the fibrous capsule, and is reflected back to attach to the anatomical head of the humerus at the articular margin. It forms a sleeve around the tendon of the long head of biceps.

Question 5

What ligament is found between the acromion and the coracoid and explain its function.

Answer 5

The coracoacromial ligament. It forms a superior arch over the shoulder joint and prevents superior dislocation of the glenohumeral joint

Question 6

What ligament is found between the coracoid and the humerus and explain its function

Answer 6

The coracohumeral ligament. It is a strong flattened band capable of suspending the arm and it reinforces the capsule superiorly

Question 7

What is the function of the transverse humeral ligament?

Answer 7

It spans between the greater tubercle and the lesser tubercle and it holds the tendon of the biceps brachii in position

Question 8

What are the glenohumeral ligaments?

Answer 8

They are three weak thickenings on the interior and anterior aspects of the capsule

Question 9

What is the function of bursae? And give examples.

Answer 9

Bursae minimise friction between tendons as they pass across bones or other tendons.

Subacromial bursae and Subdeltoid bursae (they are continuous). Subacromial bursa protects the supraspinatus and infraspinatus tendons.

Question 10

What does the sacciform synovial membrane do?

Answer 10

It allows tendons to move easily by providing lubrication

Question 11

What are rotator cuff muscles and what are some examples?

Answer 11

They provide stability to the joint.

Supraspinatus tendon, infraspinatus tendon, teres minor, subscapularis tendon

Question 12

What is the origin, insertion, nerve supply, movement and position of the subscapularis?

Answer 12

Origin: Subscapular fossa
Insertion: lesser tubercle 
Nerve Supply: upper and lower subscapular nerve
Movement: internally rotates arm
Position: Anterior side of scapula

Question 13

What is the origin, insertion, nerve supply, movement and position of the supraspinatus, infraspinatus and teres minor?

Answer 13

Origin:
Supraspinatus - supraspinous fossa
Infraspinatus - infraspinous fossa
Teres minor - lateral border of the scapula
Insertion:
Supraspinatus - superior facet of the greater tubercle
Infraspinatus - middle facet of the greater tubercle
Teres minor - inferior facet of the greater tubercle
Nerve Supply:
Supraspinatus + Infraspinatus - suprascapular nerve
Teres Minor - Axillary nerve
Movement:
Supraspinatus - Abducts arm
Infraspinatus + Teres minor - externally rotate arm

Question 14

What are the bones in the elbow joint and state where they attach to

Answer 14

The trochlear notch which is part of the olecranon (on the ulna) attaches to the trochlea (on the humerus medial to the capitulum). The superior surface of the radius attaches to the capitulum (on the humerus lateral to the trochlea). The head of the radius attaches to the radial notch (on the ulna just off the olecranon).

Question 15

What are the functions of these joints at the elbow?

Answer 15

Humero-ulnar joint: Only flexion and extension of the elbow
Humero-radial joint: Flexion and extension of elbow, rotation of forearm (supination and pronation of elbow)
Superior radial-ulnar joint: supination and pronation of elbow

Question 16

What are the ligaments found in the elbow joint and what are their functions?

Answer 16

The ulnar collateral ligament - prevents abduction of the ulna (prevents the ulna from bending outwards). It is attached to the medial epicondyle and the superior medial end aspect of the ulna.
The radial collateral ligament - prevents adduction of the radius. It extends from the lateral epicondyle to the annular ligament of the radius.
The annular ligament of the radius - It is attached to the edges of the radial notch of the ulna and it surrounds the head of the radius and it allows it to spin within the loop created during pronation and supination.