Anatomy of the Shoulder and Elbow

Question 1

What is the action of the deltoid?

Answer 1

Mainly abduction, but also flexion and extension of the arm

Question 2

What is the action of the brachialis?

Answer 2

Most powerful flexor of the elbow

Question 3

What is the action of the brachioradialis?

Answer 3

Strong flexor of elbow only in mid-position

Question 4

What is the action of the biceps brachii?

Answer 4

Most powerful supinator

Question 5

Describe the stability and mobility of the shoulder joint

Answer 5

Most mobile and least stable joint in the body

Question 6

What joints make up the shoulder joint?

Answer 6

Sternoclavicular, acromioclavicular, glenohumeral and scapulothoracic articulation

Question 7

Describe the head of the humerus in relation to the body of the humerus

Answer 7

Retroverted 30 degrees

Question 8

What are the attachments to the greater tuberosity of the humerus?

Answer 8

SIT
Supraspinatus
Infraspinatus
Teres minor

Question 9

What are the attachments to the lesser tuberosity of the humerus?

Answer 9

Subscapularis

Question 10

What are the functions of the clavicle?

Answer 10

Strut to support the shoulder
Protection of brachial plexus and vessels
Attachment for muscles (e.g. trapezius, deltoid, pec major, subclavus, SCM, sternohyoid)

Question 11

What can a fall on the shoulder result in?

Answer 11

Disruption of the AC joint

Loss of the AC and CC ligaments

Question 12

What will you see if you lose the AC and CC ligaments?

Answer 12

A big gap between the acromion and clavicle on XRay

Question 13

What is the labrum?

Answer 13

Fibrocartilaginous ring, firmly attached round the glenoid

Question 14

What is the function of the labrum?

Answer 14

Elevates the glenoid edge –> increased contact between glenoid and humerus and increased depth and so increased stability

Question 15

What is the most common type of shoulder dislocation?

Answer 15

Anterio-inferior

Question 16

What injuries may lead to axillary nerve damage?

Answer 16

Anterior dislocation of the shoulder

Surgical neck of humerus fracture

Question 17

What are the signs of axillary nerve damage?

Answer 17

Loss of sensation over deltoid (badge area) and weakness of deltoid

Question 18

What are the functions of the rotator cuff muscles?

Answer 18

Blend with the capsule and increase stability and protection
Hold head of humerus against glenoid cavity during movements
Subscapularis is a lateral rotator
Infraspinatus is a medial rotator
Teres major is a lateral rotator
Supraspinatus is an abductor

Question 19

What may cause a rotator cuff tear?

Answer 19

Injury, dislocation, ageing

Question 20

What muscles cause flexion at the shoulder joint?

Answer 20

Pec major, coracobrachialis, biceps and ant. deltoid

Question 21

What muscles cause extension at the shoulder joint?

Answer 21

Teres major, latissimus dorsi, post. deltoid

Question 22

What muscles cause abduction at the shoulder joint?

Answer 22

Mid. deltoid, supraspinatus

Question 23

What muscles cause adduction at the shoulder joint?

Answer 23

Pec. major and latissimus dorsi

Question 24

What muscles cause medial rotation at the shoulder joint?

Answer 24

Teres major and subscapularis

Question 25

What muscles cause lateral rotation at the shoulder joint?

Answer 25

Teres minor and infraspinatus

Question 26

What muscles cause flexion at the elbow joint?

Answer 26

Brachialis, biceps brachii, brachioradialis

Question 27

What muscles cause extension at the elbow joint?

Answer 27

Triceps, anconeus, gravity

Question 28

What muscles cause pronation at the radioulnar joint?

Answer 28

Pronator quadratus, pronator teres (active against resistance), gravity

Question 29

What muscles cause supination at the radioulnar joint?

Answer 29

Biceps brachii, supinator (active against slow, unresisted movements)

Question 30

What causes winging of the scapula?

Answer 30

Serratus anterior palsy (due to long thoracic nerve disruption)