Axilla & Arm

Question 1

Anconeus AAIN

Answer 1

Attachments: lateral epicondyle of humerus to lateral surface of the olecranon process
Actions: extension of elbow
Innervation: radial nerve
Nerve roots: C7-8

Question 2

Biceps Brachii AAIN

Answer 2

Attachments: coracoid process (short head) and supraglenoid tubercle (long head) of the scapula to the radial tuberosity and the deep antebrachial fascia (through the bicipital aponeurosis)
Actions: flexion of the shoulder and elbow & supination of the forearm
Innervation: musculocutaneous nerve
Nerve roots: C5-6

Question 3

Brachialis AAIN

Answer 3

Attachments: distal anterior shaft of the humerus & lateral & medial intermuscular septa to the conoid process & ulnar tuberosity
Actions: flexion of the elbow
Innervation: musculocutaneous nerve & small branch from radial nerve
Nerve roots: C5-6

Question 4

Coracobrachialis AAIN

Answer 4

Attachments: coracoid process to the proximal medial shaft of the humerus
Actions: flexion and adduction of the shoulder
Innervation: musculocutaneous nerve
Nerve roots: C6-7

Question 5

Triceps Brachii AAIN

Answer 5

Attachments: infraglenoid tubercle of the scapula (long head) and proximal posterolateral (lateral head) and distal posteromedial (medial) shaft of the humerus to the olecranon process of the ulna
Actions: extension of the shoulder (long head) and extension of the elbow (long, lateral and medial heads)
Innervation: radial nerve
Nerve roots: C6-T1

Question 6

What are the boundaries and contents of the axilla?

Answer 6

Boundaries: 1st rib, clavicle (apex), skin of armpit (base), pectoral muscles (anterior), scapula and subscap muscles (posterior), thoracic wall and serratus anterior muscles (medial), humerus (lateral)

Contents: axillary artery/vein, axillary lymph nodes, 3 cords of the brachial plexus (medial, posterior, lateral)

Question 7

Spinal cord segments of dorsal scapular nerve

Answer 7

C4-5

Question 8

Spinal cord segments of long thoracic nerve

Answer 8

C5-7

Question 9

Spinal cord segments of suprascapular nerve

Answer 9

C4-6

Question 10

Spinal cord segments of subclavian nerve

Answer 10

C5-6

Question 11

Spinal cord segments of lateral pectoral nerve

Answer 11

C5-7

Question 12

Spinal cord segments of musculocutaneous nerve

Answer 12

C5-7

Question 13

Spinal cord segments of median nerve

Answer 13

C5-C7 (lateral root)

C8-T1 (medial root)

Question 14

Spinal cord segments of medial pectoral nerve

Answer 14

C8-T1

Question 15

Spinal cord segments of medial cutaneous nerves of the arm & forearm

Answer 15

C8-T1

Question 16

Spinal cord segments of ulnar nerve

Answer 16

C7-T1

Question 17

Spinal cord segments of upper subscapular nerve

Answer 17

C5-6

Question 18

Spinal cord segments of thoracodorsal nerve

Answer 18

C6-8

Question 19

Spinal cord segments of lower subscapular nerve

Answer 19

C5-6

Question 20

Spinal cord segments of axillary nerve

Answer 20

C5-6

Question 21

Spinal cord segments of radial nerve

Answer 21

C5-T1

Question 22

Function of dorsal scapular nerve

Answer 22

PG S & M: levator scapulae & rhomboid

Question 23

Function of long thoracic nerve

Answer 23

S, PG S & M: serratus anterior

Question 24

Function of suprascapular nerve

Answer 24

S, PG S & M: supraspinatus & infraspinatus

Question 25

Function of the subclavian nerve

Answer 25

S, PG S & M: subclavius

Question 26

Function of the lateral pectoral nerve

Answer 26

S, PG S & M: pectoralis major & minor

Question 27

Function of the musculocutaneous nerve (muscular branches & lateral cutaneous nerve of the forearm)

Answer 27

Muscular branches: S, PG S & M: biceps brachii, coracobrachialis, and brachialis Lateral cutaneous nerve of the forearm: S & PG S: skin overlying the lateral aspect of the forearm

Question 28

Function of the medial pectoral nerve

Answer 28

S, PG S & M: pectoralis major & minor

Question 29

Function of the medial cutaneous nerves of the arm & forearm

Answer 29

S & PG S: skin overlying the medial aspect of the arm & forearm

Question 30

Function of the upper subscapular nerve

Answer 30

S, PG S & M: subscapularis

Question 31

Function of the thoracodorsal nerve

Answer 31

S, PG S & M: latissimus dorsi

Question 32

Function of the lower subscapular nerve

Answer 32

S, PG S & M: subscapularis & teres major

Question 33

Function of the axillary nerve

Answer 33

Muscular branches in the arm: S, PG S & M: deltoid & teres minor Superior lateral cutaneous nerve of the arm: S & PG S: skin overlying the superior lateral aspect of the arm

Question 34

Function of radial nerve (muscular branches in the arm only)

Answer 34

S, PG S & M: triceps brachii & brachialis

Question 35

What is the convention for naming cervical nerves?

Answer 35

Nerve is named after the spinous process it exits above (ex. C5-C6 would be C6)

Question 36

What is the convention for naming thoracic nerves (and all other than cervical)?

Answer 36

Nerve is named after the spinous process it exits below (ex. T1-T2 would be T1)

Question 37

What is the location/contents of the triangular space?

Answer 37

Borders: teres minor, major & triceps brachii long head Contents: circumflex scapular artery

Question 38

What is the location/contents of the triceps hiatus?

Answer 38

Borders: triceps brachii long head, teres major, humerus/triceps brachii medial head Contents: radial n, profundi brachii a

Question 39

Contents/actions/innervations/blood supply to anterior arm compartment

Answer 39

Muscles: biceps brachii, brachialis, coracobrachialis Actions: shoulder and elbow flexion Innervations: musculocutaneous n Blood supply: brachial a

Question 40

Contents/actions/innervations/blood supply to posterior arm compartment

Answer 40

Muscles: triceps brachii, anconeus Actions: shoulder and elbow extension Innervation: radial n Blood supply: profunda brachii a

Question 41

What would the most common dislocation of the shoulder be (based on joint structure and ligaments)?

Answer 41

Anterior dislocation

Question 42

What neuromuscular structures would be injured due to bone fracture at the surgical neck of the humerus? Radial groove of the humerus?

Answer 42

Surgical neck: axillary n, posterior circumflex humeral a | Radial groove of the humerus: axillary n, anterior/posterior circumflex humeral a