Arm

Question 1

C6 Dermatome

Answer 1

Lateral arm, forearm & thumb

Question 2

C7 Dermatome

Answer 2

Back of arm, back of forearm, 2nd and 3rd digits

Question 3

C8 Dermatome

Answer 3

Medial arm, forearm & hypothenar

Question 4

Brachial Artery is associated with 3 muscles

Answer 4

long head of triceps, coracobrachialis, brachialis muscles

Question 5

Brachial Artery has 3 main branches

Answer 5

deep brachial (profunda brachii; runs in radial groove posteriorly). the superior ulnar collateral, and inferior ulnar collateral arteries

Question 6

Brachial Artery has 3 important nerves

Answer 6

radial, ulnar, and median nerves

Question 7

Brachial Artery is assocaited with 3 veins

Answer 7

2 venae comitantes (brachial veins) and the basilic v.

Question 8

Musculocutaneous

Answer 8

C5-C7

1. pierces the coracobrachialis muscle; innervates the coracobrachialis, biceps, and brachialis muscles
2. Injury causes great loss of flexion of the elbow, although not complete due to brachioradialis and flexor forearm muscles
3. continues as the lateral antebrachial cutaneous nerve

Question 9

Radial

Answer 9

C5-C8, T1

1. Passes in the radial groove on the back of the humerus with the deep brachial artery (profunda brachii a.), pierces the lateral intermuscular septum, and divides into superficial and deep branches in front of the lateral epicondyle
2. In the arm, gives branches to triceps, brachioradialis, and supplies the skin of the posterior arm & forearm (posterior brachial, inferior lateral brachial, and posterior antebrachial cutaneous nerves)

Question 10

Ulnar

Answer 10

C8, T1

1. Medial to axillary and brachial arteries to the middle of the arm, pierces the medial intermuscular septum, and runs with the superior ulnar collateral artery to a groove behind the medial epicondyle of the humerus.
2. A sharp blow to the medial side of the elbow (hitting your “funny bone”) will result in paraesthesia and a shock-like feeling in the hand and forearm.
3. No branches in the arm.

Question 11

Median (C5-C8, T1)

Answer 11

1. 1st lateral to, then crosses, and finally is medial to the brachial artery
2. no branches in the arm
3. passes through the cubital fossa deep to the bicipital aponeurosis

Question 12

Cubital Fossa

Answer 12

a triangular-shaped, fat-filled depression of the anterior elbow. Superficial veins- ideal place for drawing blood.

Question 13

Cubital Fossa Boundaries

Answer 13

superior- n imaginary line connecting the medial and lateral epicondyles
medial- the forearm flexors originating from the medial epicondyle
lateral- the forearm extensors originating from the lateral epicondyle
floor- brachialis and supinator mm
roof- brachial and antebrachial fascia and reinforced by the bicipital aponeurosis, which serves to protect the deep arteries and nerves in the area

Question 14

Biceps Brachii

Answer 14

Origin: Long head- supraglenoid tubercle of scapula
Short head- tip of coracoid process of scapula

Insertion: radial tuberosity, fascia of forearm via bicipital aponeurosis

Innervation: Musculocutaneous (C5,C6)

Action: flexes and supinates forearm at elbow

Blood supply: muscular branches of brachial artery

Question 15

Brachialis

Answer 15

Origin: Distal half of anterior surface of humerus

Insertion: coronoid process and tuberosity of ulna

Innervation: Musculocutaneous and radial nerve (C7)

Action: flexes forearm at elbow

Blood supply: radial recurrent artery, muscular branches of brachial artery

Question 16

Coracobrachialis

Answer 16

Origin: Tip of coracoid process of scapula

Insertion: middle third of medial surface of humerus

Innervation: Musculocutaneous nerve

Action: flexes and adducts arm at shoulder

Blood supply: muscular branches of brachial artery

Question 17

Triceps brachii

Answer 17

Origin: Long head- infraglenoid tubercle of scapula
Lateral head-upper half of posterior humerus
medial head-distal 2/3 of medial and posterior humerus

Insertion: posterior surface of olecranon process of ulna

Innervation: radial nerve

Action: extends forearm at elbow; long head stabilizes head of abducted humerus and extends and adducts arm at shoulder

Blood supply: branch of profunda brachii artery