Upper limb - Arm muscles (MSK)

Question 1

Anterior compartment

Answer 1

Bread meats bread

Biceps brachai
Musculocutaneous nerve
Brachialis muscle

Coracobrachialis

Question 2

Biceps brachii

origin, insertion, innervation, action

Answer 2

• Long head comes from the supraglenoid tubercle and short head comes from coracoid process
• Heads come together and insert into the radial tuberosity and bicipital aponeurosis
• Musculocutaneous nerve
• supinates forearm and helps to flex
• Superficial to brachialis

Question 3

Brachialis

Origin, insertion, innervation, action

Answer 3

• Shaft of the humerus
• Tuberosity of the ulna
• Musculocutaneous nerve
• Primary flexor of the elbow
• Deep to biceps brachii

Question 4

Coracobrachialis

Origin, insertion, innervation, action

Answer 4

• Coracoid process of the scapula
• Medial shaft of the humerus
• musculocutaneous nerve (pierces through this muscle)
• Flexes the arm and acts as a weak abductor
• Lies deep to biceps brachii and brachialis

Question 5

posterior compartment

Answer 5

Triceps brachii and anconeus

Question 6

Triceps brachii

Origin, insertion, innervation, action

Answer 6

Long head - infragelnoid tubercle of the scapula
Medial head - Posterior surface of the humerus, inferior to spiral/radial groove
Lateral head - Posterior surface of the humerus, superior to the spiral/radial groove

• All insert into the olecranon of the ulna
• Radial nerve (moves out through the triangular interval with the profunda brachii artery and veins)
• Extends the forearm at the elbow
• long head helps to extend the arm at the shoulder joint

Question 7

Anconeus

Origin, insertion, innervation, action

Answer 7

• Lateral epicondyle
• Postereolateral aspect of the olecrannon
• Radial nerve
• Extends the forearm