Muscles of the Upper Arm

Question 1

4 muscles

Answer 1

Biceps brachii
Brachialis
Coracobrachialis
Triceps brachii

Question 2

Innervation of the anterior arm

Answer 2

Musculocutaneous nerve (C5-C7)
(BBC - biceps brachii, brachialis, coracobrachialis)

Question 3

Biceps brachii

Answer 3

Origin - Long head - supraglenoid tubercle of scapula
Origin - Short head - coracoid process of scapula
Attachment - radial tuberosity
Action - supination, flexes arm at elbow and shoulder

Question 4

Rupture of biceps tendon

Answer 4

Long head of biceps brachii rupture is on of the more common tendons to rupture
Produces ‘Popeye Sign’ on flexion of the elbow
Patient wouldn’t notice much weakness in upper limb due to brachialis and supinator

Question 5

Coracobrachialis

Answer 5

Origin - coracoid process of scapula
Attaches - medial side of humeral shaft at level of deltoid tubercle
Action - flexes arm and shoulder

Question 6

Brachialis

Answer 6

Origin - medial and lateral surfaces of humeral shaft
Attachment - tuberosity of ulna just distal to the elbow joint
Action - flexes elbow
Innervation - mainly musculocutaneous, small lateral portion by radial nerve

Question 7

Triceps brachii

Answer 7

Origin - Long head - infraglenoid tubercle
Origin - Lateral head - humerus, superior to the radial groove
Origin - Medial head - humerus, inferior to the radial groove
Attachment - olecranon of ulna
Action - extension of arm at elbow
Innervation - radial nerve