Arm Muscles

Question 1

Brachialis

Answer 1

O: Distal 1/2 anterior border to medial and lateral surfaces of humerus
Medial and lateral intermuscular septa

I: Ulnar tuberosity to coronoid process of ulna

N: Musculocutaneous n. (C5+6)
Radial n. - a minor branch to lateral part of muscle

A: Elbow flexion

Question 2

Coracobrachialis

Answer 2

O: Tip of coracoid process of scapula

I: Midshaft, medial surface of humerus

N: Musculocutaneous n. (C6+7)

A: Shoulder Adduction, flexion, IR, and horizontal Adduction

Question 3

Biceps brachii

Answer 3

O: Long Head- Supraglenoid tubercle of scapula, running through bicipital groove of humerus
Short Head- Tip of coracoid process of scapula

I: Radial tuberosity of radius and bicipital aponeurosis

N: Musculocutaneous n. (C5+6)

A: Elbow flexion, forearm supination, shoulder flexion, abduction, and IR

Question 4

Triceps brachii

Answer 4

O: Long head- infraglenoid tubercle of scapula
Lateral head- Posterior surface and lateral border of humerus, proximal to radial groove
Medial head- Posterior surface of humerus, distal to radial groove and medial intermuscular septum

I: Olecranon process of humerus, upper posterior surface

N: Radial nerve (C7+8)

A: Elbow extension, shoulder extension, hyper extension, and adduction

Question 5

Anconeous

Answer 5

O: Lateral epicondyle of humerus, posterior surface

I: Olecranon process of ulna, lateral side to upper posterior surface to posterior oblique line

N: Radial nerve (C7+8)

A: Elbow extension, tenses capsule of elbow joint to prevent pinching during extension