Muscles of the Arm

Question 1

biceps brachii (long head and short head)
1 PA (for each head), 2 DA, 1N2R, 3 A

Answer 1

PA:
+ short head: tip of coracoid process
+ long head: supraglenoid tubercle of scapula

DA:
+ tuberosity of radius
+ fascia of forearm via bicipital aponeurosis

N:
+ musculocutaneous nerve (C5, C6*)

A:
+ supinates forearm
+ when supinated, flexes shoulder joint
+ short head: resists shoulder dislocation

Question 2

brachialis

1 PA, 2 DA, 1N2R, 1A

Answer 2

PA:
+ distal half of anterior surface of humerus

DA:
+ coroNOID process of ulna
+ coronoid tuberosity of ulna

N:
musculocutaneous nerve (C5, C6*)

A:
+ flexes elbow in all positions

Question 3

coracobrachialis

1 PA, 1 DA, 1N3R, 3 A

Answer 3

PA:
+ tip of coracoid process of scapula

DA:
+ middle third of medial surface of humerus

N:
+ musculocutaneous nerve (C5, C6*, C7)

A:
+ flex shoulder
+ adduct shoulder
+ resists dislocation of shoulder

Question 4

triceps brachii (long head, lateral head, medial head)
1 PA (for each head), 2 DA, 1N3R, 3A

Answer 4

PA:
+ long head: infraglenoid tubercle of scapula
+ medial head: posterior surface of humerus, inferior to radial groove
+ lateral head: posterior surface of humerus, superior to radial groove

DA:
+ proximal end of olecranon of ulna
+ fascia of forearm

N:
+ radial nerve (C6, C7, C8)

A:
+ chief extensor of elbow joint
+ long head: extends the shoulder & resists humeral dislocation esp. during abduction