Arm muscles

Question 1

Biceps Brachii origin

Answer 1

Short: tip of coracoid process
Long: supraglenoid tubercle of scapula

Question 2

Biceps Brachii insertion

Answer 2

1. Bicipital (aka radial) tuberosity of radius
2. Via the bicipital aponeurosis (aka lacertus fibrosis) , a triangular, membranous band which runs from the biceps tendon across the front of the elbow into deep fascia over the flexor muscles in the medial side of the forearm

Question 3

Biceps Brachii innervation and spinal level

Answer 3

Musculocutaneous C5,6

Question 4

Biceps Brachii Action

Answer 4

Flexes and supinate the forearm, strong supination (against resistance) when the forearm is pronated, to about midrange (90).
Because the long head also crosses the Gleno-humeral joint, it also assists in flexion and abduction of the arm (more of an abductor when arm is externally rotated) and stabilize the GH joint. Short head can assist in adduction and IR

Question 5

Coracobrachialis origin

Answer 5

Tip of coracoid process of scapula

Question 6

Coracobrachialis insertion

Answer 6

Middle 1/3 of medial shaft of humerus

Question 7

Coracobrachialis innervation and spinal level

Answer 7

Musculocutaneous C6,7

Question 8

Coracobrachialis Action

Answer 8

Always described as a flexor and adductor of the arm, but best positioned for horizontal flexion (adduction) of the arm,helps with GH joint

Question 9

Brachialis origin

Answer 9

Distal 1/2 of anterior surface of humerus and intermuscular septae

Question 10

Brachialis insertion

Answer 10

Bicipital aponeurosis, coronoid process, and ulnar tuberosity

Question 11

Brachialis innervation and spinal level

Answer 11

Musculocutaneous C5,6 and sometimes (minority) radial C7

Question 12

Brachialis action

Answer 12

Flexion at elbow joint

Question 13

Triceps Brachii origin

Answer 13

Long head: infraglenoid tubercle of scapula
Medial head: posterior surface of humerus, inferior to radial groove, and intermuscular septum
Lateral head: posterior surface of humerus, superior to radial groove and intermuscular septum

Question 14

Triceps Brachii insertion

Answer 14

By a common tendon into the olecranon process of the ulna

Question 15

Triceps Brachii innervation and spinal level

Answer 15

Radial C6,7,8

Question 16

Triceps Brachii action

Answer 16

Extension at the elbow joint, long head also aids in extension and adduction of the arm

Question 17

Anconeus origin

Answer 17

Posterior aspect of lateral epicondyle of humerus

Question 18

Anconeus insertion

Answer 18

Lateral surface of olecranon

Question 19

Anconeus innervation and spinal level

Answer 19

Radial C7,8

Question 20

Anconeus action

Answer 20

Assist triceps in forearm extension, provides dynamic support to lateral side of elbow joint, maybe forearm pronation?