Forearm Flexors and Compartments

Question 0

Pronator teres

Answer 0

Origin: (humeral head) medial epicondyle of the humerus; (ulnar head) coronoid process of the ulna

Insertion: middle of convexity of the lateral surface of the radius

Innervation: median nerve (C6,C7)

Action: pronates and flexes the forearm at the elbow

Question 1

What is the roof of the carpal tunnel?

Answer 1

Flexor retinaculum

Question 2

Flexor carpi radialis

Answer 2

Origin: medial epicondyle of the humerus

Insertion: base of the 2nd (3rd) metacarpal

Innervation: median nerve (C6,C7)

Action: ABD and flexes hand at the wrist

Question 3

Palmaris longus

Answer 3

Origin: medial epicondyle of the humerus

Insertion: distal half of the flexor retinaculum and the palmar aponeurosis

Innervation: median nerve (C7,C8)

Action: flexes the hand at the wrist and tenses the palmar aponeurosis

Question 4

Flexor carpi ulnaris

Answer 4

Origin: olecranon and posterior border via the aponeurosis

Insertion: pisiform, hook of hamate, and the 5th metacarpal

Innervation: ulnar nerve (C7,C8)

Action: ADD and flexes the hand at the wrist

Question 5

Flexor digitorum superficialis

Answer 5

Origin: (humeroulnar head) medial epicondyle of the humerus and the coronoid process of the ulna; (radial head) oblique line of the radius

Insertion: shaft of the middle phalanges of the medial four digits

Innervation: median nerve (C7,C8,T1)

Action: flexes the PIP joint of the middle four digits and flexes the proximal phalanges at the MCP joint

Question 6

Flexor digitorum profundus

Answer 6

Origin: proximal three fourths of the medial and anterior surface of the ulna and the interosseous membrane

Insertion: bases of the distal phalanges of the 2-5th digits

Innervation: 2 and 3 digit - median nerve, anterior interosseous branch (C8,T1) and 4 and 5 digit - ulnar nerve (C8,T1)

Action: flexes the DIP joint of the 2-5th digits and assists with wrist flexion

Question 7

Flexor pollicis longus

Answer 7

Origin: anterior surface of the radius and the adjacent interosseous membrane

Insertion: base of the distal phalanx of the thumb

Innervation: anterior interosseous nerve of the median nerve (C8,T1)

Action: flexes phalanges of the 1st digit

Question 8

Pronator quadratus

Answer 8

Origin: distal fourth of the anterior surface of the ulna

Insertion: distal fourth of the anterior surface of the radius

Innervation: anterior interosseous nerve from the median nerve (C8,T1)

Action: pronates forearm and deepens fibers that bind the radius and ulna together