Anterior Forearm (Anterior Antebrachium)

Question 1

cutaneous innervation

What nerve runs in the most superior lateral portion of the anterior forearm?

Answer 1

Posterior antebrachial cutaneous nerve (from radial nerve (C6, C7, C8))

Question 2

cutaneous innervation

What nerve runs in the lateral portion of the anterior forearm?

Answer 2

Lateral antebrachial cutaneous nerve (C5, C6)

Question 3

cutaneous innervation

What nerve runs in the medial portion of the anterior forearm?

Answer 3

Medial antebrachial cutaneous nerve (C8, T1)

Question 4

cutaneous innervation

What nerve runs in the lateral portion of the wrist?

Answer 4

Superficial branch of the radial nerve (C6)

Question 5

cutaneous innervation

Which nerve runs in the medial portion of the wrist and palm?

Answer 5

Dorsal cutaneous branch of ulnar nerve (C8)

Question 6

Which nerves run in flexors and pronators of the forearm?

Answer 6

Median nerve and anterior interosseous nerve

Question 7

Which nerves run in extensors and supinators of the forearm?

Answer 7

Posterior interosseous nerve, deep branch of radial nerve, radial nerve

Question 8

The median nerve comes from the lateral and medial roots from the…

Answer 8

lateral and medial cords

Question 9

Which muscles does the median nerve innervate?

Answer 9

Wrist flexors and thenar muscles

Question 10

What branches come from the median nerve?

Answer 10

A deep branch: anterior interosseous nerve
A branch that supplies the hand: recurrent branches of the median nerve

Question 11

What reflex is associated with the median nerve?

Answer 11

No reflex

Question 12

How is the median nerve tested?

Answer 12

Performing wrist flexion

Question 13

Which muscles are in the superficial layer of the anterior forearm?

Answer 13

Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris

Question 14

Which muscle is in the intermediate layer of the anterior forearm?

Answer 14

Flexor digitorum superficialis

Question 15

Which muscles are in the deep layer of the anterior forearm?

Answer 15

Flexor digitorum profundus
Pronator quadratus
Flexor pollicis longus

Question 16

Pronator teres origin and insertion

Answer 16

Origin: humeral head: medial epicondyle
ulnar head: coronoid process
Insertion: midway along the lateral surface of the radius

Question 17

Innervation and spinal level of pronator teres

Answer 17

Median nerve (runs between humeral and ulnar heads) from C6 and mostly C7

Question 18

Action of pronator teres

Answer 18

Pronation of the forearm: rotation of radius on ulna, turning the palm medially and backward

Question 19

The pronator teres is recruited when?

Answer 19

When force or speed is needed

Question 20

Origin and insertion of flexor carpi radialis

Answer 20

Origin: medial epicondyle
Insertion: base of the 2nd and 3rd metacarpal

Question 21

Innervation and spinal levels of flexor carpi radialis

Answer 21

Median nerve from C6, mostly C7

Question 22

Actions of flexor carpi radialis

Answer 22

• Flexes 2nd carpometacarpal joint and the hand at wrist
• Radial deviation (abduction) with extensor carpi radialis
• Steadies the hand with flexor carpi ulnaris

Question 23

Origin and insertion of palmaris longus

Answer 23

Origin: medial epicondyle
Insertion: flexor retinaculum and the palmar aponeurosis

Question 24

Innervation and spinal levels of palmaris longus

Answer 24

Median nerve form C7, mostly C8

Question 25

Actions of palmaris longus

Answer 25

Tenses the palmar aponeurosis and weakly flexes the wrist

Question 26

Origin and insertion of flexor carpi ulnaris

Answer 26

Origin: medial epicondyle, medial aspect of the olecranon process, posterior border of the ulna Insertion: pisiform, hamate, base of the 5th metacarpal

Question 27

Innervation and spinal levels of flexor carpi ulnaris

Answer 27

Ulnar nerve from C7, C8

Question 28

Actions of flexor carpi ulnaris

Answer 28

* Flexes the 5th carpometacarpal joint * Adduction of the hand (ulnar deviation) with extensor carpi ulnaris * Steadies the wrist with the flexor carpi radialis

Question 29

Innervation and spinal levels of flexor digitorum superficialis

Answer 29

Median nerve from C7, mostly C8, T1

Question 30

Action of flexor digitorum superficialis

Answer 30

Flexes the proximal interphalangeal joints and the metacarpophalangeal joints

Question 31

Which muscle is considered the power grip muscle?

Answer 31

Flexor digitorum superficialis

Question 32

Origin and insertion of flexor digitorum profundus

Answer 32

Origin: upper 3/4ths of the anteromedial aspect of the ulna and ulnar half of the interosseous membrane Interion: its 4 tendons pass through the tendons of FDS at the bases of the middle phalanges to insert at the bases of the distal phalanges of digits 2-5

Question 33

Innervation and spinal levels of flexor digitorum profundus

Answer 33

Anterior interosseous nerve and ulnar nerve from mostly C8, T1

Question 34

Action of flexor digitorum profundus

Answer 34

Flexes the distal interphalangeal joints (DIPs) after the PIPs are flexed by FDS. Weak wrist flexor

Question 35

Which muscle is the gentle grip flexor?

Answer 35

Flexor digitorum profundus

Question 36

When all fingers are flexed into a fist, extensor tendons...

Answer 36

relax

Question 37

When only 1 finger is flexed, which tendon remains active?

Answer 37

Antagonistic extensor tendon

Question 38

What are the long flexor tendons in the palm?

Answer 38

Flexor carpi ulnaris, flexor carpi radialis, and flexor digitorum profundus (FDP)

Question 39

Origins and insertion of flexor pollicis longus

Answer 39

Origin: radial head: anterior surface of the radius and interosseous membrane humeral head: medial epicondyle and coronoid process of the ulna Insertion: base of the distal phalanx of the thumb

Question 40

Innervation and spinal levels of flexor pollicis longus

Answer 40

Anterior interosseous nerve from C7, mostly C8, T1

Question 41

Action of flexor pollicis longus

Answer 41

Flexes the interphalangeal joint and the metacarpophalangeal joint of the thumb

Question 42

Origin and insertion of pronator quadratus

Answer 42

Origin: distal 1/4th of the anterior surface of the ulna Insertion: distal 1/4th of the anterior surface of the radius

Question 43

Innervation and spinal levels of pronator quadratus

Answer 43

Anterior interosseous nerve from mostly C8, T1

Question 44

Action of pronator quadratus

Answer 44

Pronation of the forearm

Question 45

Which muscle is the principle pronator of the forearm?

Answer 45

Pronator quadratus

Question 46

What are the six entrapment sites of the median nerve?

Answer 46

1. Medial intermuscular septa 2. Pronator teres 3. FDS/FDP tunnel 4. Pronator quadratus - AIN 5. Carpal tunnel 6. FPB/APB