Forearm--Severson - Sheet1

Question 1

Musculocutaneous nerve

Answer 1

Begins from lateral chord of brachial plexus opposite of the inferior boarder of the pectoralis minor, pierces the coacobrachialis, and continues distally between the biceps and the brachialis. Supplies 1) coracobrachialis 2) biceps brachii 3) brachialis muscle. Once it emerges lateral to the biceps, it is called the lateral cutaneous nerve of the forearm.

Question 2

Ulnar nerve

Answer 2

Arrises from the medial chord (part of M). Has not branches in the axilla or arm. Inervates only the Flexor carpi ulnaris.

Question 3

Radial nerve

Answer 3

Supplies all muscles in the posterior compartment of the arm and forearm. Begins from posterior chord. Innervates 1) long and medial heads of the tricepts 2) medial head of the tricetps, then divides into deep branch (muscular) and superficial (sensory) branch of the radial nerve.

Question 4

Median nerve

Answer 4

Arrises from Medial chord. Has no braches in the axilla or arm. Runs distally in the arm on the lateral side of the brachial artery then crosses to the medial side and contacts the brachialis.

Question 5

Brachiordialis muscle

Answer 5

The brachioradialis attaches proximally to the lateral supracondylar ridge of the humerus and distally to the radius, proximal to the styloid process. The brachioradialis muscle is innervated by the radial nerve proximally.

Question 6

Superficial and deep radial nerve branches

Answer 6

The radial nerve divides into a superficial and deep branch immediately after piercing the lateral intermuscular septum. The superficial branch is sensory and continues distally beneath the brachioradialis muscle, while the deep branch of the radial nerve pierces the supinator muscle and supplies motor fibers to extensor muscles of the forearm.

Question 7

Deep radial nerve

Answer 7

the deep branch of the radial nerve pierces the supinator muscle and supplies motor fibers to extensor muscles of the forearm.

Question 8

Flexor retinaculum (transverse carpal ligament)

Answer 8

The flexor retinaculum is a thickening of the deep fascia of the forearm and serves to hold the flexor muscles in the carpal tunnel.

Question 9

Carpal tunnel

Answer 9

Transverse carpel ligament or flexor retinaculum - forms the roof of the carpal tunnel. Carpal tunnel syndrome arrises from any lesion that reduces the size of the carpal tunnel, or increases the size of some of the nine structures or their coverings that pass through it.

Question 10

Pronator teres muscle

Answer 10

The pronator teres takes origin from the medial epicondyle of the humerus (humeral head) as well as from the ulna (ulnar head). The muscle attaches distally on the radius and serves to pronate (and flex) the forearm. Median Nerve

Question 11

Flexor carpi radialis muscle

Answer 11

The flexor carpi radialis continues distally to attach to the base of the 2nd metacarpal.
Supplied by the median nerve

Question 12

Palmaris longus muscle

Answer 12

The palmaris longus attaches distally to the palmar aponeurosis. Supplied by the median nerve

Question 13

Flexor digitorum superficialis muscle

Answer 13

The flexor digitorum superficialis is sometimes placed in an intermediate layer because it is below the other muscles. It takes origin from the medial epicondyle, the coronoid process of the ulna, and the radius. It inserts on the middle phalange of the medial four digits (fingers).
Supplied by the median nerve

Question 14

Flexor carpi ulnaris muscle

Answer 14

The flexor carpi ulnaris attaches distally to the base of the 5th metacarpal. Supplied by the ulnar nerve.

Question 15

Flexor digitorum profundus muscle

Answer 15

The flexor digitorum profundus takes origin from the proximal portions of the anterior surface of the ulna and interosseous membrane. Note that the Median nerve innervates the Flexor pollicis longus, Pronator quadratus, and the radial half of the Flexor digitorum profundus. The ulnar half of the Flexor digitorum profundus is innervated by the Ulnar nerve.

Question 16

Flexor pollicis longus muscle

Answer 16

The flexor pollicis longus takes origin from the anterior radial surface and adjacent interosseous membrane and attaches distally on the terminal phalanx of the thumb. Median Nerve.

Question 17

Pronator quadratus muscle

Answer 17

The pronator quadratus attaches the distal radius and ulna, and serves to pronate the radius. Both the FPL and pronator quadratus are innervated by the median nerve.

Question 18

Radial artery

Answer 18

The brachial artery divides in the cubital fossa into the ulnar and radial arteries. The radial artery goes to the radial side and runs under the brachioradialis with the superficial branch of the radial nerve. It is present in the region of the wrist lateral to the tendon of flexor carpi radialis. It is a common site for taking the pulse.

Question 19

Ulnar artery

Answer 19

The ulnar branch of the brachial artery passes posteriorly to go deep to the superficial muscles of the forearm. A number of branches arise from the artery, a major one being the common interosseous artery. The ulnar artery passes between the superficial and deep muscles to join the ulnar nerve as they pass distally to enter the palm of the hand.

Question 20

Common interosseous artery

Answer 20

common interosseous artery arrises from a proximal branch of the ulnar artery. The common interosseous artery divides into an anterior and posterior interosseous artery.

Question 21

Anterior and posterior interosseous arteries

Answer 21

The common interosseous artery divides into an anterior and posterior interosseous artery.

Question 22

Pronator syndrome

Answer 22

Note that the median nerve passes between the two heads of origin of the pronator teres, and may become compressed by hypertrophy of the muscle, causing pain in the proximal forearm.