Lab 6: Forearm & Hand

Question 1

Tenosynovitis

Answer 1

Inflamed synovial sheath

Question 2

Carpal Tunnel arches

Answer 2

Formed by two archs of wrist bone:
(proximal arch) scaphoid and pisiform
(distal arch) trapezium and hook of Hamate

Question 3

Muscles & Nerve traversing the Carpal Tunnel

Answer 3

Flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus. Median nerve

Question 4

Flexor nerves & muscles that do NOT pass through Carpal Tunnel

Answer 4

Flexor carpi ulnaris, palmaris longus, and the ulnar nerve do not pass through the carpal tunnel

Question 5

Carpal Tunnel Syndrome

Answer 5

Relatively common condition characterized by pain a/o parathesia on palmar surface of hand. It affects the lateral 3.5 digits. There is a loss of strength and atrophy of thenar muscles and precise thumb movements

Question 6

Cubital Tunnel Syndrome

Answer 6

Ulnar nerve becomes entrapped between the humeral and ulnar heads of the flexor carpi ulnaris (CUBITAL TUNNEL). Symptoms: weakened wrist flexion, weakened grip and tingling. Affects medial 1.5 fingers (1/2 of 4th digit, 5th digit)

Question 7

Cause of Compartment Syndrome/Volkmann’s ischemic contracture

Answer 7

Loss of arterial supply to flexor compartment of forearm

Question 8

Guyon’s Canal

Answer 8

Found on palmar surface of hand where ulnar nerve traverses through, bound by the pisiform, hook of Hamate and flexor retinaculum.

Question 9

Guyon’s Canal Syndrome

Answer 9

Entrapment of the ulnar nerve as it passes through Guyon’s Canal. Symptoms: numbness, pins & needles in 5th and 1/2 of 4th digit, impaired motor function.

Question 10

Superficial posterior forearm muscles (6)

Answer 10

(lateral to medial) 
brachioradialis 
extensor carpi radialis longus
extensor carpi radialis brevis
extensor digitorum
extensor digiti minimi
extensor carpi ulnaris

Question 11

Deep/Intrinsic Posterior Forearm muscles (6)

Answer 11

Aconeus
Supinator
(Snuff box): abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus
Extensor indicis

Question 12

Superficial Anterior (Palmar) Forearm muscles (4)

Answer 12

PFPF: pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris

Question 13

Deep Anterior (Palmar) Forearm muscles (4)

Answer 13

Flexor digitorum superficialis
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus

Question 14

All (except 2) anterior forearm muscles are innervated by which nerve? Which 2 muscles are the exception and which nerve are they innervated by?

Answer 14

Median nerve. 2 exceptions are the flexor digitorum profundus (medial 1/2) and flexor carpi ulnaris. These two are innervated by the ulnar nerve

Question 15

What action does the Supinator muscle perform? Which anterior muscle performs the opposite action?

Answer 15

The supinator supinates the hand. Pronator teres does the opposite (pronates hand)

Question 16

What is tennis elbow?

Answer 16

Aka lateral epicondylitis, it is caused by inflammation of the extensor carpi radialis brevis muscle from repeated (and forceful) wrist extension

Question 17

Anterior Interosseous Syndrome

Answer 17

Entrapment of the anterior interosseus nerve. Symptoms: weakened pronation (pronator quadratus) and inability to flex DIP joints of 2nd, 3rd digits (flexor digitorum profundus) and joint of thumb (flexor pollicis longus)

Question 18

Proximal Carpal Bones

Answer 18

(lateral to medial) scaphoid, lunate, triquetrum, pisiform

Question 19

Distal Carpal Bones

Answer 19

(lateral to medial) trapezium, trapezoid, capitate, hamate

Question 20

Hand compartments

Answer 20

5 compartments: Central, interosseous, hypothenar, thenar and adductor

Question 21

Central hand compartment

Answer 21

Made up of the lumbricals, flexor tendons and the palmar arch

Question 22

Interosseous hand compartment

Answer 22

Palmar interossei (3-4), deep branch of ulnar nerve, dorsal interossei (4)

Question 23

Hypothenar hand compartment

Answer 23

Abductor digiti minimi, flexor digiti minimi, opponens digiti minimi, deep branch of ulnar nerve

Question 24

de Quervain’s Syndrome

Answer 24

Inflammation of the tendons connecting the abductor pollis longus and extensor pollicis brevis (2/3 snuff box extensors) due to repetitive movements. Symptoms: tenderness, lateral wrist pain

Question 25

Scaphoid Fracture

Answer 25

Most frequently fractured carpal bone, usually resulting from falling on outstretched hand. Not detectable on x-ray for 2-3 weeks

Question 26

Anatomical Snuffbox

Answer 26

On posterolateral side of wrist. Contains tendons of:
-abductor pollicis longus
-extensor pollicis brevis
-extensor pollicis longus
And: radial artery, radial nerve (superficial branch), cephalic vein

Question 27

Antebrachial Fascia

Answer 27

Found at wrist posterior (extensor retinaculum) and anterior (palmar carpal ligament and flexor retinaculum)

Question 28

Dupuytren’s Contracture

Answer 28

Pathological thickening, fibrosis and shortening of the fibers of the palmar aponeurosis. Results in continuous flexion of the MCP and DIP joint

Question 29

Lumbricals

Answer 29

Located in central compartment, originate from tendons of flexor digitorum profundus and insert to the extensor expansions on digits 2-5. Function: extend PIP and DIP joints, flex MCP joint

Question 30

Thumb nerve root innervation

Answer 30

C6 nerve root (radial nerve over snuffbox; median nerve at distal portions and palmar surface)

Question 31

Nerve root innervation of digits 2-5

Answer 31

Digits 2-3: C7 (median nerve)

Digits 4-5: C8 (ulnar nerve)