Upper Limb 4

Question 1

Name the muscles that extend and abduct or adduct the hand at the wrist joint

Answer 1

Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris

Question 2

What is the action of extensor carpi radialis longus and brevis on the wrist joint?

Answer 2

They both abduct and extend the wrist joint

Question 3

Apart from extending the wrist joint what other action is the extensor carpi radialis longus and brevis involved with , with the help of the flexor carpi ulnaris?

Answer 3

Clenching fist

Question 4

Name 3 muscles that extend the medial 4 digits

Answer 4

Extensor digitorum
Extensor indicis
Extensor digiti minimi

Question 5

Where does the extensor digitorum arise from?

Answer 5

Common extensor origin from the lateral epicondyle

Question 6

Where does the extensor digitorim end?

Answer 6

In the distal part of the forearm, its fleshy belly ends in a tendon which passes under cover of the extensor retinaculum, and divides into tendons for the fingers

Question 7

The extensor digitorum is an extensor of which joints?

Answer 7

Wrist and fingers

Question 8

Which nerve innervates all the muscles of the posterior compartment of the forearm?

Answer 8

Radial Nerve

Question 9

What is the innervation and action of extensor digitorum?

Answer 9

Innervation:
-Deep branch of Radial N (Post. Interosseous N)

Main action:
-Extend medial 4 digits at MCP joints

Question 10

What is the innervation and action of Extensor Carpi radials longus and brevis?

Answer 10

Innervation:

• Radial N. (Longus)
• Deep branch of Radial N. (Brevis)

Main action:
-Extend and abduct wrist joint

Question 11

WHat is the innervation and action of the Brachioradialis?

Answer 11

Innervation:
-Radial nerve

Main Action:

• Relatively weak flexion of elbow
• Maximal when forearm mid pronated

Question 12

What is the innervation and action of the extensor carpi ulnaris?

Answer 12

Innervation:
-Continuation of Deep Radial N (Post. interosseous N)

Main action:
-Extends and adducts wrist

Question 13

What is the innervation and action of the supinator?

Answer 13

Innervation:
-Deep branch of Radial N

Main action:
-Supinates forearm

Question 14

What is the innervation and action of the extensor digiti minimi?

Answer 14

Innervation:
-Deep branch of Radial N. (Post Interosseous N)

Main Action:
-Extends 5th finger at MP joint

Question 15

Where does the supinator muscle lie?

Answer 15

Envelops the neck and the proximal part of the shaft of the radius, covering it completely, except on its medial side

Question 16

What is the nerve supply to the supinator muscle?

Answer 16

Deeb branch of radial N

Question 17

What two nerves does the radial nerve divide into in the cubital fossa?

Answer 17

Superficial and deep branches

Question 18

What is the other name for the deep branch of the radial nerve?

Answer 18

Posterior interosseous nerve

Question 19

What is the function of the superficial branch of the radial nerve?

Answer 19

Sensory and distributed to skin on the dorm of the hand

Question 20

The main superficial veins of the upper limb originate where?

Answer 20

In the subcutaneous tissue on the dorsum of the hand

Question 21

What are synpvial cysts/ ganglions?

What, Where, WHat do they communicate with?

Answer 21

Non-tender cystic growth appears most commonly on the dorsum of hand.

Most often they communicate with the synovial sheaths covering the tendons

Question 22

What deep muscles of the forearm act on the thumb?

How do they form the border of the anatomical snuffbox?

Answer 22

Abductor Pollicis Longus
Extensor Pollicis Brevis
Extensor Pollicis Longus

The tendon of Abductor Pollicis Longus and Extensor Pollicis Brevis bound the anatomical snuff box laterally

The tendon of Extensor Pollicis Longus bounds it medially

Question 23

What two carpal bones can you feel in the anatomical snuff box?

Answer 23

Scaphoid

Trapezium

Question 24

Which artery lies on the floor of the snuff box?

Answer 24

Radial Nerve

Question 25

Which nerve innervates extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus?

Answer 25

Deep branch of Radial N

Post. interosseous N

Question 26

What is the action of Extensor pollicis longs?

Answer 26

Extends wrist joint

Extends distal phalanx of thumb

Question 27

What is the action of Extensor pollicis brevis?

Answer 27

Extends wrist joint

Extends proximal phalanx of thumb

Question 28

What is the action of Abductor pollicis longus?

Answer 28

Abducts thumb

Question 29

Four extensor digitorum tendons flatten to form extensor expansions (dorsal expansion or hood).

Explain the structure of these extensor expansions

Answer 29

Triangular aponeurosis that wraps around the dorm and sides of a head of the metacarpal and base of the proximal phalanx

Question 30

List the muscles that attach to the extensor expansion

Answer 30

Dorsal and Palmar Interossei
Lumbrical
Extensor Digitorum