Extensor Forearm and Hand

Question 1

What is the blood and nerve supply of the posterior (extensor) compartment of the forearm?

Answer 1

Blood: radial and interosseous arteries
Nerve: radial nerve and branches

Question 2

What are the 6 superficial muscles of the extensor compartment?

Answer 2

Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris

Question 3

What group of muscles is the brachioradialis in, what is its nerve supply, and what is its action?

Answer 3

in superficial group of muscles
supplied by radial nerve
flexes forearm

Question 4

What group of muscles is the extensor carpi radialis longus in, what is its nerve supply, and what is its action?

Answer 4

Superficial muscles of extensor compartment
supplied by radial nerve
extends and abducts hand at wrist joint

Question 5

What group of muscles is the extensor carpi radialis brevis in, nerve supply, action?

Answer 5

superficial muscles of extensor compartment
deep branch of radial nerve
extends and abducts hand at wrist joint

Question 6

Extensor digitorum:
Group of muscles that it is in?
Nerve supply? Action?

Answer 6

superficial muscles of extensor compartment
posterior interosseous branch of radial nerve
extends the fingers, knuckles, and hand at wrist joint

Question 7

Extensor digiti minimi:
Group of muscles?
Nerve supply?
Action?

Answer 7

Superficial muscles of extensor compartment
Posterior interosseous branch of radial nerve
extends the little finger

Question 8

Extensor carpi ulnaris:
Group of muscles that it is in?
nerve supply? action?

Answer 8

superficial muscles of extensor compartment
posterior interosseous branch of radial nerve
extends and adducts hand at wrist joint

Question 9

What are the 5 deep muscles of the extensor compartment?

Answer 9

Supinator
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Extensor indicis

Question 10

Supinator:
what group of muscles in extensor compartment
nerve
action

Answer 10

Deep muscles of extensor
radial nerve
supinates forearm

Question 11

Abductor pollicis longus
what group of muscles in extensor compartment
nerve
action

Answer 11

deep muscles of extensor compartment
radial nerve
abducts and extends thumb

Question 12

Extensor pollicis brevis
group of muscles in extensor compartment
nerve
action

Answer 12

deep muscles of extensor
radial nerve
extends thumb, knuckle, wrist

Question 13

Extensor pollicis longus
group of muscles in extensor compartment
nerve
action

Answer 13

deep muscles of extensor
radial nerve
extends thumb, knuckle, wrist

Question 14

Extensor indicis
group of muscles in extensor compartment
nerve
action

Answer 14

deep muscles of extensor
radial nerve
extends index finger, knuckle, wrist

Question 15

What tendon is inflammed in ‘tennis elbow’? What is this medically known as?
Where is the pain in patients?

Answer 15

The common extensor tendon of the lateral epicondyle is inflammed
presents with pain in lateral aspect of elbow

Question 16

What is the main nerve of the posterior compartment?

What two muscles does it descend between (club sandwich)?

Answer 16

Radial nerve**

Descends between brachialis and brachioradialis

Question 17

What does the radial nerve branch into, and where?

Answer 17

Radial nerve crosses in front of the lateral epicondyle and divides into superficial branch (sensory) and deep branch (motor)

Question 18

What branch of the radial nerve pierces the supinator muscle, and what does it emerge as?

Answer 18

The deep branch pierces the supinator

emerges as posterior interosseous nerve (same nerve, new name)

Question 19

What is the apex and base of the palmar aponeurosis?

Answer 19

Apex = distal border of flexor retinaculum and receives insertion of palmaris longus tendon
Base = divides at base of fingers into 4 slips which subdivide into 2 addition slips to attach to fibrous flexor sheath and deep transversal metacarpal ligament

Question 20

What is Dupuytren’s contracture?

Answer 20

Localized thickening and contracture of palmar aponeurosis

Question 21

Describe the arrangement of the 4 tendons of the flexor digitorum superficialis and the tendons of the flexor digitorum profundus in the carpal tunnel.

Answer 21

The 4 tendons of the flexor digitorum superficialis are arranged in anterior and posterior rows:
tendons for finger 3 and 4 are superficial, 2 and 5 are deep
Tendons of profundus are in the same plane and are posterior to those of the digitorum superficialis

Question 22

How does the median nerve pass through the flexor retinaculum?

Answer 22

Passes beneath it in a restricted space

Question 23

What is housed within the fibrous flexor sheaths?

Answer 23

The sheaths form a tunnel for the long flexor tendons

Question 24

What are the 3 thenar muscles of the hand? What nerve supplies all 3?

Answer 24

Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis

All supplied by the recurrent branch of median nerve

Question 25

What kind of hand muscle is the abductor pollicis brevis, what is its nerve supply and what is its action?

Answer 25

Is one of the thenar muscles supplied by recurrent branch of median nerve abducts the thumb

Question 26

What kind of hand muscle is the flexor pollicis brevis, what is its nerve supply and what is its action?

Answer 26

is one of the thenar muscles supplied by the recurrent branch of median nerve flexes thumb

Question 27

What kind of hand muscle is the opponens pollicis, what is its nerve supply, and what is its action?

Answer 27

is one of the thenar muscles supplied by recurrent branch of median nerve opposes thumb

Question 28

What is the only muscle in the adductor compartment of the hand, what is its nerve supply**, and what is its action?

Answer 28

Adductor pollicis supplied by deep branch of ulnar nerve (it adducts the thumb, and remember that adduct = ulnar) adducts the thumb

Question 29

What are the 3 hypothenar muscles of the hand? What nerve supplies all 3?

Answer 29

Abductor digiti minimi Flexor digiti minimi opponens digiti minimi All supplied by deep branch of ulnar nerve

Question 30

What type of hand muscle is the abductor digiti minimi what is its nerve supply, and what is its action?

Answer 30

Is a hypothenar muscle deep branch of ulnar nerve abducts the 5th (pinky) finger

Question 31

What type of hand muscle is the flexor digiti minimi, what is its nerve supply, and what is its action?

Answer 31

is a hypothenar muscle deep branch of ulnar nerve flexes the 5th (pinky) finger

Question 32

What type of hand muscle is the opponens digiti minimi, what is its nerve supply, and what is its action?

Answer 32

is a hypothenar muscle deep branch of ulnar nerve opposes the 5th (little) finger and deepens the palm

Question 33

What nerve supplies the lumbrical muscles** and what is their action?

Answer 33

1st and 2nd lumbricals are supplied by the median nerve 3rd and 4th by ulnar nerve Flex metacarpophalngeal joints (the knuckle) and extends the interphalangeal joint

Question 34

What hand muscles are supplied by the median nerve? What hand muscles are supplied by the ulnar nerve?

Answer 34

Only the 3 thenar muscles and the 1st and 2nd lumbricals are supplied by median nerve All the rest are supplied by the ulnar nerve

Question 35

What are the 2 types of interosseous muscles, what are they supplied by, and what are their actions?

Answer 35

There are palmar and dorsal interosseous muscles They are all supplied by the deep branch of ulnar nerve Flex metacarpophalangeal joints, extend interphalangeal joints The palmar interosseous muscles also adduct fingers towards center of 3rd finger (PAD) The dorsal interosseous muscles also abduct fingers towards center of 3rd finger (DAB)

Question 36

What tendon passes through the tunnel created by the superficialis tendon?

Answer 36

The tendons of the flexor digitorum profundus

Question 37

What provides the blood supply for each tendon?

Answer 37

Each tendon has a vincula which provides a route for vessels to reach the tendon

Question 38

What is formed by the long extensor tendons when they broaden over the knuckles?

Answer 38

forms the dorsal extensor expansion

Question 39

Which artery makes the superficial palmar arch? Which artery makes the deep palmar arch?**

Answer 39

The superficial palmar arch is made by the ulnar artery | The deep palmar arch is made by the radial artery

Question 40

Between what 2 muscles does the deep ulnar branch of the ulnar artery pass between?

Answer 40

Passes between the abductor digiti minimi and the flexor digiti minimi

Question 41

With regard to the pisiform and the ulnar nerve, how does the ulnar artery enter the hand?

Answer 41

It enters superficial to flexor retinaculum | enters lateral to ulnar nerve and pisiform bone (so closer to the thumb)

Question 42

What is supplied by the superficial palmar arch?**

Answer 42

Supplies branches to all sides of the fingers except the: thumb radial side of index finger

Question 43

What are the two branches given off of the radial artery before it continues as the deep palmar arch?

Answer 43

Radialis indicis artery (supplies lateral side of index finger) Princeps pollicis artery (supplies two sides of the thumb)

Question 44

What arteries make up the superficial palmar arch? | What arteries make up the deep palmar arch?

Answer 44

Superficial palmar arch = ulnar artery. completed laterally by the superficial palmar branch of radial artery Deep palmar arch = radial artery. completed medially by the deep branch of the ulnar artery

Question 45

What is included in the carpal tunnel?

Answer 45

The 8 flexor tendons of the flexor digitorum superficialis and flexor digitorum profundus The median nerve also passes through the carpal tunnel

Question 46

What is the tendon that runs in its own synovial sheath in the carpal tunnel?

Answer 46

The flexor pollicis longus tendon

Question 47

What is the distribution of the motor fibers of the median nerve in the palm? What is (generally) the distribution for sensory?

Answer 47

Median nerve supplies the thenar muscles and the first 2 lumbrical muscles Supplies sensory for the lateral palm (and including fingertips/nailbed for thumb, index, middle, adn half of ring finger)

Question 48

What is the distribution of motor fibers of the ulnar nerve of the palm? What is (generally) the distribution for sensory fibers?

Answer 48

``` Ulnar nerve supplies motor fibers to: hypothenar muscles 3rd and 4th lumbricals adductor pollicus palmaris brevis all interossei muscle Supplies sensory to the medial palm and medial back of hand ```

Question 49

What are the anterior and posterior borders of the anatomical snuff box?

Answer 49

Anterior: abductor pollicis longus and extensor pollicis brevis tendons Posterior: extensor pollicis longus tendons

Question 50

What are the contents of the anatomical snuff box?

Answer 50

Terminal parts of the superficial radial nerve (superifical = sensory, so the area on the hand that corresponds to radial cutaneous innervation is right around snuffbox) Radial artery and branches Scaphoid bone