Extensor Forearm Ch. 13

Question 1

General considerations: extensor forearm

Answer 1

• most attach to lateral epicondyle as proximal attachment
• act on distal phalanx: extension of fingers and wrist
• act carpus: extension, adduction and abduction
• act on thumb: extend and abduction
• assist in supination of hand by actin on the radius
• ALL are innervated by RADIAL N.

Question 2

Superficial Extensor layer

Answer 2

extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris

Question 3

Extensor Carpi Radialis Longus

Answer 3

A: extends and abducts hand
N: Radial n.

Question 4

Extensor Carpi Radialis brevis

Answer 4

“giving the birdie”
A: extends and assists in abduction of the hand
N: radial N.

Question 5

Extensor digitorum

Answer 5

A: extends digits 2-5 and assists in extension of the hand
N: radial n.
“more gross control”

Question 6

Intertendinous connections

Answer 6

obliquely oriented connective tissue bands that unite tendons of the extensor digitorum as the cross the dorsum of the hand

Question 7

Extensor Hood

Answer 7

“extensor expansion” = distal attachment of of extensor digitorum

• span dorsum of proximal, middle and distal phalanges
• provides means of distributing force exerted by extensor digitorum across MP and IP joints and and provides site of attachment for some muscles (lumbricals, interossei)

Question 8

Extensor digiti minimi

Answer 8

A: extension of fifth digit
N: radial n.

Question 9

Extensor carpi ulnaris

Answer 9

A: extends and adducts hand
N: radial n.

Question 10

Extensor Deep Layer

Answer 10

Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, supinator

Question 11

Abductor Pollicis Longus

Answer 11

“holding a ball” - takes thumb out of plain of palm
A: abducts thumb and wrist, assists with extension of the thumb
N: radial N.

Question 12

Extensor Pollicis brevis

Answer 12

A: extends proximal phalanx of thumb and first metacarpal
N: radial n.

Question 13

Extensor Pollicis longus

Answer 13

A: extends the thumb
N: radial N.

Question 14

Anatomical snuff box:

Answer 14

tendons of abductor pollicis longus, extensor policis brevis, and extensor pollicis longus
- scaphoid bone forms the floor

Question 15

extensor indicis

Answer 15

“oh no you don’t” muscle
A: extends index finger
N: Radial N.

Question 16

extensor retinaculum

Answer 16

encloses all muslces of extensor forearm that pass over the carpus

Question 17

supinator

Answer 17

A: supinates the hand
N: radial n.