Forearm Extensors

Question 1

Two groups of Forearm extensors (All posterior)
Origins?
Innervation?

Answer 1

Superficial (BR, ECRL, ECRB, EF, EDM, ECU, Anconeous) - Origin at lateral epicondyle
Deep:
Supinator, APL, EPB, EPL, EI) Origin elsewhere - Not at lateral epo
Innervation: Radial nerve

Question 2

Brachioradialis origin

Answer 2

Proximal 2/3s of supracondylar ridge

Question 3

Brachioradialis insertion

Answer 3

Lateral surface of distal end of radius

Question 4

Brachioradialis innervation

Answer 4

Radial

Question 5

Brachioradialis blood supply

Answer 5

Radial recurrent artery

Question 6

Brachioradialis action

Answer 6

Flexion of the forearm

Question 7

Muscles that extend and abduct or adduct the hand at the wrist joint: (3)

Answer 7

ECRB, ECRL, ECU

Question 8

Muscles that extend the medial 4 digits: (3)

Answer 8

Extensor digitorum, extensor indicis, extensor digiti minimi

Question 9

Muscles that extend or abduct the thumb: (3)

Answer 9

Abductor pollicis longus, extensor policis brevis, extensor pollicis longus

Question 10

Extensor tendons are held in place by? Prevents? Covered by?

Answer 10

• Extensor retinaculum
• Bowstringing at the tendons that pass over the dorsum of the wrist
• Covered by synovial tendons sheaths that reduce friction

Question 11

Four superficial extensors are attached by?

Answer 11

Lateral epicondyle

Question 12

Which muscle is the “drinking muscle”?

Answer 12

Brachioradialis

Question 13

Extensor capri radialis longus origin

Answer 13

Lateral supracondylar ridge of humerus, lateral intramuscular septum, and lateral epicondyle

Question 14

Extensor capri radialis longus insertion

Answer 14

Base of 2nd metacarpal

Question 15

Extensor capri radialis longus innervation

Answer 15

Radial nerve

Question 16

Extensor capri radialis longus action

Answer 16

Extension of hand at wrist and radial deviation

Question 17

Extensor carpi radialis brevis innervation

Answer 17

Radial nerve

Question 18

Extensor carpi radialis brevis action

Answer 18

Extension of hand at wrist

Question 19

Extensor digitorum insertion

Answer 19

Middle and distal phalanges

Question 20

Extensor digitorum action

Answer 20

Extend all joints of fingers

Question 21

When can Extensor digitorum not end all joint of fingers?

Answer 21

Can only extend IP joints when MP joints are not hyperextended

Question 22

Extensor Digiti Minimi, digitorum and carpi radialis brevis origin

Answer 22

Lateral epicondyle, intermuscular septa and antebrachial fascia

Question 23

Extensor carpi ulnaris origin

Answer 23

Lateral epicondyle and more than 1/2 of proximal posterior border of ulna

Question 24

Extensor carpi ulnaris insertion

Answer 24

Base of metacarpal of 5th digit

Question 25

Extensor carpi ulnaris innervation

Answer 25

Radial

Question 26

Extensor carpi ulnaris action

Answer 26

Aids in extension and ulnar deviation of hand at wrist

Question 27

Extensor digitorum origin

Answer 27

Lateral epicondyle, intermuscular septa and antebrachial fascia

Question 28

Extensor carpi radialis origin

Answer 28

Lateral epicondyle, intermuscular septa and antebrachial fascia