144 - Muscles of the Forearm

Question 1

Number of muscles of the forearm

Answer 1

Eight

Question 2

Muscles of the anterior compartment of the forearm (superficial) 
1
2
3
4
5

Answer 2

1) Pronator teres
2) Flexor carpi radialis
3) Palmaris longus
4) Flexor digitorum superficialis
5) Flexor carpi ulnaris

Question 3

Names of forearm flexors that have more than one origin
1
2
3

Answer 3

1) Pronator teres
2) Flexor digitorum superficialis
3) Flexor carpi ulnaris

Question 4

Insertions of flexor digitorum superficialis
1
2

Answer 4

1) Proximal ulna, CFO, oblique line of the anterior aspect of the radius
2) Tendons run across wrist, carpometacarpal joints, inserts into middle phalanx

Question 5

Flexor carpi radialis and ulnaris

Answer 5

Flexors that run on the ulnar or radial sides, join to the wrist.
Attach to base of metacarpals.
NO action on fingers

Question 6

Meaning of ‘carpi’

Answer 6

To the wrist

Question 7

Where does flexor carpi radialis insert?

Answer 7

Base of the 2nd and 3rd metacarpals (radial two fingers).

Question 8

Where does flexor carpi ulnaris insert?

Answer 8

Inserts into thepisiform bone.
Pisiform has a ligament that attaches to the base of the 5th metacarpal
(so FCU functionally attaches to 5th metacarpal)

Question 9

Palmaris longus insertion

Answer 9

Doesn’t insert into any bone.

Vestigial. Absent in ~15% of people

Question 10

Three deep muscles of anterior forearm

Answer 10

1) Flexor pollicis longus
2) Flexor digitorum profundis
3) Pronator quadratus

Question 11

Arrangement of insertions of flexor digitorum superficialis and profundis

Answer 11

As FDS splits to insert into base of each middle phalanx, FDP travels between split tendons.

Question 12

Only tendon crossing distal interphalangeal joint

Answer 12

Flexor digitorum profundis

Question 13

Deep thumb flexor

Answer 13

Flexor pollicis longus

Question 14

Where does flexor pollicis longus originate?

Answer 14

Distal shaft of the radis

Question 15

Where does flexor pollicis longus insert?

Answer 15

Base of distal phalanx (of thumb).

Question 16

What makes the roof of the carpal tunnel?

Answer 16

Flexor retinaculum

Question 17

Forearm flexors that don’t really travel through carpal tunnel

Answer 17

Flexor carpi radialis (there is a split in flexor retinaculum that FCR travels through).

Flexor carpi ulnaris (attaches to pisiform, which has a ligament attaching to 5th metacarpal)

Question 18

Carpal tunnel syndrome

Answer 18

If there is swelling of tendons in carpal tunnel, there is little give in flexor retinaculum, and median nerve can be compressed

Question 19

Muscles of the posterior forearm

1 - 9

Answer 19

1) Bracioradialis
2) Extensor carpi radialis longus
3) Externsor carpi radialis brevis
4) Extensor digitorum
5) Extensor digitorum minimi
6) Extensor carpi ulnaris
7) Abductor pollicis longus
8) Extensor pollicis brevis
9) Extensor pollicis longus

Question 20

Common extensor origin

Answer 20

Lateral epicondyle.

A lateral epicondylar ridge (lateral supracondylar ridge) is a part of the humerus leading to the lateral epicondyle.

Question 21

Where do the radialis forearm extensors originate?

Answer 21

Brachioradialis and extensor carpi radialis longus attach to lateral supracondylar ridge.
Extensor carpi radialis brevis attaches to lateral epicondyle.

Question 22

Where do the radialis forearm extensors run?

Answer 22

Down lateral compartment of posterior forearm

Question 23

Path of brachioradialis

Answer 23

Attaches to radius, just above radial styloid.

Doesn’t cross wrist.

Question 24

Role of brachioradialis

Answer 24

Elbow flexion

Question 25

Path of flexor carpi radialis longus and brevis

Answer 25

ECRL and ECRB attach to base of 2nd and 3rd metacarpals.

Extensor equivalents of flexor carpi radialis

Question 26

Effect of contracting both extensor carpi radialis longus and brevis and flexor carpi radialis

Answer 26

Radial deviation (these muscles cancel out respective flexion and extension of wrist)

Question 27

Most posterior muscles of the posterior forearm
1
2
3

Answer 27

1) Extensor digitorum
2) Extensor digitorum minimi
3) Extensor carpi ulnaris

Question 28

Relationship between extensor digitorum and extensor digitorum minimi

Answer 28

Share common origin.

Extensor digitorum minimi splits form extensor digitorum to attach to little finger

Question 29

Where do Extensor digitorum, Extensor digitorum minimi

and Extensor carpi ulnaris originate?

Answer 29

Common extensor origin

Question 30

Muscles forming the medial border of anterior forearm

Answer 30

Extensor carpi ulnaris and flexor carpi ulnaris

Question 31

Extensor carpi ulnaris role

Answer 31

Attaches to base of 5th metacarpal.
Equivalent of flexor carpi ulnaris.
Extends wrist.

Question 32

Role of extensor digitorum and ED minimi

Answer 32

Attach to fingers, extend fingers.

Question 33

Three thumb muscles of posterior forearm

Answer 33

Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus

Question 34

Structure to which three deep posterior forearm muscles attach

Answer 34

Thumb

Question 35

Path of extensor pollicis longus

Answer 35

Runs towards the posterior hand until the dorsal tubercle at the back of the radius, then runs towards thumb.

Question 36

Where does extensor pollicis longus attach?

Answer 36

Base of the distal phalanx of the thumb

Question 37

Deep posterior forearm muscles not affecting the thumb

Answer 37

1) Aconeus
2) Supinator
3) Extensor indicis

Question 38

Role of extensor indicis

Answer 38

Extra extensor of index finger

Question 39

Groups of posterior forearm muscles

Answer 39

Four groups of three

Question 40

Forearm supinator muscles

Answer 40

Biceps brachii and supinator

Question 41

Extensor tendons at the wrist

Answer 41

Travel underneath extensor retinaculum

Question 42

Role of extensor digitorum

Answer 42

Forms an ‘extensor hood’ over the back of the fingers.
Forms three tendinous slits.
Middle slit inserts into middle phalanx.
Two outer slits insert into distal phalanx.

Sort of equivalent to flexor carpi ulnaris and radialis splitting.