Myology of the Wrist and Hand

Question 1

Flexor Carpi Radialis

Answer 1

O- Medial epicondyle via common flexor tendon
I- Palmer surface bases of 2nd and 3rd metacarpal
N- Median Nerve C6-C8
A- Flexion, synergist for radial deviation

Question 2

Flexor Carpi Ulnaris

Answer 2

O- Medial epicondyle via common flexor tendon
I- Pisiform, hook of hammate, 5th metacarpal
N- Ulnar Nerve C7-8, T1
A- Flexion at wrist, ulnar deviation

Question 3

Palmaris Longus

Answer 3

O- Medial epicondyle (flexor tendon)
I- Palmer aponeurosis/ Flexor retinaculum
N- Median Nerve C7-8,
A- Tense the palmer fascia, flex wrist (weak)

Question 4

Palmer Aponeurosis

Answer 4

Triangular in shape.
Apex is continous with the Palmaris Longus tendon.
Fibers radiate to extensions at base of digits.
Key role in protection.

Question 5

Flexor Digitorum Profundus

Answer 5

O- Anterior surface of ulna and interosseous membrane.
I- 4 tendons- distal 2-4 phalanges
N- 2-3 Median Nerve C7-8, T1
4-5 Ulnar Nerve C7-8, T1
A- Flexes 2-5 fingers at MCP + distal IP joints, assists to flex wrists

Contained within fibrous sheaf after exiting the carpal tunnel.

Question 6

Flexor Digitorum Superficialis

Answer 6

O- Medial epicondyle, ulna collateral ligament, coranoid process of ulna and shaft of radius.
I- 4 tendons- middle 2-4 phalanges
N- Median Nerve C7-8, T1
A- Flexes proximal interphalangeal joint, flexes 2-5 MCP joints

Contained within fibrous sheaf after exiting the carpal tunnel.

Question 7

Extensor Carpi Radialis Longus

Answer 7

O- Lower 1/3 supracondyler ridge
I- Base of 2nd metacarpal
N- Radial Nerve C6-8
A- Extends wrist, synergist for radial deviation

Question 8

Extensor Carpi Radialis Brevis

Answer 8

O- Lateral epicondyle via common extensor tendon
I- Base of 3rd metacarpal
N- Radial Nerve C6-8
A- Extend wrist, synergist for radial deviation.

Question 9

Extensor Carpi Ulnaris

Answer 9

O- Lateral epicondyle via common extensor tendon
I- Base of 5th metacarpal
N- Radial C6-8
A- Wrist extension, synergist for ulna deviation.

Question 10

Extensor Digitorum

Answer 10

O- Lateral epicondyle via common extensor tendon
I- 4 tendons via extensor hoods to dorsal aspects of bases 2-4 middle and distal phalanges.
N- Radial Nerve C6-8
A- Extends fingers and wrist joints

Forms part of the anatomical snuffbox on radial side of wrist.

Question 11

Extensor Indicis

Answer 11

O- Posterior surface of teh distal ulna, Interosseous membrane.
I- Extensor hood at level of 2nd metacarpal (index finger)
N- Posterior interosseous nerve/ Radial nerve C6-8
A- Extend index finger

Indicis- Index finger

Question 12

Extensor Hood

Answer 12

Moveable triangular hood lying proximally over MCP joints.
Transfers force and allows fine precise movements.
BAse- wraps around sides of MCP joints and attatches to the deep transverse metacarpal ligaments.

Question 13

Thenar and Hyperthenar Muscles

Answer 13

Thenar: Flexor Pollicis Brevis, Abductor Pollicis Brevis, opponens Pollicis.

Hytperthenar: Flexor digiti minim brevis, Abductor digiti minimi, Opponenes digit minini.

Hypothenar muscles produce the hyperthenar eminence, medial side of pal.

Question 14

Flexor Pollicis Longus

Answer 14

O- Anterior surface of radius and interosseous membrane between radial tubersoity and pronanator quadratus.
I- Distal phalanx of thumb.
N- Median Nerve C7-8, T1
A- Only flexor to distal phalanx of thumb, assists wrist flexion.

Question 15

Abductor Pollicis Longus

Answer 15

O- Posterior surfaces of distal half of radius and ulna, interosseous membrane.
I- Radial side base metacarpal thumb.
N- Radial Nerve C6-8
A- Abducts thumb, extends thumb.

Snuff box formation.

Question 16

Extensor Pollicis Brevis

Answer 16

O- Middle third posterior surfaces of ulna, interosseous membrane.
I- Dorsal surface base distal phalanx thumb.
N- Radial Nerve C6-8
A- Abducts the thumb, extends MCP joints

Forms part of anatomical snuff box.

Question 17

Extensor Pollicis Longus

Answer 17

O- Middle third posterior surfaces of ulna and interosseous membrane.
I- Dorsal surface base distal phalanx thumb.
N- Radial Nerve C6-8
A- Extends all joints in thumb, abducts the wrist

Forms part of snuff box.

Question 18

Lumbircals of the hand

Answer 18

O- Surfaces of the flexor digitorum profundus tendons.
I- Extensor aponeurosis on dorsal surfaces of phalages.
N- 2-3: Median Nerve C6-8, T1. 4-5: Ulnar Nerve C7-8, T1.
A- Extend 2-5 fingers at interphalangeal joints, flex 2-5 at metacarpophalangeal joints.

Question 19

Palmer Interossei

Answer 19

O- Bases of 1, 2, 4 and 5th metacarpals.
I- Bases of proximal phalanx and extensor aponeurosis.
N- Ulnar Nerve C8, T1.
A- Abducts 1, 2, 4, 5 towards 3rd finger. Assists to flex MCP joints. Asissts to extend IP joints.

Question 20

Dorsal Interossei

Answer 20

O- Adjacent sides of all metacarpals
I- Base of proximal phalanx 2/3/4 and extensor hood.
N- Ulna nerve C8, T1
A- Abducts 2/3/4 at MCP joint, Assist to flex 2/3/4 at MCP and assist to extend all IP joints.

Question 21

Carpal Tunnel

Answer 21

Lateral to medial: Flexor Pollicis Longus, Median Nerve, 4 Flexor Digitorum Profundus Tendons, Flexor Digitorum Superficialis overlying.

Carpal Tunnel Syndrome: Pressure on nerve in wrist causing pain and numbness in hands.

Question 22

Anatomical Snuff Box

Answer 22

Lateral to medial: Abductor Pollicis Longus, Extensor Pollicis Brevis and Extensor Pollicis Longus.

All muscles share the same tenden and innervated by the radial nerve.
‘Snuff box’ as tobacco could be put there and inhaled.