Muscles of Extensor Forearm & Hand

Question 1

Pronator Teres

Answer 1

• origin: medial epicondyle of humerus
• insertion: shaft of radius
• action: pronates forearm

Question 2

Flexor Carpi Radialis

Answer 2

• origin: medial epicondyle of humerus
• insertion: base of 2nd and 3rd metacarpal
• action: flexion and radial deviation at wrist

Question 3

Palmaris Longus

Answer 3

• origin: medial epicondyle of humerus
• insertion: palmar aponeurosis
• aciton: flexion at wrist

Question 4

Flexor Carpi Ulnaris

Answer 4

• origin: medial epicondyle of humerus
• insertion: hamate, pisiform and base of 5th metacarpal
• action: flexion and ulnar deviation at wrist

Question 5

Flexor Digitorum Superficialis

Answer 5

• origin: medial epicondyle of humerus, radius and ulna
• insertion: middle phalange of digits 2-5
  action: flexes digits 2-5 (only proximal and middle)

Question 6

Flexor Digitorum Profundus

Answer 6

• origin: ulna
• insertion: distal phalanx of digits 2-5
• action: flexes digits 2-5

Question 7

Flexor Pollicis Longus

Answer 7

• origin: radius
• insertion: distal phalanx of thumb
• action: flexes the thumb

Question 8

Pronator Quadratus

Answer 8

• origin: distal ulna
• insertion: distal radius
• action: pronates forearm

Question 9

Thenar Muscles

Answer 9

group of muscles on radial side of hand which act on the thumb

Question 10

Hypothenar Muscles

Answer 10

group on muscles on ulnar side of hand which act on the little finger

Question 11

Abductor Pollicis Brevis

Answer 11

(in layer 1 of hand muscles)

• origin: carpals
• insertion: proximal phalanx of thumb
• action: abducts thumb

Question 12

Abductor Digiti Minimi

Answer 12

(in layer 1 of hand muscles)

• origin: carpals
• insertion: proximal phalanx of 5th digit
• action: abducts little finger

Question 13

Flexor Pollicis Brevis

Answer 13

(in layer 2 of hand muscles)

• origin: carpals
• insertion: proximal phalanx of thumb
• action: flexes thumb

Question 14

Flexor Digiti Minimi

Answer 14

(in layer 2 of hand muscles)

• origin: carpals
• insertion: proximal phalanx of 5th digit
• action: flexes little finger

Question 15

Lumbricals

Answer 15

(in layer 2 of hand muscles)

• origin: tendons of flexor digitorum profundus
• insertion: extensor tendons of digits 2-5
• action: flex metacarpophalangeal joints while interphalangeal joints are extended

Question 16

Opponens Pollicis

Answer 16

(in layer 3 of hand muscles)

• origin: carpals
• insertion: first metacarpal
• action: rolls thumb towards little finger

Question 17

Adductor Pollicis

Answer 17

(in layer 3 of hand muscles)

• origin: carpals and metacarpals
• insertion: proximal phalanx of thumb
• action: adducts thumb

Question 18

Opponens Digiti Minimi

Answer 18

(in layer 3 of hand muscles)

• origin: carpals
• insertion: 5th metacarpal
• action: rolls little finger towards thumb

Question 19

Palmar Inerossei

Answer 19

(in layer 4 of hand muscles)

• origin: metacarpals 2, 4, and 5
• insertion: proximal phalanx of digits 2, 4, and 5
• action: adducts digits 2, 4, and 5

Question 20

Dorsal Inerossei

Answer 20

(in layer 4 of hand muscles)

• origin: metacarpals 1-5
• insertion: proximal phalanx of digits 2, 3, and 4
• action: abducts digits 2, 3, and 4

Question 21

Palmar Carpal Ligament

Answer 21

connective tissue band that holds down flexor tendons

Question 22

Extensor Retinaculum

Answer 22

connective tissue band that holds down extensor tendons

Question 23

Structures that pass through the carpal tunnel

Answer 23

• 4 tendons of flexor digitorum superficialis
• 4 tendons of flexor digitorum profundus
• tendon of flexor pollicis longus
• median nerve

Question 24

What makes the “roof” and “floor” of the carpal tunnel?

Answer 24

• transverse carpal ligament (trapezium to hamate and pisiform) forms roof
• carpal bones form the floor