Intrinsic Muscles Of The Hand

Question 1

Palmaris brevis

Answer 1

Origin: palmar aponeurosis and flexor retinaculum
Insertion: dermis of the skin on the medial margin of hand
Innervation: superficial branch of ulnar nerve C8, T1
Function: improves grip

Question 2

Dorsal interossei (4 muscles)

Answer 2

Origin: adjacent sides of metacarpals
Insertion: extensor hood and base of proximal phalanges of index, middle, ring finger
Innervation: deep branch of ulnar nerve C8, T1
Function: abduction of index, middle, ring fingers at metacarpophalangeal joints

Question 3

Palmar interossei 3/4 muscles

Answer 3

Origin: sides of metacarpals
Insertion: extensor hoods of the thumb, index, middle, ring, little fingers and proximal phalanx of thumb
Innervation: deep branch of ulnar nerve C8, T1
Function: Adduction thumb, index, middle, ring, little fingers at metacarpophalangeal joints

Question 4

Adductor pollicis

Answer 4

Origin: transverse head- metacarpal III. Oblique head- capitate and bases of metacarpals II and III
Insertion: base of proximal phalanx and extensor hood of thumb
Innervation: deep branch of ulnar nerve C8 T1
Function: adducts the thumb

Question 5

Lumbricals 4 muscles

Answer 5

Origins: tendons of flexor digitorum profundus
Insertion: extensor hoods of index, middle, ring and little finger
Innervation: medial two by deep branch of ulnar nerve, lateral two by digital branches of median nerve
Function: flex metacarpophalangeal joints while extending interphalangeal joints

Question 6

Opponens pollicis

Answer 6

Thenar muscle
Origin: tubercle of trapezium and flexor retinaculum
Insertion: lateral margin and adjacent palmar surface of metacarpal I
Innervation: recurrent branch of median nerve C8 T1
Function: medially rotates the thumb

Question 7

Abductor pollicis brevis

Answer 7

Thenar muscle
Origin: tubercles of scaphoid and trapezium and adjacent flexor retinaculum
Insertion: proximal phalanx and extensor hood of thumb
Innervation: recurrent branch of median nerve C8,T1
Function: abducts thumb at metacarpophalangeal joint

Question 8

Flexor pollicis brevis

Answer 8

Thenar muscle
Origin: tubercle of the trapezium and flexor retinaculum
Insertion: proximal phalanx of thumb
Innervation: recurrent branch of median nerve C8 T1
Function: flexes thumb at metacarpophalangeal joint

Question 9

Opponens digiti minimi

Answer 9

Hypothenar muscle
Origin: hook of hamate and flexor retinaculum
Insertion: medial aspect of metacarpal V
Innervation: deep branch of ulnar nerve C8 T1
Function: laterally rotates metacarpal V

Question 10

Abductor digiti minimi

Answer 10

Hypothenar muscle
Origin: pisiform, the pisohamate ligament and tendon of flexor carpi ulnaris
Insertion: proximal phalanx of little finger
Innervation: deep branch of ulnar nerve C8 T1
Function: abducts little finger at metacarpophalangeal joint

Question 11

Flexor digiti minimi brevis

Answer 11

Hypothenar muscle
Origin: hook of hamate and flexor retinaculum
Insertion: proximal phalanx of little finger
Innervation: deep branch of ulnar nerve C8 T1
Function: flexes little finger at metacarpophalangeal joint