The hand and thumb

Question 1

Abductor

Pollicis Brevis

Answer 1

Origin: Tubercles of scaphoid and
trapezium bones, flexor retinaculum of hand.
Insertion: Lateral aspect of base of
proximal phalanx of thumb.
Action: Abducts thumb at its
carpometacarpal joint.
Innervation: Recurrent branch of median
nerve (C8-T1).

Question 2

Opponens

Pollicis

Answer 2

Origin: Tubercle of trapezium bone and
flexor retinaculum of hand.
Insertion: Anterolateral aspect of body of
first metacarpal bone.
Action: Opposes thumb towards other fingers.
Innervation: Recurrent branch of median nerve (C8-T1)

Question 3

Flexor Pollicis

Brevis

Answer 3

Origin: Tubercle of trapezium bone, palmar
aspects of capitate and trapezoid bones,
flexor retinaculum of hand.
Insertion: Lateral aspect of base of
proximal phalanx of thumb.
Action: Flexes thumb.
Innervation: Superficial head: recurrent
branch of median nerve (C8-T1); Deep
head: deep branch of ulnar nerve (C8-T1).

Question 4

Lumbricals of Hand

1-4

Answer 4

Origin: Tendons of flexor digitorum profundus.
Insertion: extensor expansion of fingers 2-5.
Action: Simultaneously flexes
metacarpophalangeal joint and extends
interphalangeal joints of fingers 2-5.
Innervation: 1st and 2nd: Innervation: Common palmar digital branches of median nerve (C8-T1). 3rd and 4th: Deep branch of ulnar nerve (C8-T1).

Question 5

Adductor Pollicis
Oblique +
Transverse Head

Answer 5

Origin: OH: Palmar aspects of capitate bone
and bases of second and third metacarpal bones.
TH: Palmar aspect of body of third metacarpal bone.
Insertion: base of proximal phalanx of thumb.
Action: Adducts thumb at its carpometacarpal joint.
Innervation: Deep branch of ulnar nerve (C8-T1).

Question 6

Abductor Digiti

Minimi

Answer 6

Origin: Pisiform bone and tendon of flexor carpi ulnaris.
Insertion: base of proximal phalanx of little finger.
Action: Abducts little finger at its metacarpophalangeal joint.
Innervation: Deep branch of ulnar nerve (C8-T1)

Question 7

Flexor Digiti

Minimi

Answer 7

Origin: Hook of hamate bone and flexor
retinaculum of hand.
Insertion: base of proximal phalanx of little finger.
Action: Flexes little finger at its
metacarpophalangeal joint.
Innervation: Deep branch of ulnar nerve (C8-T1).

Question 8

Opponens

Digiti Minimi

Answer 8

Origin: Hook of hamate bone and flexor
retinaculum of hand.
Insertion: Medial aspect of fifth metacarpal bone.
Action: Opposes little finger towards thumb.
Innervation: Deep branch of ulnar nerve (C8-T1)

Question 9

Palmar
Interossei
1-3

Answer 9

Origin: Sides of each metacarpal facing the mid-axis (metacarpal 3) of the hand
Insertion: Extensor expansion of proximal phalanx fingers 2-4 on side opposite
mid-axis of hand (not on finger 3) .
Action: Adducts ring finger at its metacarpophalangeal joint; simultaneously flexes metacarpophalangeal joint and extends interphalangeal joints of fingers 2-5.
Innervation: Deep branch of ulnar nerve (C8-T1).

Question 10

Dorsal
Interossei of Hand
1-4

Answer 10

Origin: Sides of metacarpals
Insertion: Base of proximal phalanx and extensor expansion of fingers 2-4 on side
opposite mid-axis of hand but on BOTH sides of finger 3.
Action: Medially abducts fingers 2-5 at the metacarpophalangeal joint; simultaneously flexes metacarpophalangeal joint and extends interphalangeal joints of fingers 2-5.
Innervation: Deep branch of ulnar nerve (C8-T1).