Intrinsic Hand Muscles

Question 1

Abductor pollicis brevis

Answer 1

Origin flexor retinaculum of hand, tubercle of the scaphoid bone

Insertion: base of the 1st phalanx of the thumb

Innervation: median nerve

Action abduction of the thumb

Question 2

Flexor policis brevis

Answer 2

origin: Superficial head flexor retinaculum and tubercle of trapezium
Deep head: arises from trapezoid and capitate bones

Insertion: both heads radial side of the base of the proximal phalanx

Innervation
superfical: median
Deep: ulna

Action: flexes the thumb at the MCPJ

Question 3

Opponens pollicis

Answer 3

Origin: flexor retinaculum and the tubercle of trapezium

Insertion: whole length of the metacarpal bone of the thumb

Innervation: recurrent branch of the median nerve

Action Opposition of the thumb i

Question 4

List the muscles of the thenar eminence

Answer 4

flexor policis brevis, abductor pollicis brevis, opponens pollicis

Question 5

List the muscle of the hypothenar eminence

Answer 5

opponens digiti minimi
flexor digiti minimi brevis
abductor digiti minimi

Question 6

Opponens digiti minimi

Answer 6

Origin hamulus of hamate bone

insertion: whole length of the 5th metacarpal

Innervation: deep branch of ulnar nerve

Action: flexes and laterally rotates the 5th metacarpal

Question 7

Flexor digiti minimi

Answer 7

Origin hamulus of hamate bone

Insertion: ulnar side of the base of the first phalanx of the little finger

Innervation ulnar nerve

Action: flexes the little finger

Question 8

abductor digiti minimi

Answer 8

origin: pisiform, pisohamate ligament and felxor retinaculum

Insertion three slips into the ulnopalmar margin of the proximal phalanx of the 5th, the palmar plate of the MCPJ and the sesamoid bone when present

innervation: deep ulnar

Action: aduction of the little finger

Question 9

Adductor pollicis

Answer 9

Oblique head
Origin: capitate bone, bases of the second and third metacarpal
Insertion: combines with flexor pollicis breves and inserted into the radial side of the proximal phalanx of the thumb

Transverse head
Origin: lower two thirds of the third metacarpal bone
Insertion: into the ulna side of the base of the proximal phalanx of the thumb

innervation: deep ulnar

Functions: adduction of the thumb

Question 10

dorsal interossei

Answer 10

4 dorsal interossei in each hand
Origin Muscles are bipennate arising from adjacent sides of the metacarpal bones

Insertion: bases of the proximal phalanges and corresponding extensor digitorum tendon

Innervation: deep ulna nerve

Function: aducts the index, middle and ring finger. The first is able to rotate the index finger slightly. When acting together with palmar flex at the mcpj and extend at the ipj

Question 11

Palmar interossei

Answer 11

Origin: shaft of the metacarpal bone of the digit on which they act

Insertion: first phalanges extansion expansion and extensor digitorium

innnervation: ulnar deep

Function: adducts index middle and ring

Question 12

Lumbricals of the hand

Answer 12

4 small muscles: These muscles do not attach to bone. Instead they attach proximally to the tendons of flexor digitorum profundus

origin 1st and second: are unipennate originate from the radial side of the most radial tendon of flexor digitorum profundus (corresponding to index) for the first and the second most radial for the second (corresponding to the middle)

Insertion 1st and 2nd: passes posterioly along the radial side of the middle finger and inserts on the extensor expansion near MCJP

innervation 1st and 2nd: median nerve

Origin 3rd and 4th: bipennate originate from the radial and ulnar side of dig profunda tendon

Insert: passes posterioly and insert into extensor expansion

3rd and 4th: deep branch of ulnar nerve

Action: flex at MCPJ, extend at IPJ

Question 13

What instrinsic hand muscle are supplied by the median nerve

Answer 13

1st and 2nd lumbicals
flexor pollicis brevis (superficial)
opponens pollicis
abductor pollicsbrevis

Question 14

Discuss the fascia of the plam

Answer 14

Continuous with the antebrachial fascia and the fascia of the hand.

The palmar aponeurosis is a strong well defined part of the deep fascia of the palm which covers the soft tissues and overlies the long flexor tendons. Apex is continuous with the flexor retinaculum and the palmaris longus tendon.

The fibrous digital sheaths are ligamentous tubes that enclose the synovial sheaths. The superficial and deep flexor tendons and the tendon of the FPL in their passage along aspect of their respective fingers .

A medial fibrous septum extends deeply from the medail border of the palmar apneurosis to the 5th metacarpal. Medial to this septum is the medial or hypothenar eminence

Similary a lateral fibrous septum extends from the lateral border to the 3rd metacarpal. Thenar eminence is lateral to this.

Between the two is a cental compartment which continas the flexor tendons and their sheaths, the lumbricals, superficial palmar artery arch and the digital vessels and their nerve.

Deepest muscular plane of the palm is the adductor compartment.

The flexor and digital sheaths enable the tendons to slide freely over each other during movemetn of the fingers.