Hand Muscles, Movement and Function

Question 1

What is the origin insertion and action for flexor pollicis brevis

Answer 1

Origin - flexor retinaculum, trapezium
Insertion - radial side of proximal phalanx of thumb
Action - flexion MCP, CMC and medial rotation of thumb

Question 2

What is the origin insertion and action for abductor pollicis brevis

Answer 2

Origin - flexor retinaculum, scaphoid, trapezium
Insertion - radial side of base of the proximal phalanx of the thumb
Action - abduction of the CMC/MCP joints of the thumb

Question 3

What is the origin insertion and action for opponens pollicis

Answer 3

Origin - flexor retinaculum, trapezium
Insertion - whole length lateral half of anterior surface of first metacarpal
Action - abduction/adduction, medial rotation, flexion

Question 4

What is the origin insertion and action for adductor pollicis

Answer 4

Origin (oblique head) - tendon FCR, bases 2-3 metacarpals, trapezoid, capitate
(Transverse head) - anterior surface shaft of the third metacarpal
Insertion - medial side of base of proximal phalanx of the thumb
Action - strong adductor

Question 5

What muscles are in the thenar eminence

Answer 5

Adductor pollicis brevis (NS - median nerve T1) - carpal bones to proximal phalanx.
Flexor pollicis brevis (NS - Median/ulnar nerve T1) - carpal bones to proximal phalanx
Opponens pollicis (NS - median nerve T1) - carpal bones to 1st metacarpal.
Adductor pollicis (NS - ulnar nerve T1&C8) - metacarpals 2,3 and 4 to proximal phalanx.

Question 6

What muscles are in the hypothenar eminence

Answer 6

Abductor digiti minimi - pisiform to proximal phalanx
Flexor digiti minimi - hamate to proximal phalanx
Opponens digiti minimi - hamate to 5th metacarpal
(Palmaris brevis) - flexor retinaculum to skin

Question 7

What is the origin insertion and action for abductor digiti minimi

Answer 7

Origin - pisiform, pisophate, pisometacarpal ligaments, tendon FCU
Insertion - ulnar side proximal phalanx of little finger and dorsal digital expansion
Action - abduction of little finger, flexion MCP

Question 8

What is the origin insertion and action for flexor digiti minimi

Answer 8

Origin - hook of hamate/flexor retinaculum
Insertion - base of proximal phalanx little finger
Action - flexes MCP little finger

Question 9

What is the origin insertion and action for opponens digiti minimi

Answer 9

Origin - hook of hamate/flexor retinaculum
Insertion - shaft of 5th metacarpal
Action - opposition 5th digit

Question 10

What is the origin insertion and action for palmaris brevis

Answer 10

Origin - flexor retinaculum and palmar aponeurosis
Insertion - skin of palm into dermis
Action - steadies and corrugates skin of palm to help with grip

Question 11

What is the function for the interossei muscles

Answer 11

Extension of IP joints.
Flexion of MCP joints (increased activity with increased flexion)
Abduction/adduction of the MCPs - DAB (Dorsal abduct), PAD (palmar adduct).
Prevention of hyper extension of the MCPs (highlighted in clawing deformity seen posterior ulnar nerve lesion)
Important in prehension activities

Question 12

What are the intermediate muscles

Answer 12

Lumbricals (NS - median/ulnar nerve T1) - tendons of flexor digitorum profundus to dorsal digital expansion (DDE) of proximal phalanx. 
Palmar interossei (NS - ulnar nerve T1) - bases and sides of metacarpals except middle - to proximal phalanx except middle. 
Dorsal interossei (NS - Ulnar nerve T1) - adjacent ides of metacarpals to proximal phalanx

Question 13

What are the functions of the hand

Answer 13

Manipulation
Sensation
Stability
Protection
Communication
Important for gripping and manipulation in daily activities
Important in communication and expresssions

Question 14

What are the nerve supply of the hand - motor innervation of issues

Answer 14

Posterior interosseus nerve - the extrinsic muscles of the hand; wrist extensors, EPL&B and APL (dropped wrist)
Ulnar nerve - hypothenar muscles, interossei (clawed hand)
Median nerve - thenar muscles and finger flexors (loss of precision)

Question 15

What are the arches of the hand

Answer 15

2 transverse arches
1 longitudinal arch
1 oblique arch
These arches aid the function of the hand and they allow the hand to conform to objects.

Question 16

Explain the transverse arches

Answer 16

Carpal arch - formed by carpal bones, concave in shape and allows little movement.
Metacarpal arch - formed by M.C. heads. It can widen and flatten, providing stability and mobility in the hand

Question 17

Explain the longitudinal arches

Answer 17

Formed by carpal bones, metacarpal bones and the corresponding phalanges. It assumes a wide variety of shapes.

Question 18

Explain the oblique arches

Answer 18

These are formed by the thumb as it opposes each of the fingers. Palmar gutter is a gutter which runs obliquely across the various oblique arches of the palm. It passes from base of hypothenar eminence to the head of 2nd M.C.

Question 19

What’s prehension

Answer 19

Grip - the use of Hands and fingers to grasp or pick up objects

Question 20

What is a type of power grip known as palmar grip

Answer 20

Involves whole hand, it’s the most powerful and the thumb acts as a buttress with fingers closing around object. Wrist synergist extension, long flexors and thenar muscles are active.
Adapted palmar grips - spherical and cylindrical grasp

Question 21

What is a type of power grip known as hook grip

Answer 21

Thumb plays no part. Object held between flexed fingers and palm. Long flexors static muscle work.

Question 22

What types of precision grips are they and their function

Answer 22

Pincer grip - tip to tip. Finest and most precise
Pad to pad - most common
Key grip - thumb pad to lateral side of middle phalanx of index finger. Most powerful and strongest
Adduction grip - generally weak with limited precision

Question 23

What is the function of precision grips

Answer 23

Involves skilful placing of small objects between thumb and finger with manipulation.
Less strength of muscle contraction to produce and control fine movements.
Good sensation is essential to carry out precision movements