Topic 5

Question 1

what type of movement do horizontal or oblique fibres produce

Answer 1

rotational movement

Question 2

how many muscles in the flexor side and extensor side

Answer 2

flexor side
- superficial = 3
- middle = 1
- deep = 2

extensor
- superficial = 5
- deep = 4

Question 3

list the muscles in the superficial layer of the posterior arm
(extensor side)

Answer 3

superficial posterior arm: lateral to medial

1. extensor carpi radialis longus
2. extensor carpi radialis brevis
3. extensor digitorum
4. extensor digiti minimi
5. extensor carpi ulnaris

Question 4

list the muscles in the deep layer of the posterior arm

Answer 4

from lateral to medial:

1. abductor pollucis longus
2. extensor pollucis brevis
3. extensor pollucis longus
4. extensor indicis

Question 5

what muscles form the anatomical snuffbox

Answer 5

extensor pollucis brevis, abductor pollucis longus, extensor pollucis longus.

Question 6

what are the other muscles in the posterior arm

Answer 6

brachioradialis
anconeus
supinator

Question 7

list the muscles in the superficial layer of the anterior arm

Answer 7

from lateral to medial
1. flexor carpi radialis
2. palmaris longus
3. flexor carpi ulnaris

Question 8

list the muscles in the middle layer of the anterior arm

Answer 8

middle layer
1. flexor digitorum superficialis

Question 9

list the muscles in the deep layer of the anterior arm

Answer 9

from lateral to medial
1. flexor digitorum profundus
2. flexor pollucis longus

Question 10

what are the other muscles in the anterior arm

Answer 10

pronator teres and pronator quadratus

Question 11

list the muscles in the thenar eminence of the hand

Answer 11

abductor pollucis brevis
flexor pollucis brevis
opponens pollucis

Question 12

middle muscles of the hand

Answer 12

adductor pollicis
lumbricals
interossei - palmer and dorsal

Question 13

list the muscles of the hypothenar eminence

Answer 13

opponens digiti minimi
flexor digiti minimi
abductor digiti minimi

Question 14

what is the acronym for the hand muscles

Answer 14

All
For
One

And

One
For
All

Question 15

adductor pollicis

Answer 15

oblique and transverse heads
arises from capitate base of 2nd MC, 3rd MC and goes to base of proximal phalanx of 2st digit.

acts at MCP and CMC joints
brings thumb to palm of hand

Question 16

Pallmaris brevis

Answer 16

arises from flexor retinaculum and palmer aponeurosis and inserts into skin on ulnar border of hand

wrinkles skin on ulnar side of hand
deepens hollow of hand

Question 17

lumbricals

Answer 17

associated with tendons of Flexor digitorum profundus and attaches to extensor expansion - flex the MCPs, extend the IPs.

has a proprioceptive role

Question 18

interossei

Answer 18

dorsal and palmer
PAD and DAB
attachment to the extensor expansion
act @ MCP and IP joint.

Question 19

list the accessory structures of the hand

Answer 19

retinaculum - extensor and flexor
palmer aponeurosis
intertendinous connections
dorsal digital expansion
fibrous sheath
synovial sheath

Question 20

extensor retinaculum

Answer 20

attachments - radius, ulnar, pisiform, triquetrum, ulnar and collateral ligament.

septa run to the carpal bones and form separate tunnels for each extensor tendon - otherwise tendons would slide on each other causing tear and wear.

Question 21

flexor retinaculum

Answer 21

attachments - scaphoid and trapezium to pisiform and hamate.

functions:
- prevents bowstringing, protect underlying structures
- additional functions of the flexor retinaculum - converts anterior concavity of carpal bones into carpal tunnel, forms the anterior boundary of carpal tunnel.
- provides attachment for muscles (6 muscles attach).

Question 22

palmer aponeurosis

Answer 22

triangular shaped sheet fo fascia, that extends from flexor ulum to the deep transverse metacarpal ligaments

functions to protect underlying vessels and nerves, anchors skin and aids grip.

Question 23

intertendinous connections

Answer 23

fibrous connections between the bands of the 5 extensor digitorum muscles just proximal to the MCP joints.

prevents independent extension of any one finger, ensures hands open as a unit when releasing grip. if we did not release grip as one unit it puts more weight and tension on each digit.

this is more proximal to digit expansion - releases grip of IP joints as one unit.

Question 24

dorsal digital expansion

Answer 24

forms an aponeurosis over the posterior surface of each finger.
receives attachment form ED, lumbricals and interossei.
ensures simultaneous extension of the IP joints in each finger when releasing grip.

Question 25

Fibrous flexor sheaths

Answer 25

forms fibro-osseous tunnels for flexor tendons in the digits.

bones posteriorly, fibrous sheath anteriorly

acts as pulleys for the flexor tendons, binding down the tendons onto bones and preventing bowstringing within digits which increases leverage and efficiency.

Question 26

synovial flexor sheaths

Answer 26

synovial sheaths surround tendon as it passes under fibrous sheath.

double layer tube

function - allows friction free movement (gliding) of tendon underneath fibrous sheath.

Question 27

describe the position of rest and position of function for the hand

Answer 27

position of rest - palm is hollow, fingers flexed, thumb slightly opposed and slightly flexed.

position of function - wrist in slight dorsiflexion, fingers slight flexion @ IP joints, more flexion @ MCP joints, thumb is opposed and slightly flexed.

Question 28

what are the functional advantages of the position of function

Answer 28

stable wrist position, ligaments taut, stable base for action of finger flexor and extensors.

long finger flexors are stretched and therefore all force of contraction exerted at finger joints rather than in taking up slack.

in most situations this is the position used for splinting because it allows prehensile grip and reduces occurrence of contractures.

Question 29

digital sweep

Answer 29

describes path taken by fingertips by fingertips as hand closes. it is desirable to have a long path so that the dinger tips make the longest arc possible which allows grip of large objects.

roles of lumbricals and interossei is to moderate the effect of flexors and extensors.

Question 30

describe the 2 types of grip

Answer 30

power grip - whole of hand
precision grip - thumb and fingers