Topic 5 Flashcards
what type of movement do horizontal or oblique fibres produce
rotational movement
how many muscles in the flexor side and extensor side
flexor side
- superficial = 3
- middle = 1
- deep = 2
extensor
- superficial = 5
- deep = 4
list the muscles in the superficial layer of the posterior arm
(extensor side)
superficial posterior arm: lateral to medial
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
list the muscles in the deep layer of the posterior arm
from lateral to medial:
- abductor pollucis longus
- extensor pollucis brevis
- extensor pollucis longus
- extensor indicis
what muscles form the anatomical snuffbox
extensor pollucis brevis, abductor pollucis longus, extensor pollucis longus.
what are the other muscles in the posterior arm
brachioradialis
anconeus
supinator
list the muscles in the superficial layer of the anterior arm
from lateral to medial
1. flexor carpi radialis
2. palmaris longus
3. flexor carpi ulnaris
list the muscles in the middle layer of the anterior arm
middle layer
1. flexor digitorum superficialis
list the muscles in the deep layer of the anterior arm
from lateral to medial
1. flexor digitorum profundus
2. flexor pollucis longus
what are the other muscles in the anterior arm
pronator teres and pronator quadratus
list the muscles in the thenar eminence of the hand
abductor pollucis brevis
flexor pollucis brevis
opponens pollucis
middle muscles of the hand
adductor pollicis
lumbricals
interossei - palmer and dorsal
list the muscles of the hypothenar eminence
opponens digiti minimi
flexor digiti minimi
abductor digiti minimi
what is the acronym for the hand muscles
All
For
One
And
One
For
All
adductor pollicis
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
Pallmaris brevis
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
lumbricals
associated with tendons of Flexor digitorum profundus and attaches to extensor expansion - flex the MCPs, extend the IPs.
has a proprioceptive role
interossei
dorsal and palmer
PAD and DAB
attachment to the extensor expansion
act @ MCP and IP joint.
list the accessory structures of the hand
retinaculum - extensor and flexor
palmer aponeurosis
intertendinous connections
dorsal digital expansion
fibrous sheath
synovial sheath
extensor retinaculum
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.
flexor retinaculum
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).
palmer aponeurosis
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.
intertendinous connections
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.
dorsal digital expansion
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.
Fibrous flexor sheaths
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.
synovial flexor sheaths
synovial sheaths surround tendon as it passes under fibrous sheath.
double layer tube
function - allows friction free movement (gliding) of tendon underneath fibrous sheath.
describe the position of rest and position of function for the hand
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.
what are the functional advantages of the position of function
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.
digital sweep
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.
describe the 2 types of grip
power grip - whole of hand
precision grip - thumb and fingers
