Lecture 13: Hand Flashcards
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what type of joint are metacarpo-phalangeal joints and what movement does it allow?
condyloid joints
flexion/extension
Adduction/abduction
what muscles does musculocutaneous nerve innervate ?
The musculocutaneous nerve innervates the three muscles of the anterior compartment of the arm: the coracobrachialis, biceps brachii, and brachialis muscles. It is also responsible for cutaneous innervation of the lateral forearm.
what type of joint are interphalangeal joints and what movement does it allow?
hinge joints
flexion/extension only
what do deep transverse metacarpal ligaments attach to?
to the edges of the palmar ligaments of the metacarpophalangeal joints
where are palmar ligaments present in the hand?
metacarpophalangeal joints
interphalangeal joints
what forms the floor of fibro-osseous tunnels?
palmar lig
where do interossei muscles pass in relation to deep transverse metacarpal ligaments?
pass on the dorsal side
where do lumbrical muscles pass in relation to deep transverse metacarpal ligaments?
on the palmar side( ventrally or anteriorly)
what are the 3 major compartments of the palm and what muscles and tendons do they house?
central( houses the long flexor tendons, lumbricals etc)
lateral(houses thenar muscles)
medial( houses the hypothenar muscles)
what muscles contribute to spreading the digits?
dorsal interossei abduct digits 2, 3, 4
abductor digit minimi(AbDM) act on the little finger(5th digit)
extensor pollicis brevis and longus extend the thumb in the same plane as palm
(abduction of fingers but extension of the thumb)
what muscles abduct the thumb in a plane perpendicular to the palm?
abductor pollicis longus( AbPL)
abductor pollicis brevis( AbPB)
what muscles adduct the digits?
palmar interossei act on 1st, 2nd, 4th, and 5th digits to adduct the digits
dorsal interossei are responsible for moving the 3rd digit if required and adductor pollicis will act on the thumb to add strength to the movement
DIMAB and POMAD
what nerve innervates adductor pollicis?
ulnar nerve(deep branch)
what nerve innervates lumbricals?
2 bipennate( 3rd and 4th lumbricals): ulnar n
2 unipennate( 1st and 2nd lumbricals): median n
what nerve innervates thenar muscles?
median n
innervation of the thenar muscles?
Recurrent branch
median n
innervation of the thenar muscles?
median n
innervation of the hypothenar muscles?
ulnar n (deep branch)
how are metacarpophalangeal joints flexed?
there is no forearm muscle that inserts into the base of the proximal phalanges
flexion partially accomplished by FDS and FDP maximally shortening, as in making a tight fist, but fine control is brought about by the actions of the interossei and lumbricals , with their insertions into the edges of the dorsal digital expansion hood as this narrows over the proximal phalanx
what brings about the flexion of the IP joints?
insertion of the tendons of FDS and FDP into the bases of the middle and distal phalanges respectively
what muscles act to achieve opposition of the thumb?
opponens pollicis(OP)
opponens digit minimi(ODM)
act together with other intrinsic hand muscles
what muscles have the ability to flex the MCP joints at the same time as extending the IP joints( e.g making a “pinch grip”)
interossei and lumbricals
thenar muscles
abductor pollicis brevis
flexor pollicis brevis
opponens pollicis
what muscles extend the thumb?
extensor pollicis brevis and longus
what muscles abduct the thumb?
perpendicular to palm
abductor pollicis longus(AbPL)
anductor pollicis brevis(AbPB)
what is another common name for the 1st Palmar interossei(PI) acting on the thumb?
often referred to as part of flexor pollicis brevis
what nerves do common palmar digital n. branch off from?
ulnar and median nerves
what do the dorsal branches of the proper palmar digital nerves innervate?
the skin on the back of the fingers and nail
what does the dorsal cutaneous branch of the ulnar nerve innervate?
back skin of the 1.5 medial digits
what nerve innervates the back skin of the lateral 3.5 digits?
the superficial branch of radial n
what nerve innervates the back skin of the lateral 3.5 digits?
the superficial branch of radial n
what does the palmar cutaneous branch of median n supply?
the skin of the palmar aspect over the lateral side of the hand
are palmar cutaneous branches of ulnar and median nerve affected by carpal tunnel syndrome?
no. branch before the flexor retinaculum
Where do you prick to test for carpal tunnel syndrome?
prick 2nd and 3rd digits supplied by the median nerve
(a median nerve is the only nerve that goes through the carpal tunnel)
what are the muscles in the hand supplied by the median nerve?
thenar muscles
Lateral 2 lumbricals(unipennate)
5 in total
what are the muscles in the hand innervated by the deep branch of the ulnar nerve?
-hypothenar muscles( abductor digiti minimi; flexor digiti minimi; opponens digiti minimi)
- dorsal interossei(4)
-palmar interossei(4)
-2 medial lumbricals
-adductor pollicis
