hand Flashcards
what are the main types of grip *
power grip
precision grip
hook grip
describe power grip *
the fingers are flexed around the object with opposing power from the thumb eg grasping a rod
muscles involved in the power grip *
long flexors of the finger and thumb
the intrinsic muscles of the palm
the extensors of the wrist joint - to give more power to the long flexors (posterior hand muscles are involved)
describe the precision grip *
the object is gripped between the tips of the fingers and the thumb
eg unbuttoning a shirt
muscles involved in the precision grip *
teh wrist and fingers are held rigidly by the long flexors and extensors
the intrinsic muscles of the hand carry out the dine movements needed
forearm control of the wrist - dont wnat the wrist to get floppy
describe the hook grip *
consumes little energy
eg carrying shopping bag
muscles involved in the hook grip *
mainly involves long flexors of the digits
summarise teh facia of the palm *
it is anatomically continuous with the fascia of the forearm
the palmar fascia is the fascia of hand that lies in the palm - dense
there are specialisations (condensations) of the palmar fascia that form the palmar aporneurosis and the fibrous digital sheaths
describe the palmar aporneurosis *
it overlies the long flexor tendons of the hand
the proximal end is continuous with the flexor retinaculum and the palmaris longus tendon
the distal end of the aporneurosis is continuous with teh fibrous digital sheaths
describe the fibrous digital sheaths *
they contain the flexor tendons and their synovial sheaths which wrap round the tendons and bones
describe the extensions of fascia called septa *
they extend from teh palmar aporneurosis to the boens of the hand - separating the space between the aporneurosis and bones into compartments
separate vessels and muscles and tendons running from wrist
a medial septum goes to the little finger metacarpal
a lateral septum goes to the middle finger metacarpal
these septi divide the space into a
- hypothenar compartment
- central compartment
- thenar compartment
- adductor compartment
deep to the thenar compartment is the adductor compartment which contains the adductor pollicus muscle
what are the bones of the wrist and hand *
the radius
ulnar
carpus (carpal bones)
- proximal row: sphenoid, lunate, triquetrum, pisiform
- distal row: trapexium, trapezoid, capitate, hamate
the metacarpal bones
the phalanges
what muscular compartments are involved in the hand region *
anterior compartment of the forearm - superficial and deep
posterior compartment of the forearm
posterior compartment of the forearm
intrinsic muscles of the hand
- thenar compartment muscles
- adductor comaprtment
- hypothenar compartment
- interossei and lumbricals
what are the muscles of the superficial anterior compartment of the forearm *
pronator teres
flexor carpi radialis
palmaris longis
flexor carpi ulnaris
flexor digitorum superficialis
what are the muscles of the deep anterior compartment of teh forearm *
flexor digitorum profundis
flexor pollicus longus
pronator quadratus
what are the muscles of the extensor compartment of the forearm *
muscles that move the wrist joint
- Extensor carpi radialis longus (ECRL)
- Extensor carpi radialis brevis (ECRB)
- Extensor carpi ulnaris (ECU)
muscles that move the digits
- Extensor digitorum (ED)
- Extensor indicis (EI)
- Extensor digit minimi (EDM)
muscles that move the the thumb
- Abductor pollicis longus (APL)
- Extensor pollicis brevis (EPB)
- Extensor pollicis longus (EPL)
other muscles
- Brachioradialis
- Supinator
what are the intrinsic muscles of the hand *
thenar muscles
- abductor pollicus brevis
- flexor pollicus brevis
- opponens pollicus
adductor muscle - single muscle
- adductor pollicus
hypothenar muscle
- abductor digiti minimi
- flexor digiti minimi
- opponens digiti minimi
interossei and lumbricals
- lumbricals
- palmer interossei (3)
- dorsal interossei (4)
other
- palmaris brevis
functions of the interossei and lumbricals *
lumbricals - flex the MCJ’s, extend the IPJ’s
palmar interossei - adduct the digits (PAD)
dorsal interossei - abduct the digits (DAB)
describe the anterior tendinous anatomy of teh hand *
teh fibrous digital sheaths extend from the level of teh metacarpal head to the base of teh distal phalanx in each digit
with the underlying bone the sheaths form the osseo-fibrous tunnels
the long flexor tendons and their synovial sheaths run in these tunnels
part of the digital sheaths form condensations called pulleys - allow for more function of the long flexor tendons
these are the annular and cruciform pulleys
after passing the wrist joint the flexor digitorum profundus and flexor digitorum superficialis pass in the carpal tunnel beneath the flexor retinaculum and enter a common tendinous sheath
the tendons pass to their respective digits in a digital synovial sheath (sheath is wrapped around the tendon forming a double layer, rather tahn the tendon being in the sheath), which is in its own fibrous digital sheath (synovial sheath prevents friction)
the digital synovial sheaths of the index, middle and ring fingers are separate from the common synovial sheath, those of the little finger and thumb are continuous with the common sheath
at the proximal base of the phalanx - the tendon of teh FDS splits around the FDP
the FDS attaches to the anterior surface of the middle phalanx and teh FDP attaches to the distal phalanx (FDS doesnt go as far)
the tendon of the flexor pollicus longus has its own synovial sheath at the flexor retinaculum - this runs to the distal phalanx of the thumb
describe the posterior tendinous anatomy of the hand *
all the extensor tendons are held to the dorsum of the wrist by the extensor retinaculum (not as tough as the flexor retinaculum)
there are synovial tendon sheaths that surround the tendons fascilitating free movement of the tendons - some sheaths are connected some are individual
the long extensor tendons to the digits are joined by intertendinous bands - they prevent free movement of 1 extensor tendon independantly of the others
at the metacarpals the long extensor tendons flatten to form extensor expansions - they form a hood on the back of the digit. they are intrically involved in the movement of the digits
the lumbrcals and interossei attach to the expansions
the extensor digitorum extends the metacarpo-pharyngeal joint and the interphalangeal joint. it extends the wrist joint after maximal extension of the digits
what are the joints in the hand *
distal radio-ulnar joint
wrist joint
intercarpal joint
carpo-metacarpal and inter-metacarpal joints
metacarpo-phalangeal joints
interphalangeal joints
what movements do the midcarpal (joint between prox and distal carpal row) and carpo-metacarpal joints allow *
flexion and extension
what are the series of intercarpal joints *
joints between the prox row
joints between the distal row
joints between the prox and distal row - midcarpal joint
what type of joint are the intercarpal joints and what is the movement *
plane synovial
gliding - augmenting the flexion and radial deviation of the wrist joint
describe the carpometacarpal joints *
the CMC joint of thumb is between the trapezium and the thumb metacarpal - synovial joint of saddle variety allows thuim to move in different direction
CMC of digits are between trapezoid, capitate, hamate and metacarpals - they are synovial elipsoid
CMC of index and middle finger is rigid
CMC of ring finger is less
CMC of little is very mobile
clinical importance of the carpometacarpal joint of the thumb *
becomes osteoarthritic
describe the intermetacarpal joints *
plane synovial joints
between the metacarpals at their bases
describe the movements at the carpometacarpal and intermtacarpal joints *
flexion and extension
radial deviation and ulnar deviationn
circumduction
describe the metacarpophalangeal joints *
condylar synovial joints between metacarpal heads and prox phalanges
what movements do the metacarpophalangeal joints allow *
flexion and extension
abduction and adduction
together - circumduction
describe the interphalangeal joints*
hinge synovial joints
there is a proximal IP and distal IP joint
in thumb only 1 IP joint
movements of the interphalangeal joints *
flexion and extension only
describe the ligaments holding teh metacarpophalangeal and interphalangeal joints together *
they include collateral ligaments both ulnar and radial
ulnar collataral ligament of thumb is frequently injured skiing
connection between phalanxes is not very strong - not good fit between bone therefore ligaments hold bone in place but only allow flexion and extensioon of IPJ
what is the volar plate *
it is on the anterior surface of the prox IP joint
it is a dense condensation of fibrous tissue formed by collateral ligaments
frequently damaged
what are the muscles that move the thumb *
abduction
- abductor pollicus longus
- abductor pollicus brevis
adduction
- adductor pollicus
- first doral interosseous
extension
- extensor pollicus longus
- extensor pollicus brevis
- abductor pollicus longus
flexion
- flexor pollicus longus
- flexor pollicus brevis
opposition
- opponens pollicus (works at carpo-metacarpal joint)
- occurs at the metacarpo-phalangeal joint and involves abduction, flexion, and adduction at the metacarpo-phalangeal joint
describe the arterial supply of the hand *
hand supplied by the radial and ulnar arteries
in the hand there are extensive anastomoses between the ulnar and radial arteries
ulnar artery runs in anterior comp of forearm - passes on ulnar side of palmar surface of wrist. artery is lateral to ulnar nerve which is lateral to flexor carpi ulnaris. the artery supplies medial muscles of the forearm - branches into the common then posterior and anterior interosseous artery. enter hand passing over the flexor retinaculum lateral to pisiform through semi-rigid ulnar (Guyon’s) canal with teh ulnar nerve. It divides just below this into
- superficial palmar arch (recieves branch from superficial palmar branch of radial artery)
- gives off 3 common palmar digital arteries - they divide into palmar digital arteries
- the deep palmar branch of ulnar artery
radial artery passes down lateral aspect of forearm under brachioradialis muscle and beside FCR at wrist. it crosses floor of anatomical snuff box and enters palm of hand between the 2 heads of the 1st dorsal interosseous muscle, then passes between the 2 heads of the adductor pollicus muscle. it anastomoses with deep palmar branch of ulnar artery to form deep palmar arch
deep palmar arch gives origin to palmar metacarpal arteries
arteries also form dorsal carpal arch
where is the radial artery palpable
at the wrist
lies superficially on palmar aspect of radial side of wrist
describe the venous drainge of the hand *
deep and superficial arterial arches have corresponding palmar venous arches - deep drainage
dorsal digital veins drain into dorsal venous arch (superficial system) on dorsum of hand
arch gives rise to cephalic and basilic vein laterally and medially
most drainage is through the superficial system
what are the 3 main nerves to the hand *
median nerve c6-t1
ulnar nerve c8-t1
radial nerve c5-t1
what nerves contribute to sensory supply of the hand *
ulnar
median
radial
they do so in the digits through digital nerves
effect of division of one of the digital nerves
anaesthesia in part of the digit
describe the path of the median nerve *
supply anterior compartment of the hand and forearm
descends through anterior comp of arm - no branches
in cubital fossa it lies medial to brachial artery (can be damaged by supracondylar fractures of humerus or dislocations)
passes between the heads of the pronator teres
at wrist lies superficially between the tendons of FDS and FDP and deep to palmaris longus
enters the carpel tunnel - here it is accompanied by 9 flexor tendons (FDP FDS FPL)
passes under the flexor retinaculum
the recurrent branch of median nerve leaves main trunk in carpel tunnel and supplies the 3 thenar muscles
what does the median nerve supply*
in forearm
- pronator teres
- FDS
- lateral protion of FDP
- FCR
- pronator quadratus
- palmaris longus
after passing under the flexor retinaculum
- the 3 thenar muscles - abductor pollicus brevis, flexor pollicus brevis and opponens pollicus
- the lateral (2 and 3) lumbricals
sensory
- palmar surface of thumb
- index and middle finger
- lateral half of ring finger
- some dorsal supply
(main nerve to the anterior compartment of the forearm, some supply to intrinsic hand muscles)
describe the path of the ulnar nerve *
initially descends in the anterior compartment of the arm
more distally enters the posterior comp - lies superficially posterior to medial epicondyle
no branches in arm
enters anterior comp of forearm between heads of flexor carpi ulnaris and descends on medial side of forearm
proximal to wrist it gives off 2 branches - palmar cutaneous branch, dorsal cutaneous branch
at wrist lies anteriorly - between FCU (medially) and ulnar artery (laterally) then passes into hand
passes over the flexor retinaculum in ulnar canal with ulnar artery, lateral to the pisiform bone
it divides distal to the flexor retinaculum to superfical and deep braches
what does the ulnar nerve supply *
in forearm
- FCU
- medial portion of FDP
palmar cutaneous branch supplies medial palm of hand
dorsal cutaneous branch supplies medial half of dorsum of hand, including little and ring fingers
superficial branch of ulnar nerve - sensory to palmar surface of little finger and medial sode of ring finger
deep branch of ulnar nerve - motor to
- hypothenar muscles (abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi)
- abductor pollicis
- the medial (fourth and fifth) lumbricals
- all interossei
it controls most of muscles involved in fine movements of the hands
describe the path of the radial nerve *
lies on the humerus in the radial groove
superior to elbow divides into superficial radial nerve (sensory) and deep radial nerve (motor)
superficial branch is cutaneous - sensory to lateral 2/3 of dorsum of hand, dorsum of thumb and proximal portions of dorsal of index and middle fingers
posterior interosseous nerve is continuation of deep radial nerve as it passes between heads of the supinator
supplies all extensor parts of forearm and arm
doesnt supply any muscles in hand