Anatomy- Hand and Wrist Flashcards
what type of joint is the 1st CMC
saddle type
what type of joint are the MCPs
condyloid
what is flexion, extension, abduction and adduction of the thumb
Extension of thumb= thumbs up, flexion back towards fingers. Abducting thumb palms flat facing ceiling, thumb up to ceiling
what muscles are in the thenar eminence
abductor pollicis brevis
flexor pollicis brevis
opponens pollicis
what is the innervation of the thenar eminence
recurrent branch of the median nerve (affected by carpal tunnel)
what muscles are in the hypothenar eminence
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi
what is the innervation of the hypothenar eminence
deep branch of the ulnar nerve
what are the muscle groups of the hand
lumbricals and interossei
what do the lumbricals do
attached to tendons of flexor digitorum profundus
cause flexion of MCP joints and extension of PIP joints
what do the interossei do
dorsal- abduction of digits
palmar- adduction of digits
(DAB and PAD)
what is the innervation of the lumbricals
lateral 2 = median nerve
medial 2 = ulnar nerve
what is the innervation of the interossei
all ulnar nerve
what forms the carpal tunnel
flexor retinaculum (anteriorly) carpals (posteriorly)
what are the contents of the carpal tunnel
long tendons of the forearm flexor muscles (flexor digitorum superficialis (x4)
flexor digitorum profundus (x4)
flexor pollicis longus (x1))
median nerve
describe the features of carpal tunnel syndrome
compression of the median nerve due to swelling in the tunnel
weakness in the thenar muscles
numbness in digits 1-3 and lateral half of digit 4
what is the volar surface
the anterior wrists
what are the compartments of the hand
central, thenar, hypothenar, adductor, interosseous
what are the spaces of the hand
midpalmar space (posterior to the central compartment) thenar space (posterior to thenar compartment)
how might deep hand infections spread to the forearm
via the midpalmar space into the anterior compartment of the forearm via the carpal tunnel
what is the superficial fascia of the hand
ligaments within connecting skin to deep fascia
what are the movements of the thumb
flexion, extension, abduction, adduction, opposition
what are the different grips of the hand
power (fist)
precision (opposition of thumb and index fingers)
hook (carrying bag in fingers)
when does optimal power grip occur
with wrist joint extended
what type of arteries are digital arteries
end arteries
how does lymph drain from the hands
via cubital and axillary nodes
what forms the flexor retinaculum
the antebrachial (deep) fascia of the anterior forearm thickens distally- firstly as the palmar carpal ligament (at wrist joint) then distally and deeper as the flexor retinaculum
what is the transverse carpal ligament
the flexor retinaculum
where does the flexor retinaculum attach
to the scaphoid/ trapezoid laterally and the pisiform and hamate medially
what is the role of the flexor retinaculum
prevents bowstringing of the tendons during flexion which would reduce muscle efficiency
what fuses with and strengthens the flexor retinaculum
the distal tendon of palmaris longus
why is the centre of the palm unaffected by carpal tunnel syndrome
as the palmar cutaneous branch of the median nerve is given off proximal to the tunnel and travels superficially to reach the skin of the palm
what are the two branches of the radial nerve
superficial and deep
how is the superficial palmar arch formed and where
The superficial palmar branch of the ulnar artery anastomoses with the superficial palmar branch of the radial artery
immediately deep to the palmar aponeurosis
what does the deep branch of the radial artery do
forms the deep palmar arch by anastomosing with the deep branch of the unlar artery
where does the deep palmar arch gi
runs across the anterior aspects of the bases of the metacarpals
what is dupuytrens contracture
pathology affecting the palmar fascia. It causes thickening and shortening (contracture) leading to fixed flexion deformities of, in particular, the ring and little fingers.
what does each finger have nerve supply wise
4 neurovascular bundles: medial palmar, lateral palmar, medial dorsal, lateral dorsal
what is ring block
involves depositing local anaesthetic in a “ring” around the base of the finger to anaesthetise all four proper digital nerves. Suturing or minor surgery can then be performed painlessly distal to the block.
what does the ulnar nerve supply in the palmar aspect
medial part of palm
little finger
medial half of ring finger
what does the median nerve supply in the palmar aspect
central/ lateral palm
lateral half of the ring finger
middle and index finger
thumb (excluding skin over the base)
what does the radial nerve supply in the palmar aspect
skin over the base of the thummb
what are the fibrous digital sheaths continuous with
the longitudinal digital bands of the palmar aponeurosis
where do the fibrous digital sheaths attach
to both sides of the phalanges
what is the role of the fibrous digital sheaths
from a secure tunnel through which the FDS, FDP, FPL and their synovial sheaths travel distally
where do the tendons of FDS, FDP and FPL attach
FDS middle phalanges
FDP and FPL distal phalages
what does tenderness in the floor of the anatomical snuffbox following trauma suggest
scaphoid fracture
what does the median nerve supply in the dorsal aspect
skin over distal phalanges/ nail beds of thumb, index, middle and ring finger
what does the ulnar nerve supply in the dorsal aspect
medial part of the dorsum of the hand
little finger
medial half of ring finger
how many lumbricals are there
4- one for each finger
where do the lumbricals attach
between the FDP tendon and the extensor expansion of the same digit
what do the lumbricals span
the anterior aspect of the 2nd to 5th MCP joints and then the posterior aspect of the 2nd to 5th PIP joints
what is the median plane of the hand
runs through the midline of the middle finger (fingers abd/ adduct from/ to this)
