hand and wrist Flashcards
what is the flexor retinaculum?
the antebrachail (deep fascia) fascia of the anterior forearm thickens distally, firstly as the palmar carpal ligament at the aspect of the wrist joint then, distally and deeper, as the flexor retinaculum (transverse carpal ligament)
where does flexor retinaculum attach
scaphoid/trapezoid laterally and the pisiform and hamate medially
what does the retinaculum prevent
bowstringing of tendons during flexion, which would reduce muscle efficiency
what strengthens the flexor retinaculum?
distal tendon of palmaris longus which also fuses with it
what is the carpal tunnel?
combination of carpal bones and the flexor retinaculum
long tendons of the forearm flexor muscles (FDS, FDP, and FPL) and the median nerve enter the palm
what is spared in carpal tunnel syndrome?
palmar cutaneous branch of median nerve because it is given off proximal to the tunnel and travels superficially to reach skin of palm
2 branches of radial artery
superficial: superficial branch of the ulnar artery forms the superficial palmar arch immediately deep to the palmar aponeurosis by anatomizing with the superficial palmar branch of the radial artery
deep: forms deep palmar arch (runs across anterior aspects of the bases of the metacarpals) by anatomizing with the deep branch of the ulnar artery
sensory innervation of the hand - palmar
ulnar nerve - medial part of palm, little finger, medial half of ring finger
median - central/lateral palm, lateral half of the ring finger, middle and index finger, thumb (excluding skin over base)
radial - skin over base of thumb
what are fibrous digital sheaths
continuous with longitudinal digital bands of the palmar aponeurosis, sheaths attach to both sides of the phalanges and form a secure tunnel thought which the FDS, FDP, and FPL tendons and their synovial sheaths travel distally
tendons attach to the middle and distal phalanges respectively
what is the anatomical snuff box?
triangular depression on the radial, dorsal aspect of the hand was to place and sniff powered tobacco, or “snuff”
snuff box pain
scaphoid fracture
sensory innervation of the hand - dorsal
ulnar - medial part of dorm of hand, little finger, half of ring finger
median nerve - skin over distal phalanges/nail beds of thumb, index finger, middle and ring fingers
radial nerve - skin over the anatomical snuffbox, lateral part of dorsum of hand, proximal thumb, index, middle and ring fingers
what are lumbricals?
attach between the FDP tendon and the extensor expansion of the same digit
span anterior aspect of the 2nd to 5th MCP joints and then the posterior aspect of the 2nd to 5th PIP joints
action is to flex the MCP and extend the PIP joints
medial 2 lumbricals are supplied by ulnar nerve and lateral by median (4 for each finger)
what are the interossei?
the palmar interossei adduct the digits (PAD) and the dorsal interossei adbuct the digits (DAB)
supplied by ulnar nerve
