7: Hand and Wrist Flashcards
flexion and extension of thumb
flexion: can flex at both the IPJ and MCPJ/ when both joints are flexed, thumb bends across the palm
extension: return flexed thumb to anatomical position
radial abduction
continuation of extension beyond the anatomical position in the same plane as the palm (coronal plane)
opposition
rotatory movement of the thumb over the palm - it enables the thumb to touch the tips of the fingers
palmar adduction/abduction
circumduction
what is the carpal tunnel
narrow passageway on the anterior (volar or palmar) surface of the wrist that serves as an entrance to the palm for numerous tendons and median nerve
what are the borders of the carpal tunnel
deep border: comprised of the carpal bones which form a concavity
superficial border: flexor retinaculum aka transverse carpal ligament
what are the attachments of the flexor retinaculum
radial (lateral): scaphoid, trapezium
ulnar (medial) : hook of hamate, pisiform
what structures pass through the carpal tunnel
- flexor pollicis longus tendon
- flexor digitorum superficialis tendons x4
- flexor digitorum profundus tendons x4
- median nerve
where is the palmar cutaneous branch of the median nerve given off
proximal to the carpal tunnel
- clinically important in carpal tunnel syndrome as when the median nerve becomes compressed, sensation to the palm is unaffected
what is guyon’s canal
aka ulnar canal
semi-rigid longitudinal canal in the wrist that allows passage of the ulnar nerve and artery into the hand
where is guyon’s canal found
superficial to the flexor retinaculum
- can be palpated just radial (lateral) to the pisiform bone, passing between pisiform and hook of hamate
- roof: formed by palmar carpal ligament
why is guyon’s canal clinically important
site of ulnar nerve compression
what is the anatomical snuffbox (aka radial fossa)
triangular depression on the radial aspect of the dorsum of the hand, at level of carpal bones
- best seen when thumb is radially abducted
what are the borders of the snuff box
- radial: tendons of abductor pollicis longus (most lateral) and extensor pollicis brevis
- ulnar: tendon of extensor pollicis longus
- proximal: styloid process of radius
- floor: scaophoid and trapezium
- roof: skin
what are the contents of the anatomical snuff box
- radial artery
- superficial branch of radial nerve
- cephalic vein
which arteries supply the hand
radial and ulnar artery supply hand via deep and superficial palmar arches
where can the ulnar artery be palpated
- may be palpated as it crosses anterior to flexor retinaculum + ulnar nerve in guyon’s canal
- here the artery lies radial to pisiform bone and ulnar nerve
in the hand, what does the ulnar artery divide into
superficial and deep branches
- both of which anastomose w corresponding branches of the radial artery to form superficial and deep palmar arches
what does the superificial palmar arch give off
common palmar digital arteries which supply the fingers
what does the ulnar artery contribute mainly to
the superificial palmar arch and therefore to the blood supply of the fingers
how does the radial artery enter the hand
between the tendons of brachioradialis and flexor carpi radialis
what does the radial artery give off
superficial branch that anastomoses w the superficial palmar arch then passes dorsally to cross the floor of the anatomical snuffbox on the dorsum of the hand before re-entering palm between two heads of adductor pollicis
what does the radial artery anastomose with
deep branch of ulnar artery to form deep palmar arch