The Wrist and Palm Flashcards
bones of the wrist
"Some Lovers Try Positions That They Can't Handle" (proximal to distal, lateral to medial) Scaphoid Lunate Triquetrum Pisiform Trapezium Trapezoid Capitate Hamate
wrist joint
- a condyloid joint (oval shaped synovial joint)
- reinforced with palmar and dorsal radiocarpal ligaments
what is the wrist joint formed by
- convex surface of proximal carpal bones
- concave surface of distal end of radius and the articular disc of the distal radioulnar joint
radiocarpal ligaments
- radial collateral: styloid process of radius to scaphoid
- ulnar collateral: styloid process of ulna to the triquetrum and pisiform
movement of the wrist joint
movement occurs between the proximal row of carpal bones and the radius/ulna. (although distal row articulates with proximal row, very little movement)
carpal groove
formed by the concavity of the ventral (anterior) side of the carpal bones; exaggerated by the tubercles of scaphoid, trapezium,and pisiform and the hook of hamate.
- the flexor retinaculum stretches over it to form the carpal tunnel
- *note: the bones are convex on the posterior surface
flexor retinaculum
- thickening of the deep layer of the antebrachial fascia
- forms the carpal tunnel from the carpal groove
- a strong transverse band between the pisiform/hamate (medial) and the scaphoid/trapezium (lateral)
- located between the superficial and deep flexor muscles
structures that pass through the carpal tunnel
- flexor pollicis longus (deep muscle)
- flexor digitorum superficialis (IM muscle) and profundus (deep muscle) .. 8 tendons
- median nerve
structures that pass anteriorly to the carpal tunnel
- palmaris longus (inserts on palmar aponeurosis)
- flexor carpi ulnaris (inserts on pisiform, hamate, and base of MC V)
- ulnar nerve/artery
* ** FLEXOR CARPI RADIALIS does not pass through the tunnel, it has its own tunnel
carpal tunnel syndrome
- due to a decrease carpal tunnel size (due to arthritis, inflammation etc.)
- results in compression of median nerve: results in numbness and both sensory/motor weakness
- due to overuse of digits, swelling of tendons, compression by a broken bone
- incision of flexor retinaculum may be necessary
tubular synovial sheath
- encase the tendons from wrist to hand/digits
- inner visceral and outer parietal layer (potential for synovial fluid between)
- ulnar bursa (FDS and FDP) , radial bursa (flexor pollicic longus), and synovial sheath for flexor carpi radialis
common synovial sheath
- encloses all the superficialis and profundus tendons (8 of them)
- aka ulnar bursa
- continuous distally beyond the middle of the palm (digital sheath for digit V), the rest ends at mid-palm **digits II-IV no synovial sheath in palm until in the digits
radial bursa
- synovial sheath that covers the tendon of flexor pollicis longus
- extends distally to the terminal phalanx of the thumb
Palmar Aponeurosis location
- deep fascia of central palm
- continuous with thenar and hypothenar fascia
- Proximal: palmaris longus
- Distally: flexor digitorum superficialis
palmar aponeurosis in relation to palmar nerves/arteries/veins
cutaneous nerves = superficial to palmar aponeurosis
arteries/nerves/tendons = deep to palmar aponeurosis
function of palmar aponeurosis
to protect contents of palm (lie deep to it)
Dupuytren’s contracture
- progressive fibrosis of the palmar aponeurosis
- results in shortening/ thickening of palmar aponeurosis… causes a pull on the digits and metacarpophalangeal joints towards the palm of the hand
anterior wrist arteries/muscles (from lateral to medial)
lateral to medial: radial artery (pulse), flexor carpi radialis (medial to which is the median nerve), palmaris longus (when present), flexor digitorum superficialis, ulnar artery (medial to which is the ulnar nerve), and flexor carpi ulnaris
extensor retinaculum
- formed by the posterior distal antebrachial fascia
- extends obliquely from the anterior border of the radius to the styloid process of the ulna
- creates 6 synovial sheaths
synovial sheaths from extensor retinaculum
- all begin proximal to the extensor retinaculum
- contain:
1. adbuctor pollicis longus/ extensor pollicis brevis
2. extensor carpi radialis longus and brevis
3. extensor pollicis longus
4. extensor digitorum and extensor indicis
5. extensor digiti minimi
6. extensor carpi ulnaris
What forms the borders of the anatomical snuff box? what runs through it?
- form it: tendons of abductor pollicis longus, extensor pollicis brevis (anterior border, together), and extensor pollicis longus (posterior border)
- roof: superficial radial nerve goes through
- floor: radial artery goes through
Location of median nerve in wrist
- found medial to the tendon of flexor carpi radialis and lateral to the palmaris longus
- enters the carpal tunnel
Affect of carpal tunnel on palm (due to median nerve)
- motor impairment to thenar muscles
- sensory impairment to palmar aspec of lateral 3.5 digits
- NO sensory impairment to the palm (median nerve sends a palmar cutaneous branch superior to the flexor retinaculum)
Branches of the median nerve in the wrist
- Palmar branch (superior to carpal tunnel, thus not affected by carpal tunnel syndrome): sensory to anterior digits I, II, III and lateral IV (posterior distal digit sensation also)
- digital nerves
- recurrent branch
