Wrist, Palmar Hand Flashcards
(32 cards)
What is the most commonly injured carpal bone?
scaphoid
Palmar Arches
distal transverse arch
proximal transverse arch
longitudinal arch
Wrist Creases
- proximal, middle, distal
- roughly correspond w/ carpal bones
Abduction of Thumb
occurs at CMC joint … trapezium + 1st metacarpal
Extension/Flexion of Thumb
occurs at CMC, MCP, and IP joints
CMC Joint Osteoarthritis
common wear-and-tear of CMC joint of thumb from manual, hands-on work
Extrinsic Muscles
- originate proximal to the wrist
- generate greater force
Intrinsic Muscles
- contained entirely w/in the hand
- precise control
Superficial Extrinsic Flexor Muscles
flexor carpi radialis
flexor carpi ulnaris
*palmaris longus
Intermediate Extrinsic Flexor Muscles
flexor digitorum superficialis
Deep Extrinsic Flexor Muscles
flexor digitorum profundus
flexor pollicis longus
pronator quadratus
Bifurication of Flexor Digitorum Superficialis
- tendon of FDS splits at proximal phalanx and inserts on middle phalanx
- tendon of flexor digitorum profundus (FDP) emerges through FDS bifurication at middle phalanx and attaches to distal phalanx
- FDS only extends fingers at PIP, while FDP extends at both the PIP and DIP
Which muscles are innervated by two different nerves?
- flexor digitorum profundus
- flexor pollicis brevis
- lumbricals
Flexor Tendon Zones (Injuries)
- 5 distinct zones
- zone 2 (where FDS bifurication occurs, proximal/middle phalanx) is “no man’s zone” due to complex repair and rehab when injured
Digital Pulley System
- annular pulleys (5)
- cruciate pulleys (4)
- keeps tendon of palmar muscles of digits in place to prevent “bowstringing”
- A2 (distal phalanx) and A4 (middle phalanx) = most important
Vincula of Extensor Hood
- vincula brevia, vinculum longum
- tendinous strands of extensor hood that keeps FDS in place
Extensor Tendon Pathways in Fingers
- extensor expansion/hood
- splits into a central slip and two lateral bands, then reconnects at terminal tendon
- sagittal band and lateral band keep extensor tendon in place
Trigger Finger
- stenosing tenosynovitis
- inflammation/nodule of A1 pulley
- leads to locking of finger in flexed position (can be extended again passively/with assistance)
Arterial Supply of Hand
- radial artery runs posteriorly to thumb and forms floor of anatomical snuffbox
- superficial palmar arch
- deep palmar arch
- digital branches around digits
Mallet Finger Deformity
- ruptured long extensor tendon (runs to distal phalanx)
- DIP in flexed position
- no active extension, but can passively extend DIP
Boxer’s Fracture
fracture of neck of 5th metacarpal commonly resulting from end-on blow of fist
Gamekeeper’s/Skier’s Thumb
injury of ulnar collateral ligament of thumb
Thenar Compartment/Eminence
flexor pollicis brevis
abductor pollicis brevis
opponens pollicis
Hypothenar Compartment
flexor digiti minimi
abductor digiti minimi
opponens digiti minimi
