Wrist/hand Flashcards
What is the angulation of the wrist joint?
palmar tilt and radial inclincation (11 and 23 degrees)
What is significant of Lister’s tubercle?
pulley for EPL tendon
What is positive ulnar variance?
when ulna lies distal to radius
What is negative ulnar variance?
when ulna lies proximal to radius
What is complication of positive ulnar variance?
increased risk to TFCC degeneration
What is complication of negative ulnar variance?
spontaneous lunate necrosis (Kienbock dsease)
What is the most commonly fractured carpal?
Scaphoid
What is typical shape of lunate on imaging?
Quadrangular AP, crescent laterally.
triangle on AP indicates potential pathology
How would you palpate the triquetrum?
medial border of wrist during radial deviation
What runs under hook of hamate?
ulnar artery/nerve
What function does longitudinal arch of hand serve?
contributes to powerful gripping
Which bone transmits more force through wrist during gripping?
radius (80%)
What motions does the radius undergo during pronation?
anteromedial and proximal.
-ulna corresponds by moving (slightly) posterolateral and distal
How much of TFCC disc is vascularized?
15-20% near apex
Where is TFCC disc thicker?
peripheral region
Is degenrative or traumatic TFCC injury more common?
degenerative
How common is degenerative TFCC injury?
50-60% of people over 50 years old have it
Which row of the carpals is more stable?
Distal-firm ligaments, with little independent movement
Where do most wrist dissociations occur
Proximal row, less stable
Which motion causes collateral ligaments of MP joints to become taut?
flexion
When splinting MP joint, which position should joint be splinted in if possible?
as much flexion as possible
What helps keep extensor tendons over metacarpal heads?
sagittal bands and dorsal hood
What motion does volar plate limit?
hyperextension
Which position should IPs be splinted in if possible
full extension to prevent contracture of collateral ligaments and volar plates
Why are collateral ligaments taut in different positions for MP and IP joints?
Metacarpal heads are cam shaped, phalangees are not
What is in first extensor compartment at wrist?
APL and EPB
Which extensor compartment does De Quervain’s occur in
1st
What is in second extensor compartment of wrist?
ECRL and ECRB
What is in third extensor compartment?
EPL
What is in 4th compartment?
ED and EI tendons
What is in 5th compartment?
EDM
what is in 6th compartment?
ECU
How do extensor tendons connect to proximal phalangees
sagittal bands.
This connection allows extensor tendon to extend MTP joint
Laxity of what contributes to swan neck deformity?
lateral bands
What is swan neck deformity?
PIP extension with DIP flexion
What is primary action of FDS
PIP flexion
What flexes DIP?
FDP
What does FDP do?
flex DIP primarily.
Secondary: flex PIP and MP
Which finger flexor performs most unloaded movements, and is stronger?
FDP
What happens during parodoxial extension?
FDP is detached/too long. Extends DIP via lumbricals
