Hand and Wirst Flashcards
Name the proximal carpal bones (4)
Scaphoid, lunate, triquetral, pisiform
Name the distal carpal bones (4)
Trapezium, trapezoid, capitate, hamate
What is a DISI (dorsal intercalated segmental instability)?
Scapholunate dissociation causes the scaphoid to flex palmar and the lunate to dorsiflex (dorsally)
What is a VISI (volar intercalated segmental instability) ?
Lunotriquetral ligament rupture - lunate goes towards the palm
How do you test for FDP?
Flex the DIPJ
How do you test for FDS?
Isolate 1 finger and stretch out the rest (as FDP has a shared muscle belly for all fingers) and then flex the one finger at the PIPJ.
How do you test for the lumbricals?
Flex MCPJs and extend the distal joints.
What is ulnar claw?
Extended MCPJs and flex distal joints
What is trigger finger?
The flexor tendon becomes temporarily trapped at the entrance to it’s sheath. This is caused by thickening of the A1 pulley.
What does a Boutonniere Deformity look like? And whats the pathogenesis?
Flexion deformity of the PIPJ.
Caused by rupture of the central slip over the PIPJ by laceration or RA. The proximal phalanx pops through the like a finger through a button hole, as the lateral slips separate.
The collateral bands then migrate to the volar side, slipping past the joint fulcrum, pulling the distal bones proximally.
What does a Swan neck deformity look like? What’s the pathogenesis?
Caused by deformity in the volar plate - becomes overly lax allowing the finger to hyperextend
Name the constituents of the 6 separate extensor compartments of the wrist.
1 - EPB and APL 2 - ECRB and ECRL 3 - EPL 4 - Extensor Indicis and EDC 5 - EDM 6 - ECU
What causes Claw hand? Describe it’s appearance.
Is the resulting deformity worse if injured at the wrist or elbow?
Ulnar nerve injury - Often at either Guyon’s canal or the cubital tunnel.
The patient cannot extend the IPJs of their ring or little fingers, resulting in fixed flexion of the IPJs and hyperextension of the MCPJs of these two fingers.
Lateral 2 lumbricals palsy if at elbow.
If at wrist - lateral two of FDP also spared which flexes DIPs and makes claw appear worse.
What causes the Hand of Benediction? Describe it’s appearance.
Median nerve injury
Patient cannot make a fist with all of their fingers. Not able to flex index or middle, resulting in unopposed extension of these 2.
What nerve is most commonly injured in a proximal humeral #?
How would this present clinically?
Radial
Wrist drop and absent finger extension at MCPJs