Wrist And Hand Flashcards
Wrist bones
SLTPTTCH
Scaphoid, lunate, triquetrum, pisoform
Trapezium, trapezoid, capitate, hamate
Scaphoid problem
Has a high incidence of non-union
Lunate Problem
Most common carpal bone dislocated (not verified, heard this in PPT)
When to refer for imaging of wrist?
- Scaphoid TTP
- Traumatic history
- Not willing to move
- Exquisite pain on palpation
Types of wrist fractures?
Colles = complete fracture of radius (close to the wrist) with dorsal displacement (and possibly radial; displacing radioulnar joint) of distal fragment
Smith = fracture of radius (usually from hyper flexion) and the distal fragment goes towards the palmar side of hand
Barton = fracture of distal radius with dislocation of radiocarpal joint (fracture can be palmar or dorsal direction)
Types of Hand Fractures?
Boxer’s = break in neck of 5th metacarpal
Bennett’s = fracture plus dislocation of 1st metacarpal bone at base of thumb
Scaphoid fracture
Hook of hamate fracture
Types of AVN in the wrist
Kienbock’s Disease = AVN of lunate
Preiser’s Disease = AVN of scaphoid
AVN of triquetrum
Wartenberg’s Disease
Superficial radial nerve entrapment between brachioradialis and ECRL. Only sensory and gives pain over distal radial forearm and paresthesias of dorsal radial hand. Often confused with DeQueirvain’s.
Peripheral nerve distribution pattern
Superficial branch radial nerve = radial thumb and dorsal 1-4 (1/2 of 4) but not the tips
Median nerve = palmar digits 1-4 (1/2 of 4) and dorsal tips
Ulnar nerve = ulnar hand and pinky plus 1/2 of ring
Claw Hand
Claw Hand: Ulnar nerve palsy at cubital tunnel that causes MCP extension, IP flexion (due to weakness of intrinsics) at digits 4 and 5.
Since the lesion is at wrist, ulnar portion of FDP is spared. The EDC is good at extending MCP’s but can’t extend IP’s due to lack of assistance from interossei through dorsal hood).
What does ulnar nerve innervation in the hand/forearm?
- Lumbricals 3 and 4
- All interosseous muscles
- Add Pollicis
- Deep head of flexor pollicis brevis
- All hypothenar muscles
- FCU
- Medial 1/2 of FDP
What muscles help extend the fingers?
The EDC isn’t strong enough to extend the IP joints, only MCP joints. The lumbricals and interossei attach onto the posterolateral aspect of the extensor hood (expansions of EDC) to help extend IP joints.
What does median nerve innervate
- FDS
- Radial FDP
- Thenar muscles
- Pronator quadratus
- Lumbricals of middle and index finger
- FPL
- FPB
Ape Hand
Median nerve injury. The thenar muscles are paralyzed and now the adductor pollocis is unopposed and pulls thumb up into plane of other fingers.
Sign of benediction
Seen with high median nerve injury and is an active sign. When person tries to make a fist they can only engage the ulnar side of the FDP that innervates the ulnar 2 fingers.
Radial Hand Common Conditions
- CMC OA
- Scaphoid or radius Fx / AVN
- DeQuervain’s
- Skier’s Thumb
Scaphoid fracture
- Usually a FOOSH
- Radial wrist pain that is worse with loading
- Positive scaphoid compression test (axial load through 1st MCP or radial deviation and axial load through 2nd/3rd MCP)
- May not have positive imaging finding immediately (be concerned about Preiser’s Disease - AVN of this)
De Quervain’s
1. Tendons affected
2. Splinting time
1.Most common in EPB, APL.
2. If indicated, 4-6 weeks
Most important wrist ligaments?
In proximal row: scapholunate and lunotriquetral (link lunate to adjacent bones).
Articular Disc of wrist
Originates from ulnar EDGE of distal radius and covers the ulna. Blends with radioulnar ligaments.
TFCC components and function
- TFC Disc (lies on distal ulna)
- Meniscus homologous (between ulnar styloid and triquetrum)
- Radioulnar ligaments
- ECU sheath
- UCL
- Ulnolunate and ulnotriquetral ligaments
Stabilizes DRUJ, ulnar carpal bones, transmits load between ulna and lunate/triquetrum.
Blood supply to hand
Superficial arch from ulnar artery, deep arch through radial artery.
Tendons through carpal tunnel
- Finger flexors
- FPL
Guyon’s Canal
Contains ulnar nerve and artery and passes between pisiform and hook of hamate.
What are the borders of the snuffbox?
From Left to Right
APL -> EPB -> EPL
Test motor function of median, ulnar, radial nerves?
Median: Thumb abduction against resistance
Ulnar: Index abduction
Radial: Pull thumb dorsally against resistance
Gilula’s Lines
Smooth continuous arcs representing the proximal and distal carpal rows. If disrupted, disorder may be present.
How long do wrist fractures USUALLY take to heal?
6-8 weeks
Most common carpal fractures
- Scaphoid
- Dorsal cortical triquetral
How to diagnose scaphoid fracture?
- Radial sided wrist pain
- TTP anatomic snuffbox
- Pain with axial loading of thumb
- MRI needed if x-ray needed and high suspicion detected