Extrinsic - hook of hamate fracture, handle bar palsy
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Zones of Guyon Canal sydrome?
Zone 1 proximal to bifurcation = mixed motor sensory
Motor here includes those by zone 2 but also Abductor Digiti Minimi
Zone 2 = deep motor branch only
Zone 3 = Sensory branch only
However, there is alot of variability
“The UN in Guyon’s canal has been found to have a significant variance in its anatomy. The most common variation is the UN branching into a deep and superficial branch within Guyon’s canal.”
“These variants can also alter the typical three-zone division of Guyon’s canal and the symptoms associated with each zone.”
‼️ What is the Bouvier test for claw/ intrinsic minus hand?
Bouvier test is an active test to evaluate the integrity of the extensor mechanism in a claw hand. it can then be classified into "simple" or "complex"
When passive correction of the MCP hyperextension allows the patient to extend the interphalangeal joints with the integrity of the extensor mechanism (Positive Bouvier´s test), the claw deformity is classified as a simple claw hand.
When the patient cannot actively extend the proximal interphalangeal joints after passive MCP hyperextension correction, extensor mechanism impairment exists (Negative Bouvier´s test), and deformity is classified as a complex claw hand.
4. Only for high palsy with paralysis of FDP ➔ FDP 2,3 tag to FDP 4,5 for finger flexion
Summary of tendon transfers
INTERESTING Ulnar nerve CASE
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*Case of "complete claw hand" but only ulnar nerve impairment
This is a clinical photo of this patient hand. Appears to be in "intrinsic minis" position and have severe wasting of the interossei muscles, also in the first interossei
Assess median nerve, ulnar nerve, check sensation by dermatomes
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What are the differentials for a COMPLETE claw hand?
Ulnar nerve + median nerve palsy ➔ check sensation of all fingers