subluxation

Pisiform

Subluxation & dislocation

 

Diagnosis

 

Pisotriquetral view

- forearm positioned 30° supinated off the neutral position

- loss of symmetry between the pisiform and triquetrum is required for the diagnosis

- carpal tunnel view may be helpful in further assessment of the joint

 

Osteoarthritis

 

Clinical

 

More common problem

 

Subluxation ECU

Anatomy

 

6th compartment

- fibro-osseous tunnel overlying 1.5 cm to 2.0 cm of distal ulna

- held tight by the extensor carpi ulnaris tendon sheath

- the extensor retinaculum passes around the ulna to insert on the palmar aspect of the carpus

- extensor retinaculum is a separate structure from the ECU tendon sheath

 

Mechanism

 

Forced supination, palmar flexion, and ulnar deviation