Extensor Mechanism of Hand

Question 1

What are the volar plates?

Answer 1

Fibrocartiligous reinforcemants at the joint capsule of the MCPs and IPJs. Volar plates contribute to finger joint stability

Question 2

What are arrangement of the extensor tendons and sagittal bands?

Answer 2

Extensor tendon of each hand broadens into a flat extensor hood at the level of the MCP. Fibres wrap around the MCP and PIPJ to form sagittal bands.

This then continues along the proximal phalanx before dividing into the central slip and lateral bands. The central slip inserts into the base of the middle phalanx. Lateral bands insert into the base of the middle phalanx.

Question 3

What can happen with central slip injury?

Answer 3

Central slip injury can be caused by damage over dorsum of hand such as laceration. This can result in a boutonniers deformity resulting in hyperflexion of the PIPJ and hyperextension at the DIPJ