Three-Knuckle Test

​TESTING FOR:

The available active range of depression of the mandible or TMJ hypomobility.

PROCEDURE:

Instruct the client to open their jaw.

Ask them to insert as many of their own flexed proximal interphalangeal joints of the non-dominant hand between their teeth.

POSITIVE SIGN:

The client can only get one knuckle or knuckles between their teeth.