College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Is Trigger Finger associated with thickening of the flexor or extensor sheaths?

1. Extensor Sheaths

2. Flexor Sheaths

3. Both flexor and extensor sheaths

4. Neither flexor nor extensor sheaths

The correct answer is: Flexor Sheaths

Trigger Finger is associated with thickening of the flexor sheaths. The condition occurs when the tendons that flex the fingers (the flexor tendons) encounter difficulty passing through the narrowed or thickened area of their respective sheaths, which are the fibrous tunnels that support these tendons. When the flexor sheaths become irritated or inflamed, they lead to the characteristic locking or catching sensation, which is the hallmark of Trigger Finger. The flexor sheaths are important as they protect the tendons during movement and allow smooth gliding. When the synovial lining of these sheaths becomes thickened, it restricts the motion and can result in the finger becoming stuck in a bent position, hence the term "Trigger Finger." In contrast, the extensor sheaths are related to the tendons that extend the fingers, and they are not typically involved in this specific condition. Understanding the anatomy and function of these sheaths is essential for recognizing the mechanics of Trigger Finger and its treatment.