A Fun Fact from a Hand Therapy Student

By: Ammie Ingwaldson

Level 2 Fieldwork at a hand therapy clinic is a fast paced and continuous learning experience. The perfect example of this occurred last week while observing a therapist provide a client with their home CMC arthritis program.  The therapist was educating the client on how to oppose their thumb to their small finger. While we watched them practice, she stated, “you have the Linburg sign!” She quickly turned to me and had me oppose my thumb to the base of my small finger, then confirmed that I had it as well. I began to become slightly concerned. We had not reviewed this sign or condition in school. I began to wonder if it was treatable and if it would affect me. My worries were put at bay when she then showed that she had it as well and provided an explanation of what it entailed.  

Linburg Comstock syndrome is an anatomical anomaly connecting the tendons of flexor digitorum profundus (FDP) of the index finger and flexor policis longus (FPL) (Puroshothaman & Powers, 2008). This connection of tendons leads to involuntary flexion of the index finger at the distal interphalangeal (DIP) joint with flexion of the interphalangeal (IP) joint of the thumb. The incidence of this anomaly is 37%, with higher distribution of unilateral sign than bilateral.

In most cases Linburg-Comstock syndrome is asymptomatic, but it can present as pain in the distal forearm, wrist, or hand. Median nerve symptoms, similar to carpal tunnel, can also be present due to tendon inflammation, presence of additional tendons, or synovitis with in the carpal tunnel (Puroshothaman & Powers, 2008). Individuals with repetitive thumb and finger movements, such as musicians, are more susceptible to pain or carpal tunnel like symptoms. Surgical release of the connection of FPL and FDP can be performed to relieve symptoms (Old, Rajaratnam & Allen, 2010). 

References

Old, O., Rajaratnam, V., & Allen, G. (2010). Traumatic correction of Linburg-Comstock anomaly: a case report. Annals of the Royal College of Surgeons of England, 92(4), W1–W3. doi:10.1308/147870810X12659688852031

Puroshothaman, P., & Powers, D. (2008) A simple diagnostic test for symptomatic Linburg-Comstock anomaly (Linburg-Comstock test). The Internet Journal of Hand Surgery, 2(2), 1-3.