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

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.

linburg comstock syndrome

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. 

5 Comments

  1. V. Jackson on January 31, 2020 at 9:03 am

    I love that great fun fact with a quick explanation, great visual representation of the UE possible problems, and treatment options that are available.

    Thanks.

  2. spencer on January 24, 2023 at 2:14 pm

    I have this issue but not just one or two fingers is every finger in both hands. if i bend thumb even my little finger goes with it. Just wondering how rare it is for that to happen?

  3. Sammie on January 14, 2026 at 1:51 pm

    Thanks for sharing! Funny enough, I also found out I had this anomaly during my level 1 OT fieldwork rotation at a hand therapy clinic! Actually, I realized I had this involuntary flexion of the index finger when I was young, in girl scouts, and I was unable to do the girl scout hand sign without my pointer finger bending. I forgot about it until my fieldwork rotation, where I found out the name of what it was and why it occurs! So, I guess another clinical test option could be to have the client try to do the girl scout hand sign 😂

  4. Claire Morrissey on April 23, 2026 at 8:43 pm

    I have it slightly on the right side, but extremely pronounced on the left side, which I only noticed after my left wrist broke and was surgically repaired with a metal plate. I can’t flex my left thumb without the 2 farthest joints of left index flexing all the way down. Can surgery or tge original injury make this condition worse?

    • Miranda Materi on April 30, 2026 at 12:01 pm

      I would recommend seeing a doctor as we are not really allowed to give out specific medical advise on this platform. Thanks

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