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Dr. Frank
Dr. Frank, Board Certified Physician
Category: Neurology
Satisfied Customers: 9000
Experience:  Board certified general Adult Neurologist, with experience in experimental neuroimaging and neurodiagnostics.
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hard lump near tendon on hand, palm side between thumb and

Customer Question

Not sure why just answer sent this to neurology instead of ortho. First time using site - may have submitted incorrectly.


re. hard lump near tendon on hand, palm side between thumb and index finger for over a month

Submitted: 4 years ago.
Category: Neurology
Expert:  Dr. Frank replied 4 years ago.

Hello. Welcome to Just Answer. I will try to answer your question. Orthopedics doesn't seem to have any experts, so they send them here. If you have a hard lump in the area between your index finger and thumb, on the palmar surface, I would ask if it is in close approximation to the index finger MCP joint? (metacarpophlangeal joint). The most common reason would be a synovial cyst. These are outpouchings of the synovial membrane of the joint and they contain synovial fluid. I will leave you a webpage on this subject, please review it and get back to me if you think it fits.

Customer: replied 4 years ago.

no it is halfway between the thumb and index finger and about an inch in from edge of hand. seems attached to thumb

Expert:  Dr. Frank replied 4 years ago.

well, it could be a synovial cyst off the MCP joint on the thumb, also known as a ganglion cyst, or is could be a sesamoid bone if it has been there forever, or a rupture of the opponens pollicis muscle tendon, if you were working hard with your hand. the latter would be painful, is there any pain? since you said it was associated with a tendon, it could be a synovial cyst as an outpouching of the sheath around a tendon, in this case flexor pollicis longus (look at how the sheath is in the webspace) or flexor dig. superficialis tendon. In those situations, you might feel some resistance to flexing your fingers, the beginning of "trigger finger" I will attach a picture of the flexor aspect of you hand. When you flex your thumb, does the bump move? let me know ok? Dr Frank t cM&imgurl=,r:7,s:0,i:92&tx=71&ty=84

Customer: replied 4 years ago.

no pain; if my palm is wide stretched and I press on the lump, it unflexes my hand if that makes any sense; attempting to attach photo with area circled:


Expert:  Dr. Frank replied 4 years ago.
Hi I cannot get a three dimensional feel from that picture, but thanks. That is right in line with the flexor tendon to your index finger. So I would like you to keep your index finger straight, and bend it or flex it back and forth at the MCP (metacarpal phalangeal joint, the first joint of three in your finger) and keep your other index finger right on the bump, does it move up and down with the flexion of the finger? that would suggest a synovial sheath cyst, or an adhesion of the tendon itself inside the sheath, the beginning of trigger finger, which is really osteoarthritis of the hand as it effects the tendons. get back to me Dr Frank T