Finger Lesions
Lesions of the fingers are common. The fingers are important tactile organs and hand function may be impaired. Painful finger lesions are dealt with on p. 153.
Causes
Acquired
Traumatic/Degenerative
Figure 21 Boutonnière deformity.
This common deformity in advanced rheumatoid arthritis results from the rupture of the central slip of the extensor tendon over the proximal interphalangeal joint. The lateral slips of the extensor tendon mechanism are displaced to the sides and maintain the deformity.
History
Congenital
These lesions will be recognisable at birth. They may be associated with other congenital abnormalities.
Acquired
Traumatic/degenerative
Dupuytren’s contracture
In the early phases, the patient may merely complain of a nodule in the palm near the base of the ring finger. Eventually, the patient complains of being unable to extend fully the MCP joint at the ring, and later, the little finger. It affects the patient’s grip. The patient complains of difficulty dressing – either poke themselves in the eye while brushing hair or catch the finger on a trouser pocket. There may be a family history. Check also for a history of epilepsy, cirrhosis or diabetes.
Implantation dermoid
Cysts occur where skin is forcibly implanted into the subcutaneous tissue as a result of injury. There is likely to be a history of injury, often minor, e.g. pinprick. Implantation dermoid used to be common in women who sewed – hence the use of protective thimbles. The patient complains of small painful swellings on the finger tips.
