swan neck deformity

swan neck deformity

[swän]

Etymology: D, zwaan + AS, hnecca, neck; L, deformis, misshapen

1 also called zig-zag. an abnormal condition of the finger characterized by flexion of the distal interphalangeal joint and hyperextension of the proximal interphalangeal joint. It is caused by a taut profundus tendon in the presence of a weakened distal interphalangeal joint and may be combined with a volar plate rupture. The condition is seen most often in rheumatoid arthritis.

2 a structural abnormality of the kidney tubules associated with rickets. The kidney tubule connecting the glomerulus with the convoluted part of the tubule is narrowed into a configuration referred to as "swan neck." There are also a thinning and atrophy of the distal tubule and a shortening of the convoluted part.

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swan neck deformity

Rheumatology A descriptor for the hyperextended proximal interphalangeal joint and compensatory flexion of the distal interphalangeal joints caused by shortening of the extensor tendon, classically seen in rheumatoid arthritis, but also in SLE, post-rheumatic fever arthritis, psoriatic arthritis, scleroderma, camptodactyly. Cf Boutonniere deformity.