MRCP UK EXAMINATIONS

Detailed explanation-1: -A Boutonniere deformity is a deformity of the fingers in which the proximal interphalangeal joint (PIP) is flexed and the distal interphalangeal joint (DIP) is hyperextended. It is an extensor tendon injury over zone III. It is also referred to as a “buttonhole deformity."

Detailed explanation-2: -Swan neck deformity is characterized by proximal interphalangeal (PIP) joint hyperextension and the distal interphalangeal (DIP) joint flexion. There is also reciprocal flexion noted of the metacarpophalangeal (MCP) joint. This is a result of an imbalance of the extensor mechanism of the digit.

Detailed explanation-3: -The degree of flexion of the proximal interphalangeal joints increases slightly across digits 2-5, however, can be generally said to be in the range of 100° to 110°.

Detailed explanation-4: -Swan-Neck Deformity (SND) is a deformity of the finger characterized by hyperextension of the proximal interphalangeal joint (PIP) and flexion of the distal interphalangeal joint (DIP). Reciprocal flexion of the metacarpal phalangeal joint (MCP) can also be present.