Poland syndrome (sequence) is a unilateral upper extremity condition that is generally not inherited. It occurs more frequently in males and more commonly affects the right upper extremity. There is frequently absence of the pectoralis major muscle and, in females, the breast on the affected side may fail to develop or may be hypoplastic. The fingers are often foreshortened and may not flex at the proximal interphalangeal joints (middle joints of the fingers). Frequently all the fingers are also webbed (syndactyly).
