Poland syndrome is characterized by partial or complete absence of the major pectoral muscle (pectoralis major). It usually affects half of the chest and presents associated abnormalities, of varying severity, involving the thoracic cage, the upper limb on the same side (the hand particularly) and the breast (in females).
Poland syndrome is characterized by partial or complete absence of the major pectoral muscle (pectoralis major).
It usually affects half of the chest and presents associated abnormalities, of varying severity, involving the thoracic cage, the upper limb on the same side (the hand particularly) and breasts (in females).

The clinical picture can vary considerably and is defined by the combination of different elements:

  • Complete or partial (presence of the section of the muscle right under the clavicle) absence of the major pectoral muscle (pectoralis major).
  • Absent or underdeveloped muscles of the thoracic cage.
  • Absent or underdeveloped breast on the affected side (including the nipple).
  • Breastbone abnormalities (escavatum, carinatum).
  • Rib abnormalities (either lacking or underdeveloped ribs; often involves rib 2, 3, 4, 5 )
  • Abnormally placed underarm (axillary) hair and chest hair for males.
  • Hand abnormalities to different degrees (brachydactyly, missing fingers).
  • Other rarest and less distinctive disorders (cardiac / renal abnormalities).