Poland’s syndrome: This is a syndrome in which the pectoralis major muscle is deficient and the fingers are joined, and was first reported in 1841 by Poland, a medical student in London, during an autopsy. It is also known as Poland’s syndrome, Poland’s syndactyly, Poland’s sequence, and Poland’s malformation. It is a rare congenital defect characterized by congenital hypoplasia or absence of unilateral pectoral muscles (rarely bilateral) with ipsilateral syndactyly of the fingers. The condition usually occurs on the right side of the body. More males than females have been identified with this condition. Clinical symptoms: Concentration on the trunk and upper extremities, more common in males, generally unilateral, rarely bilateral. In the mildest cases, there is only a defect of the head of the sternum of the pectoralis major muscle and a malformation of the 3rd to 4th fingers. In severe cases, in addition to the entire pectoralis major muscle, the pectoralis minor, serratus anterior, intercostal muscles, and even some of the adjacent latissimus dorsi, external abdominal oblique muscles, and even some of the ribs and rib cartilage of the anterior thorax are also involved. Some of them also show abnormal breathing in the chest, lung herniation, high scapulae, hypoplasia of the affected skin and subcutaneous fat, and high nipples, or small or no breast development in women. Hand deformities may include different types of syndactyly, short fingers, missing fingers, middle phalanges of 2 to 4 fingers, fusion of deep and superficial flexor tendons, fusion of carpal bones, and fusion of ulnar radius. Individual cases may also be associated with auricular deformity, hemivertebrae, scoliosis, renal deformity, and cryptorchidism. In women with Poland syndrome, reconstructive breast surgery, either with autologous tissue transplantation alone or in combination with prosthetic implants, is possible. Probability According to the National Human Genetics Research Center, Poland’s syndrome is three times more likely to occur in men than in women, and two times more likely to occur on the right side of the patient’s body than on the left side. The probability of occurrence is estimated at 1 in 7,000, 100,000. Causes The causes of Poland’s syndrome are unknown. One theory is that it is caused by inadequate blood supply to the subclavian artery of the embryo when it reaches 46 days of development.