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What is Poland syndrome?

Poland syndrome is a rare birth defect characterized by an underdeveloped chest muscle and short webbed fingers on one side of the body. The exact causes are unknown, but it likely arises during fetal development due to a disruption in the blood supply to the chest wall and hand. Poland syndrome affects males more frequently than females, and the right side of the body more often than the left. The main signs are:

Underdeveloped Chest Muscle

The key feature of Poland syndrome is an underdeveloped or absent chest muscle on one side of the body, known medically as pectoralis major. This muscle is important for moving the shoulder and arm. Its absence leads to chest asymmetry or a sunken-in appearance on the affected side. Sometimes other chest muscles are also underdeveloped, such as the pectoralis minor. The lack of chest muscle may be barely noticeable or severe enough to expose the ribs underneath.

Short Webbed Fingers

Short webbed or fused fingers, known as symbrachydactyly, are present in many cases of Poland syndrome. Typically the ring and little fingers are most affected. The fingers can range from mildly shortened to almost missing entirely. The thumb and index finger are rarely involved. The hand bones may also be underdeveloped or absent.

Other Possible Features

Some other features that may occur in Poland syndrome include:

  • Absent breast or nipple on the affected side
  • Thin or weak shoulder muscles
  • Abnormalities in the ribs or vertebrae
  • One arm or hand slightly shorter than the other
  • Loss of sensation or numbness in the hand
  • Delayed growth of arm bones

What Causes Poland Syndrome?

The exact cause of Poland syndrome is unknown, but it likely arises during early fetal development. The most well-accepted theory is that a disruption of blood supply to the fetal chest wall and hand causes impaired growth and underdevelopment of the muscles and bones. This could be due to:

  • Problems with the subclavian artery or other blood vessels
  • Abnormalities in the nervous system or nerve supply
  • Genetic mutations

In many cases, no specific cause can be identified. Poland syndrome is considered sporadic, meaning it occurs randomly. Some factors that may increase the risk include:

  • Male sex – the condition is 3 to 5 times more common in males
  • Family history – having a relative with Poland syndrome slightly increases risk
  • Maternal smoking or substance abuse during pregnancy
  • Mother’s age over 30
  • Complications during development of the embryo

Diagnosis of Poland Syndrome

Poland syndrome is diagnosed based on the physical examination findings. Diagnostic tests may include:

  • Physical exam – The doctor looks for underdeveloped chest muscles, hand abnormalities, and other associated features.
  • Imaging – An X-ray, CT or MRI scan can confirm which muscles are involved and detect any other affected bones.
  • Genetic testing – Rarely done, but may identify any genetic mutations.

The condition may be detected prenatally through fetal ultrasound. But it is often not recognized until after birth when the physical defects become apparent. Most cases are diagnosed in infancy or early childhood.

Treatment for Poland Syndrome

There is no cure for Poland syndrome. Treatment aims to help normalize appearance and improve function. Options may include:

  • Breast reconstruction – Breast implants or fat grafting can be done in late adolescence to improve breast symmetry.
  • Custom padding – Custom shoulder pads or prosthetics can help make chest contours look more balanced.
  • Physical therapy – Exercises can strengthen the affected muscles and prevent stiffness in the hand.
  • Occupational therapy – Activities and devices to improve hand dexterity and function.
  • Surgery – To separate fused fingers, reconstruct partial hand muscles, or repair bone abnormalities.

Supportive care from a multidisciplinary team provides the best outcome. This may include plastic surgeons, orthopedic specialists, pediatricians, therapists, and mental health professionals.

Prognosis of Poland Syndrome

The outlook for individuals with Poland syndrome is generally very good, especially when only one side of the body is involved. Most people have normal intellect and life expectancy. Early interventions can help improve appearance and function. However, those with extensive hand or arm abnormalities may have greater disability.


Potential complications that may arise include:

  • Restricted shoulder movement due to weak muscles
  • Breathing problems if chest wall muscles are highly abnormal
  • Bone abnormalities in the hand or arm
  • Psychological distress due to appearance

Some people may also have associated congenital heart defects, kidney abnormalities, or other problems.

Living and Coping with Poland Syndrome

Here are some tips for living with Poland syndrome:

  • Get early treatment – Early physical and occupational therapy can help improve function.
  • Consider cosmetic options – Discuss choices like breast implants, padding, or reconstruction with your doctor.
  • Protect the affected hand – Use padding or splints to prevent injury in sports or heavy labor.
  • Watch for overuse – Strengthen the affected side through exercise, but avoid repetitive motions and overexertion.
  • Seek emotional support – Join Poland syndrome support groups to connect with others.
  • Boost self-esteem – Find clothing options to balance your shape, and focus on your abilities.

With proper comprehensive care and self-acceptance, many people with Poland syndrome can thrive and live normally.


Poland syndrome is a rare congenital disorder affecting the chest muscles and hand on one side of the body. The main features are underdevelopment or absence of the chest muscle, short webbed fingers, and sometimes other bone abnormalities in the hand, chest, and arm. The exact cause is unknown, but likely relates to disrupted blood supply in fetal development.

There is no cure, but treatment aims to improve appearance and hand function through reconstructive surgery, therapy, and use of padding or prosthetics. Support from a multidisciplinary team provides the best outcome. Many people with Poland syndrome can live normal lives with minimal disability when appropriate treatment is obtained.