You are currently viewing Adducted Thumb Syndrome :‎ Medical Notes & Mindmap

A uncommon hereditary condition known as Adducted thumb syndrome alters how the thumb and fingers develop. It is distinguished by a fixed, adducted (bent inward) position of the thumb, which can make it challenging to grasp and manipulate objects. Tapering, webbing, and brachydactyly are just a few of the anomalies in the fingers that can result from adducted thumb syndrome (shortened fingers).

Adducted Thumb Syndrome :‎ [MEDNOTES+MINDMAP]


  • Definition: Rare congenital disorder characterized by abnormal development and positioning of thumb, resulting in thumb being held close to palm of hand
  • Epidemiology:
    • Prevalence: 1 in 100,000 individuals
    • More common in males
    • Can occur in all racial and ethnic groups
  • Natural history:
    • Becomes apparent at birth or in first few months of life
    • Difficulty with grasping objects and performing fine motor tasks in severe cases
    • Difficulty with certain activities in milder cases
  • Classification/Types/Stages:
    • Three types based on severity of thumb abnormalities: mild, moderate, severe
    • Four stages based on severity: stage 1 (mild), stage 2 (moderate), stage 3 (severe), stage 4 (complete adduction)
      • Mild: Thumb slightly adducted, can be extended to normal position
      • Moderate: Thumb more severely adducted, can be extended to limited degree
      • Severe: Thumb completely adducted, cannot be extended
      • Complete adduction (stage 4): Thumb adducted, additional abnormalities such as webbing between fingers or fusion of thumb and other fingers present

Risk Factors:

  • Genetics
  • Occupational factors (e.g. frequent use of vibrating tools)
  • Previous hand injuries
  • Medical conditions (e.g. rheumatoid arthritis)


  • Abnormal development of the muscles and tendons in the hand and thumb
  • Repetitive strain or overuse of the thumb
  • Trauma to the thumb


  • Thumb held in a position of adduction (closer to the body)
  • Decreased range of motion in the thumb
  • Tendency to use the side of the thumb for gripping and grasping instead of the tip


  • Pain and discomfort in the thumb and wrist
  • Weakness in the thumb
  • Difficulty with fine motor tasks that involve the thumb (e.g. tying shoelaces)


  • Inflammation and degeneration of the muscles and tendons in the thumb
  • Formation of scar tissue
  • Compression of the nerves in the thumb
  • Deformity of the thumb joint
  • Diagnosis

    • Physical examination by a healthcare provider to assess thumb position and range of motion
    • X-rays to determine the severity of the deformity
    • Genetic testing to check for any underlying genetic conditions
  • Tests Required

    • X-rays
    • Genetic testing
  • Associated with

    • Down syndrome
    • Apert syndrome
    • Pfeiffer syndrome
    • Muenke syndrome
  • Similar diseases/syndromes

    • Brachydactyly (shortened fingers or toes)
    • Camptodactyly (flexible or fixed contracture of the fingers)
    • Congenital hand abnormalities
  • Treatment

    • Splinting and physical therapy to improve range of motion and reduce adduction of the thumb
    • Surgery to correct the deformity, including osteotomies (bone cuts) and tendon transfers
    • Orthotic devices to support the thumb and improve function
    • Genetic counseling for individuals with underlying genetic conditions causing Adducted Thumb Syndrome.

Dr. Arin Nandi

Passionate About Medical Science & Helping Future Doctors Achieve Top Ranks In Medical Exams. He is professionally a dentist as well as a public health expert from JIPMER working in department