Thumb Hypoplasia and Aplasia

Also known as: hypoplastic thumb, missing thumb.

What are thumb hypoplasia and aplasia?

Thumb hypoplasia and aplasia are birth differences that affect the thumb. Thumb hypoplasia means that the thumb is typically underdeveloped and small. With thumb aplasia, the thumb is missing altogether.

What causes thumb hypoplasia and aplasia?

The precise cause of thumb hypoplasia and aplasia isn’t clear. It sometimes occurs along with other birth differences, such as radial club hand.

What are the symptoms of thumb hypoplasia and aplasia?

Children with thumb hypoplasia and aplasia may have difficulty with normal use of the hand, especially for tasks that require pinch or opposition.

What are thumb hypoplasia and aplasia care options?

In many cases, surgery may be performed improve the function and appearance of a “smaller than normal” thumb. In cases where the thumb is very small or absent, surgery may be performed to build a new thumb. Hand therapy is helpful in training a child use his or her hand as well as possible before and after the surgery.

Reviewed by: Aaron J Berger, MD

This page was last updated on: June 23, 2022 05:02 PM

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