Children's Hospital Colorado

Radial Dysplasia (Radial Longitudinal Deficiency/Radial Club Hand)

What is radial dysplasia?

Radial dysplasia – also known as radial longitudinal deficiency or radial club hand – is a condition in which:

  • The radius does not form normally, and the radius bone might be short or missing completely.
  • The thumb might be small and does not work normally or the thumb might be missing completely, known as thumb hypoplasia/aplasia.
  • Some of the bones and other structures of the forearm, wrist or hand might not be normal or are missing completely.
  • There is often a curving of the forearm toward the thumb.

About hand, wrist and forearm bones

The forearm (area between the wrist and the elbow) has two bones:

  • Radius: bone on the thumb side of the arm
  • Ulna: bone on the small finger side of the arm

The hand and wrist have many bones, including:

  • Phalanges (finger and thumb bones)
    • Each finger has three bones.
    • Each thumb has two bones.
  • Metacarpals (main bones in the palm of the hand)
  • Carpals (wrist bones)

What causes radial dysplasia?

Radial dysplasia occurs when bones of the arm do not grow normally when the baby is growing in the mother's uterus.

The cause of this is unknown. It is often part of a syndrome (a group of symptoms) and/or might be a genetic condition (passed down in families).

Get to know our pediatric experts.

Sarah Sibbel, MD

Sarah Sibbel, MD

Orthopaedic Surgery

Cailin Brazeau, PA-C

Cailin Brazeau, PA-C

Physician Assistant