What Is Ulnar Dysplasia? Babies with ulnar dysplasia (also called ulnar club hand) are born with a short or missing ulnar bone. The ulnar bone is one of the two forearm bones. The short or missing ulnar bone causes the hand and wrist to turn outward toward the pinky side of the forearm. The hand, wrist, and elbow can have changes too. What Are the Signs & Symptoms of Ulnar Dysplasia? There are four types of ulnar dysplasia . Signs and symptoms depend on what type of ulnar club hand a child has. Type I This is the mildest form of ulnar dysplasia. The ulna is just a little shorter than normal and the wrist only turns out slightly. Type II The ulna is much smaller than normal. The other bone of the forearm (the radius) is bowed and the hand turns out more. Type III There is no ulna at all. The radius is bowed and the wrist is very turned out. Type IV There is no ulna at all. The wrist is very turned out, and the bones of the elbow are fused together so the elbow joint does not move well. In all types, the fingers may be smaller than usual or completely missing. Ulnar club hand can happen on one or both sides. What Causes Ulnar Dysplasia? Ulnar dysplasia happens while a baby is developing in the womb. Ulnar dysplasia also can be associated with leg growth differences. Sometimes it can happen as part of a genetic syndrome where there are other medical problems too. Who Gets Ulnar Dysplasia? Any baby can be born with ulnar dysplasia. It usually does not run in families. How Is Ulnar Dysplasia Diagnosed? A prenatal ultrasound might show ulnar dysplasia. Otherwise, doctors diagnose it when a baby is born. X-rays of the bones in the hands and arms will help doctors decide on the best kind of treatment. Other tests might be done to see if the ulnar dysplasia is part of a genetic syndrome. How Is Ulnar Dysplasia Treated? Treatment for ulnar dysplasia depends on how severe the changes are. Treatment may include: exercises splinting and casting to help stretch the arm and wrist surgery Looking Ahead Even with challenges, children with ulnar dysplasia are very good about finding ways to use their hands well. Some tasks can be adapted, like having shoes with Velcro instead of laces. Work with the medical team to help your child learn what works best. Back to Articles Related Articles Radial Dysplasia Babies with radial dysplasia (also called radial club hand) are born with a short or missing radial bone. This makes the wrist turn in. Read More Polydactyly Polydactyly is when a baby is born with an extra finger on the hand or an extra toe on the foot. It can be on one or both hands or feet. Read More Syndactyly Syndactyly is when a baby is born with two or more fingers or toes joined or "webbed" together. Read More Symbrachydactyly Babies with symbrachydactyly are born with short often webbed fingers. Some might be missing fingers. Read More Thumb Duplication Babies with thumb duplication (or thumb polydactyly) are born with an extra thumb on one or both hands. Most will have surgery to fix the problem. Read More Thumb Hypoplasia Babies with thumb hypoplasia are born with a thumb that is smaller than normal, or with the thumb missing completely. Read More Leg Length Discrepancy Leg length discrepancy is when someone’s legs are different lengths. For a big difference or one that's likely to get worse, treatment is recommended. Read More Fibular Hemimelia Babies who have fibular hemimelia are born with a short or missing fibula. Experts who treat bone problems have several options to help kids with a hemimelia. Read More Bones, Muscles, and Joints Without bones, muscles, and joints, we couldn't stand, walk, run, or even sit. The musculoskeletal system supports our bodies, protects our organs from injury, and enables movement. Read More Occupational Therapy Occupational therapy can help improve kids' cognitive, physical, and motor skills and build their self-esteem and sense of accomplishment. Read More X-Ray Exam: Forearm A forearm X-ray can help find the causes of pain, tenderness, swelling, or deformity. It can detect broken bones, and after a broken bone has been set, help determine whether it has healed properly. Read More X-Ray Exam: Hand A hand X-ray can help find the cause of pain, tenderness, swelling, and deformity. It also can detect broken bones or dislocated joints. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.