Have you ever heard of a flail extremity? Our grandson was diagnosed with this at birth. We’re a thousand miles away in another state, with no way to know what’s going on. What is this condition?

Flail limb or extremity refers to an arm or leg that the child doesn’t seem to be moving. The cause of the problem must be determined. It could be a broken bone, damaged nerve (resulting in a condition called brachial plexus palsy), or infection. X-rays may help rule out fractures or dislocations. Lab values can be used to assess for infections. An undiagnosed infection can spread and cause considerable bone and joint damage, so time is of the essence.

Damage at birth to the nerves in the upper limb can cause brachial plexus injuries. The child doesn’t move the affected arm. The arm may be in a characteristic position that tips the examiner off as to the underlying problem. For example, with damage to the nerves at C5 and C6 in the neck, the wrist and hand may end up stuck in the waiter’s tip position. The wrist is bent and the forearm is turned with the hand facing backwards (as if holding the hand out behind the back waiting for a tip).

A painful broken bone anywhere from the collarbone down can be the reason a child doesn’t move the arm. The cause of bone fractures must be determined. It could be from prolonged labor, forceps delivery, or child abuse.

Fortunately, bone healing is fast in infants this young. A makeshift sling out of soft stockinette may be all that’s needed in the way of treatment. Even easier and possibly safer is to pin the sleeve of the infant’s shirt to the main body of the shirt.

Hopefully within a day or two, you’ll be able to call and find out what caused the problem and what’s being done about it.