Radial nerve palsy in the newborn.

1348 CMAJ, September 6, 2011, 183(12) © 2011 Canadian Medical Association or its licensors Isolated radial nerve palsy in the newborn is uncommon. However, pediatricians and primary care physicians need to be aware that it has a good prognosis, particularly if the history and clinical examination suggest a palsy related to intrauterine pressure. In this issue of CMAJ, Alsubhi and colleagues describe the largest case series of infants with isolated radial nerve palsy in the medical literature to date. Previous commentaries and case reports have described clinical findings that are consistently associated with transient radial nerve palsy. Morgan described a bruised appearance in the upper limb associated with wrist drop in the infant after prolonged labour. Subsequent reports emphasized the link be tween radial nerve palsy, long labour and areas of subcutaneous fat necrosis indicative of possible intra uterine pressure. Some of these reports clearly describe the presenting position of the newborn: arms flexed and hands tucked under the axillae, which could expose the relatively su per ficial part of the radial nerve to intrauterine pressure. Figure 1 shows the anatomy of the radial nerve in the adult arm, and an accompanying description can be found in Box 1. With their retrospective study involving 25 infants with isolated radial nerve palsy, Alsubhi and colleagues help to place these previous reports of the condition in context for family physicians and pediatricians. Recovery occurred over a period ranging from one week to six months. Most infants recovered (72%) within two months, and all infants recovered fully. This study has limitations. Al subhi and colleagues stress that they relied on referrals to their brachial plexus injury clinic and recognize that there may have been under re porting, particularly of milder cases. Because nerve conduction studies might cause distress to an infant, they were not routinely performed by the authors when the clinical presentation was consistent with isolated radial nerve palsy. In ad dition, a number of infants improved without any intervention such as splinting or physiotherapy and appeared to have normal function when examined in the clinic. For these patients, the au thors depended on the clinical description provided by the referring physician and family. Radial nerve palsy in the newborn