Four neonates presented with septic shoulders after delays in diagnosis of 7-20 days. All lacked active extension of the wrist and thumb, and three lacked active extension of the fingers. Two had positive cultures for Staphylococcus aureus, and one had a positive Escherichia coli culture. Surgical treatment was one single aspiration and three arthrotomies. Recovery of extension began in 10-21 days and was normal at 18-35 days post-treatment. At follow-up 9-13 months later, all limbs were neurologically normal. Cadaver dissections showed that the radial nerve passed close to the shoulder joint, and when the capsule was distended, it impinged on the nerve.