The brachial plexus is a network of nerves that originate in the neck region and branch off to form most of the other nerves that control movement and sensation in the upper limbs, including the shoulder, arm, forearm, and hand. A brachial plexus injury occurs when these nerves are stretched, compressed, or in the most serious cases, ripped apart or torn away from the spinal cord.
Usually when the child is in breech position (i.e. head is not towards opening), or mother is suffering from blood pressure or when mother is not in condition to push the baby or when child is suffering from any genetic disease and its body tone is low and not able to push, forceps or hand or vacuum suction is used to pull the child. At times when pressure applied is more than the required the brachial plexus nerves get damaged leading to injury, which affects movement of that particular side of arm. A brachial plexus injury occurring during birth is called birth related brachial plexus palsy or obstetric brachial plexus palsy.
Sometimes during delivery, the baby's shoulder may become impacted on the mother’s pubic bone causing the brachial plexus nerves to stretch or tear (shoulder dystocia). The prognosis for recovery depends on the pattern, complexity, and severity of injury.
Treatment for BPI is either therapy or surgical intervention depending on the severity of damage. Physiotherapy is always a part of recovery process for BPI. Even after surgery some amount of therapy is required to restore free and pain free movement to the effected part.