The nerve roots that arise from C5 to C8 and T1 segments of the spinal cord join to form the brachial plexus that branch out to form the various nerves that supply the upper limb. Injury to this important group of nerve cables can occur during difficult delivery, when the brachial plexus is stretched or torn. In some situations, the whole brachial plexus is involved. It is usually quite obvious. Typically, the newborn lies with the involved arm by its side, with the elbow extended, and does not move it.
Injuries associated with brachial plexus palsy include the neck, clavicle, shoulder and arm.
If clinical examination warrants it, X-rays are important to rule out any cervial spine injuries, fracture clavicle or humerus, or dislocation of the shoulder. The incidence of obstetric brachial plexus injuries is quite low, around 1 to 2 per 1000 live-births. It is often associated with difficult labor, and though preventable, cannot be totally eliminated. In a situation where time is of the essence to prevent fetal anoxia, brachial plexus injuries will continue to occur even in the best of hands. Your doctor will do X-rays to rule out associated injuries of the neck, clavicle or humerus.