A brachial plexus injury (BPI), also known as brachial plexus lesion, is an injury to the brachial plexus, the network of nerves that conducts signals from the spinal cord to the shoulder, arm and hand. These nerves originate in the fifth, sixth, seventh and eighth cervical (C5–C8), and first thoracic (T1) spinal nerves, and innervate the muscles and skin of the chest, shoulder, arm and hand.[1][2][3]
Brachial plexus injuries can occur as a result of shoulder trauma (e.g. dislocation[4]), tumours, or inflammation, or obstetric. Obstetric injuries may occur from mechanical injury involving shoulder dystocia during difficult childbirth,[5] with a prevalence of 1 in 1000 births.[6]
"The brachial plexus may be injured by falls from a height on to the side of the head and shoulder, whereby the nerves of the plexus are violently stretched. The brachial plexus may also be injured by direct violence or gunshot wounds, by violent traction on the arm, or by efforts at reducing a dislocation of the shoulder joint".[7]
The rare Parsonage–Turner syndrome causes brachial plexus inflammation without obvious injury, but with nevertheless disabling symptoms.[1][8]