The brachial plexus is a group of nerves that help the hand, arm and shoulder communicate with the spine, claims Mayo Clinic. It is important because these signals allow the shoulder, arm and hand to function properly. If the brachial plexus suffers a catastrophic injury, the arm, for instance, could be paralyzed.
There are five main roots that make up the brachial plexus, says the St. Louis Children's Hospital Washington University School of Medicine. They emerge from the upper spine and pass around the bones between the spine and the upper arms. They then branch into roots, upper and lower trunks, anterior and posterior divisions, lateral, medial and posterior cords, and nerves. These include the limbs of the median nerve, the axillary and radial nerves, the musculocutaneous nerve and the ulnar nerve.
The brachial plexus is subject to several types of injuries, says Johns Hopkins Medicine. These injuries affect both children and adults, and one type of brachial plexus injury, obstetric brachial plexus palsy, is a complication of childbirth. It happens when the baby's shoulder jams against the mother's pubic bone.
Other injuries that the brachial plexus is subject to include avulsions, where the nerve is torn out of the spinal cord, ruptures, stretching, severing and dividing. Tumors called neuromas also grow on the brachial plexus, explains Johns Hopkins Medicine.