In most cases, the nerve roots are stretched or torn from their origin, since the meningeal covering of a nerve root is thinner than the sheath enclosing the nerve. The epineurium of the nerve is contiguous with the dura mater, providing extra support to the nerve.<unk><unk>  lesions typically result from excessive stretching; from rupture<unk>  where the nerve is torn but not at the spinal cord; or from avulsion<unk> es, where the nerve is torn from its attachment at the spinal cord. A bony fragment, pseudoaneurysm, hematoma, or callus formation of fractured clavicle can also put pressure on the<unk> d nerve, disrupting innervation of the muscles. A trauma directly on the shoulder and neck region can crush the<unk><unk>  between the clavicle and the first rib. Although<unk> es can occur at any time, many<unk> es happen during birth: the baby's shoulders may become impacted during the birth process causing the<unk><unk>  nerves to stretch or tear. Obstetric<unk> es may occur from mechanical<unk>  involving shoulder dystocia during difficult childbirth, the most common of which result from<unk> ous stretching of the child's<unk><unk>  during birth, most often during vaginal birth, but occasionally Caesarean section. The excessive stretch results in incomplete sensory and/or motor function of the<unk> d nerve.<unk> es to the<unk><unk>  result from excessive stretching or tearing of the C5-T1 nerve fibers. These<unk> es can be located in front of or behind the clavicle, nerve disruptions, or root avulsions from the spinal cord. These<unk> es are diagnosed based on clinical exams, axon reflex testing, and electrophysiological testing.<unk> es require quick treatment in order for the patient to make a full functional recovery (Tung, 2003). These types of<unk> es are most common in young adult males. Traumatic<unk> es may arise from several causes, including sports, high-velocity motor vehicle accidents, especially in motorcyclists, but also all-terrain-vehicle (ATV) and other accidents.<unk>  from a direct blow to the lateral side of the scapula is also possible. The severity of nerve<unk> es may vary from a mild stretch to the nerve root tearing away from the spinal cord (avulsion). "The<unk><unk>  may be<unk> d by falls from a height on to the side of the head and shoulder, whereby the nerves of the<unk>  are violently stretched… The<unk><unk>  may also be<unk> d by direct violence or gunshot wounds, by violent traction on the arm, or by efforts at reducing a dislocation of the shoulder joint".<unk><unk>  lesions can be divided into three types: # An upper<unk><unk>  lesion, which occurs from excessive lateral neck flexion away from the shoulder. Most commonly, improper use of forceps during delivery or falling on the neck at an angle causes upper<unk>  lesions leading to Erb's palsy. This type of<unk>  produces a very characteristic sign called Waiter's tip deformity due to loss of the lateral rotators of the shoulder, arm flexors, and hand extensor muscles. # Less frequently, the whole<unk><unk>  lesion occurs; # most infrequently, sudden upward pulling on an abducted arm (as when someone breaks a fall by grasping a tree branch) produces a lower<unk><unk>  lesion, in which the eighth cervical (C8) and first thoracic (T1) nerves are<unk> d "either before or after they have joined to form the lower trunk. The subsequent paralysis affects, principally, the intrinsic muscles of the hand and the flexors of the wrist and fingers". This results in a form of paralysis known as Klumpke's paralysis. Backpack palsy is caused by much use of a heavy backpack whose pack-straps chronically press on the<unk><unk> .
Brachial plexus injury
Posterior cord syndrome
Diastematomyelia
Spinal cord injury
Central cord syndrome
Syringomyelia
Accessory nerve disorder
Cernunnos deficiency