Trauma accounts for a large proportion of brachial plexopathies. The mechanism of an injury and the magnitude, rate, and direction of deforming forces ultimately determine the extent and location of a traumatic brachial plexopathy.
A lesion of the brachial plexus can result in motor, sensory, and sympathetic disturbances. Impairments can be transient, as in stinger or burner injuries in football players, or they may result in intractable palsy. Because of the changing arrangement of the brachial plexus as it progresses distally, injuries to it may result in diverse paralyses, anesthesias, and paresthesias, depending on the exact level of injury and the extent of injury to the various elements at that level. 
The anterior rami of the spinal nerves C5 to T1 combine to form the brachial plexus. C5 and C6 merge into the upper trunk, C7 forms the middle trunk, and C8 and T1 merge to form the lower trunk. Anterior divisions from the upper and middle trunks form the lateral cord. The medial cord is the anterior division of the lower trunk. Posterior divisions from all 3 trunks form the posterior cord. Terminal branches originate from the C5 root, trunks, and cords to supply the upper extremity and the shoulder girdle. The spinal nerves emerge from the vertebral foramina and pass between the anterior and middle scalenes; they then pass between the clavicle and the first rib, near the coracoid and humeral head. The plexus is relatively tethered at the prevertebral fascia at its proximal aspect and by the axillary sheath in the midarm.
Brachial plexopathies may be difficult to accurately diagnose, even with a meticulous investigation. This is not only because the anatomic design of the plexus pose challenges, but also because the types of lesions and injuries that occur are frequently incomplete and complex. Even so, establishing a precise anatomic diagnosis and estimating the severity of the lesion is imperative for prognostic, surgical, and rehabilitative purposes.
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In traumatic brachial plexopathy, nerve roots may be avulsed from the cord, or the plexus may be subject to traction or compression. Any injury that increases the distance between the relatively fixed points of the prevertebral fascia and the midforearm may injure the brachial plexus.
Traction or compression may result in ischemia, which initially damages the vasa vasorum. Severe compression injuries can result in intraneural hematomas, which can compress adjacent nerve tissue.
The frequency with which traumatic brachial plexopathies occur varies according the etiology and severity of specific injuries. Brachial plexus injuries are estimated to account for 5% of peripheral nerve injuries. However, the true frequency of injuries to the brachial plexus is undetermined, primarily because of significant underreporting. Prospective studies performed at Tulane University revealed a 7.7% incidence of stingers in a group of college football players; however, other sources have reported a 40% incidence. 
As noted above, frequency varies according to the etiology and severity of the injury.
Coexistent musculoskeletal or central nervous system injury, such as spinal cord injury (SCI) or traumatic brain injury (BI), is common after violent trauma and presents a diagnostic challenge.
Narakas reported that 80% of patients with severe traumatic brachial plexopathy had multiple trauma to the head and skeletal system. 
Root avulsion and contusions of the brachial plexus and cord, which are other frequently occurring coexistent, complicating factors, pose additional diagnostic and prognostic challenges.
No race predilection is reported for traumatic brachial plexopathy.
In general, traumatic brachial plexopathy is more prevalent in men than in women because of an association with violent trauma and sports.
Certain conditions, such as thoracic outlet syndrome (TOS), are statistically more common in women than in men. 
Other regional differences influence sex- and cause-related statistics.
Because of an association with violent trauma and sports-related injuries, traumatic brachial plexopathy is most prevalent in males in their midteens and in men in their early 30s.
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