Brachial Plexus Flashcards
What is the most common mechanism for brachial plexus injuries?
Closed injury (traction, compression, or combination of the two).
What is the most common location of brachial plexus injuries?
Supraclavicular, root and trunks.
What is the typical mechanism of a C8-T1/lower trunk traction injury?
Forceful abduction of the arm overhead.
What brachial plexus injury is typically produced by violent lateral bending of the head and neck?
Traction injury of C5, C6/upper trunk.
What is a common site for brachial plexus compression injuries?
Between clavicle and first rib, near the coracoid process.
What are the demographics of the majority of patients with brachial plexus injuries?
Male, aged 15 to 25.
What proportion of brachial plexus injuries occur in motor vehicle accidents?
70%.
What type of vehicle is most commonly implicated in brachial plexus injuries?
The motorcycle (70% of motor vehicle accidents). Snow mobiles in colder climates.
At what level do most root avulsions occur?
Lower roots (C7, C8, T1)
How many nerve roots form the brachial plexus?
Five (C5–8, T1).
What term describes a contribution of the C4 nerve root to the brachial plexus?
Prefixed plexus
What phenomenon is described by the term “postfixed” brachial plexus?
T2 contribution to the plexus
What are the five separate sections of the brachial plexus?
Roots, trunks, divisions, cords, terminal branches.
(Robert Taylor Drinks Coffee Black)
What structure is formed by coalescence of the ventral and dorsal rootlets?
The nerve root.
What vascular structure is associated with the C7 root in the exposure of the cervical region of the brachial plexus?
Transverse cervical artery.
The medial cord of the brachial plexus receives contributions from which nerve roots?
C8 and T1.
Where does the nerve root leave the spinal canal?
Through the neuroforamen.
What is contained in the dorsal root ganglion?
The cell bodies of the sensory nerves.
Where do the motor nerves travel?
In the volar root ganglion. (V-volar, Vroom!!)
What is described by the term preganglionic brachial plexus lesion?
- lesion proximal to the dorsal root ganglion
- intradural rupture of the rootlets
- avulsion from spinal cord
How are the upper, middle, and lower trunk typically formed?
Upper trunk by C5 and C6.
Middle trunk by C7.
Lower trunk by C8 and T1.
What is Erb point?
Point where C5 and C6 merge to form upper trunk.
What structures join to become the posterior cord?
All three posterior divisions.
What is formed by the anterior divisions of the upper and middle trunk?
The lateral cord.
(Imagine a football announcer, “Number 34 runs up [upper trunk] the middle [middle trunk] and throws a lateral [lateral cord]!”)