Cranial Nerves XI & XII Flashcards
Where are the cell bodies located from the cranial root of the accessory nerve?
Nucleus ambiguus
What do both roots of the accessory nerve supply?
SCM, trapezius, and muscles of the soft palate, pharynx, and larynx
Where is the spinal nucleus of the accessory nerve located?
Anterior horn of the gray matter between the foramen magnum and the C5/C6 level
Does the accessory nerve contain any sensory fibers?
No, purely motor
What is the apparent origin of the cranial root of the accessory nerve?
Lateral aspect of the medulla oblongata (as a series of rootlets)
Through what osseous opening does the accessory nerve exit the cranial vault?
Jugular foramen
When does the cranial root of the accessory nerve separate from the spinal root?
After exiting the skull through the jugular foramen (leaving the CNS)
After leaving the CNS through the jugular foramen, where do the fibers of the cranial root of the accessory nerve travel to?
Join the vagus nerve at the inferior ganglion and are distributed to the pharyngeal plexus, external laryngeal nerve, and recurrent laryngeal nerve
After joining with the vagus nerve and some branches, the cranial root of the accessory nerve helps to contribute supply to which muscles?
All laryngeal muscles except cricoarytenoid
What are the two roots of the accessory nerve?
Cranial and spinal roots
What is the apparent origin of the spinal root of the accessory nerve?
Lateral aspect of the cervical cords between the anterior and posterior rootlets
What is the pathway of the spinal root before it combines with the cranial root?
Rootlets form a trunk that ascends between the posterior rootlets and denticulate ligaments to then enter the skull through the foramen magnum
When the spinal root combines with the cranial root of the accessory nerve, it travels through what osseous opening?
Jugular foramen
The spinal root of the accessory nerve traverses what triangle of the neck?
Posterior triangle
After exiting the jugular foramen with the cranial root, what muscles are supplied by the spinal root of the accessory nerve?
SCM, trapezius
Which muscle is supplied by the spinal root of the accessory nerve before it traverses the posterior triangle?
Sternocleidomastoid
Which muscle is supplied by the spinal root of the accessory nerve after it traverses the posterior triangle?
Trapezius
There is considerable evidence to suggest that what nerves also supply the trapezius muscle?
Cervical plexus
When divided out, what nerves supply the separate parts of the trapezius muscle?
Cranial nerve XI supplying upper and middle portion
Cervical plexus supplying lower 2/3
What nerve is most likely responsible for the sensory information (proprioception) of the trapezius muscle?
Cervical plexus (NOT cranial nerve XI)
The spinal nucleus of the accessory nerve is the cell body location for fibers from which root?
Spinal root
What is the primary difference between the spinal nucleus of the accessory nerve and the spinal nucleus of the trigeminal nerve?
Spinal nucleus of the trigeminal nerve is sensory in function & therefore a nucleus of termination; spinal nucleus of the accessory nerve is a nucleus of origin and motor in function
What spinal tract is likely to synapse in the location of the spinal nucleus of the accessory nerve (anterior horn of the gray)?
Tectospinal tract
Paralysis of what muscle can result with interruption to the spinal component of the accessory nerve and what action is impaired?
SCM is paralyzed; the patient is unable to turn their head to the opposite side
