Pons Flashcards
What are the cranial nerves associated with the pons?
V, VI, VII, VIII
Which fibers are in the basis pontis?
The corticospinal and corticobulbar tracts.
What are the coricopontine fibers?
Descending fibers from the cerebral cortex which synapse on the pontine nuclei in the basis pontis. They are part of the corticopontocerebellar tract
What is the middle cerebellar peduncle?
Bundles of fibers which originate in the neuronal cell bodies of the pontine nuclei, traverse the basis pontis. They cross the midline and form the contralateral middle cerbellar peduncle.
What is the abducens nerve?
It is present in the pons and is comprised of lower motor neurons which innervate the lateral recture muscle of the eye.
What is the PPRF?
the lateral gaze center, adjacent to the abducens nucleus. Fibers from here cros the midline and enter the contralateral MLF to synapse on the contralateral oculomotor nucleus.
What does the facial motor nucleus innervate?
It is a collection of lower motor neurons which innervate the muscles of facial expression.
Describe the upper part of the facial motor nucleus
It innervates the upper part of the face. It receives biltaeral corticobulbar input
Describe the lower part of the facial nucleus
It innervates the lower part of the face and receive contralateral corticobulbar input.
What happens if there is a facial motor neuron lesion?
There will be a typical lower motor syndrome of all facial muscles innervated by the nucleus ipsilateral to the nucleus.
What would an upper motor nueorn lesion do to the face?
It would not affect the upper face since the part of the nucleus gets bilateral innervation. Would only be seen contralateral to lesion.
What is another consequence of a lesion of the sixth nerve nucleus?
Destroying the rootlets of the facial nucleus
What does the motor nucleus of the trigeminal nerve do?
It is a collection of lower motor neurons that supply the muscles of mastication. It receives bilateral corticobulbar input.
What is the spinal nucleus of V replaced by at the level of the pons?
The main sensory or chief nucleus of V
What is the course of the trigeminal/V?
The primary cell bodies that have central processes that enter the brainstem adn synapse in the main sensory nucleus are located in the trigeminal ganglion. The majority of processes of neurons here cross the midline and ascend to the thalamus via the trigeminothalamic pathway.
