The floor of the fourth ventricle the rhomboid fossa see fig.
Cranial nerve nuclei in floor of 4th ventricle.
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The fourth ventricle has a roof at its upper posterior surface and a floor at its lower anterior surface and side walls formed by the cerebellar peduncles nerve bundles joining the structure on the posterior side of the ventricle to the structures on the anterior side.
The 4th ventricle is a tent like cavity of the hindbrain lined with ependyma and filled up with cerebrospinal fluid csf it s situated in the posterior cranial fossa in front of the cerebellum and behind the pons and the upper part of medulla oblongata the cavity of the ventricle seems rhomboidal lozenge shaped in the horizontal section and presents a triangular outline in the sagittal.
Axons carrying information to and from the cranial nerves form a synapse first at these nuclei lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve s they are associated with.
Cranial nerve vi the abducens nerve supplies the lateral rectus which abducts the eye hence the name of the nerve.
A cranial nerve nucleus is a collection of neurons gray matter in the brain stem that is associated with one or more cranial nerves.
The dorsal nucleus of vagus nerve or posterior nucleus of vagus nerve or dorsal vagal nucleus or nucleus dorsalis nervi vagi or nucleus posterior nervi vagi is a cranial nerve nucleus for the vagus nerve in the medulla that lies ventral to the floor of the fourth ventricle it mostly serves parasympathetic vagal functions in the gastrointestinal tract lungs and other thoracic and abdominal.
Medial to this nucleus are two bundles of fibers.
The back of the upper part of the medulla forms the floor of the fourth ventricle.
The medulla the pons and the midbrain are located just behind the basilar part of the occipital bone and the dorsum sellae.
10 3 is formed by the pons and medulla fig.
The dorsal aspect of the medulla faces almost directly backwards.
The only naturally occurring openings between the ventricles of the brain and the subarachnoid space surrounding the brain are the foramina of luschka and magendie in the fourth ventricle.
Heavily myelinated tract near midline on each side just under oculomotor and trochlear nuclei in mb and under floor of 4th ventricle in midline of pons fibers from medial vestibular nucleus and some superior vestibular nucleus ascend in mlf to oculomotor trochlear abducens nuclei vestibulo ocular reflex eye movements adjusted for head position.
Surgical treatment of brainstem lesions carries a substantial risk of postoperative morbidity because of the risk of injuring the tightly packed cranial nerve nuclei cnn and neural tracts within the rhomboid fossa and brainstem lang et al 1991 historically neurosurgeons considered this area to be a no man s land with most lesions being inoperable baker 1965.
The fibers originate from the ipsilateral abducens nucleus which is located in the caudal pons beneath the floor of the fourth ventricle fig.
