Floor Of Fourth Ventricle Cranial Nerve

The floor of the fourth ventricle often called the rhomboid fossa because of its shape is divisible into an upper triangular part formed by the posterior surface of the pons.

Floor of fourth ventricle cranial nerve.

Along with the dorsal surface of the medulla it forms part of the rhomboid fossa the floor of the fourth ventricle. Lab 3 the ventricles and blood supply cranial nerves of the medulla. 10 3 is formed by the pons and medulla fig. 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.

The floor of the fourth ventricle the rhomboid fossa see fig. The anterior median sulcus along the midline of the anterior medulla divides two longitudinal eminences called the pyramids this sulcus is obscured by small fiber bundles in the pyramidal decussation near the junction of the medulla and the spinal cord. The pontine tegmentum contains nuclei of the cranial nerves trigeminal 5th abducens 6th facial 7th and vestibulocochlear 8th cranial nerve nuclei. The back of the upper part of the medulla forms the floor of the fourth ventricle.

A lower triangular part formed by the upper part of the posterior surface of the medulla. 74 76 the responses from muscles innervated by cranial nerves vii ix x and xii can be recorded during surgery as the neurosurgeon stimulates the floor of the fourth ventricle with a. Two male patients ages 8 and 10 years presented to the emergency department and had brain magnetic resonance imaging mri scans showing brainstem fourth ventricle tumors. The caudal tip of the fourth ventricle where it becomes the central canal is known as the obex.

On the model this is the fourth ventricle this is the floor. In the pontine part of floor of fourth ventricle following features are seen. 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. The dorsal aspect of the medulla faces almost directly backwards.

The medulla the pons and the midbrain are located just behind the basilar part of the occipital bone and the dorsum sellae. 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. However the floor is the most related part to the cranial nerve nuclei. Multiple cranial nerve nuclei are located on the floor of the fourth ventricle with a high risk of permanent damage.

Each half is further subdivided by sulcus limitans into a medial area called medial eminence and lateral vestibular area.