Developmental Anatomy of the Pituitary Fossa
John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie in Basic Sciences Endocrine Surgery Rhinology, 2018
The tentorium cerebelli is the main dural sheet that loops around the brain stem and separates the cerebral hemispheres from the cerebellum, forming the floor of the middle cranial fossa. It arises from the anterior clinoid processes and has a U-shaped free border looping posteriorly. The peripheral attachments of the tentorium run from the anterior clinoid process backwards as a ridge of dura mater to the apex of the petrous temple bone. This ridge is at the junction of the roof and the lateral part of the cavernous sinus. From here the attachment runs backwards to the posterior clinoid process, forming the roof of the cavernous sinus, and is continuous with the diaphragmatica sella. The remainder of the peripheral attachment of the tentorium is to the superior surface of the petrous temporal bone in the region of the superior petrosal sinus and to the occipital bone in the region of the transverse sinuses.
Adult Autopsy
Cristoforo Pomara, Vittorio Fineschi in Forensic and Clinical Forensic Autopsy, 2020
At this stage, be very careful not to allow stretching of the cerebral peduncles. Removal of the brain is facilitated with the neck in hyperflexion; therefore, rest the head on a firm, elevated support. Cranial nerves VII, VIII, IX, XI, and XII are the next structures to be divided, but prior to their isolation, describe their position and course in situ. The vertebral arteries are described and divided in the same fashion (Figure 2.131b). Last, the cervical portion of the spinal cord is transacted. It is easier to insert the scalpel blade if the brainstem is slightly stretched (Figure 2.131c). If a critical lesion is identified, a section should be taken, then cut transversely across the area. The cerebral peduncles are exposed by gentle force, pushing the brain backward with the hands. They are then extracted from the cranial vault, along with the brainstem. Care should be taken to avoid excessive stretching of the upper portions of the cervical cord. The lateral portions of the tentorium are incised close to the petrosal bone freeing the brain, which can then be lifted out. A detailed examination of the cranial skullcap and the cranial cavities, and a proper photographic record are carried out (Figure 2.132).
Tumors of the Nervous System
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Common sites of origin include: Skull base: Tuberculum sella/olfactory groove.Sphenoid wing or ridge: may grow into the orbit/optic nerve; cavernous sinus.Petrous ridge: often grows into cerebellopontine angle.Foramen magnum.Cerebral convexity.Falx cerebri.Tentorium cerebelli.Spine (usually thoracic and located anterior to the cord).
Systemic Rosai–Dorfman disease with central nervous system involvement
Published in International Journal of Neuroscience, 2018
Song Tan, Lunliang Ruan, Kai Jin, Fuchao Wang, Jiamin Mou, Hua Huang, Gang Yang
Since there was an obvious mass effect of the intracranial lesion, a craniotomy was performed. Intraoperatively, a gray-white, solid, hypervascular mass about 6 × 5 × 4.5 cm originating from the tentorium cerebelli was observed in the left temporal lobe. Although there was a boundary between the lesion and surrounding tissue, the adhesion was tight. The intracranial lesion was completely resected. Histologically, the lesion was composed of numerous lymphocytes, a few histiocytes and plasma cells on a background of fibrosis. Some histiocytes showed lymphocytophagocytosis in which intact lymphocytes were engulfed by histiocytes. An immunohistochemical analysis revealed that the histiocytes were immunopositive for S100 and cluster of differentiation (CD)68, but immunonegative for CD1a (Figure 2). RDD was considered due to these features.
Antero posterior elongation of midbrain in traumatic brain injury- significant sign yet a mistaken entity
Published in British Journal of Neurosurgery, 2018
Raghunath Avanali, Biju Bhadran, Sunil Panchal, Krishna Kumar P., Abhishek V., Kshitij Gulhane, Harison G.
The incidence of traumatic brainstem injury in severe TBI varied from 8.8% to 52%.11,12 The most frequent location of injury is the mesencephalon.12 Most studies describe a traumatic brainstem injury which is primary in nature as well as in the background of diffuse axonal injury.12 Mechanical tissue compression of the lateral brainstem against the tentorium with notching of cerebral peduncles results in brainstem herniation syndromes.2,13 Though such secondary affection of the brainstem in traumatic intracranial haematoma can increase mortality by two to three times, the literature is poor in articles in which these effects on the brainstem structure, exclusively, are studied.1,11,14 The primary damage to the brainstem is usually observed in the tegmentum and dorsal areas, in contrast with the secondary affection where lesions are more noticed in the cerebral peduncles and basis pontis, often with bilateral affection in a distorted brainstem.11 Such affections are seen mostly with descending transtentorial herniation occurring with download herniation of both temporal lobes through the tentorial incisura compressing basal cisterns.7,15 Elongated brainstem finding was observed to be associated with almost complete obliteration of the bilateral basal cisterns, as demonstrated in the present study. Needless to say, compressed or absent basal cisterns are reported to be associated with an up to fivefold increase in mortality.15–17
The supracerebellar infratentorial approach in pineal region tumors: Technique and outcome in an underprivileged setting
Published in Alexandria Journal of Medicine, 2018
Mahmoud Abbassy, Khaled Aref, Ahmed Farhoud, Anwar Hekal
Despite of the fact that it has been reported in the literature that bridging veins between the tentorium and the cerebellum can be safely sacrificed.24,26 Several authors have reported similar complications including odema and venous infarction of the cerebellum and advocated preserving them.13 Jakola et al., has reported cerebellar venous infarction after the scarification of a single bridging vein through a paramedian approach.27 Therefore, it is better to sacrifice smaller thin walled veins and to preserve large ones keeping in mind that there it is difficult to predict which vein when occluded will result in serious complication.26,28 Avoidance of static retraction prevents continuous stretch of the bridging veins that could result in their injury or thrombosis. In addition, ischemic insult that result from continuous retraction may contribute to the post-operative cerebellar edema.26 If retraction is needed it is better to be dynamic by the use of the shaft of the suction tip.26 The precentral vein is considered to be safe to be sacrificed, however, Kanno et al. have described a case report in which the occlusion of the precentral vein resulted in progressive thrombosis of the basal veins of Rosenthal and eventually ended up in massive fatal hemorrhagic infarction.28 For this reason, it is better to excise the tumor in a piece meal fashion through the corridor between the precentral vein and the basal veins. If it has to be sacrificed, it should be cut as distal as possible form the vein of Galen.26
Related Knowledge Centers
- Brainstem
- Cavernous Sinus
- Cerebellum
- Midbrain
- Transverse Sinuses
- Occipital Lobe
- Dura Mater
- Tentorial Notch
- Anterior Clinoid Process
- Superior Petrosal Sinus