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Evaluation and Investigation of Pituitary Disease
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
The pituitary gland sits within the sella turcica of the sphenoid bone, inferior to the hypothalamus and optic chiasm. It is surgically accessible transnasally via the sphenoid sinus. The gland is composed of two lobes. The anterior pituitary (adenohypophysis) secretes luteinising hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), and prolactin. The posterior pituitary (neurohypophysis) is not a gland in itself, but a projection of the hypothalamus, and it releases antidiuretic hormone (ADH) and oxytocin. It is connected to the hypothalamus above by the pituitary stalk (infundibulum), which passes through the diaphragm that forms the roof of the sella. The function of the anterior pituitary is controlled chiefly by hypothalamic hormonal control; the hypothalamic-pituitary-peripheral axis is regulated by multiple feedback loops.
Anatomy of the head and neck
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
The paranasal sinuses are air-filled extensions of the nasal cavity within the frontal, maxillary, sphenoid and ethmoid bones and are named according to each bone. The ethmoidal sinuses consist of ethmoidal cells located within the ethmoid bone between the orbit and nose. The sphenoid air sinuses are unevenly divided like the frontal air sinuses and separated by a bony septum. They occupy the body of the sphenoid bone and are separated by thin bone from the optic chiasma, the pituitary gland, the internal carotid arteries and the cavernous sinuses.
Post-Traumatic Orbital Reconstruction: Anatomical Landmarks and the Concept of the Deep Orbit
Published in Niall MH McLeod, Peter A Brennan, 50 Landmark Papers every Oral & Maxillofacial Surgeon Should Know, 2020
The applied surgical anatomy of the sphenoid bone is discussed and reference is made to the significance of a segmentation of the sphenoid bone with respect to injuries which are sight threatening. While this is not strictly covered by the title of the paper, it is extremely useful advice. The term sphenoid trigone is used, and in my view, it is extremely important to consider in high-energy transfers to signpost the risk of optic nerve neuropathy. This is physically helpful in counseling relatives in unconscious patients that there may well be significant morbidity.
Acute Enophthalmos After Lumbar Puncture in a Patient with Type 1 Neurofibromatosis Related Sphenoid Wing Dysplasia
Published in Neuro-Ophthalmology, 2022
Deanna Ingrassia Miano, Gregory Byrd, Rani Kattoula, Aye Thet, Ryan Adkins, Ryan Cosgrove, Samantha S. Johnson
There is structural importance of the greater and lesser wings of the sphenoid bone as they serve in both anatomic support to the walls of the orbit as well as intracranial conduits for nervous and vascular components. Such structures include the optic nerve and ophthalmic artery and therefore compromise of the sphenoid bone may put patients at higher risk of visual complications. One ophthalmological complication of sphenoid wing dysplasia, which we report here is enophthalmos, or posterior displacement of the globe within the orbit.5,9 Through relative expansion of the orbit itself, the globe and surrounding orbital contents migrate posteriorly.5 Patients can present with a wide range of signs and symptoms depending on the aetiology, including pain, blurred vision, headache, and nausea, among other non-specific symptoms.5
Superior oblique palsy: A case report
Published in Cogent Medicine, 2020
Ngozika Esther Ezinne, Kingsley Kenechukwu Ekemiri, Aliyah Khan
The trochlear nerve arises from the trochlear nucleus of the brain, emerging from the posterior aspect of the midbrain (it is the only cranial nerve to exit from the posterior midbrain) (Brazis, 1993). It runs anteriorly and inferiorly within the subarachnoid space before piercing the dura mater adjacent to the posterior clinoid process of the sphenoid bone. The nerve then moves along the lateral wall of the cavernous sinus (along with the oculomotor nerve, the abducens nerve, the ophthalmic and maxillary branches of the trigeminal nerve and the internal carotid artery) before entering the orbit of the eye via the superior orbital fissure. The trochlear nerve innervates the superior oblique, which is a muscle of oculomotion (Kim et al., 2020). The tendon of the superior oblique is tethered by a fibrous structure known as the trochlea, giving the nerve its name. Although the mechanism of action of the superior oblique is complex, in clinical practice it is sufficient to understand that the overall action of the superior oblique is to depress and intort the eyeball (Morillon & Bremner, 2017).
The contribution of oncological lateral skull base surgery to the management of advanced head-neck tumors
Published in Acta Oto-Laryngologica, 2023
Elisabetta Zanoletti, Gino Marioni, Piero Nicolai, Antonio Mazzoni
The parapharyngeal space (PPS) can be the site of origin of primary tumors growing cranially towards or across the skull base, secondarily involved by tumors arising in the skull base (such ear cancer and jugular paragangliomas), or tumors arising intracranially in the posterior fossa and growing through the base into the PPS (as meningiomas and schwannomas). These tumors are characterized by a wide variety of histologies and growth patterns and can be excised with resections of various extent [3,11–13], from peri- and extracapsular resection for benign tumors to radical resections of PPS in malignancies. In this heterogeneous setting, lateral skull base surgery affords adequate exposure for surgical maneuvers and en-bloc resections. The traditional cervico-parotid approach to the PPS can be combined with a temporal craniotomy and subtemporal surgical corridor. In tumors abutting the skull base, the area involved is the inferior side of the petrous bone and the great sphenoid wing, which are the roof of the infratemporal fossa. Following the inferior aspect of the skull base, the surgical corridor runs below the petro-sphenoid bone along a bone ridge connecting the roots of mastoid, styloid process, sphenoid spine and pterygoid process. If the bony skull base has to be included in the surgical specimen as a superior margin, a temporal craniotomy is required with or without resection of the zygoma, glenoid, and supra-coronoid mandible. The intracranial-extradural subtemporal surgical corridor allows to free the skull base from the dura mater from above and perform an en-bloc resection of the PPS including the overhanging skull base.