Anatomy of the head and neck
Helen Whitwell, Christopher Milroy, Daniel du Plessis in Forensic Neuropathology, 2021
The internal carotid artery has no branches within the neck and ascends deep to the styloid process of the skull and adjacent muscles, to enter the carotid canal of the petrous temporal bone. This canal passes forwards and medially to enter the internal cavity of the skull as the foramen lacerum. The internal carotid artery is now located to the lateral side of the sphenoid bone, enclosed within the cavernous sinus. Its path now proceeds anteriorly within the sinus and then it passes out of the sinus upwards to lie adjacent to the anterior clinoid process, where it enters the subarachnoid space by piercing the dura mater. This path is clearly seen on suitable radiographs and is known as the carotid siphon. At this point, the artery gives a branch called the ophthalmic artery, which passes through into the orbit, supplying the retina via the central artery of the retina and branches to the lacrimal gland and adjacent orbital structures.
Anatomy of Neck and Blood Supply of Brain
Sudhir K. Gupta in Forensic Pathology of Asphyxial Deaths, 2022
The carotid arterial system and the vertebral arterial system (Figures 2.35 and 2.36) contribute to the arterial blood supply of the brain. Left and right common carotid arteries arise from arch of aorta and brachiocephalic trunk respectively. At the superior border of thyroid cartilage, external and internal carotid arteries arise from the common carotid arteries, with the internal carotid being more medially placed. The internal carotid artery in its intracranial course divides into anterior and middle a cerebral artery which provides the anterior cerebral circulation of brain. The posterior cerebral circulation is mainly by the vertebral arteries. Vertebral arteries traverse the foramen transversarium of cervical vertebra and enter the skull through the foramen magnum where they join to form the basilar artery and posterior cerebral arteries are their terminal branches.
Cerebrovascular Disease
John W. Scadding, Nicholas A. Losseff in Clinical Neurology, 2011
The brain is supplied by two internal carotid arteries and two vertebral arteries. The internal carotid arteries begin in the neck at the bifurcation of the common carotid artery and ascend intracranially. The first branch of the internal carotid artery is the ophthalmic artery. The former then bifurcates into the anterior and middle cerebral arteries. Both anterior and middle cerebral arteries give off other branches and deep penetrating vessels. The anterior cerebral artery supplies among other structures much of the ‘leg’ representation of the cortex. The middle cerebral artery supplies the ‘arm’ representation, some of the ‘leg’ representation, and the speech areas in the dominant hemisphere or the areas of spatial awareness in the non-dominant hemisphere. The penetrating vessels supply the deeper portions of the hemisphere, including the internal capsule, basal ganglia and visual radiation.
Visual Loss after Platelet-rich Plasma Injection into the Face
Published in Neuro-Ophthalmology, 2020
Emely Z. Karam, Alexander Gan, Rafael Muci Mendoza, Edwing Martinez, Evlyn Perez
In order to understand the pathophysiology when embolisation causes blindness it is important to remember the anatomy. The central retinal artery (CRA) is a branch of the ophthalmic artery. The ophthalmic artery is connected to the supraorbital, supratrochlear, dorsal nose, and lacrimal arteries that supply the glabellar region, forehead, nose, and lacrimal gland respectively. These arteries are part of the internal carotid artery system. The facial, angular, infraorbital, and temporal superficial arteries that supply the nasolabial and nasojugal folds, the mid-face, and temple respectively, are part of the external carotid artery system. There are anastomoses between the two systems. The mechanism by which dermal fillers induce blindness could be by direct injury to the globe or from accidental high-pressure injection of a fillers into the blood vessel causing retrograde local or distal emboli. Also, the nature of the material filler could be related. Thick, cohesive substances should theoretically be less likely to embolise, unlike oily liquids (fat injections, silicone oil) or particulate solutions (steroid suspensions).4 Also, the particle size and the amount of filler injected per injection site could also affect the risk of embolisation.9,10
The Effects of Acute Intracranial Pressure Changes on the Episcleral Venous Pressure, Retinal Vein Diameter and Intraocular Pressure in a Pig Model
Published in Current Eye Research, 2021
Deepta Ghate, Sachin Kedar, Shane Havens, Shan Fan, William Thorell, Carl Nelson, Linxia Gu, Junfei Tong, Vikas Gulati
We acknowledge inter-species differences in vascular and orbital anatomy between humans and pigs. The internal carotid artery in humans lies within the cavernous sinus. In pigs and other ungulates, the cavernous sinus is filled with a network of arteries (rostral epidural rete mirabile) from which forms the rostral part of the internal carotid artery.18 The pig optic nerve head has a larger diameter compared to the human optic nerve head and has 5–6 laterally placed retinal arteries while the human optic nerve head has a single retinal artery placed centrally.52 These differences in arterial anatomy do not affect our study of venous parameters, since the porcine ophthalmic venous anatomy is similar to the human eye.53 The porcine optic nerve head has a single centrally placed retinal vein that exits the eye through the lamina cribrosa, like humans. The venous drainage from the choroid and anterior segment occurs through the vortex vein and episcleral vein, with drainage into the cavernous sinus. Thus, the basic schema of the intra-cranial, intra-orbital and ocular anatomy is comparable between humans and pigs for the purposes of our study of changes in EVP, IOP and RVD in response to acute ICP changes. Although our study included a small number of animals, the study hypothesis and results are consistent with known anatomic and physiologic principles that regulate the fluid and vascular pressure within the cranial and orbital compartments. Our study methodology has a statistically robust basis and the outcomes find support in the numerous human and animal studies described above.
Profile of reticulated platelets in the early, subacute and late phases after transient ischemic attack or ischemic stroke
Published in Platelets, 2022
ST Lim, WO Tobin, SJX Murphy, JA Kinsella, DR Smith, SY Lim, SM Murphy, T Coughlan, DR Collins, D O’Neill, B Egan, S Tierney, DJH McCabe
The baseline demographic and vascular risk factor profiles of study participants (Table I), the TIA/stroke etiological subtypes in CVD patients (Table II), and the prescribed antiplatelet regimens in CVD patients at baseline, 14d and 90d (Table III) are outlined. One hundred and fifty-nine patients were on aspirin monotherapy at baseline, 47 were on no antiplatelet medication and 4 were on aspirin-dipyridamole combination therapy. Two patients in the subgroup who changed from aspirin to clopidogrel had recurrent TIAs during follow up. One patient had a recurrent TIA due to embolization from an aortic arch atheromatous plaque within a week of recruitment; one patient had a left hemispheric TIA due to possible embolism from a stenosed internal carotid artery within three months of recruitment. No other patients had recurrent TIA, stroke or any other new cardiovascular or venous thrombotic outcome events during follow up in this study.