Clinical anatomy : official journal of the American Association of Clinical Anatomists & the British Association of Clinical Anatomists
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There is a broad community of health sciences professionals interested in the anatomy of the cranial nerves (CNs): specialists in neurology, neurosurgery, radiology, otolaryngology, ophthalmology, maxillofacial surgery, radiation oncology, and emergency medicine, as well as other related fields. Advances in neuroimaging using high-resolution images from computed tomography (CT) and magnetic resonance (MR) have made highly-detailed visualization of brain structures possible, allowing normal findings to be routinely assessed and nervous system pathology to be detected. ⋯ The scope of the article is clinical anatomy; readers will find specialized texts presenting detailed information about particular topics. Our aim in this article is to provide a helpful reference for understanding the complex anatomy of the cranial nerves.
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Comparative Study
Similarities and dissimilarities of the blood supplies of the human sciatic, tibial, and common peroneal nerves.
The aim was to investigate the arterial supply of the sciatic, tibial, and common peroneal nerves. Thirty-six lower limbs of 18 human fetuses were studied. The fetuses had been fixed in buffered formalin and the blood vessels injected with barium sulfate. ⋯ The sciatic and tibial nerves are supplied by numerous arterial branches of different origins, which provide for collateral circulation. In contrast, the common peroneal nerve is most frequently supplied only by one elongated longitudinal blood vessel, a branch of the popliteal artery. Such a vascular arrangement may make the common peroneal nerve less resistant to stretching and compression.
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The ganglion impar is often overlooked as a component of the sympathetic nervous system. Despite its obscurity, this ganglion provides a pathway for neurons by accommodating postganglionic sympathetics, visceral afferents, and somatic fibers traveling to and from the pelvis. ⋯ The aim of this review was to provide a better understanding of the anatomy of ganglion impar, accounting for variation in size, shape, and location. In addition, the clinical importance and treatment modalities associated with the ganglion impar are outlined.
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The mylohyoid hiatus and hernia were discovered in the nineteenth century and were considered to explain the origin of the plunging ranula from the sublingual gland. This formed the rationale for sublingual sialadenectomy for the treatment of plunging ranula. However, a more recent, extensive histological investigation reported that hernias contained submandibular gland, which supported an origin of the plunging ranula from the submandibular gland and submandibular sialadenectomy for the treatment of plunging ranula. ⋯ Sublingual gland was identified in nine hernias and fat without gland in six. This investigation supports clinical and experimental evidence that the plunging ranula originates from the sublingual gland and may enter the neck through the mylohyoid muscle. It confirms the rationale of sublingual sialadenectomy for the treatment of plunging ranula.
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The internal vertebral venous plexus (IVVP) plays a putative role in thermoregulation of the spinal cord. Cold cutaneous venous blood may cool, while warm venous blood from muscles and brown fat areas may warm the spinal cord. The regulating mechanisms for both cooling and warming are still unknown. ⋯ Furthermore, the walls of the proximal parts of the posterior intercostal veins contain plicae that allow the vessel to dilate, thereby allowing it to serve as a pressure chamber. It is suggested that a cold induced closure of the intercostal/azygos opening can result in retrograde blood flow from the proximal posterior intercostal vein towards the IVVP. This blood flow would be composed of warm blood from the paravertebral brown adipose tissue and blood containing metabolic heat from the muscles draining into the intercostal veins.