Clinical anatomy : official journal of the American Association of Clinical Anatomists & the British Association of Clinical Anatomists
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Hypertrophy of abductor hallucis muscle is one of the reported causes of compression of tibial nerve branches in foot, resulting in tarsal tunnel syndrome. In this study, we dissected the foot (including the sole) of 120 lower limbs in 60 human cadavers (45 males and 15 females), aged between 45 and 70 years to analyze the possible impact of abductor hallucis muscle in compression neuropathy of tibial nerve branches. We identified five areas in foot, where tibial nerve branches could be compressed by abductor hallucis. ⋯ We also assessed whether estimation of parameters for the muscle size could identify patients at risk of having nerve compression due to abductor hallucis muscle hypertrophy. The interclass correlation coefficient for dorso-planter thickness of abductor hallucis muscle was 0.84 (95% CI, 0.63-0.92) and that of medio-lateral width was 0.78 (95% CI, 0.62-0.88) in the imaging study, suggesting both are reliable parameters of the muscle size. Receiver operating characteristic curve analysis showed, if ultrasonographic estimation of dorso-plantar thickness is >12.8 mm and medio-lateral width > 30.66 mm in patients with symptoms of nerve compression in foot, abductor hallucis muscle hypertrophy associated compression neuropathy may be suspected.
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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.