Anatomical study of petrous and cavernous parts of internal carotid artery / 대한해부학회지

The petrous and cavernous parts of internal carotid artery (ICA) are obscure and are not readily accessible to observation/imaging. These parts have broad biological and medical interest because of their peculiar shape. Given the their clinical importance and the scarce data available based mostly on imaging, the present study was aimed at studying these parts of ICA by dissection. The study was carried out on 56 ICAs obtained from embalmed adult cadavers and 10 ICAs from five fetuses. The foetal ICAs were studied in situ. The morphometric analysis of the adult ICA was done after its removal from cranial cavity to gain an insight into the geometry of the vessel, i.e., length, various bends, and diameters at various locations. ICAs in fetuses ran a relatively straighter course taking gentle curves at three positions (two intrapetrous, one cavernous). Adult ICAs were more tortuous and exhibited greater variability in length and angulations. The length of respective portions of the ICA correlate negatively with the measure of angles. The angles in the petrous and cavernous parts were positively correlated to each other. The carotid siphon was positively, highly significantly correlated to other angles. Longer vessels are more tortuous with acute bends. An acute carotid siphon is an indication of more tortuous ICA. The findings of the present study have created a reference data of unsuspected adult population and has potential implications for studying cause/effect relationship of vessel geometry and hemodynamic factors.

Mid-foot retinaculum: an unrecognized entity / 대한해부학회지

Retinacula are thickenings of deep fascia in the region of joints that hold down the tendons preventing them from bowing out of position. In the region of ankle, number of such retinacula have been described. Retinacula like superior and inferior extensor retinacula have been described which hold down the tendons of leg muscles passing to the foot beneath them. As the extensor tendons of the leg have more distal attachment to the toes, the present study was conducted to ascertain the presence of any additional retinaculum in the mid-foot region, which would tie down the tendons for their effective action at the distal joints. The aim was also to determine the attachments of the retinaculum, if present as well as the structures passing beneath them. Fifty cadaveric feet were dissected carefully for this purpose. Presence of an additional extensor retinaculum distal to the inferior band of inferior extensor retinaculum in the mid-foot region was found in 22 feet. Besides the extensor tendons, medial terminal branch of deep peroneal nerve and dorsalis pedis artery was found to pass beneath the retinaculum. A partial or complete mid-foot retinaculum existed in the mid-foot region covering the tarsometatarsal joints in about half of study population. Functionally, this retinaculum may prevent bowstringing of the extensor tendons, clinically it may predispose to entrapment of deep peroneal nerve mimicking anterior tarsal tunnel syndrome.