Carotid sheath sternum. The four major structures contained in the carotid sheath are: The carotid artery lies medial to the internal jugular vein, and the vagus nerve is situated posteriorly between the two vessels. In the upper part, the carotid sheath also contains the glossopharyngeal nerve (IX), the accessory nerve (XI), and the hypoglossal nerve (XII), which pierce the fascia of the carotid sheath. The ansa cervicalis is embedded in the anterior wall of sheath. It is formed by "descendens hypoglossi" (C1) and "descendens cervicalis" (C2-C3). The three major fascial layers in the neck contribute to the carotid sheath: the investing fascia,
Endometrial arteries arteries are coiled and is why they are also called spiral arteries. The spiral arteries are coiled towards the upper part of the endometrium and straight towards the base of the endometrium. In the endometrium there are straight and serial arteries. Straight arteries specifically branch to the base of the endometrium therefore supplying blood to the base of the endometrium. Spiral arteries supply blood to the rest of the endometrium. They grow rapidly, covering much of the space of the endometrium and end up coiled. When hormones levels are low, the endometrial arteries react by becoming narrow. Endometrial arteries supply