Internal carotid artery the ganglion and the roof of the horizontal portion of the canal. Frequently this bony plate is more or less deficient, and then the ganglion is separated from the artery by fibrous membrane. The artery is separated from the bony wall of the carotid canal by a prolongation of dura mater, and is surrounded by a number of small veins and by filaments of the carotid plexus, derived from the ascending branch of the superior cervical ganglion of the sympathetic trunk. The named branches of the petrous segment of the internal carotid artery are: The lacerum segment, or C3, is
Carotid sinus regulation of the body in sync to external conditions). The carotid sinus contains numerous baroreceptors which function as a "sampling area" for many homeostatic mechanisms for maintaining blood pressure. The carotid sinus baroreceptors are innervated by the sinus nerve of Hering, which is a branch of cranial nerve IX (glossopharyngeal nerve). The glossopharyngeal nerve synapses in the nucleus tractus solitarii (NTS) located in the medulla oblongata of the brainstem. The NTS indirectly modulates the activity of sympathetic and parasympathetic (vagal) neurons in the medulla and pons through the hypothalamus. These neurons then regulate the autonomic control of the heart and