Carotid sheath contains all structures EXCEPT

(Phrenic nerve): CAROTID SHEATH - is formed from the investing, pretracheal, and prevertebral layers of the deep cervical fasciaContents* Three carotid arteries (CCA, ECA, ICA)* Internal jugular vein* Vagus nerve* Deep cervical lymph nodesAt the level of the upper border of thyroid cartilage the common carotid artery bifurcates into the internal and external carotid arteries. The pulsations of these arteries can be felt at this levelRelations1. Ansa cervicalis lies embedded in the anterior wall of the carotid sheath2. Cervical sympathetic chain lies behind the sheath plastered to the prevertebral fascia3. The sheath is overlapped by the anterior border of the sternomastoid and is fused to all the three layers of the deep cervical fascia** Ligament of Berry is formed by - Pretracheal layerCarotid Sinus (596 - Snell 9th)* At its point of division, the terminal part of the common carotid artery or the beginning of the internal carotid artery shows a localized dilatation called the carotid sinus* The carotid sinus serve as a reflex pressoreceptor mechanism. A rise in blood pressure causes a slowing of the heart rate and vasodilatation of the arterioles