ABSTRACT
Neck is a very intricate and complex conical structure. It has various vital structures passing through, which include the trachea, esophagus, carotids, jugular veins along with the trachea-laryngeal complex. Hyoid bone is another important skeletal structure of neck. Muscles of the neck are arranged in layers that are again divided into triangles, which makes understanding of this complex anatomy easier. Blood supply to the brain is by the carotid arterial system and vertebral arterial system. Circle of Willis is the arterial network located at the base of the brain and is formed by contribution from both these arterial systems. This Circle of Willis maintains the continuous arterial supply of brain even when one of the feeding arteries is occluded or obstructed due to internal obstruction or external pressure. Collateral circulation is another important arterial connection that compensates the blood supply when there is occlusion in the path of an artery by bypassing this occlusion. These collateral circulations exist between the internal and external carotid arteries and also between external carotid arteries and vertebral arteries. Venous drainage of the brain is the other equally important part of blood supply of brain.
