Internal Carotid Artery is subdivided into four parts i.e.

• Cervical

• Petrous

• Cavernous

• Cerebral

There are seven segments of the Internal Carotid Artery which are as follows.

• Cervical Segment; extending from the Carotid division this segment enters the Carotid Canal in the Skull.

• Petrous Segment; this segment is inside the Petrous part of the Temporal bone and extends until the Foramen Lacerum.

• Lacerum Segment; considered as extradural, his segment starts above the Foramen Lacerum and ends at Petrolingual Ligament.

• Cavernous Segment; starts at the Petrolingual Ligament while extending to the Proximal Dural Ring.

• Clinoid Segment; a short segment starting after the artery exits Cavernous Sinus at proximal dural ring and extends up to Distal Dural Ring.

• Ophthalmic Segment; extends from the distal Dural ring to the Posterior Communicating artery.

• Communicating or Terminal Segment; extends from the Posterior Communicating Artery to the division of the Internal Carotid Artery.

FUNCTION

Internal Carotid Artery plays a key role by supplying blood to the nearest Brain hemisphere through the Basilar Artery. Ascending along the Neck and passing behind the Ear, it divides into two branches Middle Cerebral Artery and Anterior Cerebral Artery.

CLINICAL SIGNIFICANCE

Internal Carotid Artery has twists and turns which increases the chances of blockage. Blockage can decrease the supply of blood to the brain resulting in Stroke.