The foramen lacerum (Latin for lacerated piercing) is a triangular hole in the skull base located between the sphenoid, petrous apex of and basilar part of occipital bone.

The foramen lacerum is a foramen situated anteromedial to the carotid canal.

The petrous segment, or C2 segment, of the internal carotid artery is that which is inside the petrous part of the temporal bone. This segment extends until the foramen lacerum.

The foramen lacerum fills with cartilage after birth.

The internal carotid artery passes from the carotid canal in the base of the skull, emerging and coursing superior to foramen lacerum as it exits the carotid canal. The internal carotid artery does not travel through foramen lacerum. The segment of the internal carotid artery that travels above foramen lacerum is called the lacerum segment. The artery of pterygoid canal, the nerve of pterygoid canal and some venous drainage pass through the foramen lacerum.

In the foramen lacerum the greater petrosal nerve joins with the deep petrosal nerve to form the nerve of the pterygoid canal. The deep petrosal nerve carries sympathetic and the greater petrosal nerve carries parasympathetic fibres of the autonomic nervous system to blood vessels, mucous membranes, salivary glands, and lacrimal glands. Furthermore, one of the terminal branches of the ascending pharyngeal artery (itself a branch of the external carotid artery) passes through the foramen lacerum. The ascending pharyngeal artery is one of three possible “meningeal branches” of this vessel. Some emissary veins pass through the foramen lacerum. These connect the extracranial pterygoid plexus with the intracranial cavernous sinus and present an unopposed route for infection.