Cranial nerves and cavernous sinus
Several cranial nerves travel through the cavernous sinus. The cavernous sinus is a paired dural venous sinus located on each side of the sphenoid bone, extending between the rear end of the orbit and the petrous part of the temporal bone.
It is approximately 1 cm wide and 2 cm long irregular cavity formed within the layers of the dura mater and is one of the sinuses providing venous drainage of the cranial cavity.
The cavernous sinuses collect venous blood from several cranial veins and drain into the superior and inferior petrosal sinuses that further join the sigmoid sinus.
The following cranial nerves pass through the cavernous sinus:
- Oculomotor nerve (CN III)
- Trochlear nerve (CN IV)
- Abducens nerve (CN VI)
- Two branches of the trigeminal nerve (CN V):
Besides these nerves, the internal carotid artery passes through it traversing it horizontally. There are also sympathetic nerves (that arise from the superior cervical ganglion) creating the internal carotid plexus that surrounds the cavernous part of the internal carotid artery.
The abducens nerve (CN VI) is the only nerve that traverses the sinus (travelling lateral to the internal carotid artery), while the rest of the mentioned cranial nerves pass within the lateral wall of the sinus.
Note: Some resources claim that the maxillary division of the trigeminal nerve does not actually travel through the cavernous sinus, instead it passes outside the sinus wall, travelling along its inferolateral aspect.