(2.47)
To follow the internal carotid artery we'll take the external carotid and its branches out of the picture. We'll also remove the posterior belly of the digastric, the styloid process, and the muscles that arise from it.
The internal carotid artery runs upwards to the base of the skull without branching. The internal jugular vein is lateral to it, here. The internal carotid artery enters the carotid canal which is here in the dry skull.
The carotid canal immediately turns, to run forwards and medially. To see the other end of the carotid canal we'll go all the way round to the inside. The carotid canal comes from this direction and ends here at the foramen lacerum.
To expose the internal carotid artery we'll first remove the dura of the middle cranial fossa, then we'll remove this structure, the trigeminal ganglion, and finally these three cranial nerves: the third, fourth, and sixth. Here's the internal carotid artery coming up out of the foramen lacerum.
The internal carotid artery here lies within an irregular cavity, the cavernous sinus, that's a passageway for venous blood. We'll see it later in this section. The artery turns to run forwards, and then makes a complete 180º turn. This turn takes it under the anterior clinoid process, and brings it out here, just below and behind the optic canal.
The internal carotid artery finally emerges through the dura just beneath the optic nerve. As it completes its backward turn, it gives off a branch, the ophthalmic artery. To see that, we'll remove the optic nerve, and the dura beneath it.
Here's the start of the ophthalmic artery. It runs forwards into the optic canal along with the optic nerve. The ophthalmic artery supplies the contents of the orbit and continues forward to supply the ...
(2.47)
To follow the internal carotid artery we'll take the external carotid and its branches out of the picture. We'll also remove the posterior belly of the digastric, the styloid process, and the muscles that arise from it.
The internal carotid artery runs upwards to the base of the skull without branching. The internal jugular vein is lateral to it, here. The internal carotid artery enters the carotid canal which is here in the dry skull.
The carotid canal immediately turns, to run forwards and medially. To see the other end of the carotid canal we'll go all the way round to the inside. The carotid canal comes from this direction and ends here at the foramen lacerum.
To expose the internal carotid artery we'll first remove the dura of the middle cranial fossa, then we'll remove this structure, the trigeminal ganglion, and finally these three cranial nerves: the third, fourth, and sixth. Here's the internal carotid artery coming up out of the foramen lacerum.
The internal carotid artery here lies within an irregular cavity, the cavernous sinus, that's a passageway for venous blood. We'll see it later in this section. The artery turns to run forwards, and then makes a complete 180º turn. This turn takes it under the anterior clinoid process, and brings it out here, just below and behind the optic canal.
The internal carotid artery finally emerges through the dura just beneath the optic nerve. As it completes its backward turn, it gives off a branch, the ophthalmic artery. To see that, we'll remove the optic nerve, and the dura beneath it.
Here's the start of the ophthalmic artery. It runs forwards into the optic canal along with the optic nerve. The ophthalmic artery supplies the contents of the orbit and continues forward to supply the central part of the forehead.
To see how the internal carotid artery ends we'll add its last part, and the optic chiasm to the picture. The internal carotid artery ends by emerging from beneath the chiasm, curving laterally as it does so. We'll follow its branches in a minute.