Internal Carotid Artery Scheme (Side branches, Circle of Willis) | Anatomy — Transcript

Full transcript

1. 0:00Alright guys so this video is  about the internal carotid.
2. 0:03I just wanna start by saying that everything  you see in this video was made to be schematic
3. 0:08for you to hopefully be able to visualize it Now essentially
4. 0:13As the common carotid artery  ascends along the neck
5. 0:16It will divide, at the region of  the upper thyroid cartilage, into
6. 0:20The external and the internal carotid; with the external carotid here in orange as
7. 0:26We’re not gonna talk about this one. Now – initially the internal carotid
8. 0:30is divided into four anatomical parts, however  in a clinical setting – and this really depends
9. 0:36on the source you’re studying from, you may  find it divided into 7 anatomical segments
10. 0:42I’ll go through the four anatomical  parts, but I will also show you the
11. 0:477 segment scheme later in this video So the first part is the cervical part,
12. 0:52in the neck region, hence the name  ‘’Cervical’’ part. It goes up, then
13. 0:58Goes inside the carotid canal as you see here, Where it now becomes the Petrous part.
14. 1:04So taking this area out to Visualise it, you’ll see the carotid
15. 1:10Canal here – It’s initially a canal within the  petrous part of the temporal bone, so this is just
16. 1:17a coronal, or a frontal section of the canal. Now the internal carotid will continue up
17. 1:25through the canal, and give off  some important side branches
18. 1:31Called the caroticotympanic branches, supplying  the tympanic cavity, or the middle ear.
19. 1:38(x2) Now as it leaves the  canal and enters the middle
20. 1:43cranial fossa, it becomes the cavernous part, And here is maybe a better representation of it.
21. 1:50Going right through the cavernous sinus – the  cavernous sinus is one of the dural sinuses of
22. 1:57the head, they’re large veins draining blood  form the brain and sending them down mainly
23. 2:04through the jugular vein. And this is how it, um,
24. 2:07you see it going through the cavernous sinus  here giving it it’s name – cavernous part.
25. 2:16As it goes up it eventually gets the name  ‘’Cerebral part’’, where it divides into 5
26. 2:22terminal braches, Now, I mentioned earlier  that it could be divided into 7 segments.
27. 2:28And I’m not really gonna  spend too much time on this
28. 2:31But I made a quick scheme of the 7 segments  with the side branches of the internal carotid.
29. 2:37I mentioned the caroticotympanic branch,  but as you see there are specific side
30. 2:43branched for each segment, except the cervical  segment, lacerum and clinoid segment I guess,
31. 2:51C1, C3 and C5. They’re without side branched. You can just pause the video and take a mental
32. 2:58picture if you wanna, but I essentially  only wanna focus on the terminal end of
33. 3:02this artery cuz thos are the most important. So looking at a cranial view of the .. cranium
34. 3:09We’re going to have the ophthalamic artery, going  into the optic cavity through the optic canal
35. 3:16There’s the anterior cerebral artery, which Communicated with the other one on the opposite
36. 3:22side through the anterior communicating artery. There’s the middle cerebral artery
37. 3:29Then the posterior communicating artery,  which communicated with the posterior
38. 3:33Cerebral artery here in red.  The posterior cerebral artery
39. 3:37Is a branch of the basilary artery as you see here Which comes from the vertebral artery
40. 3:45Coming from the subclavian artery So now the last branch
41. 3:50Is the anterior choroid artery, which enters the  lateral ventricle and form the choroid plexus
42. 3:57Now I’ll try and cover these arteries in a  little more details, or rather jsyt enough for
43. 4:05you to gain a general knowledge and hopefully  pass your tests with a … comfortable grade.
44. 4:10Now all of these form the so called Circle of Willis, which supplies a
45. 4:17huge majority of the brain with blood. It’s name is after the English physicial
46. 4:21Thomas Willis, who in late 16-hundreds  researched the anatomy of the brain and
47. 4:27found this structure of arteries. So – Let’s look into each of these
48. 4:31Again the major blood supply of the brain Comes from the cerebral part of
49. 4:35the internal carotid And the basilar artery
50. 4:38The ophthalamic artery does not provide any  blood supply for the brain and so to save
51. 4:45time I’ll go through this one when I talk about  the blood supply of the eye in a separate video.
52. 4:50But first one in the list is  the anterior cerebral artery
53. 4:53Which again has this anterior communicating artery Now, essentially this artery will run
54. 5:05Along the longitudinal Cerebral  fissure as you see here
55. 5:08And this, if you look where the arrow is and Follow the artery, the whole purple area
56. 5:14will be supplied by the anterior cerebral artery And this include the whole medial surface of the
57. 5:21frontal and parietal lobe as you see here And then on the superolateral surface,
58. 5:27the whole blue area on the top is supplued  by this artery, the superior frontal gyrus,
59. 5:34the superior parietal lobule, and the  upper part of pre-/post cerebral gyrus.
60. 5:42Also – a little hard to see it here but it also  supplies the straight gyrus (or gyrus rectus) on
61. 5:51the inferior surface, So – that’s this one. Next is the
62. 5:57Medial Cerebral Artery. This a huge artery  supplying really most of the brain with blood,
63. 6:04therefor any blockage here will lead to  something called middle cerebral artery syndrome,
64. 6:10And this is quite serious Because you see how it
65. 6:13supplies many structures in the brain? It supplies the Insula, Lentiform nucleus, the
66. 6:17caudate nucleus, the internal capsule Along with the superior and middle
67. 6:23Temporal Gyrus, and the rest of  the purple areas in the brain here.
68. 6:27That’s why the middle cerebral artery syndrome  is associated with many symptoms like paralysis,
69. 6:34sensory loss and speech problems, mainly because  of brochas and werniches area are also affected.
70. 6:40Now Next we can jump over the posterior
71. 6:48communicating artery because this just goes back  communicating with the posterior cerebral artery.
72. 6:55But the anterior choroid artery is very important And I tried visualizing it here,
73. 7:01So again here’s the internal carotid, with The anterior and the middle cerebral arteries
74. 7:07The anterior choroid artery will go backwards,  to form mainly the choroid plexus in the lateral
75. 7:15and the third ventricle. So that’s mainly this one-
76. 7:23The posterior cerebral artery  coming from the basilar artery, to
77. 7:27Supply mostly the occipital Lobe as you see here in yellow,
78. 7:30as well as the inferior temporal. And remember  both occipital and inferior temporal gyrus are
79. 7:38both associated with vision. So any occlusion  in the posterior cerebral artery will result
80. 7:45in a visual defect, along with other significant  things like pain and temperature sensation loss.
81. 7:50So that’s mainly all I had for the internal  carotid and blood supply of the brain.
82. 7:56I really hope this video helped you in any way,  just as long as tou remember the circle of Willis,
83. 8:02you’re already understanding  a huge majority of this topic.