you are offline, so I will leave an answer to your question, and then please get back to me when you return to review and then write me a reply with additional questions and or comments if satisfied with this answer.
so the nomenclature to name the blood vessels in the cerebral circulation is based on an organized principle, that uses numbers with ascending order as you move away from the circle itself. So there are anterior, middle and posterior cerebral arteries. and so you could talk about A1, M1, P1, and A2, M2, P2 which denote a branch of the artery further away than the P1, after the first bifurcation from a segmental artery. /do you understand that? please get back to me if you do not.
so one issue in your circulation, which makes you, you. and not some other guy, is that your superior cerebellar artery takes its origin from the P1 segment, which becomes the posterior cerebral artery. usually the sup. cerebellar comes directly off the basilar artery before it becomes part of the circle and gives off the P1 branch. The key here is that the tentorium cerebelli, the sheet of connective tissue that carries the venous return from the brain (straight vein of Galen, etc) is between the sup cerebelllar artery (underneath to suppy the cerebellum) and the posterior cerebral artery (above to supply the visual cortex and many other things) So there has to be some twisting of the sup cerebellar artery to get under the tentorium after coming off the P1 segment. I hope I haven't confused you completely.
so since your P 1 supplies the PCA, maybe that is why it becomes more narrow before enlarging to supply the primary visual cortex and accessory visual cortices? It is an anomaly and probably is of no major concern. The blood supply to the cochlear nucleus of the right ear is usually AICA, the anterior inferior cerebellar artery, that comes off the basilar artery way before this issue with the P1 segment. ( note that I said usually, that is because again, you already had one thing anomalous, so possibly you have other differences, that doesn't mean that you have a disease, ok?)
Please get back to me and describe your TIA, do you have posterior circulation symptoms? (Dizzyness, Vertigo, diplopia or double vision, facial numbness, slurred speech, incoordination of your limbs, Ataxia or falling down?) I would like to discuss this further with you. If that is the case, you need to be on aspirin if you can tolerate that and/or plavix.
I added here a Frank Netter illustration of the posterior circulation which will show all the details of my previous statements, so review that and get back to me ok? Dr Frank (Netter, no just kidding) T.
HI. so you can have obstructive apnea, and be thin, it really comes from a laxity in the pharyngeal muscles that provide for the obstuction, there can be other reasons in the morbidly obese, features more consistent with restrictive lung disease because of the excess weight on the chest. But if you have a history of snoring, then OBSA as a possibility exists. It is based on your sleep study (polysomnogram) and the hypopnea index, and looking at the compensatory changes after an apnea or hypopnea, you can determine whether this is a central cause (stroke in the brainstem) vs. an obstructive cause of sleep apnea, so the question would be were you diagnosed with this after the posterior circulation TIA/stroke? Let me know if you would like to discuss. Neuroanatomically, AICA, the artery to the auditory nerve/cochlear nucleus can come off the vertebral artery before it joins to form the basilar, so again, you could have VBI, vertebrobasilar insufficiency and have all of these symptoms. I would inquire into the status of your AICA, and is there an approach to improving the vascular status of the artery (is it stenotic?) If you are on calcium channel blockers for your b/p, that might improve things. People try tricyclic antidepressants like elavil for symptomatic treatment of tinnitus, but there are side effect issues. Get back to me if you want to discuss further. Dr Frank T.