 Welcome back to our MedSmarter question of the week where we're taking a smarter approach to preparing future physicians. Before we get started, if you'll take just a quick minute and click that like button and also subscribe and turn the bell on so that you'll be notified when we post new videos. Let's get right to that question and as always we start at the last sentence and come back for the rest of it yet. The cranial nerve involved in this case exit the skull through which the following foramina. A 42 year old woman was admitted to the neurology service for evaluation of persistent numbness over her left jaw and lower face. MRI reveals a schwannoma which is compressing a cranial nerve as the nerve exits the skull. The cranial nerve involved in this case exits the skull through which the following foramina. So this is a pretty straightforward question. You've got a schwannoma causing numbness over the left jaw and lower face. So we're looking for what nerve will innervate that location and where does it exit the skull from. So take a minute. Look at these answer choices. Come up with your answer. Write it in the comment box below. All right. So we are looking for something that innervates the left jaw and lower face. If you remember back to your anatomy and your neuroanatomy specifically we're talking about the mandibular division of the trigeminal nerve or V3 of cranial nerve 5 section 3. And cranial nerves 5 come out respectively as standing room only. Remember standing room only is the mnemonic for the 3 foramina that the trigeminal nerve divisions will come out of. S is for superior oral fissure. R in room is for foramina rotundum. And O is for foramina valley. So we are talking about the third nerve of cranial nerve 5 is what we're dealing with. That one is going to come out of O or foramina valley. So we look through here and we find A foramina valley is our final answer. And A is the correct answer. So as we said we're dealing with cranial nerve 5 also known as the trigeminal nerve. And it is the third division of the mandibular division specifically. So the schwannoma. We don't have to know anything about schwannomas. We don't have to know anything about causes or anything else. This is just telling us it's compressing that particular cranial nerve as it exits the skull. We already know everything else. This is just a specific neuroanatomy question. V3 causes numbness on the ipsilateral jaw and lower face. You have to know the mnemonic that has to do with the different nerve divisions as they exit the skull is standing room only. And S is superior orbital fissure. R is the foramen rotundum. Foramen rotundum. And O is foramen ovale. If you found this material helpful for your studying please like and consider subscribing to the channel. Also share this video so that more people can benefit from it like you have.