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Cerebellar Neuroanatomy

Introduction Examination of the cranial nerves allows one to "view" the brainstem all the way from its rostral to caudal extent. The brainstem can be divided into three levels, the midbrain, the pons and the medulla. The cranial nerves for each of these are: 2 for the midbrain (CN 3 & 4), 4 for the pons (CN 5-8), and 4 for the medulla (CN 9-12). It is important to remember that cranial nerves never cross (except for one exception, the 4th CN) and clinical findings are always on the same side as the cranial nerve involved. Cranial nerve findings when combined with long tract findings (corticospinal and somatosensory) are powerful for localizing lesions in the brainstem. Cranial Nerve 1 Olfaction is the only sensory modality with direct access to cerebral cortex without going through the thalamus. The olfactory tracts project mainly to the uncus of the temporal lobes. Cranial Nerve 2 This cranial nerve has important localizing value because of its "x" axis course from the eye to the occipital cortex. The pattern of a visual field deficit indicates whether an anatomical lesion is pre- or postchiasmal, optic tract, optic radiation or calcarine cortex. Cranial Nerve 3 and 4 These cranial nerves give us a view of the midbrain. The 3rd nerve in particular can give important anatomical localization because it exits the midbrain just medial to the cerebral peduncle. The 3rd nerve controls eye adduction (medial rectus), elevation (superior rectus), depression (inferior rectus), elevation of the eyelid (levator palpebrae superioris), and parasympathetics for the pupil. The 4th CN supplies the superior oblique muscle, which is important to looking down and in (towards the midline). Pontine Level Cranial nerves 5, 6, 7, and 8 are located in the pons and give us a view of this level of the brainstem. Cranial Nerve 6 This cranial nerve innervates the lateral rectus for eye abduction. Remember that cranial nerves 3, 4 and 6 must work in concert for conjugate eye movements; if they don't then diplopia (double vision) results. The medial longitudinal fasciculus (MLF) connects the 6th nerve nucleus to the 3rd nerve nucleus for conjugate movement. Major Oculomotor Gaze Systems Eye movements are controlled by 4 major oculomotor gaze systems, which are tested for on the neurological exam. They are briefly outlined here: Saccadic (frontal gaze center to PPRF (paramedian pontine reticular formation) for rapid eye movements to bring new objects being viewed on to the fovea. Smooth Pursuit (parietal-occipital gaze center via cerebellar and vestibular pathways) for eye movements to keep a moving image centered on the fovea. Vestibulo-ocular (vestibular input) keeps image steady on fovea during head movements. Vergence (optic pathways to oculomotor nuclei) to keep image on fovea predominantly when the viewed object is moved near (near triad- convergence, accommodation and pupillary constriction) Cranial Nerve 5 The entry zone for this cranial nerve is at the mid pons with the motor and main sensory (discriminatory touch) nucleus located at the same level. The axons for the descending tract of the 5th nerve (pain and temperature) descend to the level of the upper cervical spinal cord before they synapse with neurons of the nucleus of the descending tract of the 5th nerve. Second order neurons then cross over and ascend to the VPM of the thalamus. Cranial Nerve 7 This cranial nerve has a motor component for muscles of facial expression (and, don't forget, the strapedius muscle which is important for the acoustic reflex), parasympathetics for tear and salivary glands, and sensory for taste (anterior two-thirds of the tongue). Central (upper motor neuron-UMN) versus Peripheral (lower motor neuron-LMN) 7th nerve weakness- with a peripheral 7th nerve lesion all of the muscles ipsilateral to the affected nerve will be weak whereas with a "central 7th ", only the muscles of the lower half of the face contralateral to the lesion will be weak because the portion of the 7th nerve nucleus that supplies the upper face receives bilateral corticobulbar (UMN) input. Cranial Nerve 8 This nerve is a sensory nerve with two divisions- acoustic and vestibular. The acoustic division is tested by checking auditory acuity and with the Rinne and Weber tests. The vestibular division of this nerve is important for balance. Clinically it be tested with the oculocephalic reflex (Doll's eye maneuver) and oculovestibular reflex (ice water calorics). Medullary Level Cranial nerves 9,10,11, and 12 are located in the medulla and have localizing value for lesions in this most caudal part of the brainstem. Cranial nerves 9 and 10 These two nerves are clinically lumped together. Motor wise, they innervate pharyngeal and laryngeal muscles. Their sensory component is sensation for the pharynx and taste for the posterior one-third of the tongue. Cranial Nerve 11 This nerve is a motor nerve for the sternocleidomastoid and trapezius muscles. The UMN control for the sternocleidomastoid (SCM) is an exception to the rule of the ipsilateral cerebral hemisphere controls the movement of the contralateral side of the body. Because of the crossing then recrossing of the corticobulbar tracts at the high cervical level, the ipsilateral cerebral hemisphere controls the ipsilateral SCM muscle. This makes sense as far as coordinating head movement with body movement if you think about it (remember that the SCM turns the head to the opposite side). So if I want to work with the left side of my body I would want to turn my head to the left so the right SCM would be activated. Cranial Nerve 12 The last of the cranial nerves, CN 12 supplies motor innervation for the tongue. Traps A 6th nerve palsy may be a "false localizing sign". The reason for this is that it has the longest intracranial route of the cranial nerves, therefore it is the most susceptible to pressure that can occur with any cause of increased intracranial pressure.  
Neurologic Exam
almost 8 years ago
#22
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Facial Nerve 1/4 - Neuroanatomy

Visit http://www.DrNajeebLectures.com for 600+ videos on Basic Medical Sciences!  
YouTube
over 4 years ago
#23
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How would you locate the transpyloric plane?

This video is part of a playlist of short videos which are intended to combine multiple choice questions' answering experience with an improved understanding...  
youtube.com
over 2 years ago
#24
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Cadiac Axis Determination – Part 1

Cardiac Rhythm Analysis, 12-Lead ECG Interpretation, Resuscitation  
ems12lead.com
over 3 years ago
#25
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Renal Anatomy 3 - Glomerular Histology

http://www.handwrittentutorials.com - This is the third tutorial in the Renal Anatomy series. This video explores the histology of the glomerulus, and discus...  
YouTube
over 4 years ago
#26
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Intro to EKG Interpretation - How to Identify Any Tachyarrhythmia with 6 Easy Questions

An approach to the differential diagnosis of tachyarrhythmias based upon EKG characteristics.  
YouTube
about 4 years ago
#27
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Pseudomembranous Colitis

Pseudomembranous colitis is an inflammatory disorder of the colon associated with antibiotic use. Bacteria such as Clostridium difficile, which are usually p...  
youtube.com
over 2 years ago
#28
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Top 6 Med Student Survival Guides

There are loads of survival guides out there to help medical students adapt well to university life but which ones should you be taking notice of? I’ve put together a list of my top 6 must reads - I hope you find them useful. 1. BMJ’s Guide for Tomorrow's Doctors If you don’t read anything else, read this. It covers everything from the pros and cons of using the library to essential medical websites (check out number 6 on the list :D). http://doc2doc.bmj.com/assets/secure/survivemedicalschool.pdf 2. Money Matters Ok, this isn’t the most exciting topic but definitely a stress you could do without. The Money Saving Expert gives some great advice on how to make money and manage your finances. http://www.moneysavingexpert.com/students/student-guide 3. Studying This guide includes 4 simple but essential study tips relevant throughout your years at university. http://blog.auamed.org/blog/bid/291655/Survival-Guide-for-First-Year-Medical-Students-Study-Strategies 4. Dos and Don’ts Some great advice from Dundee University here on the dos and don’ts of surviving medical school. http://lifeofadundeemedstudent.wordpress.com/dundee/life-in-dundee/medical-student-survival-tips/ 5. Advice to Junior Doctors Karin shares some of her hospital experiences and gives advice to junior doctors. http://www.medscape.com/viewarticle/808795 6. Looking after yourself To get the most out of university it’s important that you look after yourself. The NHS provide some great tips from eating healthily on a budget to managing stress during exam time. http://www.nhs.uk/Livewell/studenthealth/Pages/Fivehealthsecrets.aspx If you know of any other useful survival guides or would like to create your own please send them across to me nicole@meducation.net. Nicole  
Nicole Chalmers
about 5 years ago
#29
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Cutting Edge Cancer Research - The Naked Scientists

Naked Scientists - 4th Nov 2012 - Cutting Edge Cancer Research  
thenakedscientists.com
over 4 years ago
#30
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Immune Response Summary Diagram

This is a diagram I created to summarise the immune response, complete with friendly, loveable cartoon immune cells designed in an attempt to make what can be a very complicated and confusing subject seem a little less threatening. The students I taught the subject to loved the "cute" summary format and found immunology to be a much more approachable revision topic as a result! Since this image has been so popular with all you lovely people, I have also written a comprehensive article on the immune response - complete with lots of illustrations - which is available here on Geeky Medics: http://geekymedics.com/2014/07/02/immune-response/ Enjoy and good luck!  
Miss Laura Jayne Watson
over 6 years ago
#31
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Antiarrhythmics (Lesson 1 - An Introduction)

An introduction to antiarrhythmics, including a description of the Singh-Vaughan Williams classification system, and a review of the cardiac action potential...  
youtube.com
7 months ago
#32
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Thrombotic Thrombocytopenic Purpura (TTP)

Thrombotic Thrombocytopenic Purpura (TTP) Instructional Tutorial Video CanadaQBank.com QBanks for AMC Exams, MCCEE, MCCQE & USMLE URL: http://youtu.be/42jKU6...  
youtube.com
over 2 years ago
#33
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Disorders of Haemostasis

 
Devika Aggarwal
over 4 years ago
#34
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Bone Sarcoma

A sarcoma is a rare cancerous tumor or mass of abnormal tissue originating from either the soft tissues or the bones. Tumors may be benign or malignant. Beni...  
youtube.com
about 2 years ago
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Acute Otitis Media

Podcast to outline Acute Otitis Media. This is a useful topic to revise if studying paediatrics or general practice.  
Dr Alastair Buick
over 10 years ago
#36
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Cranial Nerves Examination

This video tutorial teaches a comprehensive approach to cranial nerves examination. It is part of the MedPrep video tutorial series: http://www.medprep.in/clinical-examination-videos.php On YouTube, the MedPrep video tutorial series has received nearly 24,000 hits. The video series features myself, Sohaib Rufai, third year medical student at the University of Southampton, along with Iftkhar Hussein, an Economics student at the University of Manchester playing the patient, and Fahad Khan, a Clinical Sciences student at the University of Bradford, filming. The videos were then edited by myself. The aim was to produce a useful video series that is easy to follow, at times adding a bit of humour. The patient also put in extra time at the gym especially for the videos. The MedPrep website has been developed by a group of us at University of Southampton, aiming to provide free useful learning aids for medical students.  
Soton
over 6 years ago
#37
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Lub Dub | Circulatory system physiology | NCLEX-RN | Khan Academy

Ever wonder why the heart sounds the way that it does? Opening and closing of heart valves makes the heart rhythm come alive with its lub dub beats... Rishi ...  
youtube.com
about 2 years ago
#38
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Gastric Acid Physiology (Secretion, Ulcers, Acid Reflux and Treatment) - YouTube

http://armandoh.org/ https://www.facebook.com/ArmandoHasudungan Support me: http://www.patreon.com/armando Instagram: http://instagram.com/armandohasudun...  
youtube.com
about 2 years ago
#39
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List of medical mnemonics - Wikipedia, the free encyclopedia

There are many mnemonics for the names of the cranial nerves, e.g. "OOOTTAFAGVSH" is "OLd OPen OCeans TROuble TRIbesmen ABout Fish VEnom Giving VArious ACute/SPlitting Headaches" (a mnemonic that gives enough letters to distinguish between nerves that start with the same letter), or "On old Olympus's towering tops, a Finn and German viewed some hops,"[11] and for the initial letters "OOOTTAFVGVAH" is "Oh, oh, oh, to touch and feel veronica's gooey v*g**a ... ah, heaven."[12] The differences between these depend on "acoustic" versus "vestibulocochlear" and "spinal-accessory" versus "accessory".  
en.wikipedia.org
over 3 years ago
#40
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Mnemonics to remember Pharmacology of Cephalosporins - Epomedicine

Cephalosporins are one of the most widely prescribed antimicrobial drugs. They can be classified into 5 to generations and the medical students often have hard time remembering the names of ...  
epomedicine.com
over 4 years ago