CRUX OF MRCS

Oculomotor CN III Oculomotor CN III palsy △  * Down-and-out eye medial rectus paralysis * Ptosis levator palpebrae superioris paralysis * Mydriasis loss of parasympathetic to sphincter pupillae Remember that the oculomotor CN III facilitates pupil constriction via its parasympathetic innervation to the sphincter pupillae through the ciliary ganglion. Causes of oculomotor CN III

* The most common primary brain tumor is a glioma, specifically astrocytomas, with glioblastoma being the most aggressive and prevalent type in adults. Glioblastoma multiforme is characterized by central necrosis, ring enhancement, and cross‑midline infiltration (“butterfly glioma”). * In children, pilocytic astrocytoma is the most common brain tumour. 📚 A man has

Brown-Séquard syndrome Brown-Séquard syndrome, hemisection of one side of cord side affects;  * Corticospinal tract Ipsilateral weakness * Dorsal column Ipsilateral ⬇️ proprioception, vibration, fine touch  * Spinothalamic tract Contralateral ⬇️ pain, temperature Horner's syndrome △ ptosis, miosis and ipsilateral face anhidrosis due to disturbance to the sympathetic supply to the eye and face.

👩‍⚕️ Download the pdf below and memorise all the afferents and efferents for the above reflex arcs. Then we zoom in a bit on the direct and consensual pupillary light reflex and the associated Edinger-Westphal nucleus. Summary table of reflex arcs Reflex arcsReflex arcs.pdf109 KBdownload-circle 💡A rhyme to memorise some

📚 Exam-style questions * Foramen of Monro * Foramen of Luschka & Magendie * Subarachnoid space * [[Cerebral aqueduct of Sylvius::The Cerebral aqueduct of Sylvius is the narrowest part, most frequent site of obstruction (aqueductal stenosis)]] The most common site of obstruction in hydrocephalus is: 🏠 Back to Day 1 Overview

📚 Exam-style questions * A patient sustains head trauma to the vertex with a depressed skull fracture. Which intracranial structure is most likely to be damaged? * [[Superior sagittal sinus::The superior sagittal sinus is a large venous channel running along the midline, directly under the skull at the vertex, making it susceptible

Branches of the internal carotid artery:  It starts with a few minor (irrelevant for MRCSA) ones - caraticotympanic, vividian, meningohypohyseal, inferolateral - then the main ones are: 1. Ophthalmic  2. Posterior communicating  3. Anterior choroidal  4. Anterior cerebral  5. Middle cerebral  The first branch of the internal carotid artery as