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Anatomy teaching Session 5 Neuro anatomy and RadiologyDisclaimer • The following presentation has been made for students by students and we are not held accountable for any inaccuracies. This is a learning tool that has not been reviewed by the University of Sheffield and therefore the use of this session is to facilitate your learning only. Aims and objectives • To understand the basic terminology used in Neuroanatomy. • Identify the general features of the external aspect of the brain. • Describe the anatomy of the cranial meninges. • Describe the blood supply to the brain including the circle of Willis. • Describe the venous drainage of the brain and identify the dural venous sinuses. • Iplace.y the parts of the ventricular system, and where the production and drainage of cerebrospinal fluid takes • Identify and understand the function of each brain lobe. • Understand the relevance of the Homunculus. • Identify the bones that make up the skull and the cranial fossae. • Identify the foramina in the base of the skull and know what passes through each of them. • Describe the contents of the bony orbit, including the nerves, extraocular muscles, and the eye. • Understand how different nerves and extraocular muscles contribute to different movements of the eye. • Understand how changes in the amount of light entering the eye causes changes in pupil diameter. • Describe the contents of the outer, middle, and inner ear cavities. • Interpret general anatomical features of the brain on imaging.Embryology and terminology 40271/entry_id/0_zgy98rfg/embed/dynamic?get/preview/partner_id/816122/uiconf_id/446 Anatomy handbook General features Opercula–this termmeans ‘lid’ or‘cover’. Itrefers totheparts of thefrontal, parietal andtemporal lobes thatcovertheinsulalikelips aroundamouth.. 1 2 What is the name of the sulcus on the occipital lobe? Expected to learn all of these basics. Anatomy handbook Corpus callosum • A commissural fibre. • Neurones pass through and info can cross each side of the brain. What are the association and projection fibres? These final 2 are low yield but know corpus callosum. https://en.wikipedia.org/wiki/Corpus_callosum Inferior view 3 Will make more sense when you cover them. 4 1 Pituitary gland is close to the mammillary bodies and the optic chiasm. 2 About mamillary body just need to know that it is involved in memory. handbook Lobes • Frontal lobe • Primary motor cortex which is located immediately anterior to the central sulcus. • Premotor cortex which is responsible for preparation and planning of movements. • More anteriorly is the prefrontal cortex. This area is involved in personality, behaviour, problem solving, impulse control and inhibition, and social and sexual behaviour. • Broca’s area is important for spoken language production . • Parietal lobe • The parietal lobe extends from the central sulcus (anteriorly) to the parietooccipital fissure (posteriorly). I • Primary somatosensory cortex responsible for interpretation of sensory information. 2 • operations.t parietal lobe (normally the left) is important for perception, and mathematical and language • The non-dominant parietal lobe (normally the right) is important for visuospatial functions. • Temporal lobe • Immediately below the lateral sulcus in the temporal lobe is the primary auditory cortex which is responsible for interpretation of auditory information. 1 • The amygdala has a role in the perception of fear.hippocampus which is instrumental in the formation of memory. • Wernicke’s area is important in understanding and coordinating spoken language. • Occipital lobe • Primary visual cortex which is responsible for interpreting visual information received via the optic nerves. (calcarine sulcus) • Limbic system • The limbic system is a group of structures found in the medial margins of the hemispheres including the hippocampus, amygdala and various parts of the cortex. • It also includes parts of the diencephalon. As a group, they are involved in emotion, memory and behaviour. handbookYour friend came to your clinic and their memory formation has been affected. They seem to struggle to remember many of their best memories. Which of the lobes of their brain is most likely affected? • A) Frontal • B) Temporal • C) Parietal • D) OccipitalYour friend came to your clinic and their memory formation has been affected. They seem to struggle to remember many of their best memories. Which of the lobes of their brain is most likely affected? • A) Frontal • B) Temporal • C) Parietal • D) Occipital • Hippocampus and most of memory is related to the temporal lobe.Homunculus • Common exam question. • Know the blood supplies and that will determine what part of the body will be affected at a stroke.Blood supply https://radiopaedia.org/articles/circle-of-willis Anatomy handbookClinical relevance • So a patient comes in and a have an anterior cerebral artery infarct. Which part of their body will be affected the most? • Leg functionMeninges • Pia mater: • At the capillary level, the pia fuses with the endothelial cells of the as the blood-brain barrier.ialised layer of pia and endothelial cells known • Features: (common SAQ question) • The endothelial cells are tightly bonded together to prevent molecules passing between them. • The basement membrane of the capillaries in the brain and spinal cord lacks fenestrations (small holes) that are found elsewhere in the body. • Further specialised cells known as ‘pericytes’ wrap around the endothelial cells. • flow of certain molecules.es’ further wrap around the capillaries to restrict • Arachnoid Mater • The arachnoid is a single layer that loosely follows the contours of the meningeal layer of the dura. • Between the arachnoid and the pia below is the subarachnoid space which contains cerebrospinal fluid (CSF). https://www.thoughtco.com/brain-anatomy-meninges-4018883Sinuses • The dura has two layers • The outer endosteal layer is adherent to the interior of the skull. • The inner meningeal layer completely envelops the brain and spinal cord. • Know sinuses but most important are transverse and sigmoid leading to internal jugular vein. https://en.wikipedia.org/wiki/Dural_venous_sinusesCase • Patient Presentation: • Name: John Doe, 25-year-old male. • History: Helmeted motorbike accident; initially alert with mild headache. • Progression in ED: • Initial Vitals: Stable, GCS 15/15. • After 1 Hour: GCS drops to 10/15; drowsy, worsening headache, nausea, right pupil dilated and unresponsive. • Task 1: Differential Diagnosis • Task 2: CT Scan Findings • Describe what you can see. • Why didn’t we order an X-ray ? • When is an X-ray used for head? https://radiopaedia.org/articles/extradural-haemorrhage-summary?lang=gbCase • Key Findings: • Biconvex, hyperdense collection in right temporoparietal region. • Midline shift. • Answers: • Likely diagnosis: Extradural haemorrhage. • Injured structure: Middle meningeal artery. • Lucid interval: Temporary compensation as blood accumulates slowly, delaying symptoms until intracranial pressure rises. • Likely differentials: • Extradural haemorrhage (EDH). • Subdural haemorrhage (SDH). • Intracerebral haemorrhage (ICH). • X-rays have low resolution as don’t penetrate the skull. • X-rays are used for facial such as maxillary bone injury.Haemorrhage on CT scan extradural subdural subarachnoidCircle of willis 1 • Know it. • Common question will be consequence of each occlusion. 2 • Anterior cerebral artery (ACA) • These vessels supply the medial aspects of the frontal and parietal lobes. 3 • Lower limb • Middle cerebral artery (MCA) • parts of the hemispheres.y the vast majority of the lateral aspects and deep • Face, arms and trunk, and a structure called the internal capsule • Posterior cerebral artery (PCA) • cortex, but also a small portion of the inferior temporal lobe.he visual • Basilar artery • This large singular vessel carries arterial blood from the vertebral arteries to the circle of Willis. 4 • It gives off small branches to supply the pons. handbookA patient is admitted to the stroke ward. He was examined and he had a motor score of 3/10 for his right leg and a score of 8/10 for his left leg. Which artery is most likely to be affected? • A) Right anterior cerebral artery • B) Left anterior cerebral artery • C) Right Middle cerebral artery • D) Left Middle cerebral arteryA patient is admitted to the stroke ward. He was examined and he had a motor score of 3/10 for his right leg and a score of 8/10 for his left leg. Which artery is most likely to be affected? • A) Right anterior cerebral artery • B) Left anterior cerebral artery • C) Right Middle cerebral artery • D) Left Middle cerebral artery • As the left side is affected then right of the brain is responsible and according to the homunculus the anterior cerebral artery suppled the legs. • This can easily be a SBA.Case • Patient Presentation: • Name: Mr. John Carter • Age: 67 years • Complaint: Sudden right-sided weakness and slurred speech. • Key Findings: • History: Hypertension, hyperlipidemia, smoking, and family history of stroke. • Examination: • Right-sided hemiparesis (2/5 power). • Decreased sensation on the right. • Non-fluent aphasia. • BP: 180/95 mmHg. • Imaging: • You order a CT Brain without contrast. • • Result: Hyperdense MCA sign on the left; early ischemic changes in the left frontal and parietal lobes.Case • Middle cerebral artery stroke. • Next Steps: • Administer tPA • If within 4.5 hours of symptom onset and no contraindications. • CT Perfusion • Assesses salvageable brain tissue if outside tPA window. • Consult neurosurgery for thrombectomy • Especially if large vessel occlusion is confirmed on CTA or perfusion shows penumbra.Cerebrospinal Fluid • Lateral ventriclesà interventricular foramen 2 (Monroe) à third ventricle à cerebral aqueduct 1 à4th ventricle • CSF is recycled back into the bloodstream by arachnoid granulations. • Choroid plexus can be a question as well. What is it? 3 Skull fossa Name the cranial fossa 1 2 3 Anatomy handbookfossa Common exam question to ask you to name these and say what passes through! • Anterior Cranial Fossa • The frontal lobes rest in the anterior cranial fossa, and it is formed of three bones: • Orbital part of the frontal bone • Cribriform plate and the crista galli of the ethmoid bone • Lesser wings of the sphenoid bone • Cribriform plate – transmits olfactory fibres that allow our sense of smell. • Middle Cranial Fossa • Petrous and squamous parts of the temporal bone • Greater wing and body of the sphenoid bone • The foramina located on each side of the middle cranial fossa are the: • Optic canal – transmits the optic nerve into the bony orbit. • Superior orbital fissure – transmits several nerves that provide motor innervation (oculomotor, trochlear and abducens nerves) and sensation (ophthalmic branch of the trigeminal nerve) to the orbital region. • Foramen rotundum – transmits the maxillary branch of the trigeminal nerve. • Foramen ovale – transmits the mandibular branch of the trigeminal nerve. • Carotid canal – the internal carotid artery Foramen lacerum is located within this canal • Foramen spinosum – transmits the middle meningeal artery.Posterior fossa • Posterior cranial fossa • The occipital lobes, cerebellum and brainstem rest in the posterior cranial fossa and it is formed primarily by the occipital bone, but part of the petrous part of the temporal bone makes up its most anterior border. • Internal auditory meatus – transmits the vestibulocochlear and facial nerves into the inner ear cavity. • Jugular foramen – transmits the glossopharyngeal, vagus and accessory nerves, and the internal jugular vein. • Hypoglossal canal – transmits the hypoglossal nerve. • Foramen magnum – this central singular foramen is very large and allows central nervous system fibres to leave the skull and become the spinal cord. • Know pterion is where the middle meningeal passes and bones join.Ocular muscles • A useful mnemonic to remember the nerves that supply the extraocular muscles is LR6SO4 – lateral rectus is supplied by cranial nerve 6, superior oblique is supplied by cranial nerve 4. The rest of muscles are supplied by cranial nerve 3. • Elevation – to look up. • Depression – to look down. • Adduction – to look medially. • Abduction – to look laterally. • Extorsion – to rotate the eye, so the top of the eye rotates laterally. • Intorsion – to rotate the eye, so the top of the eye rotates medially.Ocular muscles https://link.springer.com/chapter/10.1007/978-981-287-846-5_16Accommodation and Pupils Pupillary dilation and constriction • Accommodation • Focusing light to varying amounts depending on A circular muscle within the iris known as constrictor how far away the object is that is being pupillae will constrict the pupil. visualised is called accommodation. This muscle is also supplied by parasympathetic fibres • The ciliary muscles are responsible for this. within the oculomotor nerve (CN III). • They are supplied by parasympathetic fibres Within the iris known as dilator pupillae will dilate the that travel within the oculomotor nerve (CN III). pupil. This muscle is supplied by sympathetic fibres.Pupillary reflex • The pupillary light reflex, which is responsible for automatically adjusting the amount of light entering the eye, has an afferent (sensory) and efferent (motor) nerve. • The afferent nerve is the optic nerve and it synapse with the Edinger-Westphal nucleus, which instructs the efferent nerve (the oculomotor nerve) to initiate constriction of the constrictor pupillae muscle in the iris. • Direct and consensual pupillary response. • TEdinger-Westphal nuclei. pupil constricts as well is because there is a connection between the right and left • Lacrimal gland • The secretomotor nerve supply to the lacrimal gland is via the parasympathetic fibres within the facial nerve (CN VII).Ear • Know the ossicles : Malleus, incus, and stapes. • Tensor tympani is supplied by the mandibular branch of the trigeminal nerve (CN V). • Stapedius is supplied by the facial nerve (CN VII). • Cochlea –The sound waves first enter the cochlea via the oval window. • The round window is located nearby and bulges in and out to allow the fluid within the cochlea to move. • Vestibular system – consists of the semicircular canals, utricle and saccule. • The vestibular system contains fluid, which flows when we move our heads. • The three semicircular canals, positioned perpendicular to each other in three dimensions, allow us to perceive movement. • The utricle and saccule allow us to perceive linear acceleration. https://storymd.com/journal/bmpz95qu6j-ear-anatomy/page/4qbp2tdgax-inner-earA patient has a severe head injury and their skull was fractured. Identify what bone in the skull this image is. • A) Squamous part of temporal bone • B) Petrous part of temporal bone • C) Squamous part of parietal bone • D) Petrous part of parietal bone • E) Frontal bone https://www.getbodysmart.com/skull-cranial-bones/temporal-bone-anatomy/A patient has a severe head injury and their skull was fractured. Identify what bone in the skull this image is. • A) Squamous part of temporal bone • B) Petrous part of temporal bone • C) Squamous part of parietal bone • D) Petrous part of parietal bone • E) Frontal bone https://www.getbodysmart.com/skull-cranial-bones/temporal-bone-anatomy/A patient is admitted to the A&E with a suspected stroke. His right eye is severely affected. Which lobe of their brain is most likely damages? • A) Left frontal • B) Right frontal • C) left occipital • D) Right occipitalA patient is admitted to the A&E with a suspected stroke. His right eye is severely affected. Which lobe of their brain is most likely damages? • A) Left frontal • B) Right frontal • C) left occipital • D) Right occipitalWhich nerve passes through this foramen? • A) Maxillary branch of Trigeminal • B) Mandibular branch of trigeminal • C) Ophthalmic branch of Trigeminal • D) Optic nerve 6655747/4.htmleanpng.com/png-foramen-rotundum-foramen-ovale-skull-tuberculum-se-Which nerve passes through this foramen? • A) Maxillary branch of Trigeminal • B) Mandibular branch of trigeminal • C) Ophthalmic branch of Trigeminal • D) Optic nerve • Foramen rotundum it is smaller than Ovale 6655747/4.htmleanpng.com/png-foramen-rotundum-foramen-ovale-skull-tuberculum-se-A patient has conductive hearing loss and the muscle attached to their stapes has been affected. Which nerve innervates the muscle affected? • A) Phrenic • B) Vagus • C) Trigeminal • D) FacialA patient has conductive hearing loss and the muscle attached to their stapes has been affected. Which nerve innervates the muscle affected? • A) Phrenic • B) Vagus • C) Trigeminal • D) Facial • I remembered that Trigeminal has a T so supplies tensor tympani with and stapedius doesn’t have a T !!Which one of the following nerves causes lacrimal gland secretion? • A) Glossopharyngeal • B) Facial • C) Mandibular branch of trigeminal • D) Maxillary branch of trigeminal.Which one of the following nerves causes lacrimal gland secretion? • A) Glossopharyngeal It is a lot lower down • B) Facial • C) Mandibular branch of trigeminal • D) Maxillary branch of trigeminal. Not parasympatheticHow is the CSF absorbed back to the venous circulation? • A) Arachnoid granulation • B) Sigmoid sinus • C) Internal jugular vein • D) It doesn’t go the veinsHow is the CSF absorbed back to the venous circulation? • A) Arachnoid granulation • B) Sigmoid sinus Could be SBA • C) Internal jugular vein • D) It doesn’t go the veinsA patient has had an oculomotor nerve palsy which of the following muscles of the eye is least likely to be affected? • A)Lateral Rectus • B)Medial Rectus • C)Inferior rectus • D)Superior RectusA patient has had an oculomotor nerve palsy which of the following muscles of the eye is least likely to be affected? • A)Lateral Rectus • B)Medial Rectus • C)Inferior rectus • D)Superior Rectus • LR6SO4Which one is true? • A) The semicircular canals help us to detect linear acceleration primarily. • B) The ossicles are found in the outer ear. • C) The stapes connects to the round window of the cochlea • D) The utricle and saccule help us detect linear acceleration.Which one is true? • A) The semicircular canals help us to detect linear acceleration primarily. Their main function is balance • B) The ossicles are found in the outer ear. Middle ear • C) The stapes connects to the round window of the cochlea. Oval window not round • D) The utricle and saccule help us detect linear acceleration. https://medienportal.siemens-stiftung.org/en/inner-ear-section-101951Thanks for listening Session 5 psanikhani1@Sheffield.ac.ukReferences • Anatomy handbook. University of Sheffield. School of medicine and population health. Neuro anatomy. • https://en.wikipedia.org/wiki/Corpus_callosum • https://www.kaltura.com/index.php/extwidget/preview/partner_id/816122/uiconf_id/44640271/entry_id/0_zgy98rfg/embed/dynamic? • https://www.thoughtco.com/brain-anatomy-meninges-4018883 • https://en.wikipedia.org/wiki/Dural_venous_sinuses • https://radiopaedia.org/articles/extradural-haemorrhage-summary?lang=gb • https://jetem.org/dense_mca_sign/ • https://link.springer.com/chapter/10.1007/978-981-287-846-5_16 • https://storymd.com/journal/bmpz95qu6j-ear-anatomy/page/4qbp2tdgax-inner-ear • https://www.cleanpng.com/png-foramen-rotundum-foramen-ovale-skull-tuberculum-se-6655747/4.html • https://medienportal.siemens-stiftung.org/en/inner-ear-section-101951