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Anatomy teaching Session 6 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 • Identify the three parts of the brainstem and describe their gross anatomical features and main functions. • Identify all 12 cranial nerves and describe the location of their nuclei, their functions and where they exit the skull. • Understand how visual information is conveyed from the retina to the primary visual cortex and how disruptions to this pathway causes various visual field defects. • Describe the gross anatomy and functions of the cerebellum. • Identify important midline structures of the brain visible on a sagittal section. • Describe the main functions and parts of the limbic system. • Identify the parts of the basal ganglia and the internal capsule. • Describe the anatomy of the vertebral column, including the features of each type of vertebrae. • Identify the intervertebral discs, ligaments and muscles that support the vertebral column. • Describe the anatomy of the spinal cord including the formation of spinal nerves. • Describe the three main spinal tracts, including their courses, functions, and locations within the cord. • Understand how the basal ganglia and brainstem structures look on imaging. • Interpret general anatomical features of the brain on imaging. Midbrain Tectum The superior colliculi are involved in regulating eye movements and reflexes associated with visual stimuli The inferior colliculi are involved sound location, pitch discrimination and reflexes associated with auditory stimuli. Tegmentum It contains the substantia nigra which is important in motor control by producing dopamine. It also contains the cerebral peduncles on its most ventral surface. The red nuclei which are involved in supporting motor control of the limbs. Surrounding the cerebral aqueduct is the periaqueductal grey (PAG) which is a collection neuronal cell bodies that plays a role in modulation of pain. Contains the nuclei of the oculomotor (CN III) and trochlear (CN IV) nerves, and the Edinger-Westphal. Remember this!! Anatomy handbook PAG is Lower yield Pons Contains the nuclei of the trigeminal (CN V), abducens (CN VI), facial (CN VII) and vestibulocochlear (CN VIII) nerves. It also contains the pneumotaxic and apneustic centres which are involved in the regulation of breathing. which cranial nerve exits posteriorly? Trochlear https://www.brainkart.com/article/The-Pons--gross-anatomy_18923/ Medulla The medulla contains the two medullary pyramids, which form two distinct lumps of the ventral surface, separated by this fissure. Essential motor tracts known as the corticospinal tracts run inside the pyramids. Lateral to the medullary pyramids are another pair of prominent ridges known as the medullary olives. The dorsal column medial lemniscus (DCML) pathway runs in the dorsal part of the medulla within two pairs of nerve bundles: fasciculus gracilis and fasciculus cuneatus. The medulla contains the nuclei of the glossopharyngeal (CN IX), vagus (CN X), accessory (CN XI) and hypoglossal (CN XII) nerves. https://www.earthslab.com/anatomy/medulla-oblongata/ Imaging Which one is medulla? Is this CT or X-rays or MRI? https://www.radiologymasterclass.co.uk/tutorials/ct/ct_brain_anatomy/ct_brain_anatomy_cerebellum HandbookCranial nerves Very high yield. Please memorise!Common exam questionWhat nerve passes through this foramina? • A) olfactory nerve • B) optic nerve • C) Occulomotor nerve • D) maxillary branch of the trigeminalWhat nerve passes through this foramina? • A) olfactory nerve • B) optic nerve • C) Occulomotor nerve • D) maxillary branch of the trigeminal • Optic canal Visual pathway- High yield Each visual field is divided into a temporal field and a nasal field. The temporal field is the lateral half of the visual field, and nasal field is the medial half. Visual information from the retinas first travels to the optic chiasm. At the optic chiasm, visual information from the temporal visual fields (nasal retinas) from each eye cross over. After the optic chiasm, the visual information travels along the optic tracts. When the tracts reach the thalamus, the majority of fibres synapse in the lateral geniculate nucleus. After they synapse, the fibres divide into a superior and inferior pathway on each side, known as optic radiations. The superior optic radiation travels in the parietal lobe, and is therefore known as the parietal radiation, and the inferior optic radiation travels in the temporal lobe, and is known as the temporal radiation, also known as ‘Meyer’s loop’. Common question would be a pituitary tumor would cause a condition. What is that? handbook Common complication Bitemporal hemianopia – this term means ‘both – temporal – half – vison loss’ and is caused by damage to the optic chiasm. The fibres that cross at the optic chiasm are carrying visual information from the nasal retinas, and therefore information about the temporal visual fields. https://www.youtube.com/watch?v=alii0GcqUnM Cerebellum The anterior lobe is found on the superior surface of the cerebellum and is divided from the larger posterior lobe by the primary fissure. A horizontal fissure is present within the posterior lobe. The third lobe, the flocculonodular lobe, is located most ventrally and is made of the flocculus and nodule. The flocculus is located beneath the cerebellar peduncles, and the nodule is found in the midline. https://www.slideshare.net/binuenchappanal/anatomy-of-cerebellum-124645619 Low yield to ask too much details but easy question to ask about the functional area. Limbic system Fornix Mammillary bodies – small, round nuclei located at the anterior tip of the fornix. 1 Hippocampus: integral in converting short-term to long-term memory. 2 Parahippocampal gyri – as their name suggests, these gyri of the temporal cortices are located next to the hippocampi. Cingulate gyrus and cingulate sulcus – this is a large gyrus and associated sulcus that is superior to it which are located immediately superior to the corpus callosum on both sides of the cerebrum. Association fibres Other parts of the limbic system include sections of the olfactory and insular cortex, thalamus, hypothalamus, and nucleus accumbens and amygdala 3 Know that Papez cycle exists. Don’t bother memorising it. https://medicoapps.org/m-limbic-system/ Basal ganglia There is the direct and indirect pathways. Don’t usually come up in exams. Caudate nucleus – a c-shaped structure that rests immediately lateral to, and follows the curvature of, the lateral ventricle. Globus pallidus – a triangular-shaped nucleus that can be divided into an internal and external part. Putamen – an oval-shaped nucleus found immediately lateral to the globus pallidus. dopamine.a nigra – a black nucleus found in the midbrain. Notable for producing Subthalamic nucleus – a small nucleus, located inferior to the thalamus, but superior to the substantia nigra. handbook Imaging What anatomical planes are these images taken from? MRI handbook Types of MRI • T1-weighted MRI: Highlights fat and is ideal for anatomical details. • T2-weighted MRI: Highlights fluid, making it ideal for detecting pathological changes, such as oedema or inflammation. Vertebral column You should be able to name all of these It ismadeup of 33 vertebrae (singular: vertebra), although someof themarefused together: •7 cervical •12 thoracic •5 lumbar •5 sacral •4 coccygeal (only 1 pairof nerve) •But 31 pairs of spinalnerves. Cervical lordosis in the neck. Thoracic kyphosis in the upper back. Lumbar lordosis in the lower back. Handbook Types of vertebral bodies What is the type of joint between atlas and axis? Atlanto-axial Atlas Other cervical Lumbar Axis Thoracic Sacral and coccygeal Is atlas or axis C1? Atlas Handbook Intervertebral disk Low yield but important for lumbar puncture. Low yield Anterior longitudinal ligament – along the anterior surfaces of the vertebral bodies. Posterior longitudinal ligament – along the posterior surfaces of the vertebral bodies, but anterior to the spinal canal. Ligamentum flavum – along the inside of the laminae. This ligament appears yellow due to amount of the elastin protein within it. Interspinous ligament – between the spinous processes. Supraspinous ligament – along the very tips of the spinous processes. Anatomy handbook Spine At the level of approximately the L1-L2 junction, the spinal cord tapers off into a cone shape (called the conus medullaris) and terminates. The pia mater thickens after the cord terminates to form a thin strand of fibrous tissue known as the filum terminale. Shortly before the cord terminates, it gives off all of its remaining spinal nerves that are yet to leave (L3-L5, S1-S5 and Co1) and this mass of spinal nerves dangling within the spinal canal resembles a horse’s tail and hence it is called the cauda equina. Common exam question is at what level does the spine end. https://spinesurgeons.ac.uk/Cauda-Equina-SyndromeA patient had an accident and therefore suffered from a vertebral injury. What vertebral level is it more likely to be according to the image? • A) C1 • B)C2 • C)T1 • D)L1 https://www.researchgate.net/figure/The -1-st-cervical-vertebra_fig3_368667463A patient had an accident and therefore suffered from a vertebral injury. What vertebral level is it more likely to be according to the image? • A) C1 • B)C2 • C)T1 • D)L1 • This atlas which is C1. As it lacks the odontoid process. • Tough question! https://www.researchgate.net/figure/The -1-st-cervical-vertebra_fig3_368667463 Spinal tracts High yields DCML fine touch, two-point discrimination, vibration and proprioception. They synapse at their named nuclei: the gracile and cuneate nuclei. (medulla) After the synapse, the second order neurones decussate within the medulla, and the tract continues to the thalamus on the contralateral side. handbook Spinothalamic Crude touch, pain and temperature. usually after travelling upwards one or two spinal levels, handbook These 3 are important and the other ones are less common in the exam Corticospinal Pyramidal These motor tracts are located laterally in the spinal cord and carry motor impulses to the limbs. They decussate within the medulla at the level of the medullary pyramids and continue contralaterally in the spinal cord. This tract is sometimes referred to as a pyramidal tract for this reason. handbook Case Presentation: A 25-year-old male presents after a motorcycle accident. He reports right leg weakness and left leg numbness. Key Findings: • Right leg: Weakness (2/5), loss of proprioception and vibration sense. • Left leg: Loss of pain and temperature sensation. Diagnosis: Brown-Séquard Syndrome due to a T9 spinal cord hemisection. Radiology: MRI T2-weighted axial view shows a right-sided T9 vertebral fracture compressing the spinal cord with hyperintense edema. Management: • High-dose steroids. • Neurosurgery consultation. • Rehabilitation for recovery. Takeaway: Brown-Séquard involves motor and dorsal column deficits on the injury side and spinothalamic deficits on the opposite side. MRI confirms the injury site. https://www.mdpi.com/1422-0067/20/8/1841A patient had an accident and you are checking their nerves. Which one of the following tracts carries information about crude touch? A) Spinothalamic B) Corticospinal C) DCML D) TectospinalA patient had an accident and you are checking their nerves. Which one of the following tracts carries information about crude touch? A) Spinothalamic B) Corticospinal C) DCML D) Tectospinal Tectospinal is for eye reflexes. A patient was admitted to your ward with suspected Bell’s palsy. (damage to facial nerve). So you decided to test their cranial nerve. Which of the following is a function of the facial nerve? B) Sensation from the phranyxr third of the face C) Motor to the muscles of mastication D) Taste from anterior 2/3 of the tongue A patient was admitted to your ward with suspected Bell’s palsy. (damage to facial nerve). So you decided to test their cranial nerve. Which of the following is a function of the facial nerve? B) Sensation from the phranyx (Glossopharyngeal) (Ophthalmic) C) Motor to the muscles of mastication (Mandibular) D) Taste from anterior 2/3 of the tongue A patient has lost their sense of taste. Which of the nerves is not involved in taste sensation? B) Facialpharyngeal C) Vagus D) Trigeminal All exam questions will be positive so this question won’t pass the review but it is really good. A patient has lost their sense of taste. Which of the nerves is not involved in taste sensation? B) Facialpharyngeal C) Vagus D) Trigeminal All exam questions will be positive so this question won’t pass the review but it is really good.What is this structure highlighted by the blue box? • A) Transverse process • B) Spinous process • C) Lamina • D) PedicleWhat is this structure highlighted by the blue box? • A) Transverse process • B) Spinous process • C) Lamina • D) PedicleA patient had a head injury and has got anterograde memory loss. Which of the structures in the brain is responsible for long term memory formation? • A) Mammillary bodies • B) Amygdala • C) hippocampus • D) Cingulate gyrusA patient had a head injury and has got anterograde memory loss. Which of the structures in the brain is responsible for long term memory formation? • A) Mammillary bodies • B) Amygdala • C) hippocampus • D) Cingulate gyrus Select the best answer. All of these are involved but not their primary function.A patient had an incident of injury to their spinal cord. The doctor wants to know if his spine is damaged. At what vertebral level does the spine end? • A)S1/2 • B)T12 • C)L1/2 • D)L4/5A patient had an incident of injury to their spinal cord. The doctor wants to know if his spine is damaged. At what vertebral level does the spine end? • A)S1/2 • B)T12 (oesophagus through diaphragm) • C)L1/2 • D)L4/5 (this is where aorta divides to iliac arteries)A patient has had an injury and they lost their 2 point discrimination sensation on their legs which tract is more likely to be affected? • A) Lateral corticospinal • B) Lateral spinothalamic • C) DCML • D) Spinocerebellar tractA patient has had an injury and they lost their 2 point discrimination sensation on their legs which tract is more likely to be affected? • A) Lateral corticospinal • B) Lateral spinothalamic • C) DCML • D) Spinocerebellar tractWhich of the following statements is true? • A) There are 8 pairs of cervical nerves • B) The cervical nerves do not have any sympathetic fibers. • C) Cervical nerves have parasympathetic fibers • D) There are 4 pairs of nerves coming out of the coccyxWhich of the following statements is true? • A) There are 8 pairs of cervical nerves • B) The cervical nerves do not have any sympathetic fibres. • C) Cervical nerves have parasympathetic fibres • D) There are 4 pairs of nerves coming out of the coccyxThanks for listening Session 6 psanikhani1@Sheffield.ac.ukReferences • Anatomy handbook. University of Sheffield. School of medicine and population health. Neuro anatomy. • https://www.radiologymasterclass.co.uk/tutorials/ct/ct_brain_anatomy/ct_brain_anatomy_cerebellum • https://www.earthslab.com/anatomy/medulla-oblongata/ • https://www.brainkart.com/article/The-Pons--gross-anatomy_18923/ • https://www.youtube.com/watch?v=alii0GcqUnM • https://www.slideshare.net/binuenchappanal/anatomy-of-cerebellum-124645619 • https://medicoapps.org/m-limbic-system/ • https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0925492703001239&psig=AOvVaw0moXuKx8Y Pd-uaNdftLHmT&ust=1736125707340000&source=images&cd=vfe&opi=89978449&ved=0CBcQjhxqFwoTCNiKwLWy3YoDFQAAAAAdAAAAABAK • https://spinesurgeons.ac.uk/Cauda-Equina-Syndrome