Brain Stem Anterior View Posterior View 3 4 9,10,11 5 Adducent Facial colliculus 7 & 8th 12 Striae Medullare

Medulla Oblongata Nuclei in the medulla are associated w/ autonomic control, cranial nerves, and motor/sensory relay. Autonomic nuclei: Cardiovascular centers Cardioinhibitory/cardioacceleratory centers alter the rate and force of cardiac contractions Vasomotor center alters the tone of vascular smooth muscle Respiratory rhythmicity centers Receive input from the pons Additional Centers Emesis, deglutition, coughing, hiccupping, and sneezing

Medulla….

Medulla Sagittal Section And Cranial Nuclei

Cranial Nuclei

Section of Medulla

Section of Medulla At the level of Pyramid

Medullary syndromes Medial Lateral medullary syndromes

Medial Medullary Syndrome Cranial Nerves Tongue Paralysis -Hypoglossal Nerve Motor Pathways Contralateral Spastic Paralysis -- Pyramids Sensory Pathways Contralateral loss Fine Touch and Proprioception -- Medial Lemniscus Alternating hemiplegia

Deviation of Tongue to affected side Atrophy of Tongue Muscles Hypoglossal Palsy Lower Motor Neuron Syndrome Deviation of Tongue to affected side Atrophy of Tongue Muscles

Lateral medullary syndrome (Wallenberg's syndrome) This is the commonest of the brain stem strokes. Involvement of the spinothalamic tract results in contralateral loss of pain and temperature sensation below the neck. Involvement of the descending nucleus and tract of V results in loss of pain and temperature sensation on the face ipsilateral to the lesion.

Lateral medullary syndrome Involvement of descending autonomic fibers results in an ipsilateral Horner's syndrome (ptosis, meiosis, and anhidrosis). Involvement of the nucleus ambiguus causes palatal weakness and dysphagia. Involvement of the inferior cerebellar peduncle (restiform body) causes ipsilateral ataxia. Alternating hemianaesthesia

Brain stem Anterior view

Brain stem Posterior view

Section of Pons at the level of Facial colliculus

Section of pons at the level of trigeminal nuclei

Vestibular component of VIII Nerve

Cochlear component of VIII Nerve

Pontine syndromes Medial pontine Syndrome Sign Contralateral spastic hemiparesis of the body Contralateral loss of position and vibration of the body Medial strabismus Raymond's Syndrome Alternating abducent hemiplegia Miller-gubler syndrome Alternating Facial hemiplegia. Structures Associated CST Medial lemniscus 6th nerve fibers 7th nerve fibres

Lateral pontine syndrome Structure ICP Spinal 5 Spinothalamic Fibers of 7 Fibers of 8 Sign Ipsilateral limb ataxia Ipsilateral pain and temp loss - Face Contralateral pain and temp-Body Horner’s syndrome (Ipsilateral) Hearing loss Ipsilateral facial paralysis

Section of Mid Brain at Inferior colliculus

Section of Mid Brain at superior colliculus

At Superior colliculus

Ventromedial Superior Midbrain Syndrome (Weber’s Syndrome) Contralateral paralysis of face, arm and leg Ipsilateral III palsy (fascicular) Artery paramedian perforators of terminal basilar, or peduncular perforating branches of posterior cerebral artery

Paracentral (Tegmental) Superior Midbrain Syndromes (Claude’s and Benedikt’s syndromes) Contralateral ataxia with tremor (red nucleus) ± hemichorea (subthalamic nucleus) Ipsilateral III fascicular palsy Artery paramedian perforators of terminal basilar, or interpeduncular branches of Posterior Cerebral Artery

Dorsal Superior Midbrain Syndrome (Parinaud’s, of Sylvian Aqueduct) Paralysis of upgaze ± convergence Light/near dissociation Eyelid retraction Convergence/retraction nystagmus Artery - posterior choroidal/quadrigeminal (Note - usually not vascular)

“Top of the Basilar” Syndrome Usually due to embolic occlusion Posterior Cerebral Artery cortical territory infarction (unilateral or bilateral) hemianopia/cortical blindness amnesia Basilar/Posterior Cerebral Artery thalamic/midbrain territory infarction impairment of ocular movements (e.g. skew deviation, vertical gaze palsies) pupillary abnormalities (various)