PROF DR. ÇİĞDEM ÖZKARA

1. PROF DR. ÇİĞDEM ÖZKARA BRAIN STEM ANATOMY & CLINICAL PRESENTATIONS

2. In vertebrateanatomy the brainstem (or brain stem) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. • The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves. • Though small, this is an extremely important part of the brain as the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body pass through the brain stem.

3. This includes the corticospinal tract (motor), the posterior column-medial lemniscus pathway (fine touch, vibration sensation and proprioception) and the spinothalamic tract (pain, temperature, itch and crude touch). • The brain stem also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system, and is pivotal in maintaining consciousness and regulating the sleep cycle.

4. BRAIN STEM Includes: • medulla oblongata (myelencephalon), • pons (part of metencephalon), • midbrain (mesencephalon). • Less frequently, parts of the diencephalon are included.

5. 1.Cerebrum 2.Thalamus 3.Mesencephalon - Midbrain 4.Pons 5.Medulla oblongata 6.Medulla spinalis - Spinal cord

9. Midbrain (mesencephalon) The midbrainis divided into three parts. The first is the tectum, which is "roof" in Latin. The tectum includes the superior and inferior colliculi and is the dorsal covering of the cerebral aqueduct. The inferior colliculus, involved in the sense of hearing sends its inferior brachium to the medial geniculate body of the diencephalon. Superior to the inferior colliculus, the superior colliculus marks the rostral midbrain. It is involved in the special sense of vision and sends its superior brachium to the lateral geniculate body of the diencephalon. The second part is the tegmentum and is ventral to the cerebral aqueduct. Several nuclei, tracts and the reticular formation are contained here. Last, the ventral side is composed of paired cerebral peduncles. These transmit axons of upper motor neurons.

10. Midbrain Periaqueductal gray: The area around the cerebral aqueduct, which contains various neurons involved in the pain desensitization pathway. Neurons synapse here and, when stimulated, cause activation of neurons in the nucleus raphemagnus, which then project down into the dorsal horn of the spinal cord and prevent pain sensation transmission.Occulomotor nerve nucleus: This is the nucleus of CN III.Trochlear nerve nucleus: This is the nucleus of CN IV.Red Nucleus: This is a motor nucleus that sends a descending tract to the lower motor neurons.Substantianigra: This is a concentration of neurons in the ventral portion of the midbrain that uses dopamine as its neurotransmitter and is involved in both motor function and emotion. Its dysfunction is implicated in Parkinson's Disease.Reticular formation: This is a large area in the midbrain that is involved in various important functions of the midbrain. It contains lower motor neurons, is involved in the pain desensitization pathway, is involved in the arousal and consciousness systems, and contains the locus ceruleus, which is involved in intensive alertness modulation and in autonomic reflexes.Central tegmental tract: Directly anterior to the floor of the 4th ventricle, this is a pathway by which many tracts project up to the cortex and down to the spinal cord.

11. BEYİN SAPI • Mezensefalon beyinsapının en üst bölümünü oluşturur. Üçüncü (N. Oculomotorius) ve IV. (N. Trochlearis) kranyal sinirlerin nukleusları buradadır

12. Fibria Corticospinalis Substania Nigra

13. N.Oculomotorius III N.oculomotorius(CN3): has 2 nuclei: • Nüc nervi oculomotorii motor nucleus. At collikulussuperior: AllextraoculermuclesexceptforM.obliquussuperior& m.rectus lateralis& m.levator palpebra superioris i wereinnervated . Upwardandinternalgaze • nüc visseralis (edinger westphal): Parasympatheticnucleus. Innervates M. sphincterpupillae& M. ciliaris. Lesion: ptosis , mydriazis, eyedownandoutdeviation, verticaldiplopi, lightreflex & accomodationloss.

14. N. trochlearis(CN4) • Onlysomatomotor . • M.obliquussuperioruinnervation. • Unique CN leavesbrainstemfromposterior • Lesion: cannotlookdownandout , vertikaldiplopiComplainswhencomingdownthestairs. • Ifnucleus n. troclearisin is damaged: contrlateralm.obliquussuperior is effected (exceptionforother CN)

15. Weber sendromu:(superior alternating hemiplegia) is a form of stroke characterized by the presence of an oculomotor nerve palsy and contralateralhemiparesis or hemiplegia. It is caused by midbraininfarction as a result of occlusion of the paramedian branches of the posterior cerebral artery or of basilar bifurcation perforating arteries.[1] 1. Substantia nigra, akinesia (parkinsonism) 2. Corticospinal fibers, contralateral spastic hemiplegia 3. Corticonuclear fibers, contralateral lower facial and hypoglossal paralysis, supranuclear 4. Corticopontine tract, contralateral dystaxia 5. Root fibers of oculomotor nerve, ipsilateral oculomotor paralysis with wide fixed pupil

16. BENEDIKT SYNDROME: Caused by a lesion ( infarction, hemorrhage, tumor, or tuberculosis) in the tegmentum of the midbrain and cerebellum. It can result from occlusion of the posterior cerebral artery Characterized by the presence of an CN III oculomotor nervepalsy and contralateral hemiparesis (weakness) and cerebellar ataxia including tremor. Neuroanatomical structures affected include CNIII nucleus, Red nucleus, corticospinal tracts, brachium conjunctivum, and cerebellum. 1. Medial lemniscus, contralateral decrease in sensations of touch, position, and vibration 2. Red nucleus, contralateral hyperkinesia (chorea, athetosis) 3. Substantia nigra, contralateral akinesia (parkinsonism) 4. Root fibers of oculomotor nerve, ipsilateral oculomotor paralysis, wide fixed pupil

17. Parinaud's Syndrome : results from injury, either direct or compressive, to the dorsal midbrain. Specifically, compression or ischemic damage of the mesencephalictectum, including the superior colliculus adjacent oculomotor (origin of cranial nerve III) and Edinger-Westphal nuclei, causing dysfunction to the motor function of the eye. 1. Cerebral aqueduct, stenosis with occlusive hydrocephalus 2. Superior colliculi, conjugated upwards gaze paralysis 3. Oculomotor nucleus, eventual oculomotor paralysis and ptosis (trochlear paralysis) 4. Medial longitudinal fasciculus, nystagmus

18. PONS Named after the Latin word for "bridge" or the 16th-century], It is superior to (up from) the medulla oblongata, inferior to (down from) the midbrain, and ventral to (in front of) the cerebellum. In humans and other bipeds this means it is above the medulla, below the midbrain, and anterior to the cerebellum. This white matter includes tracts that conduct signals from the cerebrum down to the cerebellum and medulla, and tracts that carry the sensory signals up into the thalamus. Posteriorly, it consists mainly of two pairs of thick stalks called cerebellar peduncles. They connect the cerebellum to the pons and midbrain. The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.[3] Within the pons is the pneumotaxic center, a nucleus in the pons that regulates the change from inspiration to expiration.[

19. Cranial nerves are the abducensnerve VI, facial nerveVII and the vestibulocochlearnerve VIII, respectively. • At the level of the midpons,trigeminal nerveV, emerges.

22. N. trigeminus(CN5): has 3 sensoriel, 1 motor nucleus • nuc. spinalisnervitrigemini: relatedtocorneareflex • Nuc. spinalisnervitrigemini: faceandheadpainandtemperaturesensations 2nd neuron. • Nuc. mesensefalikusnervitrigemini • Nuc. motoriusnervitrigemini • Gangliontrigeminale (gasserganglionusemilunarganglion): sensationganglion

23. N. Trigeminusbranches • N.ophtalmikus (V1): onlysensitivefibres. Bulbusoculiinnervates, tip of nose, upperpart of eyes . • N.maksillaris(V2): onlysensitivefibres , lowerpart of eyes, upperlipinnervation. • N.mandibularis(V3) Motor & sensitivefibres. Masticatorymuscles, lowerlipandlowerpart of mouth , 2/3 anterorpart of tongue , externalearandtemporalregioninnervation.

24. N.abducens(CN6): Only motor fibres. M.rektus lateralisi innervation. Lesion: effected eye pulled medially, horizontal diplopia. Lies in sinus kavernosus lateral to A. carotis interna

25. N.facialis(CN7) • Involves motor, sensoryandparasympaticfibres: • nüc.nervi facialis: Motor nuc.Innervatesmimicmuscles :m.stapedius,m.stylohyoideus,m.digastrikusventerposteriorun • Nüc.lacrimalis ve nüc.salivatorius: Parasympathicnuclei • Nüc traktussoliterius:2.neurons of taste • Centralfacialparalysis: Supranuclearlesions, mouthcommissuredeviatestohealthyside (lesion), can closeeyescorneareflex is normal. • Periphericfacialparalysis (Bell’spalsy):Intranuclearorinfranuclearmouthcommissuredeviatestohealthyside , corneareflexdisappears, cannotcloseeye

26. Millard-Gubler syndrome It is a syndrome of unilateral softening of the brain tissue arising from obstruction of the blood vessels of the pons. VI and VII cranial nerves fibers of the corticospinal tract, Clinicalpresentation: Paralysisof the abducens(including diplopia, internal strabismus, and loss of power to rotate the affected eye outward) facial nerves ( periphericipsilateral) Contralateral Hemiplegiaof the extremities. It is also known as "crossed hemiplegia".

27. 1. Medial lemniscus, contralateral decrease of touch, position and vibration sensations in the lower extremities 2. Lateral lemniscus, hypacusia 3. Nucleus of facial nerve, peripheral ipsilateral paralysis of facial muscles 4. Anterior spinothalamic tract, contralateral analgesia and thermanesthesia of body 5. Pyramidal tract, contralateral spastic hemiplegia 6. Abducent nerve, ipsilateral peripheral paralysis of lateral rectus muscle

28. Peripheral facial paralysis

29. Central facial paralysis

30. Kranyal Sinirler (devam) • N.vestibulocohlearis: N.vestibularis: carries the informaion related to position and movements of of head , N.cohlearis: primery audituar fibres.

31. Medulla oblongata (bulbus) is the lower half of the brainstem. The medulla contains the cardiac, respiratory, vomitingand vasomotor centers and deals with autonomicfunctions, such as breathing, heart rate and blood pressure.

32. Functions • The medulla oblongata controls autonomic functions, and relays nerve signals between the brain and spinal cord. • It is also responsible for controlling several major points and autonomic functions of the body: • respiration– chemoreceptors • cardiac center – sympathetic, parasympathetic system • vasomotor center – baroreceptors • reflex centers of vomiting, coughing, sneezing, and swallowing • balancing the human body.

33. Nuclei of Medulla oblongata Lastfivecranialnervenuclei: • Nuc. Grasilis ve nuc. kuneatus: secondneurons of consciousproprioceptive, vibration, twopointdiscriminationsensations • Nuc. Traktus solitarius: Relatedto VII,IX,X. cranialnerves. Upperpart is callednuc. Gustatoriusandinvolvesneurons of taste • Nuc. Spinalis nervi trigemini: Painandtemparaturesensation of face • Nuc. Ambiguus: motor nuclei of IX,X,XI cranialnerves • Nuc. Salivatorius inferior: Parasempatik nuclei of XI. CN . Thefibresfromthisnucleigoestoglandulaparotidea

35. N. Glossofaryngeus(CN9 3 nuclei, 2 ganglions, Motor: nüc.ambiguus…. İnnervates m.stylofaringeus Nüc salivatorius inferior parasempatik nucleus, innervates glandula parotidea Nuctraktus solitarius 1/3 posterior of taste sensation of tongue , tonsilla palatina and middle ear sense. Lesion: uvula deviates to healthy side . The integrity of the glossopharyngeal nerve may be evaluated by testing the patient's general sensation and that of taste on the posterior third of the tongue. The gag reflex can also be used to evaluate the glossphyaryngeal nerve

36. N.vagus(CNX) 3 nuclei, 2 ganglion Motor nuc: nuc.ambiguus, Parasympaticnuc: nucposteriornervivagi, Taste : nuc. ractussolitarius The vagus nerve supplies motor parasympathetic fibers to all the organs except the suprarenal (adrenal) glands, from the neck down to the second segment of the transverse colon. The vagus also controls a few skeletal muscles, namely: • Cricothyroid muscle • Levatorvelipalatini muscle • Salpingopharyngeus muscle • Palatoglossus muscle • Palatopharyngeus muscle • Superior, middle and inferior pharyngeal constrictors • Muscles of the larynx (speech).

37. This means that the vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech (via the recurrent laryngeal nerve) and keeping the larynx open for breathing (via action of the posterior cricoarytenoid muscle, the only abductor of the vocal folds). It also has some afferent fibers that innervate the inner (canal) portion of the outer ear, via the Auricular branch (also known as Alderman's nerve) and part of the meninges. This explains why a person may cough when tickled on their ear (such as when trying to remove ear wax with a cotton swab)

38. N.accessorius(CNXI) • Pure motor. • Somefibresfrombulbussomefromservikal m. Spinalis sup. Segment ant horncells. • Leavescranialcavityfromforamenjugulareverycloseto IX. & X. CNs • The nerve functions to control the sternocleidomastoid and trapeziusmuscles.

39. N. Hypoglossus (CNXII) • Motor nerve of tongue. • Nucleus in bulbus. • Lesion: tongue deviates to the paralysed side, atrophy at that side • Unilateral involment: No tongue movements

40. IŞIK REFLEXİ

41. WALLENBERG’S SYNDROME (lateral medulla syndrome) It is the clinical manifestation resulting from occlusion of the posterior inferior cerebellar artery (PICA) or one of its branches or of the vertebral artery, in which the lateral part of the medulla oblongata infarcts, resulting in a typical pattern. 1. Inferior vestibular nucleus, nystagmus and ipsilateral inclination to fall 2. Dorsal nucleus of vagus nerve, tachycardia and dyspnea 3. Inferior cerebellar peduncle, ataxia and ipsilateral asynergia 4. Nucleus of solitary tract, ageusia ipsilateral 5. Ambiguus nucleus, ipsilateral paralysis of palate, larynx, and pharynx 6. Nucleus of cochlear nerve, hypacusia 7. Nucleus of trigeminal spinal tract, ipsilateral analgesia and thermanesthesia of face 8. Central sympathetic pathway, Horner's syndrome. Hypohidrosis, ipsilateral vasodilation in face 9. Anterior spinocerebellar tract, ataxia, ipsilateral hypotonia 10. Lateral spinothalamic tract, analgesia and thermanesthesia contralateral over body

42. Horner sendromu • Miyozis • Pitozis • Anhidrozis

43. Medial medüller syndrome(Dejerine’in anterior medüller sendrom: Obstruction of a. spinalis anterior veya a. vertebralis 1. Medial longitudinal fasciculus, nystagmus 2. Medial lemniscus, contralateral decrease of touch, vibration, and position sensations 3. Olive, ipsilateral myorhythmia in velum and pharynx 4. Hypoglossal nerve, ipsilateral flaccid paralysis of hypoglossal muscle with atrophy 5. Pyramidal tract, contralateral, spastic hemiplegia with positive Babinski reflex

44. Tractus Pyramidalis

45. Spinothalamic tract: pain, tempartature, itch, crude touch Posterior column fine touch, vibration, conscious proprioceptive Cortico spinal tract: motor

46. Cranial nerve reflexes

47. Kranyal Sinirler (devam)