Brain StemAnterior View Posterior View

Adducent7 & 8th

12

9,10,115

3

4

Facial colliculus

Striae Medullare

Case.1

A 55 year old overweight man was brought to the emergency room unconscious after he had collapsed while loading a truck.After he regained consciousness, an exam revealed a paresis of both right limbs with a Babinski sign on the right. The patient's tongue deviated to the left upon protrusion, and he had no vibratory sense on the right side of the body. These findings suggest.

A.A lesion in the medial medullaB.A lesion in the medial ponsC.An infract PICAD.A lesion in the lateral medulla

Case cont…2A 35-year-old visits hospital because of severe headache.

The patient says that the headache, which seems to be localized area behind his ears, it has been intermittent but persistent since he was involved in the baseball game while on his vacation. Shortly after he returned from his vacation, he made an appointment with his family physician because he was worried about the headache and the fact that he had developed noticeable clumsiness. When physician questioned, he mentioned unusual frequent bouts of nausea and vertigo. Physical examination reveals mild hoarseness of voice and some difficulty swallowing oral secretions. The left side of his face is affected by Horner’s syndrome, He has decreased sensitivity to light touch on the left side of his face, flattening of the left nasolabial fold, and paresis of the left soft palate. Finger to nose testing shows left sided Dysmetria. When asked to walk across the examining room, his gait is ataxic and he deviates to the left. There is diminished pain and thermal sensation on the right side. Reflexes are symmetric. There is no Babinski reflex, and the remainder of the motor and sensory examination is normal.

Case Cont….318. Which one of the following vessels should

be the primary suspect? a)Middle cerebral arteryb)Internal carotid artery at the cavernous

sinusc)Superior cerebellar arteryd)Posterior inferior cerebellar arterye)Anterior communicating artery

Case cont…4

45 year-old women with a history of high blood pressure experienced a sudden onset of Dizziness, nausea, and vomiting. She was brought to the emergency room where a neurological Exam revealed horizontal nystagmus, dysphagia and hoarseness. Absent of gag reflex on the left. Alteration of taste sensations from the tongue. Analgesia and thermal anesthesia on the left side of the face . Analgesia and thermal anesthesia on the right side of the body. Homer’s syndrome and significant hearing loss on the left as compared to the right

Case cont…5

The dysphagia and hoarseness in this case are to due to lesion of which structure?

A.Dorsal motor nucleus of vagusB.Nucleus solitariusC.Nucleus ambigusD.Inferior salivatory nucleusE.Superior salivatory nucleus

Case cont 6….The analgesia and thermal anesthesia on

the left side of the face in this case most likely Resulted from a lesion of which structure?

A.The trigeminal nerveB.The Mesencephalic nucleus of trigeminal C.The principal (chief) nucleus of D.The spinal tract of trigeminal E.The trigeminal ganglia

Level Nuclei

Midbrain III, IV, mesencephalic V

Pons V (main nucleus)

Caudal pons VI, VII

Ponto-medullary junction VIII

Medulla

N. of the descending tract of V.N. ambiguusN. tractus solitariusMotor XXII

Cervical cord XI

Medial Medullary Syndrome

Medial Medullary Syndrome/ Inferior Alternating Hemiplegia(branches of anterior spinal artery occlusion)contralateral hemiplegia of arm & leg(pyramid—corticospinal fibers)contralateral loss position sense, vibration, discriminatory touch(medial lemniscus)deviation of tongue to ipsilateral side when protruded; muscle atrophy(CN XII hypoglossal nerve in medulla or CN XII nucleus)

Lateral medullary Syndrome (Wallenberg's)

contralateral body pain & temp loss(anterolateral system/spinothalamic tract)ipsilateral face pain & temp loss(spinal trigeminal tract & nucleus)dysphagia, soft palate paralysis, hoarseness, diminished gag reflex(nucleus ambiguus, roots of 9th and 10th nerves)ipsilateral Horner’s Syndrome (miosis, ptosis, anhydrosis)(descending hypothalamospinal fibers)nausea, diplopia, vertigo, nystagmus(vestibular nuclei—CN 8)ataxia to the ipsilateral side(restiform body & spinocerebellar fibers)

Case 8..65. A 46-year-old woman presents to her physician with "double vision" and is unable to adduct her right eye on attempted left lateral gaze. Convergence is intact. Both direct and consensual light reflexes are normal. Which of the following structures is most likely to be affected?a) Left oculomotor nerveb) Medial longitudinal fasciculusc) Right abducens nerved) Right oculomotor nervee) Right trochlear nerve

Case 9..A patient with a bullet wound to the head is referred to you for neurological examination. Upon entering the hospital room you find the patient on a respiratory and cardiac monitor. You have difficulty arousing the patient and once awake you note the following: Right pupil is constricted; there is medial strabismus of the right eye and upon attempted right lateral gaze the left eye fails to adduct; loss of pain and temperature sensitivity on the right side of the face and left side of the body; deafness of the right ear; a pronounced intention tremor in the right arm and leg. The deep tendon reflexes on the right side are not as brisk as those on the left and there appears to be a complete facial paralysis on the right side.

  The likely site for this lesion is:

a) The left internal capsuleb) The right caudal ponsc) The left cerebellar hemisphered) The left side of the midbrain at the level of the superior

colliculuse) The right side of the medulla at the level of the dorsal

column nuclei

Pontine Syndromes Medial Pontine Syndrome/ Middle

Alternating Hemiplegia(paramedian branches of basilar

artery occlusion)contralateral hemiplegia of arm & leg(corticospinal fibers in basilar pons)contralateral loss/decrease of

proprioception, vibration, discriminative touch(medial lemniscus)ipsilateral lateral rectus muscle

paralysis(abducens nerve fibers or nucleus—

CN 6)paralysis of conjugate gaze toward

side of lesionMedial Strabismus(paramedian pontine reticular formation/pontine gaze center) 

Lateral Pontine Syndrome ).

  *note: combination of symptoms varies with caudal to rostral level of lesion*

ataxia, unsteady gait, fall toward side of lesion (middle & superior cerebellar peduncles—caudal & rostral pons

lesions)vertigo, nausea, nystagmus, deafness, tinnitus, vomiting (vestibular & cochlear nerves and nuclei—CN 8)ipsilateral paralysis of facial muscles (facial motor nucleus—CN 7—caudal pons lesions)ipsilateral paralysis of mastication muscles (trigeminal motor nucleus—CN 5—midpontine lesions)ipsilateral Horner’s Syndrome (descending hypothalamospinal fibers)ipsilateral face pain & temp loss (spinal trigeminal tract & nucleus)contralateral body pain & temp loss (anterolateral system/spinothalamic tract)paralysis of conjugate gaze(paramedian pontine reticular formation—mid to caudal pons lesions)(Long circumferential branches of basilar artery occlusion)

Case 10 Jones likes to play golf. Usually he is a very

competitive member of the team USA , but his game has been off lately. He has been unable to maintain his well-practiced grip on his favorite clubs (particularly with his right hand), causing the club to slip out of alignment as he begins his swing.

Additionally, as all great golfers know, maintaining visual contact with the ball is critical to accurate placement of the ball on the green. Jones has begun to complain that he sometimes sees two balls (double vision), and that occasionally he swings at the ‘wrong’ one. He has been unable to keep his eyes on the ball as he swings and he has not been able to watch it as it sails to its destination. Today has been particularly hot, and the entire team becoming fatigued as they near the final hole. It’s at this point that one of the partners who is a neurologist notices that Jone's left eye is crossed.

On further examination Neurologist noticed fallowing

Case 10 Left eye is crossed (diplopia); an inability to

move the Left to the left. He has Spastic paralysis of the right upper

and right lower limb muscles.His left side of the body seems to be

functioning normal.

Case 7…60 year old woman suddenly remarked that she was seeing double and felt a weakness in her left arm and leg. Her husband noticed that her right eyelid was drooping. At the hospital, she was awake, oriented, and articulate. Her visual fields were normal but here right eye deviated to the right. On attempted lateral gaze to the left only the left eye responded; only the left eye constructed in response to light. Upon smiling, there was a minor weakness on the left. The gag, corneal, and jaw jerk reflexes were normal as were the sensory examinations of the face and body. Motor strength was normal in the extremities on the right but reduced on the left especially in the arm where there was a heightened biceps reflex and resistance to passive stretch.

 Where is the site of lesion?

a) Cerebellumb) Substantia nigrac) Mid braind) None of above.

 

At Superior colliculus

Medial Midbrain (Weber) Syndrome/ Superior Alternating Hemiplegia

(paramedian branches of P1 segment of PCA occlusion)1.contralateral hemiplegia of arm & leg corticospinal fibers in crus cerebri)ipsilateral paralysis of eye movement, oriented down & out, pupil dilated & fixed (oculomotor nerve—CN 3)2. Central Midbrain Lesion (Claude Syndrome)ipsilateral paralysis of eye movement, oriented down & out, pupil dilated & fixed (oculomotor nerve—CN 3)contralateral ataxia and tremor of cerebellar origin (red nucleus & cerebellothalamic fibers)3. Benedikt Syndrome: includes both regions, both sets of symptoms from above

Classification

Archicerebellum Paleocerebllum Neocerebellum

Classification by its Connections

Vestibulocerebellum Spinocerebellum cerebrocerebellum

Cerebellum

Inputs of the cerebellum

MLFMLF

Main Connections of the VestibulocerebellumMain Connections of the VestibulocerebellumMain Connections of the VestibulocerebellumMain Connections of the Vestibulocerebellum

lower motor neuronlower motor neuron

LMNLMN

vestibulospinal tractvestibulospinal tract

FASTIGIALFASTIGIAL NUCLEUSNUCLEUS

VestibularVestibular OrganOrgan FloculonodularFloculonodular

LobeLobe

VermisVermis

ARCHICEREBELLUMARCHICEREBELLUM

VESTIBULAR NUCLEUSVESTIBULAR NUCLEUS

Main Connections of the PaleocerebellumMain Connections of the PaleocerebellumMain Connections of the PaleocerebellumMain Connections of the Paleocerebellum

lower motor neuronlower motor neuron

SPINAL CORDSPINAL CORD

rubrospinal rubrospinal tracttract

NUCLEUSNUCLEUSINTERPOSITUSINTERPOSITUS

InferiorInferior OlivryOlivryNucleusNucleus

ANTERIOR ANTERIOR LOBELOBEPARAVERMAL PARAVERMAL ZONEZONE

PALEOCEREBELLUMPALEOCEREBELLUM

RED RED NUCLEUSNUCLEUS

spinocerebellar spinocerebellar tracttract

CEREBRALCEREBRAL CORTEXCORTEX

CEREBRALCEREBRAL CORTEXCORTEX

DENTATEDENTATENUCLEUSNUCLEUS

DENTATEDENTATENUCLEUSNUCLEUS

Main Connections of the NeocerebellumMain Connections of the NeocerebellumMain Connections of the NeocerebellumMain Connections of the Neocerebellum

lower motor neuronlower motor neuron

LMNLMN

pyramidal pyramidal tracttract POSTERIOR POSTERIOR

LOBELOBECEREBELLARCEREBELLAR HEMISPHEREHEMISPHERE

POSTERIOR POSTERIOR LOBELOBE

CEREBELLARCEREBELLAR HEMISPHEREHEMISPHERE

THALAMUSTHALAMUSTHALAMUSTHALAMUS

NEOCEREBELLUMNEOCEREBELLUM

PontinePontineNucleusNucleusPontinePontineNucleusNucleus

upper motor neuronupper motor neuron

UMNUMN

upper motor neuronupper motor neuron

UMNUMN

BASALBASALGANGLIAGANGLIABASALBASAL

GANGLIAGANGLIA

Pyramidal Tract and Associated CircuitsPyramidal Tract and Associated CircuitsPyramidal Tract and Associated CircuitsPyramidal Tract and Associated Circuits

lower motor neuronlower motor neuron

UMNUMN

lower motor neuronlower motor neuron

UMNUMN

pyramidal tractpyramidal tract

CerebellumCerebellumCerebellumCerebellum

Functions Of Cerebellum

Maintenance of Equilibrium - balance, posture, eye movement Coordination of automatic

movement of walking and posture maintenance - posture, gait Adjustment of Muscle Tone Motor Leaning – Motor Skills Cognitive Function

Cerebellum Disorders

Ataxia: incoordination of movement - decomposition of movement - dysmetria, post-pointing- dysdiadochokinesia(Adidydakokinesia)- rebound phenomenon of Holmes - gait ataxia, truncal ataxia, titubationIntention TremorHypotonia, Nystagmus

Cerebellum Disorders

Archicerebellar Lesion: medulloblastoma

Paleocerebellar Lesion: gait disturbance

Neocerebellar Lesion: hypotonia, ataxia, tremor

Case 1…..A patient delays initiation of movement, displays an uneven trajectory in moving her hand from above her head to touch her nose, and is uneven in her attempts to demonstrate rapid alternation of pronating and supernating movements of the hand and forearm. Which of the following regions most likely contains the lesion?

A.Hemispheres of the posterior cerebellar lobeB.Flocculonodular lobe of the cerebellumC.Vermal region of the anterior cerebellar lobeD.Fastigial nucleusE.Ventral spinocerebellar tract

The classic appearance of a patient with a lesion of the cerebellar hemispheres

is one in which voluntary and skilled movements are affected.

They are uncoordinated, and there are errors in the range, force, and direction

of movement. The relationships between the cerebellum and the

motor regions of the cerebral cortex have been disrupted. Lesions of other

regions, such as the flocculonodular lobe, vermal region of the anterior

cerebellar cortex, or fastigial nucleus, produce different symptoms (disturbances

of balance and nystagmus associated with the flocculonodular lobe

and vermal regions, disturbances of muscle tone associated with the anterior

cerebellar cortex). Although pure lesions limited to the ventral spinocerebellar

tract have not been reported, it is likely that such a lesion could

not account for the symptoms indicated in this question. Information carried

by this tract concerns activity of Golgi tendon organs of muscles of the

lower limbs.

Case 2…..As a result of a dysfunction in development, a 4-year-old boy has

difficultywalking and maintaining balance. It is later determined that there issignificant loss of neurons in the cerebellum that disrupts the neuronalorganization of the cerebellar glomerulus. Which of the following bestcharacterizes this glomerulus?

A. Mossy fiber terminals, Golgi axons, and axon terminals of granule cells

B. Climbing fiber terminals, Golgi axons, and granule cell dendritesC. Mossy fiber terminals, Purkinje cell axons, and granule cell dendritesD. Mossy fiber terminals, Golgi and granule cell dendrites, and Golgi

cell axon terminalsE.Climbing fiber terminals, Golgi cell dendrites, Purkinje cell dendrites,

and axon terminals of parallel fibers

Case 3…..A 55-year-old male had been complaining about his having difficultyin coordinating the use of his arms in meaningful ways. For example, whenexamined by a neurologist, the patient was unable to move his fingerAccurately to his nose from his side when requested to do so but instead Would undershoot or overshoot the target. He also had difficulty in making Rapid alternating rotational movements of the hand. The neurologist

believedthat the patient was suffering from a disorder that resulted in a lesion of aregion of the cerebellum or structures related to it. Which of the followingregions most likely contained this lesion?

A.Fastigial nucleusB. Vermal regionC.Cerebellar hemsipheresD. Inferior cerebellar peduncleE. Vestibular nuclei

The answer is c. This patient presented with a disorder associated with a lesion of the cerebellar hemisphere. This region of the cerebellar cortex is linked anatomically and functionally with the cerebral cortex. Its linkage is through the dentate nucleus, whose axons project to

the VL thalamic nucleus, which in turn, project to the motor and premotor regions of the cerebral cortex. This feedback is essentialfor producing smooth, accurate movements of the limbs that are Well coordinated. Loss of such feedback thus results in the

deficits seen in this patient. Other regions listed in this question bear no relation to this disorder but relate to other functions such as

balance, modulation of muscle tone and posture.

Case 4…..A man presents with a wide-based, ataxic gait during his attempts at walking. He is also unsteady, sways when standing, and displays a tendency to fall backward or to either side in a drunken manner. In which of the following structures is a lesion most likely located?

A.Hemispheres of the posterior cerebellar lobeB.Anterior limb of the internal capsuleC.Dentate nucleusD.Anterior lobe of the cerebellumE.Flocculonodular lobe of the cerebellum

Answer is E

Since the flocculonodular lobe receives and integrates inputs from the

vestibular system, it is understandable why lesions that disrupt this integrating

mechanism for vestibular inputs would result in difficulties in

maintaining balance. Indeed, this is a classic feature of lesions of the

Flocculonodular lobe but is not associated with lesions in the hemispheres of

the posterior lobe, the anterior limb of the internal capsule, or the dentate

nucleus, which are functionally linked to the frontal lobe. Lesions of the

anterior lobe also do not affect mechanisms of balance.

Case 5…..

A 25-year-old man, who began to have difficulty in walking, is examined by a neurologist and neurosurgeon. They conclude that a tumor is compressing upon the lateral aspect of his spinal cord, affecting primarily the spinocerebellar tracts. Which of the following structures is the principal region within the cerebellum that receives these fibers?

A. Anterior lobeB. Posterior lobeC. Flocculonodular lobeD. Fastigial nucleusE. Dentate nucleus

Horizontal eye movementGenerated from horizontal gaze center in

PPRF which is connected to ipsilateral 6th nerve nucleus.

From 6th CN nucleus internuclear neurons cross midline and pass to contralateral MLF to innervate medial rectus in the 3rd nerve complex

Stimulation of PPRF on one side causes a conjugate movement of the eyes to the same side.

Vertical eye movements

Generated from vertical gaze center ( rostral interstitial nucleus of the MLF ) which lies in midbrain.

rostral interstitial nucleus of medial longitudinal fasciculus (riMLF) is a portion of the medial longitudinal fasciculus which controls vertical gaze.

medial longitudinal fasciculus (MLF)

It yokes the CN nuclei III and VI together, and integrates movements directed by the gaze centers (frontal eye field) and information about head movement.

it is an integral component of saccadic eye movements as well as Vestibulo-ocular reflex

Lesions of the MLF produce internuclear ophthalmoplegia. Lesions to the MLF are very common manifestations of the disease Multiple sclerosis ,where it presents as nystagmus and occasionally diplopia .

PPRF lesion gives rise to ipsilateral horizontal gaze palsy with inability to look in the direction of lesion.

MLF lesion gives rise to INO

Left INOStraight eyes in primary position.Defective left adduction.Ataxic nystagmus of the right eye in

right gaze.Convergence is intactVertical nystagmus on attempted

upgaze.

SUPRANUCLEAR DISORDERS OF EYE MOVEMENT

1. Horizontal gaze palsies

2. Vertical gaze palsies

• Internuclear ophthalmoplegia• Combined internuclear and PPRF (‘one-and-a-half syndrome’)

• Parinaud dorsal midbrain syndrome• Progressive supranuclear palsy

MLF

Internuclear ophthalmoplegia

• Demylination - usually bilateral • Vascular disease

Important causes

• Tumours of brainstem

Defective left adduction and ataxic nystagmus of right eye

Normal left gaze

Convergence intact if lesion discrete

Lesion involving left MLF

‘One-and-a-half syndrome ’

• Ipsilateral (left) gaze palsy • Defective left adduction• Normal right abduction with ataxic nystagmus

Combined lesion of left MLF and PPRF

Parinaud dorsal midbrain syndrome

• In young adults: demylination, trauma and a-v malformations• In children: aqueduct stenosis, meningitis and pinealoma

• Supranuclear upgaze palsy

• Large pupils with light-near dissociation

• Lid retracton (Collier sign)

Important causes

• Normal downgaze

• Convergence weakness

• Convergence-retraction nystagmus

• In elderly: vascular accidents and posterior fossa aneurysms

Progressive supranuclear palsy

• Affects elderly

Initially involves downgaze

Subsequent defective up and horizontal gaze

• Pseudobulbar palsy

• Extrapyramidal rigidity

( Steele-Richardson-Olszewski syndrome )

• Gait ataxia

• Dementia