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I went light on the cranial nerves, reference OG Clin Supp or wire diagrams
Ipsilateral deficits
Injuries to cranial nerve nuclei lead to what?
Contralateral superior oblique
Why is the trochlear nucleus an exception to the norm/what does it innervate?
Trigeminal
carries GSA axons for discriminative touch, proprioception, vibratory sense, pain, thermal sense and SVE axons to innervated muscles derived from the 1st pharyngeal arch. Nearly all GSA axons have cell bodies in the
trigeminal ganglion
Where do (nearly) all GSA axons have cell bodies?
Branch
Injury to a ______ from the trigeminal nerve results in complete sensory loss (all modalities) in the distribution of the injured nerve.
Main Trunk
Injury to the ____ of CN V (in the lateral pons, cistern, Meckle’s cave) results in complete sensory loss (all modalities) and weakness/paralysis of the muscles of mastication.
Spinal trigeminal Nucleus
Origin includes: sensory receptor in the skin, ST capsules of glands and mucose of the head. Modality: pain, temperature, and crude touch
Trigeminal ganglion, spinal trigeminal nucleus, VPM thalamus
Cell bodies of the spinal trigeminal nucleus
lateral medulla
Injuries in the ________ affect both the spinal trigeminal tract and nucleus and result in ipsilateral loss of pain and thermal sense on the face.
Chief/principal nucleus
Origin includes sensory receptors in the skin and joint capsules. Modality: discriminative touch and vibratory sense
Dorsal trigeminothalamic tract
neurons receiving information from the skin around the mouth give rise to axons that form the ________ (DTTT; does not cross the midline)
Somatosensory cortex
Injuries to the VTTT, VPM, PLIC, or face region of ________ result in contralateral loss of discriminative touch, vibratory sense, pain and thermal sense on the face
Mesencephalic nucleus
Origin includes: muscle spindles in muscles of mastication, etc. Modality: proprioception
Shingles
This trigeminal syndrome is characterized by reactivation of varicella zoster infection in the trigeminal ganglion, and development of a painful rash in the distribution of the one of the branches of the trigeminal nerve; may be associated with pain/sensory loss and motor loss.
Neuralgia (tic douloureux)
This trigeminal syndrome is characterized by brief and persistent episodes of stabbing pain in the distribution of trigeminal nerve or its branches; may be caused by compression of nerves by arterial loops
Bell palsy
IL LMN paralysis of the muscles innervated by CN VII; may have also dry eye, dry mouth, loss of taste on anterior 2/3 of tongue, hyperacusis and ear pain.
Ramsay Hunt syndrome
involves a herpes infection in the geniculate ganglion (CN VII); results in blistering lesions in the external auditory meatus, but may also include Bell palsy, hyperacusis and/or loss of taste
Glossopharyngeal Neuralgia
characterized by severe stabbing pain in the oropharynx or middle ear; may be triggered by swallowing, yawning or coughing; may be triggered by vascular compression
Crossed
Localized brainstem lesions (e.g. infarcts) typically result in “_____” syndromes (IL cranial nerve signs and CL UMN s/s and/or sensory loss)
CN III > CN IV
What cranial nerve is affected in an injury at this level of the brainstem: midbrain
CN V, VI, or VII
What cranial nerve is affected in an injury at this level of the brainstem: pons
CN IX, X, or CN XII (and/or spinal trigeminal nucleus)
What cranial nerve is affected in an injury at this level of the brainstem: medulla
Medial medullary syndrome
S/S: IL deviation of tongue on protrusion (hypoglossal nucleus or nerve), CL UMN weakness/paresis (corticospinal tract), CL loss of discriminative touch, proprioception and vibration (medial lemniscus), and an infarct in territory of anterior spinal artery
Lateral medullary syndrome (Wallenberg Syndrome)
S/S: IL loss of pain and temperature on face (spinal trigeminal tract), CL loss of pain and temperature on body (spinothalamic tract), CL beating nystagmus (vestibular nuclei/inferior cerebellar peduncle/CN VIII), dizziness, nausea (vestibular nuclei), IL sagging palate, dysphagia, hoarseness (nucleus ambiguous), loss of taste (solitary nucleus), ataxia (restiform body, inferior cerebellar peduncle), IL Horner syndrome (hypothalamospinal fibers), Hiccups (hypothalamospinal/solitospinal axons/”respiratory center”), and/or blockage of vertebral a -> infarct in territory of posterior inferior cerebellar artery
Tonsillar herniation
S/S: Central apnea, hypertension, hyperventilation, loss of consciousness
Rostral medial pontine syndrome
S/S: CL UMN weakness/hemiparesis (CST), lower facial paralysis, sagging palate, UMN tongue weakness (CNT), CL – UL loss of discriminative touch, proprioception and vibratory sense (medial lemniscus), IL ataxia, nystagmus, intranuclear ophthalmoplegia (medial longitudinal fasciculus), palatal myoclonus (rubro-olivary axons; olivocerebellar axons), and/or infarct in territory of paramedian branches from the basilar
Locked in syndrome
Bilateral lesion of basilar pons. Damages both R and L CST = spastic quadraplegia. Damages both R and L CNT = palsies of CN VII, IX-XII >> CN V, VI. Only CN III and IV are intact (midbrain) → vertical eye movements and blinking are intact. Results from pontine hemorrhage
Midpontine Basis syndrome
S/S: CL UMN weakness/hemiparesis (CST), paralysis of IL jaw muscles (CN V), loss of sensation on IL face (CN V), ataxia (middle cerebellar peduncle), spares pontine tegmentum. Infarct in territory of paramedian and short circumferential branches of basilar
Caudal medial pontine syndrome
S/S: CL UMN weakness/hemiparesis (CST), sagging palate, UMN tongue weakness (CNT). Maybe CN VII (can be CL lower facial paralysis (CNT) or complete IL facial paralysis (facial colliculus)). CN VI (maybe also intranuclear ophthalmoplegia), nystagmus, ataxia (middle cerebellar peduncle), CL loss of discriminative touch, proprioception and vibration (medial lemniscus). Infarct in territory of paramedian branches of basilar
Rostral pontine syndrome
Lesion in posterolateral aspect of the pontine isthmus. S/S: CL loss of all sensation on face and body (medial lemniscus & spinothalamic tracts), IL dizziness, nystagmus, ataxia (SCP), Horner syndrome (hypothalamospinal axons). Infarct in territory of the superior cerebellar artery
Lateral Pontine Syndrome - Upper
S/S: IL ataxia (MCP), ipsilateral paralysis of muscles of mastication (CN V), loss of all sensation on ipsilateral face (CN V), CL loss of pinprick sensation on body (spinothalamic tract), Horner syndrome (hypothalamospinal axons). Infarct in territory of long circumferential branches of basilar
Lateral pontine syndrome - Lower
S/S: IL loss of pain and temperature on face (spinotrigeminal nucleus/tract), CL loss of pain and temperature on body (spinothalamic tract), IL facial paralysis (facial nerve or nucleus), nystagmus, vomiting, nausea (vestibular nuclei), ataxia (pontine nuclei/MCP), hearing loss (SOC/tz), Horner syndrome (hypothalamospinal axons), may produce contralateral [spastic] hemiparesis if CST is affected. Infarct in territory of long circumferential branches of basilar/AICA
Cerebellopontine angle syndrome
Space occupying lesions at the cerebellopontine angle can compress CNS VII, VIII & CN V. Key s/s are hearing loss, tinnitus, vertigo, nystagmus, decreased corneal reflex, facial numbness, weakness in CN innervated muscles, Bell palsy. The most common causes are: Vestibular Schwannoma, Meningioma, Ependymoma in choroid plexus at the foramen of Luschka, Aneurysm
Central pontine myelinolysis
also known as “osmotic demyelination syndrome”; occurs mainly in patients with malnutrition or alcoholism complicated by hyponatremia → rapid correction of the hyponatremia results in demyelination in the pons and progressive quadriparesis and lower cranial nerve palsies (diplopia [CN VI], facial paralysis, dysphagia, dysarthria).
Facial nerve
A LMN injury to _____ (or nucleus in lateral pons or periphery) results in complete facial paralysis (ipsilateral, cannot wrinkle forehead or smile)
Corticonuclear tract
An UMN lesion of _____ (in pons or above, e.g. internal capsule) results in contralateral lower facial paralysis (can wrinkle forehead but cannot smile)
Parinaud syndrome
Caused by pinealoma >> MS. S/S: paralysis of vertical gaze (vertical gaze center, superior colliculus), light-near dissociation (pupils accommodate but do not respond to light; Edinger-Westphal nuc), nystagmus, obstructive hydrocephalus
Weber syndrome
Lesion in crus cerebri. S/S: IL diplopia, dilated pupil (CN III), CL [spastic] hemiparesis (corticospinal tract), paralysis of lower face, sagging palate, deviation of tongue to CL side (CNT), tremor (substantia nigra). Infarct in the territory of paramedian branches from posterior cerebral artery
Claude syndrome
Lesion in midbrain tegmentum. S/S: IL diplopia, dilated pupil (CN III), tremor, hyperkinesia (red nucleus), IL/CL/BL ataxia (cerebellothalamic fibers, SCP). Infarct in territory of paramedian branches from posterior cerebral artery
Benedikt syndrome
Weber + Claude syndromes: lesion involves both cerebral peduncle and tegmentum. May include CL loss of discriminative touch, proprioception and vibration (medial lemniscus). Infarct in territory of paramedian branches from posterior cerebral artery
Nothnagel syndrome
Tumor or abscess compressing the tectum. S/S: IL or BL diplopia (CN III), ataxia (superior cerebellar peduncle), nystagmus
Uncal herniation
usually results from a mass (tumor, hemorrhage, abscess) in the cerebral hemisphere that causes the temporal lobe to compress the midbrain: i.e. the uncus herniates over the tentorium to compress the crus cerebri. S/S: IL diplopia, dilated pupil (CN III), CL hemiparesis (CST), paralysis of lower face, deviation of tongue to CL side, weakness of ipsilateral SCM and trapezius (CNT)
Basilar artery thrombosis
A blockage in the basilar artery will reduce vascular perfusion in the posterior circulation. S/S: Hemi or tetraparesis (CST), Dysarthria (nucleus ambiguous), Lower facial paralysis (CNT), Altered consciousness (reticular formation), Visual disturbances (lateral geniculate/optic tract), Sensory loss (medial lemniscus, spinothalamic tract, thalamus)
