2. Anatomy and Physiology 2

Question 1

Neuromuscular junction This is the 2nd synapse in which spinal tract?

Answer 1

Lateral corticospinal tract

Question 2

Lower vs. Upper motor neuron lesion

Answer 2

Lower MN lesion = everything lowered (less muscle mass, decr muscle tone, decr reflexes, downgoing toes) Upper MN = everythinig up (tone, DTRs, toes)

Question 3

Spinal tract: UMN vs. LMN lesion: Weakness

Answer 3

Both

Question 4

What motor neuron sign is present in both UMN and LMN lesions?

Answer 4

Weakness

Question 5

Spinal tract: UMN vs. LMN lesion: Atrophy

Answer 5

Atrophy in LMN only

Question 6

Spinal tract: UMN vs. LMN lesion: Fasciculations (muscle twitching)

Answer 6

Present in LMN lesions only

Question 7

What motor neuron signs are only present in LMN lesions?

Answer 7

Atrophy and fasciculations/fibrillations

Question 8

Spinal tract: UMN vs. LMN lesion: Reflexes

Answer 8

Increased in UMN Decreased in LMN

Question 9

Does UMN/LMN lesions lead to increased, decreased or the same reflex?

Answer 9

UMN vs. LMN lesion: Reflexes

Question 10

Spinal tract: UMN vs. LMN lesion: Tone

Answer 10

Increased in UMN, decreased in LMN

Question 11

What is increased in UMN lesion but decreased in LMN?

Answer 11

UMN vs. LMN lesion: Tone

Question 12

Spinal tract: UMN vs. LMN lesion: Babinski sign (upgoing toes – normal in infants)

Answer 12

(+) in UMN, (-) in LMN

Question 13

What does Babinski sign suggest about lesion?

Answer 13

UMN

Question 14

Spinal tract: UMN vs. LMN lesion: Spastic paralysis

Answer 14

(+) in UMN (-) in LMN

Question 15

What lesion does clasp knife spasticity suggest?

Answer 15

UMN

Question 16

Spinal cord lesions: Poliomyelitis and Werdnig-Hoffmann disease What areas are affected? What are the Sx?

Answer 16

Lower motor neuron lesion only, due to destruction of anterior horns; flaccid paralysis

Question 17

Lower motor neuron lesion only, due to destruction of anterior horns; flaccid paralysis What diseases (2) are associated with this?

Answer 17

Poliomyelitis and Werdnig-Hoffmann disease

Question 18

Spinal cord lesions: Multiple sclerosis What areas are affected? What are the Sx?

Answer 18

Mostly white matter of cervical region; random and asymmetric lesions, due to demyelination; scanning speech, intention tremor, nystagmus

Question 19

Mostly white matter of cervical region; random and asymmetric lesions, due to demyelination; scanning speech, intention tremor, nystagmus What disease is associated with this?

Answer 19

Multiple sclerosis

Question 20

Spinal cord lesions: ALS What areas are affected? What are the Sx?

Answer 20

Combined upper and lower motor neuron deficits with no sensory deficit; both upper and lower motor neuron signs.

Question 21

Combined upper and lower motor neuron deficits with no sensory deficit; both upper and lower motor neuron signs. What disease is associated with this?

Answer 21

ALS

Question 22

Spinal cord lesions: Complete occlusion of the anterior spinal artery What areas are affected? What are the Sx?

Answer 22

Spares dorsal columns and tract of Lissauer; upper throacic ASA territory is a watershed area, as artery of Adamkiewicz supplies ASA below ~T8

Question 23

Spares dorsal columns and tract of Lissauer; upper throacic ASA territory is a watershed area, as artery of Adamkiewicz supplies ASA below ~T8 What disease is associated with this?

Answer 23

Complete occlusion of the anterior spinal artery

Question 24

Spinal cord lesions: Tabes dorsalis (tertiary syphilis) What areas are affected? What are the Sx?

Answer 24

Degeneration of dorsal roots and dorsal columns; impaired proprioception, locomotor ataxia

Question 25

Degeneration of dorsal roots and dorsal columns; impaired proprioception, locomotor ataxia What disease is associated with this?

Answer 25

Tabes dorsalis (tertiary syphilis)

Question 26

Spinal cord lesions: Syringomyelia What areas are affected? What are the Sx?

Answer 26

Crossing fibers of spinothalamic tract damaged (2nd order neuron); bilateral loss of pain and temperature sensation. (usually C8-T1); seen with Chiari I types 1 and 2; can expand and affect other tracts

Question 27

Crossing fibers of spinothalamic tract damaged; bilateral loss of pain and temperature sensation. What disease is associated with this?

Answer 27

Syringomyelia

Question 28

Spinal cord lesions: Vitamin B12 neuropathy, Vitamin E deficiency and Friedrich’s ataxia What areas are affected? What are the Sx?

Answer 28

Demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts; ataxic gait, hyporeflexia, impaired position and vibration sense.

Question 29

Demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts; ataxic gait, hyperreflexia, impaired position and vibration sense. What diseases (3) are associated with this?

Answer 29

Vitamin B12 neuropathy, Vitamin E deficiency and Friedrich’s ataxia

Question 30

Poliomyelitis: Cause and Transmission?

Answer 30

Cause: poliovirus (fecal-oral) and replicates in oropharynx and small intestines -> spreads through bloodstream to CNS -> destruction of cells in anterior horn of spinal cord, leading in turn to LMN destruction.

Question 31

Poliomyelitis: Sx?

Answer 31

Malaise, hedache, fever, nausea, abdominal pain, sore throat. Signs of LMN lesions – muscle weakness and atrophy, fasciculations, fibrillation, and hyporeflexia.

Question 32

Poliomyelitis: Findings?

Answer 32

CSF w/ lymphocytic pleocytosis w/ slight elevation of protein (w/ no change in CSF glucose). Virus recovered from stool or throat.

Question 33

Werdnig-Hoffman dz. Genetics, Presentations and Prognosis

Answer 33

Infantile spinal muscular atrophy; Autosomal-recessive inheritance; presents at birth as a “floppy baby,” tongue fasciculations; median age of death 7 months. Associated w/ degeneration of anterior horns. LMN involvement only.

Question 34

Amyotrophic lateral sclerosis (commonly known as Lou Gehrig’s dz). Clinical presentation, genetics, treatment.

Answer 34

Associated with LMN and UMN signs; no sensory, cognitive or oculomotor deficits. Can be caused by superoxide dismutase 1 (SOD1). Commonly presents as fasciculations and eventual atrophy; progressive and fatal. Riluzole treatment modestly lengthens survival by decreasing presynaptic glutamate release; associated with betel nut ingestion.

Question 35

Tabes dorsalis. Etiology and Clinical presentations.

Answer 35

Degeneration of dorsal columns and dorsal roots due to tertiary syphilis, resulting in impaired proprioception and locomotor ataxia. Argyll Robertson pupils

Question 36

Associated with Tabes dorsalis

Answer 36

Charcot’s joints (neuropathic arthropathy), Shooting (lightning) pain, Argyll Robertson pupils (accomodate, but do not react), Absence of deep tendon reflexes, positive Romberg, sensory ataxia at night.

Question 37

Friedrich’s ataxia: Genetics, Etiology, and Presentation

Answer 37

Autosomal-recessive trinucleotide repeat disorder (GAA) in frataxin gene -> impairment in mitochondrial functioning; staggering gait, frequent falling, nystagmus, dysarthria, pes cavus (high arch), hammer toes, hypertrophic cardiomyopathy (cause of death). Presents in childhood with kyphoscoliosis.

Question 38

Brown-Séquard Syndrome: What is it?

Answer 38

Hemisection of the spinal cord

Question 39

Brown-Séquard Syndrome: Findings?

Answer 39

1.) Ipsilateral UMN signs (corticospinal tract) below lesion 2.) Ipsilateral loss of tactile, vibration, proprioception sense (dorsal column) below lesion 3.) Contralateral pain and temperature loss (spinothalamic tract) below lesion 4.) Ipsilateral loss of all sensation at level of lesion 5.) LMN signs (e.g., flaccid paralysis) at level of lesion
If lesion occurs above T1, presents w/ Horner’s syndrome

Question 40

Horner’s syndrome. Symptoms and Etiology.

Answer 40

Sympathectomy of face: 1.) P tosis (slight drooping of eyelid) 2.) A nhidrosis (absence of sweating) and flushing (rubor) of affected side of face 3.) M iosis (pupil constriction)
Associated w/ lesion of spinal cord above T1 (e.g., Pancoast (pulmonary sulcus) tumor, Brown-Séquard syndrome (cord hemisection), late-stage syringomyelia)

Question 41

3-Neuron oculosympathetic pathway involved in Horner’s syndrome

Answer 41

1. Hypothalamus -> intermediolateral column of spinal cord; synapse in lateral horn (T1)
2. Second neuron projects to up sympathetic trunk to superior cervical ganglion (C2)
3. Third neuron sends projects along external carotid artery to sweat glands of face, along opthalmic division of trigeminal nerve to smooth muscles of eyelids and pupillary dilator.
   Interruption of any of these pathways result in Horner’s syndrome.

Question 42

Clinically important landmarks for a pudendal nerve block (to relieve pain of pregnancy)

Answer 42

Ischial spine

Question 43

Clinically important landmarks for Appendix

Answer 43

2/3 of the way from the umbilicus to the anterior superior iliac spine (McBurney’s point)

Question 44

Clinically important landmarks for lumbar puncture

Answer 44

Iliac crest.

Question 45

Landmark dermatomes: C2

Answer 45

Posterior half of a skull “cap”

Question 46

Landmark dermatomes: C3

Answer 46

High turtleneck shirt

Question 47

Landmark dermatomes: C4

Answer 47

Low-collar shirt

Question 48

Landmark dermatomes: T4

Answer 48

At the nipple. (T4 at the teat pore )

Question 49

Landmark dermatomes: T7

Answer 49

Xiphoid process

Question 50

Landmark dermatomes: T10

Answer 50

At the umbilicus (important for early appendicitis pain referral) (T10 at the belly butTEN )

Question 51

Landmark dermatomes: L1

Answer 51

At the inguinal ligament (“L1 is IL [I nguinal L igament])

Question 52

Landmark dermatomes: L4

Answer 52

Includes kneecaps

Question 53

Landmark dermatomes: S2, S3, S4

Answer 53

Erection and sensation of penile and anal zones (“S2, 3, 4, keep the penis off the floor”)

Question 54

Muscle spindles vs. Golgi tendon organs

Answer 54

Muscle spindles monitor muscle length (help you pick up a heavy suitcase when you didnt know how heavy it was). Golgi T endon organs monitor muscle T ension (make you drop a heavy suitcase you’ve been holding too long).

Question 55

Muscle spindle: pathway?

Answer 55

In parallel with muscle fibers. Muscle stretch –> intrafusal stretch –> stimulates Ia afferent –> stimulate alpha motor neuron –> reflex muscle (extrafusal) contraction

Question 56

Spindle muscle control: the Gamma loop

Answer 56

CNS stimulates gamma motor neuron –> contracts intrafusal fiber –> increased sensitivity of reflex arc

Question 57

Clinical reflexes and their respective nerve roots: Achilles? Patella? Biceps? Triceps?

Answer 57

Achilles = S1 nerve root; Patella = L4 nerve root; Biceps = C5 nerve root; Triceps = C7 nerve root
*Note that they count up in order: S1,2 L3,4 C5,6 C7,8

Question 58

Babinski sign

Answer 58

Dorsiflexion of the big toe and fanning of other toes; sign of UMN lesion, but normal reflex in 1st year of life.

Question 59

Primitive reflexes. When do they disappear or reappear? What are they (6)

Answer 59

Normally disappear within 1st year of life. May reemerge following frontal lobe lesion.
Include: Moro reflex (3-6 months), rooting reflex (most immediate survival), suckling reflex, palmar and plantar reflexes (1-2 months), Babinski reflex (1 year), Galant reflex.

Question 60

Moro reflex

Answer 60

“hang on for life” reflex - abduct/extend limbs when startled, and then draw together; 3-6 months disappear

Question 61

Rooting reflex

Answer 61

Movement of head toward one side if cheek or mouth is stroked (nipple seeking)

Question 62

Sucking reflex

Answer 62

Sucking response when roof of mouth is touched

Question 63

Palmar and palantar reflexes

Answer 63

Curling of fingers/toes if palms of hands/feet are stroked (1-2 months)

Question 64

Galant reflex

Answer 64

Stroking along one side of the spine while newborn is in ventral suspension (face down) causes lateral flexion of lower body toward stimulated side.

Question 65

Cranial nerves that lie medially at the brainstem

Answer 65

III, VI, XII Remember: 3 (x2) = 6 (x2) = 12

Question 66

Which cranial nerve arises dorsally and emerges ventrally?

Answer 66

CN IV

Question 67

Dorsal brainstem structures: Pineal gland

Answer 67

Melatonin secretion, circadian rhythms.

Question 68

Dorsal brainstem structures: superior colliculi

Answer 68

Conjugate vertical gaze center. (“you have your eyes above your ears, and the superior colliculus (visual) is above the inferior colliculus (auditory).”)

Question 69

Dorsal brainstem structures: inferior colliculi

Answer 69

Auditory (“you have your eyes above your ears, and the superior colliculus (visual) is above the inferior colliculus (auditory).”)

Question 70

Parinaud syndrome

Answer 70

Paralysis of conjugate verticle gaze due to lesion in superior colliculi (e.g., pinealoma)

Question 71

Cranial nerves: Olfactory (CN I) function? type? mnemonic?

Answer 71

Smell (only CN w/o thalamic relay to cortex) S ensory; “S ome” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 72

Which cranial nerve is this? (Function, type, mnemonic) Smell (only CN w/o thalamic relay to cortex) S ensory; “S ome” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 72

Olfactory (CN I)

Question 73

Cranial nerves: Optic (CN II) function? type? mnemonic?

Answer 73

Sight. S ensory; “S ay” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 74

Which cranial nerve is this? (Function, type, mnemonic) Sight. S ensory; “S ay” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 74

Optic (CN II)

Question 75

Cranial nerves: Oculomotor (CN III) function? type? mnemonic?

Answer 75

Eye movement (SR, IR, MR, IO), pupillary constriction, accommodation, eyelid opening (levator palpebrae) M otor; “M oney” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 76

Which cranial nerve is this? (Function, type, mnemonic) Eye movement (SR, IR, MR, IO), pupillary constriction, accommodation, eyelid opening (levator palpebrae) M otor; “M oney” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 76

Oculomotor (CN III)

Question 77

Cranial nerves: Trochlear (CN IV) function? type? mnemonic?

Answer 77

Eye movement (SO) M otor; “M oney” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 78

Which cranial nerve is this? (Function, type, mnemonic) Eye movement (SO) M otor; “M oney” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 78

Trochlear (CN IV)

Question 79

Cranial nerves: Trigeminal (CN V) function? type? mnemonic?

Answer 79

Mastication, facial sensation. B oth, “B ut” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 80

Which cranial nerve is this? (Function, type, mnemonic) Mastication, facial sensation.

Answer 80

B oth, “B ut” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”] Trigeminal (CN V)

Question 81

Cranial nerves: Abducens (CN VI) function? type? mnemonic?

Answer 81

Eye movement (LR) M otor; “M y” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 82

Which cranial nerve is this? (Function, type, mnemonic) Eye movement (LR) M otor; “M y” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 82

Abducens (CN VI)

Question 83

Cranial nerves: Facial (CN VII) function? type? mnemonic?

Answer 83

Facial movement, taste from anterior 2/3rds of tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), stapedius muscle in ear B oth; “B rother” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 84

Which cranial nerve is this? (Function, type, mnemonic) Facial movement, taste from anterior 2/3rds of tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), stapedius muscle in ear B oth; “B rother” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 84

Facial (CN VII)

Question 85

Cranial nerves: Vestibulocochlear (CN VIII) function? type? mnemonic?

Answer 85

Hearing, balance. S ensory; “S ays” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 86

Which cranial nerve is this? (Function, type, mnemonic) Hearing, balance. S ensory; “S ays” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 86

Vestibulocochlear (CN VIII)

Question 87

Cranial nerves: Glossopharyngeal (CN IX) function? type? mnemonic?

Answer 87

Taste from posterior 1/3rd of tongue, swallowing, salivation (parotid gland), monitoring carotid body and sinus chemo- and baroreceptors, and stylopharyngeus (elevates pharynx, larynx) B oth; “B ig” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 88

Which cranial nerve is this? (Function, type, mnemonic) Taste from posterior 1/3rd of tongue, swallowing, salivation (parotid gland), monitoring carotid body and sinus chemo- and baroreceptors, and stylopharyngeus (elevates pharynx, larynx) B oth; “B ig” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 88

Glossopharyngeal (CN IX)

Question 89

Cranial nerves: Vagus (CN X) function? type? mnemonic?

Answer 89

Taste from epiglottic region, swallowing, palate elevation, talking, coughing, thoracoabdominal viscera, monitoring aortic arch chemo- and baroreceptors. B oth; “B rains” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 90

Which cranial nerve is this? (Function, type, mnemonic) Taste from epiglottic region, swallowing, palate elevation, talking, coughing, thoracoabdominal viscera, monitoring aortic arch chemo- and baroreceptors. B oth; “B rains” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 90

Vagus (CN X)

Question 91

Cranial nerves: Accessory (CN XI) function? type? mnemonic?

Answer 91

Head turning, shoulder shrugging M otor; “M atter” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 92

Which cranial nerve is this? (Function, type, mnemonic) Head turning, shoulder shrugging M otor; “M atter” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 92

Accessory (CN XI)

Question 93

Cranial nerves: Hypoglossal (CN XII) function? type? mnemonic?

Answer 93

Tongue movement M otor; “M ore” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Question 94

Which cranial nerve is this? (Function, type, mnemonic) Tongue movement M otor; “M ore” [Mnemonic for type of information carried by CN’s: “Some Say Marry Money, But My Brother Says Big Brains Matter Most.”]

Answer 94

Hypoglossal (CN XII)

Question 95

Cranial nerve nuclei: Where are they located, generally?

Answer 95

Located in tegmentum portion of brainstem (btw dorsal and ventral portions). Lateral nuclei = sensory M edial nuclei = M otor

Question 96

Cranial nerve nuclei located in the midbrain

Answer 96

Nuclei of CN III and IV

Question 97

Cranial nerve nuclei located in the pons

Answer 97

Nuclei of CN V (mid pons), VI, VII, and VIII (lower pons)

Question 98

Cranial nerve nuclei located in the medulla

Answer 98

Nuclei of CN IX, X, XI, and XII

Question 99

Which cranial nerves are involved in corneal reflex and lacrimation? (both afferent and efferent)

Answer 99

Corneal reflex: Afferent (V1 ophthalmic - levator palpebrae); Efferent: VII (temporal branch; orbicularis oculi)
Lacrimation: V1 (loss of reflex does not preclude emotional tears); Efferent: VII

Question 100

Afferent = V-1 Efferent = VII What CN reflex is this?

Answer 100

Corneal OR Lacrimation (use the same nerves)

Question 101

CN reflexes: Jaw jerk Afferent? Efferent?

Answer 101

Afferent = V-3 (sensory - muscle spindle from masseter) Efferent = V-3 (motor - masseter)

Question 102

Afferent = V-3 (sensory) Efferent = V-3 (motor) What CN reflex is this?

Answer 102

Jaw jerk

Question 103

CN reflexes: Pupillary Afferent? Efferent?

Answer 103

Afferent = II Efferent = III

Question 104

Afferent = II Efferent = III What CN reflex is this?

Answer 104

Pupillary

Question 105

CN reflexes: Gag Afferent? Efferent?

Answer 105

Afferent = IX Efferent = IX and X

Question 106

Afferent = IX Efferent = IX and X What CN reflex is this?

Answer 106

Gag

Question 107

Vagal nuclei: Nucleus Solitarious

Answer 107

Visceral S ensory information (e.g., taste, baroreceptors, gut distension) CN VII, IX, X (“S olitarius = viS ceral S ensory”)

Question 108

Vagal nuclei: Nucleus ambiguous

Answer 108

M otor innervation of pharynx, larynx, and upper esophagus (e.g., swallowing, palate elevation) CN’s IX, X, XI (“aM biguous = M otor”)

Question 109

Vagal nuclei: Dorsal motor nucleus

Answer 109

Sends autonomic (parasympathetic) fibers to heart, lungs, and upper GI.

Question 110

Cranial nerve and vessel pathways: What exits via the cribiform plate?

Answer 110

CN I

Question 111

Cranial nerve and vessel pathways: What exits via the middle cranial fossa?

Answer 111

CN II-VI, thru the sphenoid bone: 1.) Optic canal : CN II, ophthalmic artery, central retinal vein 2.) S uperior orbital fissure : CN III, IV, V-1, VI, ophthalmic vein 3.) Foramen R otundum : CN V-2 4.) Foramen O vale : CN V-3 5.) Foramen spinosum : middle meningeal artery (“Divisions of CN-V exit owing to S tanding R oom O nly”)

Question 112

Cranial nerve and vessel pathways: What exits via the Posterior cranial fossa?

Answer 112

CN VII-XII, thru the temporal and occipital bone: 1.) Internal auditory meatus : CN VII, VIII 2.) Jugular foramen : CN IX, X, XI, jugular vein 3.) Hypoglossal canal : CN XII 4.) Foramen magnum : Spinal roots of CN XI, brain stem, vertebral arteries

Question 113

What/where is the cavernous sinus? What is the route of blood thru it?

Answer 113

A collection of venous sinuses on either side of the pituitary. Blood from eye and superficial cortex -> Cavernous sinus ->Internal jugular vein

Question 114

What nerves pass through the cavernous sinus?

Answer 114

CN II, IV, V-1, V-2, VI, and postganglionic sympathetic fibers en route to the orbit all pass thru the cavernous sinus. Only CN VI is “free-floating”. Cavernous portion of internal carotid artery is also here.

Question 115

What is cavernous sinus syndrome?

Answer 115

Nerves that control extraocular muscles (plus V-1 and V-2) pass thru the cavernous sinus. Therefore, cavernous sinus syndrome (e.g., due to mass effect): ophthalmoplegia, ophthalmic and maxillary sensory loss.

Question 116

CN XII lesion (LMN) What is the defect?

Answer 116

Tongue deviates toward the side of the lesion (“lick your wounds”) due to weakened tongue muscles on the affected side

Question 117

CN V motor lesion. What is the defect?

Answer 117

Jaw deviates toward the side of lesion due to unopposed force from opposite pterygoid muscle

Question 118

CN X lesion. What is the defect?

Answer 118

Uvula deviates away from side of lesion. weak side collapses and uvula points away.

Question 119

CN XI lesion. What is the defect?

Answer 119

Weakness turning head to contralateral side of lesion (SCM). Shoulder droop on side of lesion (trapezius).

Question 120

Facial lesions: UMN lesion

Answer 120

Lesion of motor cortex or connection btw cortex and facial nucleus. Contralateral paralysis of lower face only, since upper face recives bilateral UMN innervation.

Question 121

Facial lesions: LMN lesion

Answer 121

Ipsilateral paralysis of upper and lower face.

Question 122

Facial lesions: Bell’s palsy

Answer 122

Complete destruction of the facial nucleus itself or its branchial efferent fibers (facial nerve proper). Peripheral ipsilateral facial paralysis w/ inability to close eye on involved side. Can occur idiopathically; gradual recovery in most cases.

Question 123

In what dz’s/disorders is Bell’s palsy seen as a complication?

Answer 123

A IDS L yme dz H erpes simplex S arcoidosis T umors D iabetes (“AL exander graH am Bell with STD”)

Question 124

KLM sounds (kuh, la, mi). Which nerves are involved?

Answer 124

Say it aloud. “Kuh-kuh-kuh” tests palate elevation (CN X - vagus) “La-la-la” tests tongue (CN XII - hypoglossal) “Mi-mi-mi” tests lips (CN VII - facial) (“It would be a K aL aM ity to lose CN X, XII, and VII”)

Question 125

Muscles of mastication

Answer 125

3 Muscles close jaw: M asseter, teM poralis, and M edial pterygoid (“M ‘s M unch”) 1 Muscle opens jaw: Lateral pterygoid (“M’s Munch. Lateral Lowers” – [when speaking of pterygoids with respect to jaw motion]) “It takes more muscle to keep your mouth shut.” All above are innervated by the trigeminal nerve (V-3)

Question 126

Muscles with glossus

Answer 126

All muscles with the root glossus in their names (except palatoglossus, innervated by vagus nerve) are innervated by the hypoglossal nerve. Palat : vagus nerve Glossus : hypoglossal nerve

Question 127

Muscles with palat

Answer 127

All muscles with the root palat in their names (except tensor veli palatini , innervated by mandibular branch of CN V) are innervated by vagus nerve. Palat : vagus nerve (except TENS or, who was too TENSE )

Question 128

Inner ear as a “series of tubes”

Answer 128

A series of tubes in the temporal bone (bony labrynth) filled with perilymph (Na+ rich, similar to ECF) that includes cochlea, vestibule, and semicircular canals. W/in the bony labyrinth is a 2nd series of tubes (membranous labyrinth) filled w/ endolymph (K+ rich, similar to ICF) that includes cochlear duct (w/in the cochlea), utricle and saccule (w/in the vestibule), and semicircular canals. *peri = think outside of the cell (Na+), vs. Endo = think inside the cell (K+)

Question 129

Where is the endolymph (of the inner ear) made?

Answer 129

Made by the stria vascularis.

Question 130

What do the utricle and saccule contain? What do they detect?

Answer 130

Contain maculae - detect linear acceleration.

Question 131

What do the semicircular canals contain? What do they detect?

Answer 131

Contain A mpullae, detect A ngular acceleration.

Question 132

Hair cells (of the inner ear): Where are they? What do they do?

Answer 132

Located w/in the organ of Corti. Are the sensory elements in both vestibular apparatus (spatial orientation) and cochlea (hearing).

Question 133

How can you remember where frequencies are sensed along the cochlear membrane?

Answer 133

The cochlear membrane = scuba flipper: narrow/stiff at the base (high frequency), and wide/flexible at the apex (low frequency).

Question 134

Conductive hearing loss

Answer 134

Abnormal rinne test (bone>air); Weber test localizes to affected ear.

Question 135

Sensorineural hearing loss

Answer 135

Normal Rinne test (air>bone); Weber localizes to normal ear.

Question 136

Hearing loss in the elderly

Answer 136

High frequency –< low frequency

Question 137

What are the muscles that make up the iris? What receptors do they have, and what are their effects?

Answer 137

Dilator/radial muscle (alpha1 –> myd riasis [pupillary d ilation]) Sphincter/circular/constrictor muscle (M3 –> miosis [pupillary constriction])

Question 138

Where are the ciliary muscles? What receptors do they have, and what effect?

Answer 138

M3 –> accomodation

Question 139

Where is aqueous humor made? Where is it reabsorbed? [give the whole pathway]

Answer 139

Aqueous humor is made by ciliary process -> Travels past lens to posterior Chamber -> Anterior chamber -> Trabecular meshwork (absorbs aqueous humor -> Canal of Schlemm (collects aqueous humor from trabecular meshwork)

Question 140

Glaucoma (general pathogenesis)

Answer 140

Impaired flow of aqueous humor -> Increased intraocular pressure -> Optic disk atrophy w/ cupping

Question 141

Open angle glaucoma

Answer 141

Obstructed outflow (e.g., canal of Schlemm); associated w/ myopia, advanced age, African-American race. More common, “silent,” painless.

Question 142

Closed angle glaucoma

Answer 142

Obstruction of flow btw iris, lens –> pressure builds up behind iris. Very painful, impaired vision, rock-hard eye, frontal headache. An opthalmologic emergency. Do NOT give epinephrine.

Question 143

Cataract

Answer 143

Painless, bilateral opacification of lens, leading to decrease in vision; glare from headlights. Risk factors: age, smoking, EtOH, sunlight, diabetes (sorbital), trauma, congenital infection, classic galactosemia, galactokinase deficiency, long term steroid use

Question 144

Papilledema

Answer 144

Increased intracranial pressure –> elevated optic disk with blurred margins, bigger blind spot (can be seen in hydrocephalus)

Question 145

Innervation of the extraocular muscles?

Answer 145

CN VI innervates the L ateral R ectus CN IV innervates the S uperior O blique CN III innervates the R est Thus, the “chemical formula”: LR6 SO4 R3

Question 146

What are the 3 actions of the superior oblique?

Answer 146

It abducts, intorts, and depresses.

Question 147

CN III damage

Answer 147

Eye looks down and out; ptosis, pupillary dilation, loss of accomodation.

Question 148

CN IV damage

Answer 148

Diplopia w/ defective downward gaze

Question 149

CN VI damage

Answer 149

Medially directed eye.

Question 150

Testing extraocular muscles

Answer 150

To test fxn of each muscle, have the pt look in the following directions: [*note that the oblique muscles are tested by looking medially and opposite to what you would expect from “superior” and “inferior”] “IOU : to test I nferior O blique, have pt look U p.”

Question 151

Strabismus vs. Amblyopia

Answer 151

Strabismus is misalignment of eyes. Multiple etiologies. Amblyopia is a reduction of vision from disuse in critical period. May be secondary to strabismus, deprivation, unequal refractive errors.

Question 152

What controls pupillary constriction (miosis)

Answer 152

P upillary sphincter muscle (aka circular muscle), P arasympathetic innervation. Innervation – CN III from Edinger-Westphal nucleus –> ciliary ganglion.

Question 153

What controls pupillary D ilation (myD riasis)?

Answer 153

RaD ial muscle (aka pupillary D ilator muscle), sympathetic. Innervation – T1 preganglionic sympathetic –> superior cervical ganglion –> postganglionic sympathetic –> long ciliary nerve.

Question 154

Pupillary light reflex

Answer 154

Light in either retina sends a signal via CN II to pretectal nuclei (dashed lines, below) in midbrain that activate bilateral Edinger-Westphal nuclei; pupils constrict bilaterally (consensual reflex). Result: illumination of 1 eye results in bilateral pupillary constriction.

Question 155

Marcus Gunn pupil

Answer 155

Afferent pupillary defect (e.g., due to optic nerve damage or retinal detachment). Decreased bilateral pupillary constriction when light is shone in affected eye.

Question 156

CN III in cross-section

Answer 156

Output to ocular muscles - affected primarily by vascular disease (e.g. diabetes: glucose -> sorbitol) due to decreased diffusion to interior. Symptoms: ptosis, “down and out” gaze.

Parasympathetic output - affected 1st by compression (e.g. PCOM berry aneurysm, uncal herniation); use pupillary light reflex in assessment, “blown pupil”.

Question 157

Retinal detachment

Answer 157

Separation of neurosensory layer of retina from pigment epithelium -> Degeneration of photoreceptors -> Vision loss May be secondary to trauma, diabetes; flurries

Question 158

Age-related macular degeneration (ARMD)

Answer 158

Degeneration of macula (central area of retina). Causes loss of central vision (scotomas). “Dry”/atrophic ARMD is slow, due to fat deposits, and causes gradual decrease in vision “Wet” ARMD is rapid, due to neovascularization.

Question 159

Visual field defects: Where is the lesion?

Answer 159

#1, below
 Right anopia

Question 160

Visual field defects: Where is the lesion?

Answer 160

2, below. Bitemporal hemianopia (pituitary denoma, prolactinoma; mass in sella turcica)

Question 161

Visual field defects: Where is the lesion?

Answer 161

3, below; Left homonymous hemianopia.

Question 162

Visual field defects: Where is the lesion?

Answer 162

4, below. Left upper quadrantic anopia. Right temporal lesion, MCA

Question 163

Visual field defects: Where is the lesion?

Answer 163

5, below; Left lower quadrantic anopia (right parietal lesion, MCA)

Question 164

Visual field defects: Where is the lesion?

Answer 164

6, below; Left hemianopia w/ macular sparing -> bilateral projection to occiput

Question 165

Visual field defects: Where is the lesion?

Answer 165

7, below;Central scotoma (macular degeneration)

Question 166

Internuclear ophthalmoplegia (MLF syndrome)

Answer 166

Lesion in the medial longitudinal fasciculus (MLF) –> medial rectus palsy on attempted lateral gaze. Nystagmus in abducting eye. Convergence normal. Syndrome is seen in many pts w/ multiple sclerosis (“M LF = M S”)
When looking left, the left nucleus of CN VI fires, which contracts the lateral rectus and stimulates the contralateral (right) nucleus of CN III via the right MLF to contract the right medial rectus.

Question 167

Renitis. What is it?

Answer 167

Retinal necrosis + edema leading to atrophic scar (seen in Aids patients with CMV)

Question 168

What is iritis?

Answer 168

Systemic inflammation (e.g. Reiter’s [reactive arthritis])

Question 169

How do eye muscles change for near vision?

Answer 169

Ciliary muscle contracts (zonular fibers relax -> lens relax -> more convex)

Question 170

How do eye muscles change to allow for distant vision?

Answer 170

Ciliary muscle relaxes -> lens flattens

Question 171

How does aging affect the eye?

Answer 171

Sclerosis and decreased elasticity causes presbyopia (no near vision) due to change in lens shape?

Question 172

Retinal artery occlusion. Etiology and Presentation.

Answer 172

Acute, painless monocular loss of vision; pale retina and cherry-red macula (has its own blood supply from choroid artery). Major cause of central retinal artery occlusion is atheroma or embolism.

Question 173

Where is Meyer’s loop?

Answer 173

Loops around inferior horn of lateral ventricle; inferior retina

Question 174

Where is dorsal optic radiation?

Answer 174

Takes shortest path through internal capsule; superior retina