1 Motility Disorders Overview CN CN Which cranial

1 Motility Disorders: Overview CN… CN… Which cranial nerves innervate the extraocular muscles (EOMs)?

2 Motility Disorders: Overview CN 3 CN 6 CN 4 Which cranial nerves innervate the extraocular muscles (EOMs)?

3 Motility Disorders: Overview CN 3 ? CN 6 ? CN 4 ? What is the name for the collections of neurons that give rise to each of these cranial nerves? (This is not a trick question--the answer is as obvious as it seems. )

4 Motility Disorders: Overview CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus What is the name for the collections of neurons that give rise to each of these cranial nerves? (This is not a trick question--the answer is as obvious as it seems. )

5 Motility Disorders: Overview Um, Dr Flynn, 4 comes before 6. Why are these nuclei listed out of order? CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus

6 Motility Disorders: Overview Um, Dr Flynn, 4 comes before 6. Why are these nuclei listed out of order? This will be explained shortly CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus

7 Motility Disorders: Overview Nuclear CN 3 Nucleus (As we shall soon see, this ‘nuclear level’ serves as a useful point around which to organize the EOM-control pathway. ) CN 6 Nucleus CN 4 Nucleus

8 Motility Disorders: Overview ? ? Nuclear ? CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus With respect to pathology of the EOM control pathways, there are four major ‘locations. ’ One of these (the nuclear) has been identified already. What are the other three? (Hint: Their names reflect the relationship each has to the nuclear level. )

9 Motility Disorders: Overview ? Note: While you’re familiar with these terms… ? Nuclear ? CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus With respect to pathology of the EOM control pathways, there are four major ‘locations. ’ One of these (the nuclear) has been identified already. What are the other three? (Hint: Their names reflect the relationship each has to the nuclear level. )

10 Motility Disorders: Overview ? Note: While you’re familiar with these terms… ? Nuclear ? CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus With respect to pathology of the EOM control pathways, there are four major ‘locations. ’ One of these (the nuclear) has been identified already. What are the other three? (Hint: Their names reflect the relationship each has to the nuclear level. ) …you may not be with this one, although you’ll agree it makes sense in context. (Further, and importantly, it is used in the BCSC Neuro book. )

11 Motility Disorders: Overview Supranuclear Note: While you’re familiar with these terms… Internuclear Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus With respect to pathology of the EOM control pathways, there are four major ‘locations. ’ One of these (the nuclear) has been identified already. What are the other three? (Hint: Their names reflect the relationship each has to the nuclear level. ) …you may not be with this one, although you’ll agree it makes sense in context. (Further, and importantly, it is used in the BCSC Neuro book. )

12 Supranuclear What sorts of inputs comprise the supranuclear pathways? Those from the cortex, cerebellum, vestibular system, and a number of brainstem and other nuclei An important rule-of-thumb can be stated regarding supranuclear motility disorders and diplopia--what is it? It is this: With four important exceptions, supranuclear pts do not complain of diplopia Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus

13 Supranuclear What sorts of inputs comprise the supranuclear pathways? Those from the cortex, cerebellum, vestibular system, and a number of brainstem nuclei An important rule-of-thumb can be stated regarding supranuclear motility disorders and diplopia--what is it? It is this: With four important exceptions, supranuclear pts do not complain of diplopia Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus

14 Supranuclear What sorts of inputs comprise the supranuclear pathways? Those from the cortex, cerebellum, vestibular system, and a number of brainstem nuclei An important rule-of-thumb can be stated regarding supranuclear motility disorders and diplopia--what is it? It is this: With four important exceptions, supranuclear pts do not complain of diplopia Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus

15 Supranuclear What sorts of inputs comprise the supranuclear pathways? Those from the cortex, cerebellum, vestibular system, and a number of brainstem nuclei An important rule-of-thumb can be stated regarding supranuclear motility disorders and diplopia--what is it? It is this: With four important exceptions, supranuclear pts do not complain of diplopia Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus

16 (Almost) all of these pts will not c/o diplopia Supranuclear Internuclear Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

17 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a all of number of brainstem nuclei these pts Why don’t pts with supranuclear disorders have diplopia? will not Because supranuclear disorders affect both eyes in c/oa An important rule-of-thumb can be stated regarding symmetric fashion diplopia supranuclear motility disorders and diplopia--what is it? It is this: With four important. Internuclear exceptions, supranuclear pts do not complain of diplopia Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

18 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a all of number of brainstem nuclei these pts Why don’t pts with supranuclear disorders have diplopia? will not Because supranuclear disorders affect both eyes in c/oa An important rule-of-thumb can be stated regarding symmetric fashion diplopia supranuclear motility disorders and diplopia--what is it? It is this: With four important. Internuclear exceptions, supranuclear pts do not complain of diplopia Nuclear Infranuclear CN 3 Nucleus CN 6 Nucleus (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

19 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a all of number of brainstem nuclei these pts Why don’t pts with supranuclear disorders have diplopia? will not Because supranuclear disorders affect both eyes in c/oa An important rule-of-thumb can be stated regarding symmetric fashion diplopia supranuclear motility disorders and diplopia--what is it? It is this: With four important exceptions, supranuclear pts Internuclear do not complain of diplopia What are the four supranuclear disorders Nuclear Infranuclear in which pts c/o diplopia? -CN 3 CN 6 -Nucleus --- (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

20 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a all of number of brainstem nuclei these pts Why don’t pts with supranuclear disorders have diplopia? will not Because supranuclear disorders affect both eyes in c/oa An important rule-of-thumb can be stated regarding symmetric fashion diplopia supranuclear motility disorders and diplopia--what is it? It is this: With four important exceptions, supranuclear pts Internuclear do not complain of diplopia What are the four supranuclear disorders Nuclear Infranuclear in which pts c/o diplopia? --Skew deviation CN 3 CN 6 --Divergence insufficiency Nucleus --Convergence insufficiency --Convergence spasm (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

21 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a What are some of the supranuclear disorders all of that present typically, number of brainstem nuclei ie, without diplopia? these pts Why--don’t pts with supranuclear disorders have diplopia? will not Because supranuclear disorders affect both eyes in -c/oa An important rule-of-thumb can be stated regarding symmetric fashion diplopia -supranuclear motility disorders and diplopia--what is it? -- It is this: With four important. Internuclear exceptions, supranuclear pts do not complain of diplopia What are the four supranuclear disorders Nuclear Infranuclear in which pts c/o diplopia? --Skew deviation CN 3 CN 6 --Divergence insufficiency Nucleus --Convergence insufficiency --Convergence spasm (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

22 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a What are some of the supranuclear disorders all of that present typically, number of brainstem nuclei ie, without diplopia? these pts Why--Gaze don’t pts with supranuclear palsies, eg, Parinauddisorders syndromehave diplopia? will not Because supranuclear disorders affect(COMA) both eyes in --Congenital ocular motor apraxia c/oa An important rule-of-thumb can be stated regarding symmetric fashion diplopia --Progressive palsy (PSP) supranuclear motility supranuclear disorders and diplopia--what is it? --Saccadic disorders It is this: With four important. Internuclear exceptions, supranuclear pts do not complain of diplopia What are the four supranuclear disorders Nuclear Infranuclear in which pts c/o diplopia? --Skew deviation CN 3 CN 6 --Divergence insufficiency Nucleus --Convergence insufficiency --Convergence spasm (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

23 Supranuclear What sorts of inputs comprise the supranuclear pathways? Motility Disorders: Overview (Almost) Those from the cortex, cerebellum, vestibular system, and a What are some of the supranuclear disorders all of that present typically, number of brainstem nuclei ie, without diplopia? these pts Why--Gaze don’t pts with supranuclear have diplopia? palsies, eg, Parinauddisorders syndrome will not Because supranuclear disorders affect both eyes in --Congenital ocular motor apraxia (COMA) c/oa An important rule-of-thumb can be stated regarding symmetric fashionsupranuclear palsy (PSP) diplopia --Progressive supranuclear motility disorders and diplopia--what is it? --Saccadic disorders It is this: With four important. Internuclear exceptions, supranuclear pts do not complain of diplopia What are the four supranuclear disorders Nuclear in which pts c/o diplopia? --Skew deviation CN 3 CN 6 --Divergence insufficiency Nucleus --Convergence insufficiency --Convergence spasm Each of these is addressed in detail in other slide-sets--check the To. C Infranuclear (Almost) all of these pts will c/o diplopia CN 4 Nucleus Relationship between level of pathology and diplopia: The rule of thumb

24 Motility Disorders: Overview Supranuclear Internuclear Nuclear CN 3 Nucleus Are lesions of the CN 3 nucleus commonly encountered in clinical practice? Infranuclear CN 6 Nucleus CN 4 Nucleus

25 Motility Disorders: Overview Supranuclear Internuclear Nuclear CN 3 Nucleus Are lesions of the CN 3 nucleus commonly encountered in clinical practice? No, they are rare Infranuclear CN 6 Nucleus CN 4 Nucleus

26 Motility Disorders: Overview Supranuclear Internuclear Nuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus Are lesions of the CN 4 nucleus commonly encountered in clinical practice? Infranuclear

27 Motility Disorders: Overview Supranuclear Internuclear Nuclear CN 3 Nucleus CN 6 Nucleus CN 4 Nucleus Are lesions of the CN 4 nucleus commonly encountered in clinical practice? No, these are even rarer Infranuclear

28 Motility Disorders: Overview Supranuclear Internuclear Nuclear CN 3 Nucleus CN 6 Nucleus Are lesions of the CN 6 nucleus commonly encountered in clinical practice? Infranuclear CN 4 Nucleus

29 Motility Disorders: Overview Supranuclear Internuclear Nuclear CN 3 Nucleus CN 6 Nucleus Are lesions of the CN 6 nucleus commonly encountered in clinical practice? While not common, they are a well-known clinical entity Infranuclear CN 4 Nucleus

30 Motility Disorders: Overview Supranuclear Internuclear ? CN 4 Nucleus ^ CN 6 Nucleus ^ ? ^ CN 3 Nucleus ^ Nuclear Which two nuclei share an internuclear connection that is of wellestablished clinical importance? Infranuclear

31 Motility Disorders: Overview Supranuclear Internuclear Infranuclear CN 6 Nucleus ^ CN 3 Nucleus ^ Nuclear CN 4 Nucleus Which two nuclei share an internuclear connection that is of wellestablished clinical importance? 3 and 6 (Apropos a previous question: This is why the nuclei are not in numeric order!)

32 Motility Disorders: Overview Supranuclear Internuclear ? CN 6 Nucleus ^ CN 3 Nucleus ^ Nuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) CN 4 Nucleus

33 Motility Disorders: Overview Supranuclear Internuclear MLF CN 6 Nucleus ^ CN 3 Nucleus ^ Nuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) CN 4 Nucleus

34 Motility Disorders: Overview Supranuclear Internuclear MLF CN 6 Nucleus ^ CN 3 Nucleus ^ Nuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) CN 4 Nucleus

35 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) CN 4 Nucleus

36 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) CN 4 Nucleus

37 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) CN 4 Nucleus

38 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear What is the name of the internuclear pathway connecting the CN 3 and CN 6 nuclei? The medial longitudinal fasciculus (MLF) Infranuclear In which direction do impulses travel along the MLF? From the CN 6 to the CN 3 nucleus What condition is caused by disruption of the MLF? Internuclear ophthalmoplegia (INO) INO is addressed in detail in its own slide-set (N 20) CN 4 Nucleus

39 Motility Disorders: Overview Supranuclear Infranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Next we will turn our attention to the infranuclear pathway, which proceeds in an ordered fashion from the nuclei to the extraocular muscles themselves

40 Motility Disorders: Overview Supranuclear ? ? Infranuclear ? ? MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus The first portion of the nerve as it leaves the nucleus, but before leaving the substance of the brainstem

41 Motility Disorders: Overview Supranuclear Fascicular ? Infranuclear ? ? MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus The first portion of the nerve as it leaves the nucleus, but before leaving the substance of the brainstem

42 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular The cranial-nerve ? nuclei and their fascicles are located within the brainstem. Given this, it shouldn’t come as a surprise that, generally speaking, lesions of ? the nuclei and/or fascicles do not present with isolated EOM abnormalities; ie, Infranuclear the ophthalmoparesis is almost always accompanied by nonocular signs and symptoms of CNS? damage. ? What general term is used to describe conditions presenting with motility dysfunction 2 ndry to fascicle damage + non-ocular CNS findings? ? Fascicular syndrome

43 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular The cranial-nerve ? nuclei and their fascicles are located within the brainstem. Given this, it shouldn’t come as a surprise that, generally speaking, lesions of ? the nuclei and/or fascicles do not present with isolated EOM abnormalities; ie, Infranuclear the ophthalmoparesis is almost always accompanied by nonocular signs and symptoms of CNS? damage. ? What general term is used to describe conditions presenting with motility dysfunction 2 ndry to fascicle damage + non-ocular CNS findings? ? Fascicular syndrome

44 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular The cranial-nerve ? nuclei and their fascicles are located within the brainstem. Given this, it shouldn’t come as a surprise that, generally speaking, lesions of ? the nuclei and/or fascicles do not present with isolated EOM abnormalities; ie, Infranuclear the ophthalmoparesis is almost always accompanied by nonocular signs and symptoms of CNS? damage. ? What general term is used to describe conditions presenting with motility dysfunction 2 ndry to fascicle damage + non-ocular CNS findings? ? Fascicular syndrome

45 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular ? Infranuclear ? ? Speaking of fascicular syndromes…the Neuro book describes four involving the CN 3 fascicle, and two for the CN 6. Name them. CN 3 fascicular syndromes: ----CN 6 fascicular syndromes: --Foville syndrome --Millard-Gubler syndrome

46 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular ? Infranuclear ? ? Speaking of fascicular syndromes…the Neuro book describes four involving the CN 3 fascicle, and two for the CN 6. Name them. CN 3 fascicular syndromes: --Weber syndrome --Benedikt syndrome --Claude syndrome --Nothnagel syndrome CN 6 fascicular syndromes: --Foville syndrome --Millard-Gubler syndrome

47 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular ? Infranuclear ? ? Speaking of fascicular syndromes…the Neuro book describes four involving the CN 3 fascicle, and two for the CN 6. Name them. CN 3 fascicular syndromes: --Weber syndrome --Benedikt syndrome --Claude syndrome --Nothnagel syndrome CN 6 fascicular syndromes: ---

48 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular ? Infranuclear ? ? Speaking of fascicular syndromes…the Neuro book describes four involving the CN 3 fascicle, and two for the CN 6. Name them. CN 3 fascicular syndromes: --Weber syndrome --Benedikt syndrome --Claude syndrome --Nothnagel syndrome CN 6 fascicular syndromes: --Foville syndrome --Millard-Gubler syndrome

49 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular ? Infranuclear ? ? Speaking of fascicular syndromes…the Neuro book describes four involving the CN 3 fascicle, and two for the CN 6. Name them. CN 3 fascicular syndromes: --Weber syndrome The fascicular syndromes --Benedikt syndrome --Claude syndrome are addressed in detail in --Nothnagel syndrome their own slide-set (N 14) CN 6 fascicular syndromes: --Foville syndrome --Millard-Gubler syndrome

50 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular ? Infranuclear ? ? The next portion commences once the fascicles exit the brainstem--now they’re a nerve. Named for the space in which the nerves travel.

51 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear ? ? The next portion commences once the fascicles exit the brainstem--now they’re a nerve. Named for the space in which the nerves travel.

52 Motility Disorders: Overview Supranuclear MLF Fascicular Subarachnoid Infranuclear ? ? CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Which cause of ophthalmoparesis--common among vasculopaths--is attributed to damage occurring to the subarachnoid segments? Ischemic palsies (ie, a so-called ‘diabetic’ 3 rd or 6 th nerve palsy)

53 Motility Disorders: Overview Supranuclear MLF Fascicular Subarachnoid Infranuclear ? ? CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Which cause of ophthalmoparesis--common among vasculopaths--is attributed to damage occurring to the subarachnoid segments? Ischemic palsies (ie, a so-called ‘diabetic third’ or ‘diabetic sixth’)

54 Motility Disorders: Overview Supranuclear MLF CN 6 Nucleus ^ CN 3 Nucleus Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear ? ? The nerves then leave the subarachnoid space by diving into a space of a very different sort. This portion is named for the space entered into.

55 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? The nerves then leave the subarachnoid space by diving into a space of a very different sort. This portion is named for the space entered into.

56 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus What is the hallmark of ophthalmoplegia 2 ndry to a cavernous sinus process? The involvement of two or more cranial nerves simultaneously Which nerves may be involved? --CN 3 --CN 4 --CN 6 --V 1 --V 2 --Sympathetics

57 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus What is the hallmark of ophthalmoplegia 2 ndry to a cavernous sinus process? The involvement of two or more cranial nerves simultaneously Which nerves may be involved? --CN 3 --CN 4 --CN 6 --V 1 --V 2 --Sympathetics

58 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus What is the hallmark of ophthalmoplegia 2 ndry to a cavernous sinus process? The involvement of two or more cranial nerves simultaneously Which nerves may be involved? -------

59 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus What is the hallmark of ophthalmoplegia 2 ndry to a cavernous sinus process? The involvement of two or more cranial nerves simultaneously Which nerves may be involved? -Involvement manifests as ophthalmoplegia ---Involvement manifests as facial hypoesthesia --Involvement manifests as Horners

60 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus What is the hallmark of ophthalmoplegia 2 ndry to a cavernous sinus process? The involvement of two or more cranial nerves simultaneously Which nerves may be involved? -Involvement manifests as ophthalmoplegia ---Involvement manifests as facial hypoesthesia --Involvement manifests as Horners

61 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus What is the hallmark of ophthalmoplegia 2 ndry to a cavernous sinus process? The involvement of two or more cranial nerves simultaneously Which nerves may be involved? --CN 3 Involvement manifests as ophthalmoplegia --CN 4 --CN 6 --V 1 Involvement manifests as facial hypoesthesia --V 2 --Sympathetics Involvement manifests as Horners

62 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus ? ? ? Getting pretty close now. Post-cavernous sinus, another well-defined space.

63 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital ? ? Getting pretty close now. Post-cavernous sinus, another well-defined space.

64 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Superior orbital fissure Orbital ? ? BTW, the answer superior orbital fissure is just as good here as ‘orbit’ (if not better, as the Neuro book breaks out the fissure as a separate structure in the pathway)

65 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Superior orbital fissure Orbital apex Orbital ? ? Likewise, the answer orbital apex would also be reasonable at this junction

66 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Superior orbital fissure Orbital apex Orbital ? ? Motility disorders 2 ndry to pathology in these areas are addressed in detail in their own slide-set (N 19)

67 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital ? ? Where the journey ends for the nerves.

68 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital Neuromuscular junction ? Where the journey ends for the nerves.

69 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital Neuromuscular junction ? Per the Neuro book, what is the “prototypical” disease of the neuromuscular junction? Myasthenia gravis

70 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital Neuromuscular junction ? Per the Neuro book, what is the “prototypical” disease of the neuromuscular junction? Myasthenia gravis

71 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital Neuromuscular junction ? And finally…Don’t forget pathology here when evaluating motility disorders!

72 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus Orbital Neuromuscular junction Extraocular muscle And finally…Don’t forget pathology here when evaluating motility disorders!

73 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus What. Orbital sorts of conditions are included here? Restrictive (eg, thyroid eye dz); inflammatory (eg, orbital myositis); myopathies (eg, chronic progressive Neuromuscular junctionexternal ophthalmoplegia) Extraocular muscle

74 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF CN 6 Nucleus ^ Nuclear ^ Internuclear CN 4 Nucleus Fascicular Subarachnoid Infranuclear Cavernous sinus What. Orbital sorts of conditions are included here? Restrictive (eg, thyroid eye dz); inflammatory (eg, orbital myositis); myopathies (eg, chronic progressive Neuromuscular junctionexternal ophthalmoplegia) Extraocular muscle

75 Motility Disorders: Overview Supranuclear CN 3 Nucleus MLF Fascicular Subarachnoid Infranuclear Cavernous sinus CN 6 Nucleus ^ Nuclear ^ Internuclear Commit this slide to memory, and use it to organize your thought process when dealing with an ophthalmoparesis pt! Orbital Neuromuscular junction Extraocular muscle CN 4 Nucleus