The feeding artery for thalamus and midbrain is
Case 286
【Progress】
He was scheduled to receive rehabilitation for a week and thereafter, to discharge.
【Discussion】
Brain nerve nuclei exist in brain stem: midbrain, pons and medulla oblongata. Oculomotor nucleus (III) and trochlear nucleus (IV) situate in midbrain. Trigeminal nucleus (V), abducens nucleus (VI) and facial nucleus (VII). Vestibular (acoustic) nucleus (VIII), glossopharyngeal nucleus (VIX), vagus nucleus (X), accessory nucleus (XI) and hypoglossal nucleus (XII) in medulla oblongata. Midbrain has two brain nerve nucleus: oculomotor nucleus and trochlear nucleus.
Oculomotor nerve nucleus exists in midbrain, adjacent to midbrain aqueduct. In details, there are two subnuclei in oculomotor nucleus; oculomotor subnuclei which innervates four external eyeball muscles: another oculomotor accessory nuclei called Edinger–Westphal nucleus which innervates eyelid muscle, causing eyelid to elevate, innervates sphincter pupil muscle which constricts pupil (miosis), and innervates ciliary muscle which contract lens to bulge (accommodation) (1-3).
Oculomotor nerve palsy is largely divided into two symptoms: ptosis and/or no light reflex (no constricted pupil) and disorder of eye movement. Because of the 6 extra eye muscles, oculomotor nerve innervates 4 eye muscles: superior rectus muscle, internal rectus muscle, inferior rectus muscle and inferior oblique muscle, when oculomotor nerve disorder occurs, ipsilateral eyeball cannot move inward, upward and downward (4-6). Meanwhile, because abductor nerve innervates lateral rectus muscle, when abductor nerve palsy occurs, ipsilateral eyeball cannot move outward. Further, because trochlear nerve innervates superior oblique muscle, when trochlear nerve palsy occurs, ipsilateral eyeball cannot move down obliquely (1-3).
Midbrain gets blood supply from posterior cerebral artery, pons does from basilar artery and medulla oblongata does from basilar artery, posterior inferior cerebellar artery and posterior spinal branch artery (1-3).
Oculomotor nucleus and trochlear nucleus exist in midbrain. On heavy T2WIMRI, oculomotor nerve branches from anterior part of midbrain to interpeduncular cistern and trochlear nerve branches from dorsal part of midbrain at midbrain aqueduct level.
In our case, he experienced disorder of moving inward of right eyeball and body swing. Brain DWIMRI showed high signal intensity in midbrain and thalamus, indicative of occlusive change of posterior cerebral branch artery.
【Summary】
We presented an eighty eight-year-old old male for diplopia and body swinging. DWIMRI depicted a lesion with high signal intensity at midbrain adjacent to midbrain aqueduct and thalamus, indicative of fresh infarction. Eye movement examination revealed disorder of inward movement, corresponded to oculomotor nerve palsy. It is borne in mind that oculomotor nucleus innovates 4 extrinsic eyeball muscles including superior rectus muscle, inferior rectus muscle, medial rectus muscle and inferior oblique muscle, and oculomotor accessory nucleus innovate intrinsic eyeball muscle including sphincter pupil muscle and eyelid muscle. Oculomotor palsy indicates disorder of both two nuclei causing ptosis and miosis plus disorder of inward eyeball movement and disorder of single nucleus, indicative of disorder of extrinsic eyeball muscle alone. Oculomotor nerve palsy of our case was disorder of extrinsic eyeball muscle alone. Both of midbrain including oculomotor nerve nucleus and thalamus are innervated by posterior cerebral branch artery.
【References】
1.Christopher J et al. (2022), "Neuroanatomy, Cranial Nerve 3 (Oculomotor)", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 30725811, retrieved 2022-09-24
2.James S, et al. Lopez-Ojeda, Wilfredo (2022), "Neuroanatomy, Cranial Nerve", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 29261885, retrieved 2022-09-24
3.Hogan, H, et al. (2022), "Neuroanatomy, Edinger–Westphal Nucleus (Accessory Oculomotor Nucleus)", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32119442, retrieved 2022-09-24
4.Işikay CT, et al. Isolated nuclear oculomotor nerve syndrome due to mesencephalic hematoma. Acta Neurol Belg 2000;100:248–51.
5.Takamatsu K, et al. Partial nuclear oculomotor nerve palsy, MLF syndrome, hallucinose pédonculaire due to midbrain infarction—a case report. Rinsho Shinkeigaku 1994;34:341–6.
6.Toyoda K , et al. Isolated nuclear oculomotor nerve palsy due to mesencephalic infarction. Rinsho Shinkeigaku 1991;31:197–201
2022.12.23