Oculomotor nerve – osmcq

89. The tarts

The cranial nerves passing through the superior orbital fissure in order from top to bottom:

Lacrimal nerve. (T/F?)
Frontal nerve. /T/F?)
Trochlear nerve. (T/F?)
Superior branch of the oculomotor nerve. (T/F?)
Nasocilliary nerve. (T/F?)
Abducens nerve. (T/F?)
Inferior branch of the oculomotor nerve. (T/F?)

Answers...

81. One and a half syndrome

The one and a half syndrome is characterized by a conjugate horizontal gaze palsy in one direction and an impairment of the abduction of the eyes in the other. (T/F?)
Horizontal gaze palsy is seen on looking away from the side of the lesion. (T/F?)
The ipsilateral eye has no horizontal movement. (T/F?)
The most common cause of the one-and-a-half syndrome in the young people is Miller-Fisher syndrome. (T/F?)
The most common cause of the one-and-a-half syndrome in older people is multiple sclerosis. (T/F?)
When the lesion that causes a damage to PPRF or abducens nucleus and medial longitudinal fasciculus, also affects the facial nerve, we can talk about an eight-and-a-half syndrome. (T/F?)

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64. Cavernous sinus (Gray-571)

Henry Vandyke Carter [Public domain], via Wikimedia Commons

Ophtalmic nerve

Internal carotid artery

Maxillary nerve

Oculomotor nerve

Cavernous sinus

Sphenoidal sinus

Trochlear nerve

59. Axial section through the midbrain (Gray-710)

Henry Vandyke Carter [Public domain], via Wikimedia Commons

Cerebral aqueduct

Lateral lemniscus

Corpora quadrigemina

Oculomotor nucleus

Temporopontine fibers

Periductal gray

Substantia nigra

Medial lemniscus

Corticospinal fibers

Oculomotor nerve

Medial longitudinal fasciculus

Frontopontine fibers

58. Structures that leave or enter the skull through the superior orbital fissure

Oculomotor nerve. (T/F?)
Trochlear nerve. (T/F?)
Frontal nerve. (T/F?)
Superior and inferior ophthalmic veins. (T/F?)
Ophthalmic artery. (T/F?)
Abducens nerve. (T/F?)

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53. Exits of cranial nerves from the skull

Cribriform plate: Olfactory nerve. (T/F?)
Optic foramen: Optic nerve. (T/F?)
Superior orbital fissure: Ophtalmic nerve. (T/F?)
Foramen ovale: Maxillary nerve. (T/F?)
Foramen rotundum: Mandibullary nerve. (T/F?)
Jugular foramen: Vagus nerve. (T/F?)

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19. Cranial nerve nuclei – location

Trochlear nucleus: Mesencephalon?
Dorsal cochlear nucleus: Pons?
Ventral cochlear nucleus: Medulla?
Oculomotor nucleus: Mesencephalon?
Facial nucleus: Pons?
Edinger-Westphal nucleus: Pons?

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18. Abducens nerve

Innervates only one single muscle of the eye, the lateral rectus muscle?
Axons from the abducens nerve loop around the facial motor nucleus, creating the facial colliculus that is visible on the floor of the fourth ventricle?
Besides the motor neurons, which directly innervate ipsilateral lateral rectus muscle via the abducens nerve, abducens nucleus contains also interneurons, which project to the contralateral oculomotor nucleus and cause conjugate movement (adduction) of the contralateral eye?
Besides the motor neurons, which directly innervate ipsilateral medial rectus muscle via the oculomotor nerve, oculomotor nerve nucleus contains also interneurons, which project to the contralateral abducens nucleus and cause conjugate movement (abduction) of the contralateral eye?
A lesion to the nucleus of the abducens nerve causes inability to move the eyes together in the direction of the side with the lesion?
In peripheral abducens palsy, the contralateral eye is slightly adducted because of the unopposed tonic action of the medial rectus muscle?

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4. Oculomotor nerve

Is the third cranial nerve. (T/F?)
Has two nuclei: oculomotor nucleus and the Edinger-Westphal nucleus. (T/F)
Runs in the lateral wall of the cavernous sinus. (T/F?)
Enters orbit through the inferior orbital fissure. (T/F?)
Its upper division supplies the superior rectus and the superior oblique muscles. (T/F?)
Its inferior branch innervates medial rectus, inferior rectus and inferior oblique muscles. (T/F?)

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The Edinger–Westphal nucleus or accessory oculomotor nucleus is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.
Picture:

Henry Vandyke Carter [Public domain], via Wikimedia Commons
It enters the orbit via the superior orbital fissure.
Henry Vandyke Carter [Public domain], via Wikimedia Commons
The upper division supplies the superior rectus muscle and levator palpebrae superioris (elevating muscle of upper eyelid). The superior oblique muscle is innervated by the trochlear nerve (the fourth cranial nerve).