BB2 Anatomy1 Part2 Flashcards
Through which skull base foramina do the 3rd, 4th and 6th cranial nerves pass? [1]
Superior orbital fissure
State which muscles CN3 provides motor innervation to [5]
Motor fibres to:
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
Levator palpabrae superioris
State to which structures CN3 provides parasympathetic innervation to [2] and the effect this causes [2]
Sphincter Pupillae muscle via ciliary ganglion (causes pupillary constriction)
Ciliary muscle via ciliary ganglion (causes accomodation)
Lesions to the oculomotor nerve result:
The pupil []
The eyelid [] because of loss of innervation to the [] muscle
Lesions to the oculomotor nerve result in a resting ‘down and out’ position of the eye
Pupil dilates due to loss of parasympathetic innervation to the pupil
Eyelid droops because of loss of innervatio to the levator palpabrae superiorsis (ptosis)
Why is the trochlea nerve often torn when severe head injuries occur? [1]
Due to its long intracranial course
Which muscle does the trochlea nerve innervate? [1]
What movement does this cause? [1]
superior oblique muscle: downward and laterally
Explain the characteristics of trochlea nerve damage? [1]
State a classic symptom of trochlea nerve damage [1]
Trochlea innervates the superior oblique muscle
Double vision / diplopia when looking down
The superior oblique assists the inferior rectus in depressing the pupil and is the only muscle to do so when the eye is adducted
Often fall down the stairs
The abducens is somatic motor to one extraocular muscle, the []
The abducens is somatic motor to one extraocular muscle, the lateral rectus.
What is the abducens nerve commonly affected by and why? [2]
Raised ICP [1]
Due long intradural course and the** sharp bend along** the petrosal part of the temporal bone,
How does damage to the abducens nerve present? [2]
Complete paralysis of abducens causes medial deviation due to the unopposed action of medial rectus.
Diplopia is present in all ranges of movement, except when looking away from the lesion.
Which cranial nerve palsy has occured? [1]
Oculomotor nerve palsy
The right eye has ptosis, and can only look laterally (due to SO and LR) suggesting a medical 3rd nerve palsy.
What are the major divisions of the trigeminal nerve? [3]
Opthalmic (V1)
Maxillary (V2)
Mandibular (V3)
The trigeminal ganglion is comparable to the [] of spinal nerves
trigeminal ganglion is comparable to the dorsal root ganglion of spinal nerves