C15 - Motor cranial nerves Flashcards
1
Q
List the motor cranial nerves
A
- III. n. oculomotorius
- IV. n. troclearis
- VI. n. abducent
- XI. n. accessorius
- XII. n. hypoglossi
2
Q
Cranial nerve III.
A
- N. oculomotorius
Origin:
- Nucl. parasympatheticus (visceral motor fibers)
- Nuc. motorius (somatic motor fibers)
Leaves the cranial cavity through:
- Fissura orbitalis
- Ru: for. orbirotundum
(shares a common dural sheath with n. opthalmichi and n. abducent before leaving the cranial cavity)
Division when entering the orbit:
- R. dorsalis
- R. ventralis
Motor innervation:
- R. dorsalis:
- M. levator palpebrailis
- M. rectus dorsalis
- R. ventralis:
- M. rectus medialis
- M. rectus ventralis
- M. obliquus ventralis
Parasympathetic innervation:
- Travels with r. dorsalis + synapse in ggl.ciliare
- Post ggl. fibers to:
- M. ciliaris (optic)
- M. sphinter papillaris (light accomondation)
Sensory innervation:
- Some sensory fibers join V1 → terminal ggl.
3
Q
Cranial nerve IV.
A
- N. trochlearis
Origin:
- Nucl. trochlearis
Leaves the cranial cavity through:
- Only nerve to leave brain at dorsal side, crosses to contralateral side at decussation n. trochlearium
- Penetrates dura mater at ventral fold of tentorium cerebelli
- Leaves the skull via:
- For. rotundum
- Eq: for. trochleare
- Ru: for. orbirotundum ?
Motor innervation:
- M. obliquus dorsalis (of the eye)
4
Q
Cranial nerve VI.
A
- N. abducent
Origin:
- Motor nucleus of n. abducent
Leaves the cranial cavity through:
- Fissura orbitalis (with V2, III. and IV)
Motor innervation:
- M. rectus bulbi lateralis (of the eyeball)
- M. retractor bulbi (of the eyeball)
5
Q
Cranial nerve XI
A
- N. accessorius
- Part of vagus group
- Parasympathetic? fibers from ggl. cervicale craniale
Origin:
- Caudal part of nucl ambiguus (ikke rostral???)
- Medulla oblongata
- Fibers leave XI to joint X
-
Nucl. accessorius
- Cervical part of spinal cord
- Fibers leaves spinal cord at lateral aspect and combine in a trunk that rung along the cord to enter the skull via for. magnum
Leaves the cranial cavity through:
- For. jugulare (with the other nerves of the vagus group: IX, X
Branches:
- Divides ventral to ala atlantis:
- R. dorsalis
- R. ventralis
Motor innervation:
- R. dorsalis:
- M. brachiocephalicum (ø m. cleidobrachialis)
- M. omotransversarius
- M. trapezius
- R. ventralis:
- M. sternocephalicus
6
Q
Cranial nerve XII
A
- N. hypoglossus
Origin:
- Nucl. hypoglossus (of caudal medulla)
Leaves the cranial cavity through:
- Canalis n. hypoglossi
Branches:
- Passes rostral between X and XI to reach the tongue and branches into:
- Rr. superficialis
- Rr. profundus
Motor innervation:
- Extrinsic and intrinsic muscles of the tongue (n. hypoglossus is the only motor nerve to the tongue)
Horse:
- Passes through medial compartments of gutteral pouch
- Runs parallell with tr. linguofacialis to radix linguae