skanuj0004 (505)

Neuroanatomy

6. Brainstem

Oariomotor    Interpeduncular    Cerebral

«ve(CNIII)    fossa    pedunde

Brachium of inferior coiliculus

Olive

Pyramid of

medulla

oblongata

inerve CS XII)

Anterior median fissure

■ccessory nerve (CN XI)

Cl spinał nerve, Decussation ventral root of pyramids

^uadrigeminal piąte, superior coiliculus

Pineal

Brachium of superior coiliculus

Quadrigeminal piąte, inferior coiliculus

Superior medullary velum

Superior

cerebellar

pedunde

Rhomboid

fossa

Inferior

cerebellar

pedunde

Vestibular

area

Trochlear nerve

Trigeminal

nerve

Medial

eminence

Middle

cerebellar

pedunde

Facial

coiliculus

Trigone of hypoglossal nerve

Trigone of vagus nerve

Tuberde of nucleus cuneatus

Tuberde of nucleus gracilis

Striae

medullaris

Taenia

cinerea

Cerebral    Brachium of

pedunde inferior coiliculus

Superior coiliculus

Accessory

nerve

Posterolateral

sulcus

ryngeal

nerve

fpoglossal nerve

Olive

Cl spinał nerve, ventral root

Anterolateral

sulcus

Inferior coiliculus

Trochlear nerve

Superior cerebellar pedunde

Middle cerebellar pedunde

Inferior cerebellar pedunde

Lateral aperture

Vagus nerve

E Brainstem

a Anterlorview. The sites ofentryand emergence oftheten pairs oftrue cranial nerves (III—XII) are particularly well displayed in this view. Notę: Cranial nerve II (optic nerve) is a derivative of the diencepha-lon. Notę also the site belowthe pyramids where the pyramidal fibers cross over the midline from each side (decussation of the pyramids). Most of the axons of the large motor pathway for the trunk and limbs cross to the opposite side at this level. b Posterior view. Since the cerebellum has been removed, we can see the rhomboid fossa, which forms the floor of the fourth ventricle. The surface of the fossa is raised by several cranial nerve nuclei, which bulge into the fourth ventride. The cerebellum is connected to the brainstem by three cerebellar peduncles on each side:

•    Superior cerebellar pedunde

•    Middle cerebellar pedunde

•    Inferior cerebellar pedunde

The superior and inferior cerebellar peduncles border portions of the rhomboid fossa and thus contribute to the boundaries of the fourth ventride.

c Left lateral view. In addition to the cerebellar peduncles, this view displays the superior and inferior colliculi. Together with their coun-terparts on the right side, the colliculi form the quadrigeminal piąte (see b), which is a prominent structure of the mesencephalon. The two superior colliculi are part of the visual pathway, while the inferior colliculi are part of the auditory pathway. The trochlear nerve (CN IV) runs forward below the inferior coiliculus, and is the only cranial nerve that emerges from the dorsal side of the brainstem. The olive appears as a prominence on the side of the medulla oblongata. The nuclei within the olive function as a relay station for the motor system (see p. 342).