Pons Flashcards
Connects the medulla oblongata to the midbrain
Pons
Important ascending and descending tracts of Pons
Corticonuclear Corticopontine Corticospinal Medial longitudinal fasciculus Medial, Spinal, and Lateral Menisci
Pons cranial nerves
Trigeminal - 5
Abducent - 6
Facial - 7
Vestibulocochlear - 8
Convex from side to side and shows many transverse fiver that converge on each side to form the _______
Middle cerebellar peduncle
A shallow groove in the midline found on the anterior surface which lodges the basilar artery
Basilar groove
Nerve that emerges on each side of the anterolateral surface.
Trigeminal nerve
The trigeminal nerve contains 2 roots. What is the size and laterality of each root.
Motor - smaller and medial
Sensory - larger and lateral
CN 6-8 emerge from?
groove between the pons and cerebellum
Pons are limited laterally by the __________ and divided symmetrically by a ___________.
Superior cerebellar peduncles
Median sulcus
An elongated elevation located laterally to the median sulcus
Medial eminence
Medial eminence is bounded laterally by ______
Sulcus limitans
Formed from the slight expansion of the inferior end of the medial eminence
Facial colliculus
2 cranial nerve roots responsible for the facial colliculus
root of the facial nerve winding around the nucleus of the abducent nerve
Floor of the superior part of the sulcus limitans which is bluish-gray in color due to the pigmented nerve cells
Substansia ferruginea
Located lateral to the sulcus limitans
Area vestibuli
Area vestibuli is produced by the underlying _______
vestibular nuclei
o Rotates as it passes from the medulla into the
pons
o Situated in the most anterior part of the tegmentum, with its long axis running transversely
o Accompanied by the spinal and lateral lemnisci
Medial lemniscus
o Lies posterior to the lateral part of the medial lemniscus; fibers wind around the nucleus of the abducent nerve, producing the facial colliculus.
o The fibers then pass anteriorly between the facial nucleus and the superior end of the nucleus of the spinal tract of the trigeminal nerve
Facial nucleus
o Situated beneath the floor of the fourth ventricle on either side of the midline
o Main pathway that connects the vestibular and cochlear nuclei with the nuclei controlling the extraocular muscles (oculomotor, trochlear, and abducent nuclei)
Medial longitudinal fasciculus
o Situated lateral to the abducent nucleus and is in close relationship to the inferior cerebellar
peduncle
o The superior part of the lateral and the inferior part of the superior vestibular nucleus, the posterior and anterior cochlear nuclei are also found at this level
Medial vestibular nucleus
Lie on the anteromedial aspect of the inferior cerebellar peduncle
Spinal nucleus of the trigeminal nerve and its tract
o Made up of fibers derived from the cochlear nuclei and the nuclei of the trapezoid body
o Run transversely in the anterior part of the tegmentum
Trapezoid body
o Small masses of nerve cells located at the basilar part of the pons
o Where the corticopontine fibers of the crus cerebri terminate
Pontine nuclei
o The axons of these cells give origin to the transverse fibers of the pons, which cross the midline and intersect the corticospinal and corticonuclear tracts, which breaks them up into small bundles.
Pontine nuclei
o Situated beneath the lateral part of the fourth ventricle within the reticular formation
o The emerging motor fibers travel anteriorly through the substance of the pons and exit on its anterior surface.
Motor nucleus of the trigeminal nerve
o Situated on the lateral side of the motor nucleus
o Continuous inferiorly with the nucleus of the spinal tract
o The entering sensory fibers travel through the substance of the pons and lie lateral to the motor fibers.
Principal sensory nucleus of the trigeminal nerve
o Situated posterolateral to the motor nucleus of the trigeminal nerve
o It is joined by the anterior spinocerebellar tract.
Superior cerebellar peduncle
Lie at the lateral extremity of the medial lemniscus
Lateral and Spinal lemnisci
Blood supply of the pons
Basilar artery
Branches of basilar artery
o Pontine arteries
o Anterior Inferior Cerebellar Artery
o Superior Cerebellar Artery
