Neurology - Pontine (Pons) Anatomy and Introduction to Pontine Lesions

I want to discuss Pontine Lesions but for easy understanding, I will be talking about the Pontine Anatomy and what it does. I will be looking at it at the trigeminal level and at the abducens level.

At the dorsal part of the pons are the pontine nuclei which have descending motor fibers coming from the cerebral motor cortex synapsing with some of them to become the pontocerebellar fibers. The Pontocerebellar fibers move towards the controlateral cerebellar into the middle cerebellar peduncles. In the tegmental part of the pon where the trapezoid body is, and the trapezoid body is where cochlear nuclei cross to the lateral lemniscus. At the medial portion of the pons is the medial lemniscus which carries sensory information from the dorsal column as well as proprioception, and vibration, then the trigeminal lemniscus which carries proprioception, fine discriminative touch, pressure sensations, then the spinal lemniscus which carries pain temperature pressure sensation, and finally the lateral lemniscus which carry sensory information from the cochlear. After the lemnicus are the ascending tract which are of the ventral spinocerebellar tract that carry propioceptive informations from tendons, joint, and send them to the cerebellum. In the middle of the Pons are the Rubrospinal tract which are descending motor tracts for flexion of the upper extremities. The tectospinal tract which sends motor information from the tectum to the motor neurons which are responsible for movement of the head, neck and eye, from visual and auditory stimuli. Close to the tectospinal tract is the medial longitudinal fasciculus which connects the third cranial nerve, the forth cranial nerve, and the sixth cranial nerve. In the upper part of the tegmentum is the trigeminal motor nucleus, and close to it is the central Pontine nucleus of the Trigeminal nerve. The fourth ventricle is above the tegmental region of the pons, it is a fluid filled cavity that has cerebral spinal fluid and is recived from the cerebral aqueduct. At the anterior of the superior cerebellar peduncles is the superior medullary velum. ^{, ,}

Towards the facial colliculus of the pon, is the Motor nucleus of the facial nerve which supplies the muscles of facial expression, and the platysma, and they are Special Visceral Efferent Fibers, also connected to the facial nerve is the superior salivatory nucleus which has its axons going to the lacrimal glands, and salivary glands. Also at the facial colliculus is the nucleus of tractus Solitarius which is responsible for the sensation of taste in the tongue. Also the Abducens nerve which has its motor fibers go to the lateral rectus which is responsible for the abduction of the eyes. Also at the area of the facial colliculus is the dorsal cochlear nuclei. Vestibular nuclei complex which has a superior nucleus , a lateral nucleus , medial nucleus, and inferior nucleus all nuclei are situated in the pons except the inferior nucleus which is situated at the upper part of the medula. Still in the pons are the cochlear nuclei which also has posterior cochlear nuclei which is posterior to the inferior cerebellar poduncles , also the ventral cochlear nuclei is anterior to the inferior cerebellar poduncles. At the level of the cortico ponto cerebellar fibers, there are decending motor fibers which move through the cross cerebri and gets to the pontine nuclei which which will send fibers to the middle cerebellar poduncles which connects the cerebellar to the pons then to the cerebellum.^,

I just quickly had to run through the fibers and structures of the Pons, in my next post, I will be discussing Pontine Lesions, where I will be talking about Ventral Pontine Syndrome (Millard Gubler Syndrome) where I will look at the structures of the pons and the lession at the ventreal aspect of the pons which is the base of the pon and these structures includes the pontine nuclie, the middle cerebellar poduncle, and the corticospinal fibers. The Foville Syndrome which affects the ventral aspect of the pons and the tegmentum, Ventromedial pontine syndrome (Raymond Syndrome), Lateral Pontine Syndrome, and locked-in Syndrome.

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