Anatomy: Brainstem and CN (Pons) Flashcards
How is the pons different to the midbrain and the medulla?
There is no central canal in pons (but there is in the midbrain and medulla)
The pons is related posteriorly to, and opens up into the 4th ventricle
CN5 emerges from the ventral surface
Label the external features of the pons
The cerebellum is connected to the brainstem by…
The cerebellum is connected to the entire brainstem by three peduncles:
Superior cerebellar peduncle (midbrain)
Middle cerebellar peduncle (pons)
Inferior cerebellar peduncle (medulla)
Label the anterior surface of the brainstem, specifically focusing on the pons
Label the external features of the pons
Label the posterior brainstem
What are the internal features of the pons and what is it divided into?
Label the vertical and transverse fibres, and the pontine nuclei on the basilar part of the pons
On the tegmental pons, label:
The peduncles, the lemniscii and the Trapezoid body
Label:
Medial longitudinal fasciculus
Reticular formation
Tectospinal tract
Rubrospinal tract
Label the CN nuclei locations on the pons
Label which nuclei are found in the lower pons
Use this diagram to show what neurobiotaxis is
The facial nucleus winds around the abducent nuclei, then emerges between the spinal nucleus of the trigeminal nerve and the facial nuclei. (the blue line)
This is called neurobiotaxis = a nerve tends to migrate to the region that its going to innervate.
So if the facial and spinal nucleus of the trigeminal nerve are both related to the sensations and muscles of the face, the nerve tries to move towards that.
Which nuclei are found in the upper pons?
Motor nucleus of trigeminal nerve to muscles of mastication
Sensory nucleus of trigeminal nerve for touch and
pressure- fibres are 2nd order neurons that decussate and
ascend as the trigeminal lemniscul to the VPM thalamus
Mesencephalic trigeminal nerve nucleus for proprioception
Describe the ascending acoustic pathway
The cochlear nerve decussates in the cochlear nucleus. The fibres then go to opposite sides to the superior olivary nucleus. These decussating fibres form the trapezoid body.
From the superior olivary nucleus, the fibres ascend to reach the inferior colliculus (midbrain). This tract is called the lateral lemniscus.
Fibres from the inferior colliculus travel up to the thalamus and then to the acoustic areas.
Describe the 4 nuclei related to the facial nerve
Motor nucleus of Facial nerve: branchiomotor fibres for the muscles of 2nd arch
Superior salivatory nucleus: Preganglionic secretomotor fibres for lacrimal, submandibular, sublingual salivary glands, glands of palate and nasal cavity
NTS: Taste sensation from anterior 2/3rd of tongue
Spinal nucleus of trigeminal nerve: Sensation from the concha of auricle and external acoustic meatus
arterial supply to the pons?
What is the corneal reflex pathway?
The corneal reflex causes both eyes to blink in response to tactile stimulation of the cornea
Pathway: Inputs are detected by trigeminal primary afferent fibers. These primary afferents synapse on secondary afferents in the spinal trigeminal nucleus, which send axons to reticular formation interneurons. These interneurones–> bilateral facial nuclei which sends axons through the facial nerve to the orbicularis oculi muscle, which lowers the eyelid.
Millard - Gubler syndrome?
Pontocerebellar syndrome?
What type of tumour affects the cerebellar pontine angle?
What is pontine haemorrage?
Fatal bleeding within the pons
