Exam 1 (Lecture 5) - Pons Flashcards
What neural tube structure is the pons derived from?
Metencephalon
What other structure is derived from the metencephalon?
Cerebellum
What ponsilar structures are visible on the dorsal pons?
1) Cerebellar peduncles
2) Tegmentum
Which tracts originate in the pons? Where do they go?
Motor tracts (basilar pons); they go to the motor cortex and to the spinal cord
What are the branches of the trigeminal nerve?
1) Ophthalmic branch/nerve (V1)
2) Maxillary branch/nerve (V2)
3) Mandibular branch/nerve (V3)
The nucleus of which nerve originates in the pons?
The motor nucleus of the trigeminal nerve
What region of the face does the ophthalmic nerve provide sensory innervation to?
The area just dorsal to the eye.
What region of the face does the maxillary nerve provide sensory innervation to?
From the tip of the nose, caudally to just behind the eye area and ventral to the level of the superior cheek teeth.
What region of the face does the mandibular nerve provide sensory innervation to?
The mandible ventrally and from the base of the ear ventrally (the rest of the skull not innervated by the other two nerves).
Information from the branches of the trigeminal nerve responsible for touch and pressure travel through the trigeminal ganglion to which nucleus?
Pontine nucleus of the trigeminal (in the pons).
Information from the branches of the trigeminal nerve responsible for proprioception travel through the trigeminal ganglion to which nucleus?
Nucleus of the mesencephalic tract of the trigeminal (in the midbrain).
Information from the branches of the trigeminal nerve responsible for information from painful stimuli travel through the trigeminal ganglion to which nucleus?
Nucleus of the spinal tract of the trigeminal (in the medulla).
If you stick a pen in the L nostril of a dog and it illicits no response, what is your potential anatomical diagnosis?
A problem with the L maxillary nerve that’s responsible for touch and pressure. This would indicate a potential lesion in the pontine nucleus.
What are the muscles of mastication and which nerve are they innervated by?
1) Masseter muscle
2) Temporalis muscle
3) Digastricus muscle
4) Pterygoideus medialis muscle
They are innervated by the mandibular nerve. (Motor nucleus of the trigeminal).
What is your anatomical diagnosis in a patient that presents unable to close his jaw and unresponsive to pain/pressure applied to the maxillary region?
The jaw is open (digastrics muscle) and can’t close (temporals muscle); so there is potentially a bilateral problem with the mandibular branch of the trigeminal. The motor nucleus is affected/lesioned. Since the patient was also unresponsive to the pain/pressure stimulus applied to the maxillary region, there is also a problem with the maxillary branch of the trigeminal.
