Medulla
How long is the Medulla?
3cm
How long is the Pons?
2.5cm = 1 inch.
In what Notch does the midbrain lie?
Tentorial Notch of Tentorium Cerebelli.
Mention its position.
In Post. Cranial Fossa
Below Tentorium Cerebelli.
What Nerve exits the antero-lateral sulcus?
Hypoglossal (12th) Nerve
Mention depressions of Pons.
Ventro-laterally=
1. Basilar Groove-basilar artery.
2. Sulcus Limitans.
3. Sup. Fovea
What is Corpora Quadrigemina? Mention one structure related to them.
It's the 4 rounded elevations on the dorsal side of the midbrain.
1. 2 Superior Colliculi = Centers for Visual Reflexes.
2. 2 Inferior Colliculi = Centers for Auditory Reflexes.
The Trochlear Nerve emerges below the Inferior Colliculus.
Mention its blood supply.
1. Sup. Cerebellar Artery = from Basilar Artery.
2. Ant. Inf. Cerebellar Artery = from Basilar Artery.
3. Post. Inf. Cerebellar Artery = from Vertebral Artery.
Mention nerves exitting the postero-lateral sulcus.
Glossopharyngeal (9th) - Vagus (10th) - Accessory (11th)
Mention the elevations of Pons.
Ventrally:
1. Transverse Pontine Fibers- that for the middle cerebellar peduncle.
Dorsally:1. Medial Eminence- which at its end forms facial colliculus- produced by abducent nucleas and encircling facial nerves.
2. Upper Vestibular Eminence- overlies Sup., Lat. and upper half of Med. Vestibular Nuclei.
What is found between the two cerebral peduncles?
Interpeduncular fossa which contains:
1. Post. perforated substance
2. Occulomotor N.
Mention Lobes of Cerebellum.
1. Ant. Lobe = In front of Primary Fissure on Sup. Surface.
2. Post. Lobe = B/w Primary and Postero-lateral fissures, on both Sup. and Inf. Surfaces.
3. Flocculo-Nodular Lobe = 2 Flocculi + Brachii + Nodule, Ant. to Postero-lateral Fissure on Inf. Surface.
Mention all depressions of medulla.
Ventro-laterally=
1. Ant. Median Fissure
2. Antero-lateral Sulcus
3. Postero-lateral Sulcus.
Dorsally:
1. Post. Median Sulcus
2. Vertical Median Sulcus
3. Inf. Fovea.
Mention cranial nerves in Pons.
1. Trigeminal (5th) Nerve = front of pons.
2. Abducent (6th) Nerve = sulcus b/w pyramid and pons.
3. Facial (7th) and vestibulo-cochlear (8th) nerves = cerebello-pontine angle.
What are the peduncles of the midbrain?
1. Cerebral peduncles = [Ventral] 2 large bundles of nerve fibers emerging from pons that ascend and diverge to enter cerebral hemispheres.
2. Sup. Cerebellar peduncles = [Dorsal] 2 bundles of nerve fibers running downwards and laterally to enter cerebellum.
Mention Fissures of Cerebellum.
1.Primary Fissure = b/w Culmen and Declive + b/w Ant. and Post. Lobes on Sup. Surface.
2. Horizontal Fissure = b/w Sup and Inf. Surfaces.
3. Secondary Fissure = b/w Uvula and Pyramid of Inf. Vermis on Inf. Surface.
4. Postero-Lateral Fissure = b/w Flocculo-Nodular Lobe and Inf. Surface.
5. Retro-Tonsillar Fissure = b/w Cerebellar Tonsil and rest of cerebellum.
Mention all elevations of Medulla. 😇
Ventro-laterally:
1. Pyramid-Pyramidal Tract
2. Olive-Inf. Olivary Nucleus
Dorsally:
1. Gracile-Gracile Nucleus
2. Cuneate-Cuneate Nucleus
3. Tuberculum Cinereum-Spinal Nucleus of Trigeminal
4. Hypoglossal Trigone-Hypoglossal Nucleus
5. Vagal trigone-Vagas Dorsal Nucleus
6. Lower vestibular eminence-Inferior and lower half of Medial Vestibular Nuclei.
What are the structures crossing the Lat. Surfaces of midbrain?
1. Optic Tract and Trochlear Nerve.
2. Sup. Cerebellar and Post. Cerebral Arteries.
3. Basilar Vein.