Stalk Like. Stalk Like. Connects: Connects: Narrow Spinal Cord with the Expanded Fore Brain. Narrow Spinal Cord with the Expanded Fore Brain. Occupies: Occupies: Posterior Cranial Fossa. Posterior Cranial Fossa. Lies Against: Lies Against: Basilar part of Occipital Bone. Basilar part of Occipital Bone. Largely Covered by: Cerebellum. Largely Covered by: Cerebellum.

MEDULLA OBLONGATA PONS MID BRAIN

BULB. BULB. Entering Fibers: Entering Fibers: Cortico Bulbar. Cortico Bulbar. Syndromes Associated: Syndromes Associated: Pseudo Bulbar Palsy. Pseudo Bulbar Palsy. Bulbar Palsy. Bulbar Palsy.

(1) A conduit for: (1) A conduit for: Ascending and Descending tracts between the Spinal Cord and the Higher Centers in the Forebrain. Ascending and Descending tracts between the Spinal Cord and the Higher Centers in the Forebrain. (2) Contains: (2) Contains: A. Cranial Nerve Nuclei (111-x11). A. Cranial Nerve Nuclei (111-x11). B. Reflex Centers for Respiratory and Cardiovascular systems. B. Reflex Centers for Respiratory and Cardiovascular systems. (3) Controls over: Level of Consciousness

The Ventral Median Fissure The Ventral Median Fissure Divides it into Two Halves. Divides it into Two Halves. Each Half Presented the following : Each Half Presented the following :

A Longitudinal Elevation along the side of the fissure. A Longitudinal Elevation along the side of the fissure. The pyramids are composed of: The pyramids are composed of: Bundles of Nerve Fibers (Corticospinal). Bundles of Nerve Fibers (Corticospinal). They originate from Large Nerve Cells in the Motor Cerebral Cortex. They originate from Large Nerve Cells in the Motor Cerebral Cortex.

The Pyramids Taper Inferiorly. The Pyramids Taper Inferiorly. The Majority of the Descending Fibers (75-90%) Cross Over to the opposite side. They form The Majority of the Descending Fibers (75-90%) Cross Over to the opposite side. They form Decussation of the Pyramids. Decussation of the Pyramids. It partially obscures the ventral fissure. It partially obscures the ventral fissure.

Oval Elevation. Lateral to the Upper Part of the Pyramid. Produced by The underlying Inferior Olivary Nucleus It is Important in the Control of Movement.

1. Hypoglossal (12 TH) nerve: 1. Hypoglossal (12 TH) nerve: Between the Pyramid and Olive. Between the Pyramid and Olive. 2. Glossopharyngeal, Vagus and Cranial part of Acessory (9, 10 and11 TH) nerves : 2. Glossopharyngeal, Vagus and Cranial part of Acessory (9, 10 and11 TH) nerves : Between the Olive and the Inferior Cerebellar Peduncle. Between the Olive and the Inferior Cerebellar Peduncle.

The Anterior surface is Convex from side to side. The Anterior surface is Convex from side to side. It shows: It shows: Basilar Sulcus : Basilar Sulcus : A Median Groove which lodges the Basilar Artery. A Median Groove which lodges the Basilar Artery. Many Transverse Pontocerebellar Fibers. Many Transverse Pontocerebellar Fibers. They are collected Laterally to form the Middle Cerebellar Peduncles. They are collected Laterally to form the Middle Cerebellar Peduncles.

1. Trigeminal (5 th ) nerve: 1. Trigeminal (5 th ) nerve: Attached to the side of the Pons near its upper border. Attached to the side of the Pons near its upper border. It has Two Roots: It has Two Roots: Large Sensory. Large Sensory. Small Motor. Small Motor. Motor root is Antero Medial to the Sensory root. Motor root is Antero Medial to the Sensory root.

2. Abducent (6 th ) nerve: 2. Abducent (6 th ) nerve: Between the Lower border of the Pons and the Pyramid. Between the Lower border of the Pons and the Pyramid. 3. Facial (7 th ) nerve : 3. Facial (7 th ) nerve : Between the Lower border of the Pons and the Inferior Cerebellar Peduncle. Between the Lower border of the Pons and the Inferior Cerebellar Peduncle. 4. Vestibulo cochlear (8 th ) nerve : 4. Vestibulo cochlear (8 th ) nerve : Lateral to the Facial. Lateral to the Facial. The vestibular nerve is anterior to the cochlear. The vestibular nerve is anterior to the cochlear.

It is the : It is the : Massive Basis Pedunculi (Crura Cerebri). Massive Basis Pedunculi (Crura Cerebri). The Crura are made by: The Crura are made by: Corticobulbar. Corticospinal Fibers. Corticobulbar. Corticospinal Fibers.

Separates the Cerebral Peduncles. Separates the Cerebral Peduncles. Boundaries: Boundaries: Inferiorly : Inferiorly : Pons. Pons. Anteriorly : Anteriorly : Optic Chiasma. Optic Chiasma. Laterally: Laterally: Optic Tracts. Optic Tracts. Posterolaterally: Posterolaterally: Cerebral Peduncles. Cerebral Peduncles.

Oculo motor (3 rd ) nerve : Oculo motor (3 rd ) nerve : At the medial side of the cerebral peduncle. At the medial side of the cerebral peduncle.

Closed (Lower) Medulla It is the Continuation of the Posterior Surface of the Spinal Cord. Closed (Lower) Medulla It is the Continuation of the Posterior Surface of the Spinal Cord. Posterior Median Sulcus divides it into two halves. Posterior Median Sulcus divides it into two halves.

Gracile Tract: Gracile Tract: A Longitudinal Column on both sides of the Median Sulcus. A Longitudinal Column on both sides of the Median Sulcus. Superiorly: Superiorly: It expands. It expands. It ends in the Gracile Tubercle (produced by the underlying (Gracile Nucleus). It ends in the Gracile Tubercle (produced by the underlying (Gracile Nucleus). Cunate Tract and Tubercle : Cunate Tract and Tubercle : Lateral to the Gracile Tract and Tubercle respectively. Lateral to the Gracile Tract and Tubercle respectively.

Forms the Lower 1/3 of the Floor of the Fourth Ventricle. Forms the Lower 1/3 of the Floor of the Fourth Ventricle. Divided by the Median Sulcus into two halves. Divided by the Median Sulcus into two halves. Has an inverted (V) Shaped Depression (Inferior Fovea). Has an inverted (V) Shaped Depression (Inferior Fovea). The Fovea separates: Motor nuclei (Medial) from Sensory nuclei (Lateral). The Fovea separates: Motor nuclei (Medial) from Sensory nuclei (Lateral).

Medial : Medial : Hypoglossal Nucleus. Hypoglossal Nucleus. Lateral : Lateral : Vestibular Nucleus. Vestibular Nucleus. At the Fovea : At the Fovea : Nuclear Complex (Glossopharyngeal and Vagus nerves). Nuclear Complex (Glossopharyngeal and Vagus nerves). The Fovea represents the Sulcus Limitans of the Spinal Cord. The Fovea represents the Sulcus Limitans of the Spinal Cord.

Forms the Upper 2/3 of the Floor of the 4 th Ventricle. Forms the Upper 2/3 of the Floor of the 4 th Ventricle. Hidden by the Cerebellum. Hidden by the Cerebellum. Widest at the Pontomedullary junction. Widest at the Pontomedullary junction. Lateral Aperture (Foramen of Luschka): Lateral Aperture (Foramen of Luschka): Allows passage of CSF from the 4 TH ventricle to the Subarachnoid space around the brain. Allows passage of CSF from the 4 TH ventricle to the Subarachnoid space around the brain.

Divided into Symmetrical Halves by the Median Sulcus. Divided into Symmetrical Halves by the Median Sulcus. Medial Eminence: Medial Eminence: An Elongated Elevation Lateral to the Sulcus. An Elongated Elevation Lateral to the Sulcus. Facial Colliculus: Facial Colliculus: The Inferior Expanded end of the Eminence. The Inferior Expanded end of the Eminence. Produced by the fibers of the Facial Nerve winding around the Abducent Nucleus. Produced by the fibers of the Facial Nerve winding around the Abducent Nucleus.

Vestibular Area Vestibular Area Lateral to the Medial Eminence. Lateral to the Medial Eminence. Produced by the underlying Vestibular Nuclei. Produced by the underlying Vestibular Nuclei.

Corpora Quadregimina Four Rounded Colliculi Divided into Superior and Inferior Pairs. Corpora Quadregimina Four Rounded Colliculi Divided into Superior and Inferior Pairs. Superior Colliculi: Centers of Visual Reflexes. Superior Colliculi: Centers of Visual Reflexes. Inferior Colliculi: Lower Auditory Centers. Inferior Colliculi: Lower Auditory Centers. The Cerebral Aqueduct traverses through the length of the mid brain. The Cerebral Aqueduct traverses through the length of the mid brain.

Trochlear Nerve Trochlear Nerve It is the Only cranial nerve that can be identified in the dorsal aspect of brain stem. It is the Only cranial nerve that can be identified in the dorsal aspect of brain stem. It emerges in the midline. It emerges in the midline. Caudal to the Inferior Colliculs. Caudal to the Inferior Colliculs.

Superior. Superior. Middle. Middle. Inferior Peduncles. Inferior Peduncles. Connect Cerebellum to : Connect Cerebellum to : Mid brain. Mid brain. Pons. Pons. Medulla. Medulla.

Middle. Middle. Inferior Cerebellar Peduncles. Inferior Cerebellar Peduncles. Olive. Olive. Pyramid. Pyramid. Attached Cranial Nerves. Attached Cranial Nerves.