Gross anatomy of the brainstem and cerebellum Fourth
Gross anatomy of the brainstem and cerebellum Fourth ventricle Dr Gallatz. Katalin
The brain n Telencephalon n Diencephalon n Cerebellum n Brainstem
Parts of the brainstem n Mesencephalon n Pons n Medulla
Ventral surface of the hypothalamus and brainstem 1. cerebral peduncle 3 2. interpeduncular fossa 1 2 3. optic tract pons 5 medulla 5
Dorsal surface of the diencephalon and brainstem sc – superior colliculus, ic – inferior colliculus, scp – sup. cerebellar peduncle thalamus sc ic pons medulla scp
Brain Stem Midbrain Cranial Nerve III. , IV. n pupillary reflex n eye movements
The midbrain or mesencephalon (from the Greek mesos – middle, and enkephalos) - is associated with vision, hearing, motor control, pain control, sleep/wake, and temperature regulation
Parts of the mesencephalon TECTUM inferior colliculi superior colliculi CEREBRAL PEDUNCLE tegmentum crus cerebri TECTUM TEGMENTUM
Midbrain - Mesencephalon Ventral surface n n n Cerebral peduncle(1) Interpeduncular fossa (2) oculomotor nerves (3) Posterior perforated substance 1 2 3
Midbrain - Mesencephalon trochlear n. Dorsal surface n Superior colliculus (1) centers for visual reflexes n Inferior colliculus (2) associated with auditory pathway n Brachium of superior colliculus n LGB n Brachium of inferior colliculus MGB scp
Brainstem PONS Cranial nerves V. , VII.
Parts of the pons tegmentum – dorsal surface base –venral surface
pontine tegmentum base
Pons Ventral surface n n Basilar sulcus Pontomedullary junction: from medial to lateral, VIII nerves Middle cerebellar peduncle n n Trigeminal nerve Pontocerebellar trigone: the junction of medulla, pons and cerebellum
Pons Dorsal surface – rostral part of the rhomboid fossa part n Medial eminence (1) n Facial colliculus (2) n Locus ceruleus (3) 1 2 3
Brain Stem Medulla Cranial Nerves IX, X, XII n Pharyngeal (Gag) Reflex n Tracheal (Cough) Reflex Cardiovascular, respiratory centers
Parts of the medulla opened part – rostral part – fourth ventricle closed part – caudal part - central canal dorsal surface ventral surface
Medulla n n Pyramid: contain pyramidal tract (corticospinal tract) Decussation of pyramid: formed by crossing fibers of corticospinal tract Olive: inferior olivary nucleus Medial parolivary sulcus hypoglossal nerve XII Lat. parolivary sulcus: glossopharyngeal, vagus accessory nerves IX, X. , XI. , ventral surface
Medulla Dorsal surface Caudal portion • Gracile tubercle • Cuneate tubercle • Inferior cerebellar peduncle • Obex Rostral portion: • forms the caudal half of rhomboid fossa • hypoglossal and vagal trigones X XII
Fourth ventricle Position n Situated ventral to the cerebellum, and dorsal to the pons and cranial half of medulla
FLOOR OF THE IV. VENTRICLE RHOMBOID FOSSA Inferolateral: inferior cerebellar peduncle Superolateral: superior cerebellar peduncle n Lateral recess
Rhomboid fossa n n n Facial colliculus, medial eminence Hypoglossal triangle hypoglossal nucleus Vagal triangle: dorsal nucleus of vagus nerve Funiculus separans Area postrema: blood –brain barrier free Locus ceruleus: noradrenerg area
Roof of the fourth ventricle n n n Anterior part: formed by superior cerebellar peduncle and superior medullary velum Posterior part: formed by inferior medullary velum, tela choroidea and choroid plexus of IVth ventricle Three apertures Median aperture (Magendi) Two lateral apertures (Luschka)
Position of the cerebellum n It lies in the posterior cranial fossa n The tentorium cerebelli separates it from the occipital lobe of the cerebrum
Cerebellar peduncles - superior cerebellar peduncle (1) 1 connects it with medulla 2 - middle cerebellar peduncle (3) connects it with pons, - inferior cerebellar peduncle (2)- connects it with midbrain, 3
External features Consists of two cerebellar hemispheres united in the midline by the vermis
Lobes and fissures of the cerebellum n Fissures • Primary fissure • Horizontal fissure • Posterior fissure n Three lobes • Flocculonodular lobe flocculus and nodulus • Anterior lobe • Posterior lobe
MIDSAGITTAL SECTION: VERMIS, IV. VENTRICLE
Internal structures Cerebellar nuclei Fastigial nucleus Globose nucleus Dentate nucleus Emboliform nucleus Cerebellar cortex
Functional divisions n Cerebrocerebellum • Neocerebellum • Lateral zone n Spinocerebellum • Paleocerebellum • Vermis and intermediate zone Intermediate zone Vermis n Vestibulocerebellum • Archicerebellum • Flocculonodular lobe
REVISION
EARLY DEVELOPMENT OF THE BRAIN VESICLES Cavity of the telencephalon become the lateral ventricles. Cavity of the diencephalon becomes the third ventricle. Cavity of mesencephalon becomes the cerebral aueduct. Cavity of rhombencephalon become the fourth ventricle.
Myelencephalon
Development of the brain
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