Download Medulla Oblangata (Bulbus)

Medulla Oblongata
(bulbus/medulla)
Prof. Dr. Selda Önderoğlu
Medulla Oblongata
• The most inferior
part of brain stem.
• It is like the
widening of spinal
cord upwards.
surfaces of Medulla oblongata
• Anterior
• posterior
structures on the anterior surface
(from midline laterally)
-Ant. Median fissure
-Pyramid
-pyramidal
Decussation
-Anterolateral Sulcus
exits:Hypoglossal N.
-Olive
-Retroolivary
Sulcus
Exits:
Glossophryngeal N.
vagus N.
accessory N.
Posterolateral surface of
Medulla oblongata
• glossopharyngeal
•
•
•
N.
Vagus N.
Accessory N.
inferior cerebellar
Peduncle
Inferior Cerebellar Peduncle
connects medulla to cerebellum
Contains fibers of:
• post. Spinocerebellar
Tract
• Some fibers of ant.
Spinocerebellar tr.
• cuneocerebellar tr.
• Olivocerebellari tr.
• vestibulocerebellar tr.
• fibers from cerebellum
to vestibular&reticular
nuclei
Posterior surface of Medulla Oblangata is
the lower triangle of rhomboid fossa
Rhomboid Fossa
• Is the space bw.
•
Medulla+pons&cereb
ellum.
Filled with
cerebrospinal fluid
• Lower triangle is
•
related to: medulla
oblongata
Upper triangle to:
pons
inferior part of post. Surface of Medulla
Oblongata-from midline laterally has
• posterior median
•
•
•
•
Sulcus
Fasciculus gracilis
Tuberculum
gracilis(medial)
Tuberculum cuneatus
(lateral)
Fasciculus cuneatus
Superior part of post. Surface of Medulla
oblangata
( Rhomboid fossa’s lower triangle)
From midline
laterally has:
• post. median
sulcus
• Medial Eminence
• Sulcus limitans
• vestibular Area
• Stria medullaris
Vestibular Nuclei
• 4 vestibular nuclei
1- superior
2- inferior
3-medial
4-lateral
Medial&inferior are
at bulbus level
Cranial nerves emerging from
medulla oblongata
• Last 4 cranial nn.
• glossopharyngeal
•
•
•
n. (9)
Vagus n. (10)
Accessory n. (11)
Hypoglossal n. (12)
Cranial nerve Nuclei in
brainstem
Nuc. ambiguus
• It is the The motor
nucleus of
• glossopharyngeal n.
• Vagus n.
• Cranial part of
accessory nerve
the nuclei of those 3
nn. Unite and form
the nucl. Ambiguus
Spinal tract and nucleus of
Trigeminal nerve
• Related to pain and
temperature sensation
carried from head and
neck regions.
• Located at pons, medulla
and upper 1-2 segments
of spinal cord.
• At medulla level it is
located posterolaterally
• Nuc. spinalis nervi
trigemini bu tractus’un
medialinde bulunur.
Solitary Tract Nucleus
Dorsal Nucleus of Vagus Nerve
Inferior Salivatory Nucleus
Brain stem (Cranial nerves)
• Bulbus
Reticular Nuclei at medulla level
• Nuc. reticularis lateralis
• Nuc. reticularis ventralis
• Nuc. reticularis
•
•
•
gigantocellularis
Nuc. reticularis
parvocellullaris
Nuc. reticularis
paramedianus
Nuclei raphes
– Nn. raphes obscurus
– N. raphes pallidus
– N. raphes magnus
Internal structure of Medulla Oblongata
(transverse section at lower levels)
Pyramidal Decussation
Fasciculus gracilis
Fasciculus cuneatus
Transverse section at the level
of pyramidal decussation
• Nuc. cuneatus
• Nuc. Gracilis
• Spinal tract&
nucleus of
trigeminal nerve
Transverse section through the
inferior level of olive
• Cuneate nucleus
• Accessorius
•
•
•
cuneate nucleus
Nucleus gracilis
Spinal tract&
nucleus of
trigeminal nerve
lateral reticular
Nucleus
Transv.Section through the level
of inferior olivary complex
principal olivary nuc.
Nuc.olivarius accessorius
posterior
Nuc. olivarius accessorius
med.
accessory cuneate
Nuc.
Transv.Section through upper
levels of medulla
• Medial vestibular
•
•
•
•
•
•
nuc.
ınf. vestibular nuc.
Gigantocellullar
reticular nuc.
Dorsal cochlear
nuc.
inferior olivary nuc.
Pyramis
Vagus nerve
Transv. Section at teh junction
of medulla and Pons
• 4th Ventricle
• Cerebellar nuclei
• inf. cerebellar
•
•
•
Peduncle
Ventral& dorsal
cochlear Nuc.
medial Lemniscus
Arcuate Nuc.