The Brain & The Spinal Cord
I- The brain:
1- The Meninges:
Dura Matter
Arachinoid Matter
Pia Matter
2- The forebrain
Cerebrum
Diencephalon
4- The Hind Brain
Pones
Medulla
Cerebellum
II- The spinal cord
3- Midbrain
Midbrain
– Connect the diencephalon
to the pons and lies in the
posterior cranial fossa.
– Consist of right and left
halves each forming the
cerebral peduncle,
– Divided into ventral and
dorsal part with a narrow
cavity running through the
dorsal part, the aqueduct
The Brain & The Spinal Cord
I- The brain:
1- The Meninges:
Dura Matter
Arachinoid Matter
Pia Matter
2- The forebrain
Cerebrum
Diencephalon
3- Midbrain
II_ The spinal cord
4- The Hind Brain
Pones
Medulla
Cerebellum
Hindbrain
• The Pons:
• Lie on the anterior surface of the cerebellum
below the midbrain and above the medulla.
– Fibres
• Composed mainly of:
– nerve fibres connecting the two halves of the
cerebellum
– ascending and descending fibres connecting the
forebrain, midbrain and spinal cord
• The sensory and motor roots of the 5th cranial
nerve
Hindbrain
Pons
• Cells:
– Some serve as relay stations while others
form cranial nerve nuclei.
•
•
•
•
•
•
Pontine nuclei, relay station in the ventral surface
5th – 8th cranial nerves nuclei, dorsal part
Trigeminal, abducent, facial, vestibulotrochlear
Motor nucleus of the 5th nerve, upper pons
Sensory nucleus of the 5th nerve lateral to the motor
Superior salivary nuclei (Parasympathetic), fibres join
nervus intermedius
• Inferior salivary nucleus, fibres join glossopharyngeal N
Hindbrain
Medulla
• Medulla oblongata:
– Conical in shape and lie vertically connecting the
Pons to the spinal cord, passes through foramen
magnum
• Pyramid
– a deep groove in the midline on the ventral surface,
contain the corticospinal fibres.
• Olive
– convex structure, lateral to the pyramid, contain the
inferior salivary nucleus
• Inferior cerebellar peduncle
– behind the olive, connect the medulla to the cerebellum
Hindbrain
Medulla
• Structures:
– Nucleus:
• 9th –12th cranial nerves
– Reticular formation:
• is an irregular mass of cell and fibres that extend up into
the pons and down into the spinal cord
– The cells:
• Cardiac and respiratory centers
• vomiting center
• Chemoreceptor trigger zone communicate with the cardiac
and respiratory centers.
•Cerebellum:
Hindbrain
• Cerebellum:
– Occupy the posterior cranial fossa posterior to
the pons and medulla
– Consist of two hemisphere united in the
midline by the vermis.
• Each hemisphere consist of a small anterior and a
large posterior lobe separated by shallow groove,
primary fissure
– Connected to the midbrain, pons and medulla
by the superior, middle and inferior cerebellar
peduncles
Hindbrain
•Cerebellum:
• Structure:
– Surface layer is the cortex of grey cells, with
white matter internal.
– The cortex is thrown into folds or folia,
separated by transverse fissures
– The dentate nucleus is a mass of grey matter
• Control of muscle tone and co-ordination of
muscle movement on the same side
Hindbrain
• The fourth ventricle:
– Is the cavity of the hindbrain and bounded in front
by the pons and medulla and from behind by the
cerebellum.
– It is connected above to the third ventricle by the
cerebral aqueduct, and below it is continuous with
central canal of the spinal cord.
– It communicate with subarachnoid space by three
openings in the lower part of the roof, a median and
two lateral openings.
The Brain & The Spinal Cord
I- The brain:
1- The Meninges:
Dura Matter
Arachinoid Matter
Pia Matter
2- The forebrain
Cerebrum
Diencephalon
3- Midbrain
4- The Hind Brain
Pones
Medulla
Cerebellum
•II- The spinal cord
The spinal cord
• Is cylindrical in shape, begins at the foramen
magnum and terminate inferiorly at the lower
border of the 1st lumber vertebra.
– Surrounded by the three meninges, Dura,
Arachnoid and Pia matter.
– CSF fills the Subarachnoid space, add protection.
– 31 pairs of spinal nerves are attached to the spinal
cord by an anterior (motor) and posterior
(sensory) roots
The spinal cord(cont)
• Structure:
– Consist of a central mass of grey matter
surrounding a central canal, a downward
continuation of the fourth ventricle, enclosed in a
cylindrical mass of white matter.
– The anterior fissure and the posterior septum
divide the cord into two halves
– Both the grey & white matter are divided into
anterior, lateral and posterior horns & columns of
cells and fibres.
The spinal cord(cont)
– Grey matter:
• H-shaped, enlarged in the cervical and
lumbosacral region due to increase in the
number of the cells in the anterior horn root
– White matter.
• contain three types of fibres, ascending,
descending and intersegmental