Cranial Fossa:
Brain and Spinal Cord
PA 481 A&P
Tony Serino, Ph.D.
Biology Dept.
Misericordia Univ.
Central Nervous System (CNS)
• Gray vs. White matter
• Protection of CNS
– Meninges
– CSF flow
• Brain
– Development
– Selected structures
• Spinal cord
– Selected structures
Cranial Fossa
Anterior
Middle
Posterior
CNS (Central Nervous System)
• Brian and spinal cord
• Displays gray and white matter
– Gray matter are areas of CNS with many cell
bodies of neurons present (little myelinated
nerve fibers)
– White matter are area of CNS with few cell
bodies but many myelinated nerve fibers
• Protected by bone and membranes
Gray and White Matter
• Since the cerebrum and
cerebellum outgrow
their cores, gray matter
ends up on outside of
both structures.
Meninges
• Dura Mater –outermost; tough, fibrous CT
– In brain, divided into two layers (periosteal and
meningeal)
– In spine, only one layer with fat filled space
above the layer called the epidural space
• Arachnoid –middle; web-like appearance
– Potential space between Dura and arachnoid is
the subdural space
• Pia Mater –innermost, delicate membrane
fused with CNS surface
– Space between Pia and Arachnoid is the
subarachnoid space
Meninges of the Spinal Cord
Epidural space
Subdural space
Pia mater
Arachnoid
Dura mater
Meninges
Subarachnoid space
Dorsal Root
Ganglion
Centrum
Brain Meninges
Extensions of Dura Mater
hold brain in cavity
Sellar diaphragm (not shown)
Venous Sinuses of Cranium
Superior Sagittal
Inf. Sagittal
Straight
Transverse
Sigmoid
Cavernous
Lateral Venous Lacunae
Arachnoid villi
Middle Meningeal Artery
Middle Meningeal A.
Maxillary A.
Brain Ventricles
Choroid Plexus
CSF (cerebral-spinal fluid) Flow
Hydrocephalus
• Blockage of CSF flow
can lead to severe
brain and/or head
enlargement.
• In an adult, such
swelling would be
fatal.
Brain
• Development
• Structures
• Functional Areas
Neural
Tube
forming
Neural Tube
Brain Vesicles
Flexures and Cerebral Cortex Growth
Major Divisions of Brain
Brain Stem = midbrain + pons + medulla
Brain Anatomy (req’d)
Projections vs. Commissures
Functional Anatomy of Brain
Functional Areas of Cerebrum
Primary Motor and Somatosensory Gyri
Basal Nuclei: cerebral nuclei
Putamen and
Globus Pallidus
Subthalamic nuclei and
the Substantia nigra are
usually included
Reticular Formation
Extends along length of brain stem; used in maintaining alertness
while awake; also includes motor nuclei such as centers for Cardiac,
Respiratory and Vasomotor control.
RAS receives inputs from eye, ear and genral
sensation to maintain alertness
Limbic System: functional system;
responsible for emotion and memory
Cingulate Gyrus
Fornix
Mammillary body
Hypothalamus Control of Pituitary
Posterior Pituitary
Anterior Pituitary
Pineal Gland
• Plays a major role in
circadian rhythm
control through its
sympathetic
connection to the
hypothalamus
• Melatonin increases at
night and decreases
during daylight
• Implicated in the
control of major life
changes (such as the
onset of puberty and
adulthood
Internal Carotid Artery
Blood Supply
(Circle of Willis)
Ant. Cerebral
Ant. Communicating
Middle Cerebral
Internal Carotid A.
Post. Communicating
Post. Cerebral
Basilar A.
Vertebral A.