Brain–Neuroanatomy
1. Introduction 3
2. Meninges of the Brain and Cerebrospinal Fluid 25
3. Spinal Cord 34
4. Cranial Nerves 56
5. Brainstem 100
6. Cerebellum 117
7. Fourth Ventricle 128
8. Cerebrum, Diencephalon, Basal Nuclei and White Matter 134
9. Third Ventricle, Lateral Ventricle and Limbic System 168
10. Some Neural Pathways and Reticular Formation 179
11. Blood Supply of Spinal Cord and Brain 185
12. Investigations of a Neurological Case, Surface and Radiological Anatomy 200
and Evolution of Head
13. Autonomic Nervous System 205
Appendix: Ventricles, Cranial Nerves, Arteries and Clinical Terms 215
, Ichchak dana, beechak dana, dane upar dana
Hands naache, feet naache, brain hai khushnama
Ichchak dana
Seventh ka nucleus ghoom kar aaye fifth ke pass,
nucleus ambiguus laterally jaye
Spinal accessory neeche ko aaye,
motor sensory pass ho jayen,
kaisa aashikana—ichchak dana
Bolo kya—Neurobiotaxis, bolo kya—Neurobiotaxis
, 1
Introduction
The capacity of the mind is as great as that of space .
—Wei Lang
Nervous system is the chief controlling and co- coordinating the sensory information and ordering
ordinating system of the body. appropriate motor actions. CNS is the seat of
It is responsible for judgement, intelligence and learning, memory, intelligence and emotions.
memory. Nervous system is highly evolved at the cost
2 Peripheral nervous system (PNS) includes 12 pairs of
of regeneration.
It is the most complex system of the body. cranial nerves and 31 pairs of spinal nerves. These
It adjusts the body to the surroundings and regulates provide afferent impulses to CNS and carries
all bodily activities both voluntary and involuntary. The efferent impulses to muscles, glands and blood
sensory part of the nervous system collects information vessels (Flowchart 1.1).
from the surroundings and helps in gaining knowledge
and experience, whereas the motor part is responsible FUNCTIONAL
for responses of the body. Peripheral nervous system functionally has two
Average weight of adult brain in air is 1500–2000 components:
grams. Since brain floats in cerebrospinal fluid, it only
1 Afferent component provides sensory information to
weighs 50 grams which is comfortable.
CNS.
There are about 180–200 billion neurons in an adult
brain (very rich). 2 Efferent component carries motor information to
muscles, glands, blood vessels and heart via:
DIVISIONS OF NERVOUS SYSTEM a. Somatic nervous system for the control of skeletal
muscles.
ANATOMICAL b. Autonomic nervous system for control of heart,
It is divided into: smooth muscle of the organs, glands and blood
1 Central nervous system (CNS) which comprises brain vessels. It is subdivided into sympathetic and
and spinal cord. It is responsible for integrating, parasympathetic parts.
Flowchart 1.1: Divisions of nervous system
3
, BRAIN–NEUROANATOMY
4
CELLULAR ARCHITECTURE second. A neuron shows dynamic polarity in its
processes. The impulse flows towards the cell body in
The nervous tissue is made up of: the dendrites, and away from the cell body in the axon
1 Nerve cells or neurons (Fig. 1.1). (Fig. 1.1).
2 Neuroglial cells (neuroglia), forming the supporting
(connective) tissue of the CNS. In peripheral nervous Classification of Neurons
system, these are replaced by Schwann’s cells. According to the Number of their Processes
Both types of cells are supplied by abundant blood 1 Multipolar neurons. Most of the neurons in man are
vessels. multipolar, e.g. all motor and internuncial neurons
(Fig. 1.1).
NEURON 2 Bipolar neurons are confined to the first neuron of the
Each neuron is made up of the following. retina, ganglia of eighth cranial nerve, and the
1 A cell body: Collectively forms grey matter, the nuclei olfactory mucosa (Fig. 1.2a).
in the CNS, and ganglia in the peripheral nervous 3 Pseudounipolar neurons are actually unipolar to begin
system. with but become bipolar functionally and are found
2 Cell processes of two varieties: in dorsal nerve root ganglia and sensory ganglia of
a. Dendrites (Greek branch of a tree) are many, short, the cranial nerves (Fig. 1.2b).
richly branched and often varicose (Fig. 1.1). 4 Unipolar neurons are present in the mesencephalic
b. The axon is a single elongated process. Collec- nucleus of trigeminal nerve and also occur during
tively the axons form tracts (white matter) in the foetal life. These cells are more common in lower
CNS, and nerves in the peripheral nervous system. vertebrates (Fig. 1.2c).
The branches of axons often arise at right angles According to Length of Axon
and are called the collaterals.
Functionally, each neuron is specialized for sensi- 1 Golgi Type I: These neurons have long axons and
tivity and conductivity. The impulses can flow in them numerous short dendrites. These are seen in pyra-
with great rapidity, in some cases about 125 meters per midal cells of cerebral cortex (Fig. 1.3a), Purkinje cells
of cerebellum and anterior horn cells of spinal cord
(Fig. 1.3b).
Brain–Neuroanatomy
Fig. 1.1: Multipolar neuron Figs 1.2a to c: Types of neurons
1. Introduction 3
2. Meninges of the Brain and Cerebrospinal Fluid 25
3. Spinal Cord 34
4. Cranial Nerves 56
5. Brainstem 100
6. Cerebellum 117
7. Fourth Ventricle 128
8. Cerebrum, Diencephalon, Basal Nuclei and White Matter 134
9. Third Ventricle, Lateral Ventricle and Limbic System 168
10. Some Neural Pathways and Reticular Formation 179
11. Blood Supply of Spinal Cord and Brain 185
12. Investigations of a Neurological Case, Surface and Radiological Anatomy 200
and Evolution of Head
13. Autonomic Nervous System 205
Appendix: Ventricles, Cranial Nerves, Arteries and Clinical Terms 215
, Ichchak dana, beechak dana, dane upar dana
Hands naache, feet naache, brain hai khushnama
Ichchak dana
Seventh ka nucleus ghoom kar aaye fifth ke pass,
nucleus ambiguus laterally jaye
Spinal accessory neeche ko aaye,
motor sensory pass ho jayen,
kaisa aashikana—ichchak dana
Bolo kya—Neurobiotaxis, bolo kya—Neurobiotaxis
, 1
Introduction
The capacity of the mind is as great as that of space .
—Wei Lang
Nervous system is the chief controlling and co- coordinating the sensory information and ordering
ordinating system of the body. appropriate motor actions. CNS is the seat of
It is responsible for judgement, intelligence and learning, memory, intelligence and emotions.
memory. Nervous system is highly evolved at the cost
2 Peripheral nervous system (PNS) includes 12 pairs of
of regeneration.
It is the most complex system of the body. cranial nerves and 31 pairs of spinal nerves. These
It adjusts the body to the surroundings and regulates provide afferent impulses to CNS and carries
all bodily activities both voluntary and involuntary. The efferent impulses to muscles, glands and blood
sensory part of the nervous system collects information vessels (Flowchart 1.1).
from the surroundings and helps in gaining knowledge
and experience, whereas the motor part is responsible FUNCTIONAL
for responses of the body. Peripheral nervous system functionally has two
Average weight of adult brain in air is 1500–2000 components:
grams. Since brain floats in cerebrospinal fluid, it only
1 Afferent component provides sensory information to
weighs 50 grams which is comfortable.
CNS.
There are about 180–200 billion neurons in an adult
brain (very rich). 2 Efferent component carries motor information to
muscles, glands, blood vessels and heart via:
DIVISIONS OF NERVOUS SYSTEM a. Somatic nervous system for the control of skeletal
muscles.
ANATOMICAL b. Autonomic nervous system for control of heart,
It is divided into: smooth muscle of the organs, glands and blood
1 Central nervous system (CNS) which comprises brain vessels. It is subdivided into sympathetic and
and spinal cord. It is responsible for integrating, parasympathetic parts.
Flowchart 1.1: Divisions of nervous system
3
, BRAIN–NEUROANATOMY
4
CELLULAR ARCHITECTURE second. A neuron shows dynamic polarity in its
processes. The impulse flows towards the cell body in
The nervous tissue is made up of: the dendrites, and away from the cell body in the axon
1 Nerve cells or neurons (Fig. 1.1). (Fig. 1.1).
2 Neuroglial cells (neuroglia), forming the supporting
(connective) tissue of the CNS. In peripheral nervous Classification of Neurons
system, these are replaced by Schwann’s cells. According to the Number of their Processes
Both types of cells are supplied by abundant blood 1 Multipolar neurons. Most of the neurons in man are
vessels. multipolar, e.g. all motor and internuncial neurons
(Fig. 1.1).
NEURON 2 Bipolar neurons are confined to the first neuron of the
Each neuron is made up of the following. retina, ganglia of eighth cranial nerve, and the
1 A cell body: Collectively forms grey matter, the nuclei olfactory mucosa (Fig. 1.2a).
in the CNS, and ganglia in the peripheral nervous 3 Pseudounipolar neurons are actually unipolar to begin
system. with but become bipolar functionally and are found
2 Cell processes of two varieties: in dorsal nerve root ganglia and sensory ganglia of
a. Dendrites (Greek branch of a tree) are many, short, the cranial nerves (Fig. 1.2b).
richly branched and often varicose (Fig. 1.1). 4 Unipolar neurons are present in the mesencephalic
b. The axon is a single elongated process. Collec- nucleus of trigeminal nerve and also occur during
tively the axons form tracts (white matter) in the foetal life. These cells are more common in lower
CNS, and nerves in the peripheral nervous system. vertebrates (Fig. 1.2c).
The branches of axons often arise at right angles According to Length of Axon
and are called the collaterals.
Functionally, each neuron is specialized for sensi- 1 Golgi Type I: These neurons have long axons and
tivity and conductivity. The impulses can flow in them numerous short dendrites. These are seen in pyra-
with great rapidity, in some cases about 125 meters per midal cells of cerebral cortex (Fig. 1.3a), Purkinje cells
of cerebellum and anterior horn cells of spinal cord
(Fig. 1.3b).
Brain–Neuroanatomy
Fig. 1.1: Multipolar neuron Figs 1.2a to c: Types of neurons
