Neuroanatomy lecture for the medical students

2.  The cerebrum is divided into 2 parts:
1. Diencephalon: which forms the central
core
2. Telencephalon: which forms the
cerebral hemispheres

5.  It consists of 3rd ventricle & the structures
that form its boundaries which include:
1. Thalamus
2. Subthalamus
3. Epithalamus
4. Hypothalamus
 Diencephalon can be described through its
inferior, superior and lateral surfaces

7.  It is formed by:
1. Hypothalamus
2. Optic chiasma with optic tract on both
sides
3. Infundibulum with the tuber cinerium
4. Mammillary bodies

11.  It is formed by the roof of the 3rd ventricle
(Consisting ependymal cells and its choroid
plexus) which is concealed by the fornix
 The fornix is a thick bundle of fibers
originating into the hippocampus of the
temporal lobe. It arches posteriorly over the
thalamus to join the mammillary body

15.  It is formed by the internal capsule which
consists of the nerve fibers that connect
the cerebral cortex with other parts of
brainstem and spinal cord

17.  The medial surface of the diencephalon is
actually the lateral surface of 3rd ventricle
on each side
 It is formed by the:
1. Medial surface of thalamus above
2. Hypothalamus below
 These two areas are separated from
each other by hypothalamic sulcus

19.  It is large ovoid mass of gray matter forming
the major part of the diencephalon
 It is situated on each side of the 3rd ventricle
 It is cell relay station to all the main sensory
systems (except the olfactory pathway) and
cerebral cortex
 It integrates many visceral & somatic
functions

21.  It is situated on each side of 3rd ventricle
 Its anterior end forms the posterior boundary of
interventricular foramen
 Its posterior end forms pulvinar which
overhangs the superior colliculus, the superior
brachium & LGB
 Its superior surface is covered by the floor of
lateral ventricle
 Its inferior surface is continuous with
tegmentum of midbrain

23.  Medial surface of the thalamus forms the
lateral surface of 3rd ventricle and it is
connected to the opposite thalamus by
interthalamic connection (adhesion)
which is a band of gray matter
 Lateral surface of the thalamus is formed by
the internal capsule which separates it from
the lentiform nucleus

25.  It lies below the thalamus and above the
tegmentum of midbrain
 Craniomedially it is also related to
hypothalamus
 The subthalamic nucleus takes the
connections from the red nucleus and
substantia nigra below
 It is involved in the control of muscle
activity

26.  It consists of:
1. Habenular nuclei & its connections
2. Pineal gland (body)

28.  It is situated posterior to the thalamus
 It is center for integration of olfactory, visceral &
somatic afferent pathways
 It has connections with:
1. Amagdaloid nucleus
2. Hippocampus
3. Fornix
4. Habenular commissure fibers which cross to
the opposite side
5. Interpeduncular nucleus
6. Tectum of midbrain
7. Thalamus
8. Reticular formation

31.  It is a small conical structure attached to
the diencephalon via pineal stalk
 It lies posterior to the midbrain
 It contains two types of cells
1. Pinealocytes
2. Glial cells
 With progressing age, the calcified
material accumulates within the gland,
known as brain sand

33.  It is an endocrine gland
 Pinealocytes produce hormones which
inhibit directly or via hypothalamus, the:
1. Pituitary gland
2. Islets of Langerhans of pancreas
3. Parathyroids
4. Adrenal cortex & medulla
5. Gonads
 Pineal gland does not possess blood-brain
barrier

34.  It exhibits a circadian rhythm that is
influenced by light
 It is full of melatonin and related enzymes
 These are releases into the blood or CSF of
3rd ventricle, then they pass to the anterior
pituitary to inhibit the release of gonadotropic
hormone
 Plasma melatonin level rises in darkness &
falls during the day

35.  It is the part of diencephalon which extends
from the region of optic chiasma to the
mammillary bodies
 It lies below the hypothalamic sulcus on the
lateral wall of 3rd ventricle

36.  Anteriorly: Preoptic area, which extends
from optic chiasma to lamina terminalis &
anterior commissure
 Inferiorly: it merges into the tegmentum of
the midbrain
 Superiorly: thalamus
 Inferolaterally: subthalamus

38.  When observed from below, the
hypothalamus is seen to be related to the
following structures from anterior to posterior
1. Optic chiasma
2. Tuber cinereum & infundibulum
3. Mammillary bodies

40.  It influences almost every activity of the body
 It controles & integrates the functions of:
1. Autonomic nervous system
2. Endocrine system
3. Maintaining body homeostasis
4. Regulation of body temperature & body
fluids
5. Drives to eat and drink, sexual behaviour &
emotion

41.  It lies near the floor of 3rd ventricle
 Superior surface is attached to the lamina
terminalis
 Inferiorly it is related to dhypophysis cerebri,
from which it is separated by diaphragma
sellae
 Anterolaterally connects to optic nerves
 Posterolaterally connects to optic tracts

43.  It is a convex mass of gray matter
 It is continuous inferiorly with infundibulum
 Median eminence is the raised part of tuber
cinereum, which is attached to the
infundibulum
 The median eminence and the posterior lobe
(pars nervosa) of the hypophysis cerebri
together form the neurohypophysis

45.  These are two small hemispherical bodies
situated side by side posterior to the tuber
cinereum
 They possess the central core of gray matter
surrounded by a capsule of myelinated nerve
fibers

47.  It is derived from the forebrain vesicle
 Lies between two thalami
 Its boundaries are:
1. Anterior wall
2. Posterior wall
3. Lateral wall
4. Superior wall
5. Inferior wall

48.  It is formed by the lamina terminalis, across
which runs anterior commissure
 The anterior commissure connects the
right and left temporal lobes
 It is a round bundle of nerve fibers that are
situated anterior to the anterior columns of
the fornix

50.  It is formed by the opening into the cerebral
aqueduct
 Above the duct, there is posterior
commissure
 Above the posterior commissure, there is
pineal recess, which goes to the pineal body
 Above the pineal recess, there is habenular
commissure

51.  It is formed by the medial surface of
thalamus above & hypothalamus below
 Both are separated by hypothalamic sulcus
 The upper limit of the lateral wall is stria
medullaris thalami
 Lateral walls are joined by the interthalamic
connection

52.  It is formed by the ependyma, above which
lies pia matter having the tela choroidea of
the 3rd ventricle
 Above the roof of 3rd ventricle, lies the fornix
and the corpus callosum

55.  It is formed by the:
1. Optic chiasma
2. Tuber cinereum
3. Infundibulum
4. Mammillary bodies
 Hypophysis is attached to the infundibulum

56.  Cause: thrombosis or hemorrhage of
arteries supplying the thalamus
 Lesions may lead to impairment of all
forms of sensation on contralateral side
 The senses lost include light touch, tactile
localization & discrimination, loss of
appreciation of joint movements

57.  Lesions of the subthalamus result in the
manifestations like that of extrapyramidal
pathways
 Manifestations may include sudden, forceful
involuntary movements in a contralateral
extremity
 The movements may be jerky (Choreiform) or
violent (Ballistic)

58.  Calcareous concretions in pineal gland
may appear in radiographs, giving an idea
of neighboring SOLs
 As the functions of pineal gland are
inhibitory to the pituitary gland, islets of
Langerhans, parathyroids & gonads; so
their functions may be affected e.g.
reproductive function

59.  Causes: infection, trauma, vascular
disorders
 Pituitary or pineal tumors may lead to:
1. Genital hypoplasia or atrophy
2. Diabetes insipidus
3. Obesity or emaciation
4. Disturbances of sleep
5. Irregular pyrexia
6. Adiposogenital dystrophy syndrome

60. The end