The thalamus is a vital structure in the brain that plays a central role in sensory relay and integration. While direct surgical interventions targeting the thalamus are relatively rare, there are specific neurosurgical procedures and interventions that may involve the thalamus. Neurosurgeons carefully consider the indications, patient factors, and potential benefits when deciding on interventions involving the thalamus. The field of thalamic neurosurgery is evolving, with ongoing research and advancements in techniques aimed at improving patient outcomes.

1. Dr / Ahmed Salah Ashour(Ph.D.)
Associate professor of human anatomy
Dr.Ahmedashour@gmu.ac.ae
USMLE Clinical Anatomy

2. Case report

3. A 48-year-old Caucasian woman with a well-treated hypercholesterolemia and a 20-
year history of adult-onset type 1 diabetes experienced over 8 hours a progressive
alteration in sensations from the left side of her body (including the head), causing
her to feel as if she was split in two. She reported unpleasant symptoms such as
numbness, coldness and paresthesia, but was told by the doctor on call not to worry.
Eventually, on examination 6 days later, a slight dysesthesia was reported on touch
and pinprick in a complete hemisensory pattern. Magnetic resonance imaging
(MRI) revealed an infarct in her right thalamus .

4. Magnetic resonance image shows thalamic infarctions

5. THALAMUS

6. The thalamus is a vital structure in the brain that plays a central role in sensory relay
and integration. While direct surgical interventions targeting the thalamus are
relatively rare, there are specific neurosurgical procedures and interventions that
may involve the thalamus. Neurosurgeons carefully consider the indications, patient
factors, and potential benefits when deciding on interventions involving the
thalamus. The field of thalamic neurosurgery is evolving, with ongoing research and
advancements in techniques aimed at improving patient outcomes.

8. Thalamus
Fornix
Caudate nucleus
Midbrain
Corpus
callosum
Pineal body
Sup. colliculus
Lentiform nucleus
Internal capsule
External capsule
Habenular commissure
Posterior commissure

9. • Function:
All sensation relay in thalamus except
1. Smell
2. Unconsious proprioceptive sensation

10. • Relations
Inferior surface:
o Hypothalamus
o Midbrain
Thalamus
Hypothalamus
Midbrain

11. Thalamus
Midbrain

12. Superior surface:
o Fornix
o Central part of the lateral ventricle
o Caudate nucleus
Caudate nucleus
lateral ventricle

13. Head Caudate
Fornix
.
Thalamus

14. Medial surface:
o 3rd ventricle.
3rd ventricle
Thalamus

15. Lateral surface:
o Lentiform nucleus
o Internal capsule.

16. Lt. caudate
Lt. Lentiform nucleus
Lt. thalamus

17. Head caudate
Insula
Extreme capsule
Claustrum
External capsule
Putamen
Globus pallidus
Internal capsule
Thalamus
3rd ventricle

18. • Structure of the thalamus
a- White matter:
External medullary lamina: covers its lateral surface.
Internal medullary lamina: Y-shaped.
External medullary lamina
Internal medullary lamina

19. b- Grey matter:
1- Anterior
2- Medial
3- Lateral.
*Dorsolateral
*Ventrolateral
- Anterior
- Intermediate
- posterior
* Medial
* Lateral
External medullary lamina
Internal medullary lamina
Anterior
Medial Lateral

20. Right thalamus
Anterior
Medial Dorsolateral
Medial Lateral
Anterior
Intermediate
posterior
VPL
VPM

21. The pulvinar corresponds to the posterior expansion of the thalamus, which
overhangs the superior colliculus

22. pulvinar
superior colliculus

23. • Thalamic radiation
o Anterior thalamic radiation: to the
frontal lobe.
o Superior thalamic radiation: to the
parietal lobe
o Posterior thalamic radiation : to the
occipital lobe.
o Inferior thalamic radiation: to the
temporal lobe.

24. Thalamic pain syndrome
The most common clinical
manifestation of a lesion to the
thalamus is severe impairment of
somatic sensations on the
contralateral side of the body
(face, arm, and leg).
An ischemic stroke in the
thalamus is usually due to
occlusion of the thalamogeniculate
artery, which is a branch of the
posterior cerebral artery.
Clinical Insight

25. Thalamic pain syndrome
The VPL and VPM are the
thalamic nuclei involved in this
syndrome.
In addition to sensory loss, severe
pain in the contralateral face, arm,
and leg can be a chronic
complication.
This is referred to as the thalamic
pain syndrome.
Clinical Insight

26. Lateral geniculate body Medial geniculate body

27. Lateral geniculate body Medial geniculate body
• Connected with the superior
colliculus of the midbrain
• Mediate visual reflexes
• It connected with inferior colliculus
of the midbrain
• Mediate auditory information
Lateral geniculate body
Medial geniculate body
superior colliculus
inferior colliculus

28. Pineal body Habenula

29. Pineal body Habenula
• Lies below the splenium of corpus
callosum
• Anterior relations:
ü Superiorly: habenular commissure
ü Inferiorly: Posterior commissure
• Triangular depressed area lateral to
the pineal body
Pineal body
Habenula

30. Pineal Tumors
may cause obstruction of CSF flow and increased intracranial pressure.
Clinical Insight

31. Pineal Tumors
Compression of the upper midbrain and
pretectal area by a pineal tumor results in
Parinaud syndrome, in which there is
impairment of conjugate vertical gaze and
pupillary reflex abnormalities.
Clinical Insight

33. The hypothalamus is a small but mighty structure
located at the base of the brain. Despite its size, it
plays a crucial role in regulating various functions
within the body.
• The Hypothalamus Is the Master Regulator.
• It Controls the Pituitary Gland.
• The Hypothalamus Helps Regulate Body
Temperature.
• It Controls Hunger and Satiety.
• The Hypothalamus Regulates Sleep-Wake
Cycles.
• t Plays a Role in Emotional Responses.

34. Optic chiasma
Infundibulum
Mamillary bodies
Posterior perforated substance

36. The lentiform nucleus is a lens-shaped
structure located lateral to thalamus.
The lentiform nucleus is composed of
two main structures:
§ Putamen: This is the larger and more
lateral portion of the lentiform
nucleus. It is involved in motor
control and is interconnected with
other basal ganglia nuclei.
§ Globus pallidus: This is the smaller
and more medial portion of the
lentiform nucleus.

37. • Relations
o Anterior end:
Head of the caudate.
o Posterior end:
Optic radiation in the
retrolenticular part of
internal capsule
head of the caudate
lentiform nucleus
Putamen
Globus pallidus
optic radiation

38. o Lateral surface:
1. external capsule
2. Claustrum
3. Extreme capsule
4. Insula .
o Medial surface:
1. Internal capsule
2. Head of caudate
3. Thalamus.
Head of caudate
Internal capsule
Thalamus
external capsule
Claustrum
Extreme capsule
insula

40. The claustrum is a thin bilateral
collection of neurons that plays
an important role in
consciousness.
• Relations:
1. Insula laterally, separated
from it by extreme capsule
2. Putamen medially, separated
from it by external capsule
Head of caudate
Internal capsule
Thalamus
external capsule
Claustrum
Extreme capsule
insula

42. Body
Columns
Crura
Hippocampus
Thalamus

43. • Body of the fornix:
Superior relations:
trunk of corpus callosum
Inferior relations:
3rd ventricle, thalamus,
septum pellucidum
corpus callosum
septum pellucidum
Body of the fornix
3rd ventricle
Thalamus

44. • Columns of the fornix:
Anterior relations:
Anterior commissure
Posterior relations:
Interventricular foramen
Anterior commissure
Columns of the fornix
Interventricular foramen

45. • Crura of the fornix:
These are the continuation of the fimbria
of hippocampus and dentate gyrus
Crura of the fornix
fimbria of hippocampus
dentate gyrus

47. Caudate nucleus
Thalamus
Lentiform nucleus
Thalamus
Caudate nucleus
Lentiform nucleus
Internal capsule
Head
B
o
d
y
T
a
i
l
Internal capsule

48. The caudate nucleus is an elongated C-shaped nucleus that surrounds the thalamus
Lt. thalamus
Lt. lentiform
Lt. caudate
Body
Lt. caudate
Head
Lt. caudate
Tail

49. • Head :
Related laterally to the
anterior limb of the
internal capsule.
Medially to anterior
horn lateral ventricle
1. Head caudate
2. anterior limb of the internal
capsule.
3. anterior horn lateral ventricle
1
2
3

50. • Body:
Related laterally to the posterior limb of the internal capsule.
Caudate nucleus
Thalamus
Lentiform nucleus
Head
B
o
d
y
T
a
i
l
Internal capsule

51. • Tail
Is the narrowest part that curves behind the thalamus
Caudate nucleus
Thalamus
Lentiform nucleus
Head
B
o
d
y
T
a
i
l
Internal capsule

52. Intracranial hemorrhage
•Patients with intracranial hemorrhage typically present with
A. Nausea
B. Headache
C. Hemiplegia
D. Sensory loss.
Non-contrast CT:
Show acute blood as hyperdense areas.
Clinical Insight

53. Hypertension associated microaneurysms rupture
Hypertension is the most important risk factor for nontraumatic intracranial
hemorrhages due to rupture of microaneurysms of the deep arteries of the
A. Basal ganglia
B. Thalamus
C. Internal capsule
D. Cerebellum.
Clinical Insight

54. Bouchard microaneurysms
•Hypertensive intracerebral hemorrhage is
usually caused by rupture of Bouchard
microaneurysms of the deep arteries.
•Ballooning of the wall results in
formation of a fusiform aneurysm.
•Increased blood pressure can result in
aneurysmal rupture.
Clinical Insight

55. Huntington's Disease
Is an inherited genetic disorder that leads
to degeneration of the basal ganglia,
particularly the striatum (caudate nucleus
and putamen). It manifests with motor
dysfunction, including involuntary
movements (chorea), as well as cognitive
and psychiatric symptoms.
Key components of the basal ganglia:
1.Caudate Nucleus
2.Lentiform nucleus
3.Subthalamic Nucleus (STN)
4.Substantia Nigra
Clinical Insight

56. Formative Quiz

57. Q1: A 65-year-old woman comes to the emergency department because of a severe
headache, vomiting, and right-sided weakness that began 2 hours ago. She has a
history of type 2 diabetes mellitus and hypertension. Blood pressure is 190/110 mm
Hg. Physical examination reveals slurred speech and decreased strength and
sensation of her right upper and lower extremities. Babinski is positive in the right
foot. A noncontrast CT is shown. Which of the following is most likely responsible
for this patient’s condition?
A. Amyloid angiopathy
B. Arteriovenous malformation
C. Charcot-Bouchard aneurysmal hemorrhage
D. Invasive growth
E. Lenticulostriate artery thrombosis

58. Q2 A 60-year-old male with a history of hypertension presents to the emergency
department with sudden-onset severe headache, nausea, and vomiting. On
examination, he is drowsy, and there are focal neurological deficits, including
weakness on the right side and slurred speech. A non-contrast CT scan of the head
reveals hyperdensity in the left basal ganglia with surrounding edema. Which of the
following is the most likely diagnosis?
A) Ischemic stroke
B) Subarachnoid hemorrhage
C) Intracerebral hemorrhage
D) Epidural hematoma
E) Subdural hematoma

59. Q3 A 45-year-old individual presents with involuntary choreiform movements,
personality changes, and cognitive decline. Family history reveals that the patient's
father had similar symptoms. On examination, there is evidence of hyperkinesia and
impaired coordination. Genetic testing confirms the presence of an expanded CAG
repeat in the HTT gene. What is the most likely diagnosis?
A) Parkinson's disease
B) Amyotrophic lateral sclerosis (ALS)
C) Huntington's disease
D) Alzheimer's disease
E) Multiple sclerosis

60. Q4 A dazed homeless man is brought to the emergency room. He seems confused
and lethar- gic. He has difficulty following objects in all directions and walks with a
broad-based gait, but his muscle strength is normal and he exhibits no tremor either
at rest or during- movements. On the basis of the assumption that this patient is an
alcoholic, thiamine is administered, which relieves'the ocular paresis and the
confusion. Despite the thiamine treatments, the patient seems to be unable to
remember past events well and tends to make up stories to cover this deficit. Which
part of the brain may show thiamine-resistant pathological changes in this patient?
Hippocampus
Amygdala
Hypothalamus
Cerebellarhemisphere
Frontallobe

61. Q5 A16-year old female patient with a long history of epileptic seizures that could
not be controlled pharmacologically had part of her brain ablated bilaterally.
Afterward she is unable to identify friends and family members. She goes on eating
binges, exhibits a tendency for heightened sexual activity, and seems unable to
respond with appropriate emotions to external stimuli. What neural structure may
have been removed bilaterally?
Fornix
Mamillary body
Splenium of corpus callosum
Amygdala
Cingulate cortex

62. Q6 A 47-year-old banker exhibits a personality change over a period of weeks. He
becomes irritable and no longer seems to be getting along at work. He exhibits jerky
movements when trying to pick up a cup of coffee or hold a pen to write. The
patient's wife recalls that the patient’s mother died in her 60s of a progressive illness
that started likeher husband's. CT imaging reveals apparent degeneration of a neural
structure situated medial to the anterior limb of the internal capsule, which normally
protrudes into the lateral ventricle. The affected structure in this patient is the
caudate nucleus
globus pallidus
corpus callosum
thalamus
putamen

63. Q7 A 63-year-old homeless woman is brought to the emergency department (ED) by
the po- lice because she is disoriented and confused. On questioning the patient
frequently forgets what she has been asked. She provides seem- ingly plausible
details of the events prior to her coming to the hospital, but her accounts are entirely
inconsistent with the police report. On physical examination she is emaciated and
has nystagmus and an unsteady gait. ED records indicate that she has presented
multiple times in the past for alcohol withdrawal and alcohol- related injuries. The
lesion accounting for the patient’s signs and symptoms is located in which part of
the brain?
Amygdala
Basal ganglia
Broca area
Mamillary bodies
Wernicke area

64. Q1: Charcot-Bouchard aneurysmal hemorrhage
Q2 Intracerebral hemorrhage
Q3 Huntington's disease
Q4 Hypothalamus
Q5 Amygdala
Q6 caudate nucleus
Q7 Mamillary bodies

65. List of Texts and Recommended Readings
• Last's Anatomy, Regional and Applied. Chummy S. Sinnatamby. 12th edition 2011, ISBN:13 - 978 0 7020 3394 0
(Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3-s2.0- C2009060533X)
• Estomih Mtui, Gregory Gruener and Peter Dockery. Fitzgerald's Clinical Neuroanatomy and Neuroscience. 7th
edition; 2016, ISBN: 13 - 978-0-7020- 6727-3 (Available in ClinicalKey:
https://www.clinicalkey.com/#!/browse/book/3-s2.0- C20130134113
• Drake, Richard L. Gray's Anatomy for Students, Third Edition, Elsevier Saunders 2015. ISBN-13: 978-0702051319
(Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-C20110061707).
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.1, 15th Edition; 2013, ISBN: 9780702052514 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/content/book/3- s2.0-B9780702052514500067)
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.2, 15th Edition; 2013, ISBN:13 - 978-0-7020-5252-1 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-C20130046919)

66. Recap