This document provides an overview of the anatomy of the insula and sylvian fissure. It describes the insula as the 5th lobe of the brain, located deep within the sylvian fissure hidden by the frontal, parietal, and temporal opercula. The document outlines the surgical anatomy of the insula including its pyramidal shape, surfaces, gyri, and relations to surrounding structures like the external capsule and internal capsule. It also discusses the arterial supply to the insula from the middle cerebral artery and various surgical approaches to access the insula like trans-sylvian and transcortical techniques.

1. Anatomy Of Insula and Sylvian
Fissure
PRESENTED BY
DR ANKIT JAIN

2. HISTORY
• The island or insula of Reil is named after the
German anatomist, physiologist and
psychiatrist, Johann Christian Reil (1759–
1813), who in 1809 first described this
anatomically and functionally complex
structure situated in the depth of the Sylvian
fissure and hidden by the opercula of the
frontal, parietal and temporal lobes

3. SURGICAL ANATOMY
• 5th lobe of brain.
• Mesocortical structure , link between
allocortex and neocortex.
• Part of para limbic system

4. Sylvian fissure
Fissure
Sulcus
Fossa

6. Illustration of the M1–M4 segment, in coronal
view, left side

7. Anatomy of Insula
• Mesocortex (paralimbic structure)

8. SURGICAL ANATOMY
• A well-defined cerebral
cortical surface
• Pyramidal in shape.
• Base medially.
• 3 surfaces.
• Hidden by frontal
temporal and parietal
operculum.

9. SURGICAL ANATOMY
• Central sulcus divides
insula into anterior and
posterior part.
• 3 short gyri in anterior
lobule- ant middle and
posterior and
transverse and
ascessory gyri.
• Posterior lobule
consists of an anterior
and a posterior long
insular gyrus.

10. SURGICAL ANATOMY

13. SURGICAL ANATOMY
• EXTREME CAPSULE
• CLAUSTRUM
• EXTERNAL CAPSULE
• LENTIFORM NUCEUS
• INTERNAL CAPSULE

14. SURGICAL ANATOMY
INSULA
CORONA RADIATA
ARCUATE
FASCICULUS
UNCINATE
FASCICULUS
RETROLENTIFORM
AND
SUBLENTIFORM
FIBERS
INTERNAL CAPSULE

15. SURGICAL ANATOMY
• M1-
LATERAL
LENTICULOSTRIATE
ARTRIES.
• M2 –
SHORT PERFORATORS.
LONG PERFORATORS.

16. SURGICAL ANATOMY.
• Lateral Lenticulostriate
Arise from M1.
1- 15 in number.
0.5-1.5 mm in diameter.
Supply Internal capsule and
Lentiform nucleus.
Related to Limen insulae(1.5 cms).
May supply insula.

17. SURGICAL ANATOMY
• M2 PERFORATORS
Short and medium
perforators supply insula and
can be sacrificed.
Long perforators – arise in the
postero superior part of
insula and supply corona
radiata.

18. Limen Insulae
• The limen insulae is a
slightly raised, arched
ridge located at the
junction of the
sphenoidal and
operculoinsular
compartments of the
sylvian fissure and
extends from the
temporal pole to the
orbital surface of the
frontal lobe
• LIMEN RECESS:
between the medial border
of the limen insulae and the
lateral limit of the anterior
perforated substance, which
isthe point of entrance of
the most lateral LSA :
MEDIAL BORDER OF
RESECTION

20. Arterial Supply of Insula : via M2

21. The limen area, inferior limiting sulcus, long gyri, and central insular sulcus
are drained by the deep MCV (purple area). The SSV drained the middle short gyrus and
insular apex more commonly than any other insular
area (light blue area). The transitional zone, which is usually drained by both the
superficial and deep venous systems, included the anterior
and posterior short gyri and the anterior limiting sulcus (stippled area).

22. Functions
• Insular language area
• Cognitive control of emotions
• Consciousness
• Pain perception
Relations
- To the sylvian fissure
- To the Cerebral fibre system and basal ganglia
- To the Lateral ventricle

23. Relation to the fibres

24. Relation to the lateral ventricle
The foramen of Monro is located deep to the middle portion of the posterior short
gyrus. The posterior end of the insula and the junction of superior and inferior
limiting sulci are located superficial to the anterior edge of the atrium.

25. The vertical distance from the inferior
limiting sulcus to the posterior edge of the head of the hippocampus
is approximately 1 cm.

26. CLASSIFICATION
TYPE LOCATION SUBCATEGORY
1 TEMPORAL
MEDIOBASAL
a.Medial temporal pole.
b.Amygdalar.
c.Hippocampal.
d.Parahippocampal.
2 Cingulate Gyrus a. anterior.
b. Middle.
c. Posterior.
3 Insular and
parainsular
a. Pure Insular anterior
posterior
entire
b. Insular frontobasal
c. Insular temporomediobasal.
d. Insular forntobasal-
temporomediobasal
4 Medial limbic
association areas
a. Fornicial
b. Septal
c. mamillary
5 Entire limbic system

27. BERGER AND SANAI CLASSIFICATION
ZONE 1 – Antero superior
ZONE 2- Postero superior.
ZONE 3 – Postero inferior.
ZONE 4- Antero inferior
GIANT- Involving all zones

30. SURGICAL APPROACHES
• TRANS-SYLVIAN.
• TRANSCORTICAL

31. TRANSYLVIAN APPROACH.
Pioneered by Yasargil
Most suitable for purely insular gliomas
Wide exposure.
Tumor devascularisation.
Less chance of injury to eloquent structures
DISADVANTAGES:
Wide retraction required retraction related
temporary deficits.
Chances of vascular injury more.
Vasospasm.

34. TRANSCORTICAL APPROACH
• Most appropriate for tumors with opercular spread.
• Avoids injuries to vessels while maintaining
dissection with in pia.
• Less chance of vasospasm.
• Need for preoperative functional MRI and intraop
cortical mapping.
• Trans cortical windows are created through the
nonfunctional cortex above and below the sylvian
fissure-Window technique.

35. TRANS CORTICAL

36. COMPLICATIONS
• HEMIPARESIS.
• APHASIA
• VISUAL DEFICITS.
• NEURO PSYCHOLOGICAL WORSENING.

37. THANK YOU