Anatomy of the Sellar Region

1. ANATOMY OF
THE SELLAR REGION
BY
AHMED MOHAMED EL GHOUL

2. To Understand The Anatomy of
Sellar Region
Below Sella Above
Nasal Cavity
Sphenoid Bone
Pituitary Fossa
Pituitary Gland
Suprasellar &
Ventricular Relations
Sphenoid Sinus Diaphragma
Inter Cav. Conn.

3. Below
Sella
Nasal Cavity
Sphenoid Bone
Sphenoid Sinus

4. Nasal Septum is formed by
 Anteriorly And Superiorly : perpendicular plate of the ethmoid.
 Inferiorly And Posteriorly : vomer.
Posterior Nasal Aperture is boardered by
 Above : anterior aspect of the sphenoid body,
 Below : posterior margin of the hard palate.
 Medially : nasal septum formed by the vomer.
 Laterally : medial pterygoid plate.
Nasal Cavity

5. Lateral Nasal Wall 3 Concha + 3 Ostia (superior, middle, inferior)

7. The Frontoethmoidal Suture
Anterior And Posterior Ethmoidal
Foramina
Sphenoethmoidal Recess
 Paired
 Above, behind superior concha
 Sphenoid ostium

8. Sphenoid Bone
Parts
Body + 2 lesser wings + 2 greater wings + 2 pterygoid processes

10. Sphenoid Sinus
It is present as minute cavities at birth, but its main development takes place after puberty.
There are three types :
 Conchal
 Presellar
 Sellar

11. (Hiremath et al. 2018)

12. Sphenoid Sinus Septae
 Vary greatly in size, shape, thickness, location, and relation to sellar floor.
 The cavities within the sinus are seldom symmetrical from side to side.
 Role of imaging : CT Paranasal Sinuses + MRI

13. Carotid Prominence
The carotid prominences are seen lateral to the anterior wall of the sella
3 parts
 Retrosellar segment posterolateral part of the sinus. ( Sellar Type )
 Infrasellar segment below the sellar floor.
 Presellar segment anterolateral to the anterior sellar wall.
The bone separating the artery and the sphenoid sinus is thinner over the anterior than the
posterior parts
The shortest distance between both carotid bulges into the sphenoid sinus is usually located at
the level of the tuberculum sellae .

18. • Superolateral portion of the sinus optic canal protrusion
• Midlateral wall below the optic canal superior orbital fissure prominence
• Inferolateral part maxillary nerve protrudes
NOTE
Lateral Wall Of The Sphenoid Sinus

20. Mid Sagittal View

21. Opticocarotid Recess
 A pneumatized diverticulum of the sinus extends laterally into the optic strut.
 This pneumatization may extend into the anterior clinoid process
 This explains CSF can leak into the sinus after an anterior clinoidectomy with resulting rhinorrhea.

22. Sella
Pituitary Fossa
Pituitary Gland
Diaphragma
Inter Cav. Conn.

23. Pituitary Fossa

24.  Anterior Lobe + Posterior Lobe + Stalk
 The anterior lobe wraps around the lower part of the pituitary stalk to form the pars tuberalis
Pituitary Gland

26.  Roof of the sella
 Covers the pituitary gland, except for A small central opening in its center (stalk)
 Rectangular
 Convex/concave
 A deficiency of the diaphragm sellae is assumed to be A precondition to empty sella
 Central opening in diaphragm > diameter of stalk
 Outpouching of the arachnoid through the central opening >> CSF LEAK
Diaphragma Sellae

28.  The distance separating the medial margin of the carotid artery and the lateral surface of the pituitary
gland is an important consideration in trans sphenoidal surgery
 The proximity of the carotid arteries to the midline is extremely important in pituitary surgery
 Arterial bleeding during transsphenoidal surgery has been reported as due to
o Carotid artery injury,
o Tear in inferior hypophyseal artery
o Avulsion of a small capsular artery from the carotid artery
Pituitary Gland and Carotid Arteries

29.  Six sagittal sections of the sellar region
showing variations in the intercavernous
connections within the dura.
 The variations shown include combinations of
anterior, posterior, and inferior intercavernous
connections and the frequent presence of a
basilar sinus posterior to the dorsum.
Intercavernous Venous Connections

30. Above
Sella
Suprasellar &
Ventricular Relations

31. SUPRASELLAR & 3RD VENTRICULAR REGION
Ventricular &
Cisternal
Relationships
Cranial
Nerves
Arterial
Relationships
Venous
Relationships
Anterior
Incisural
Space
Optic Chiasm
Occulomotor N
ICA
P. CoA
Ant. Choroidal A
ACA
Basilar Bif.
Small Tributaries
Basal Vein
Internal Cer. V
Great Vein

32. Anterior Incisural Space = Suprasellar Area
Superior Part of Anterior Incisural Space above chiasm
- Superiorly rostrum of the corpus callosum
- Posteriorly lamina terminalis
- laterally medial surfaces of the frontal lobes
Laterally, the anterior incisural space opens into the part of the sylvian fissure
Posterior Part of The Anterior Incisural Space Interpeduncular Cistern
Between cerebral peduncles and the dorsum sellae
Separated from the chiasmatic cistern by liliquest membrane.
Chiasmatic Cistern communicates with Cisterna Laminae Terminalis.
Ventricular & Cisternal Relationships

33. The optic chiasm is situated at the junction of the
anterior wall and floor of the third ventricle
ABOVE
 ACA, A-CoA
 Lamina terminalis
 3rd Ventricle
BEHIND
 Tuber cinereum
 Infundibulum
LATERALLY
The internal carotid arteries
BELOW
 Diaphragma sellae
 Pituitary gland
OPTIC CHIASM
NEURAL RELATIONSHIPS

34. Lateral of the Suprasellar Region

35. The relationship of the chiasm to the sella
 The normal chiasm overlies the diaphragm
 The prefixed chiasm overlies the tuberculum.
 The postfixed chiasm overlies the dorsum.

36. NOTE
 If the chiasm is prefixed and the tumor is seen through a thin, stretched
arterial wall of the third ventricle, the lamina terminalis may be opened to
expose the tumor, but this exposure is infrequently used for pituitary
adenomas, and they more commonly form craniopharyngiomas and
gliomas involving the third ventricle.
 If the space between the carotid artery and the optic nerve has been
enlarged, by a lateral or parasellar extension of tumor, the tumor may be
removed through this space

37.  Arises in the interpeduncular cistern from the midbrain on the medial side of the cerebral peduncle
and courses between the posterior cerebral and superior cerebellar arteries .
 Courses in the lateral wall of the interpeduncular cistern and forms the pillars to which Liliquist’s
membrane attaches.
 Liliquist’s membrane arises from the arachnoid membrane covering the dorsum sellae and separates
the chiasmatic and interpeduncular cisterns.
 The uncus of the temporal lobe is situated lateral to the oculomotor nerve.
 The oculomotor nerve pierces the roof of the cavernous sinus and slopes downward in the
superolateral corner of the cavernous sinus.
OCULOMOTOR NERVE
NEURAL RELATIONSHIPS

39. Arterial
Relationships
Venous
Relationships
ICA
P. CoA
Ant. Choroidal A
ACA
Basilar Bif.
Small Tributaries
Basal Vein
Internal Cer. V
Great Vein

40. Superiorview of the Suprasellar Region
 The carotid arteries course along the lateral margin of
the chiasmatic cistern.
 The basilar bifurcation is located above and behind the
sella.
 The posterior communicating arteries travel backward
across the dorsum to join the posterior cerebral
arteries.
 The posterior communicating arteries usually course
above and medial to the oculomotor nerves.

42. Subfrontal Approach
A Opening
B Subchiasmatic A
C Opticocarotid A
D Lamina Terminalis
E Transfrontal Transsphenoidal A

44. REFRENCES
 Rhoton, Albert L., Jr. 2002. “The Sellar Region.” Neurosurgery 51 (4 Suppl): S335–74
 Hiremath, Shivaprakash B., Amol A. Gautam, Keerthy Sheeja, and Geena Benjamin. 2018. “Assessment
of Variations in Sphenoid Sinus Pneumatization in Indian Population: A Multidetector Computed
Tomography Study.” The Indian Journal of Radiology & Imaging 28 (3): 273–79.