Annals of Anatomy · 2026

Combinatorial Perisphenoidal Anatomy on CBCT

A CBCT study of 153 patients (306 sides) that codes the internal carotid artery, optic nerve, foramen rotundum, vidian canal, and intersphenoid sinus septum as an integrated perisphenoidal system. The central message is heterogeneity: single structures may look familiar, but combinations diversify quickly.

Munteanu IM · Tudose RC · Albu AC · Rusu MC · Ann Anat. 2026 Oct;268:153357 · PMID 42600756 · doi: 10.1016/j.aanat.2026.153357

This microsite condenses the paper into interactive reading paths. Use the buttons below to switch between anatomical logic, key findings, and practical implications.

Five structures

Five coded structures, one shared surgical field

The article integrates categorical anatomy of the ICA, optic nerve, foramen rotundum, vidian canal, and intersphenoid sinus septum (ISS). Reading them together reveals more operative complexity than studying each one in isolation.

ICA

ICA type 1 and type 3 were nearly tied as the leading categories (36.6% and 36.3%).

FR / ON / VC

FR type II predominated (70.3%), ON DeLano type 1 was most frequent (54.2%), and VC type 2 was most frequent (51.0%).

ISS

The septum was single in most patients (75.2%), but posterior attachment remained clinically important.

Take-home point: The perisphenoidal region behaves as a combinatorial anatomical field, not as a set of independent landmarks.

Perisphenoidal reading frame

ICACarotid prominence pattern shapes parasellar risk.

Optic nerveDeLano relationship calibrates orbital/apical caution.

FR & VCNeural and vidian landmarks anchor route planning.

ISSSeptal attachment matters because the septum may terminate on vulnerable structures.

Coding agreement with the senior anatomist supported category reliability.
The paper favours explicit categorical language over impressionistic description.
Combinations are more informative than single-structure prevalence tables.

Combinations

Why combinations matter more than isolated prevalences

As more variables are combined, the number of distinct phenotypes grows and left-right exact matching falls. This is the paper’s core combinatorial insight.

Rising dimensionality

Distinct configurations rose to 41 when four variables were considered together.

Declining symmetry

Single-variable bilateral symmetry ranged from 63.4% to 80.4%, but exact all-four symmetry dropped to 27.5%.

Unsafe assumptions

The opposite side cannot be assumed to reproduce the same integrated pattern.

Take-home point: The paper warns against “if one side, then the other side” assumptions in skull-base planning.

Dimensionality effect

Single variablesModerate-to-high bilateral matching is common.

Two- and three-variable setsPattern diversity increases as structures are paired.

Four-variable phenotypesMany exact combinations appear, shrinking bilateral duplication.

This does not mean chaos; it means clinically relevant structured heterogeneity.
Combinatorial anatomy supports side-specific planning on both sides, even in the same patient.
Exact mirror symmetry becomes increasingly uncommon as more structures are jointly described.

Septal risk

The intersphenoid septum is not a harmless divider

Septal termination is crucial because posterior attachments may involve the ICA. The paper reports ICA-involving posterior septal termination in 43.1% of patients, while bilateral ICA-attached termination was uncommon (5/153; 3.3%).

Posterior attachment

Septal attachment may transform a routine bony landmark into an extraction risk during sphenoid surgery.

Single vs bilateral

Most patients had a single septum, but the clinically most delicate scenario is attachment to the carotid wall.

Practical reading

Septal description should accompany ICA, ON, FR, and VC coding rather than be treated as an afterthought.

Take-home point: Septal anatomy should be reported as part of the integrated perisphenoidal phenotype.

ISS risk ladder

Single septumMost common overall arrangement.

Posterior septal terminationRequires attention to where the septum ends.

ICA-attached terminationCritical because bony manipulation may transmit force to the carotid prominence.

The combination of ICA category and septal attachment is surgically more meaningful than either item alone.
Even uncommon bilateral ICA-attached termination deserves mention because of its hazard profile.
CBCT can support a highly explicit side-by-side preoperative map.