What is the Sphenoid Rostrum?
The sphenoid rostrum is a midline bony ridge or crest that projects inferiorly from the anterior wall of the sphenoid sinus body, forming a key anatomical landmark for transsphenoidal surgical approaches to the sella turcica. 1
Anatomical Description
The sphenoid rostrum represents the most anterior and inferior projection of the sphenoid bone in the midline, serving as a critical reference point during endoscopic skull base surgery. 1 This structure:
- Projects downward from the anterior face of the sphenoid sinus as a prominent midline ridge 1
- Articulates superiorly with the vomer bone, creating the sphenoidal crest 1
- Marks the precise midline of the sphenoid sinus, making it one of the most reliable intraoperative landmarks for surgical orientation 2
Clinical Significance in Transsphenoidal Surgery
The sphenoid rostrum serves as a fundamental anatomical reference during endoscopic transsphenoidal approaches to sellar lesions:
- The "spheno-sellar point" corresponds to the midpoint of the sellar floor at the level of the sphenoid rostrum, located approximately 40.1 mm anterior and 23.3 mm superior to the external acoustic meatus 1
- The superior sphenoid rostrum is one of the most reliable intraoperative midline markers during endoscopic skull base surgery, particularly when sphenoid sinus anatomy is complex with multiple asymmetric septa 2
- Linking the sphenoid rostrum with the nostril creates the "spheno-nostril line", which represents the direct surgical path for transsphenoidal access to the sella turcica 1
Surgical Navigation Value
In cases where other bony landmarks are ill-defined or obscured by disease:
- The rostrum remains consistently identifiable as a midline structure even when other landmarks like the opticocarotid recess or carotid protuberances are absent 2
- Bilateral parasellar and clival carotid protuberances, combined with the vomer and superior sphenoid rostrum, provide the most reliable intraoperative orientation when sphenoid sinus configuration is complex 2
- The rostrum serves as the starting point for all modular endoscopic skull base approaches, as the sphenoid sinus is the central corridor for accessing ventral skull base pathology 3
Common Pitfalls
- In cases of poor sphenoid sinus pneumatization (presellar type), the rostrum may be less prominent and fluoroscopic guidance may be necessary to confirm instrument position relative to this landmark 1
- Complex sphenoid sinus septal configurations (occurring in 29% of patients with 2 or more asymmetrical septa, 3 or more septa, or horizontal septa) can make intraoperative correlation more challenging, requiring careful identification of the rostrum as a midline reference 2