PURPOSE: To study the anatomic and radiographic features of the inferomedial orbital strut (IOS), with particular emphasis on the region of the posterior IOS. METHODS: Cadaver dissection study of the IOS was performed on 20 orbits of 10 fresh-frozen cadaver specimens. Radiographic volumetric analysis was performed on CT scans of 20 orbits to measure the volume available for decompression in the region of the posterior IOS. RESULTS: The anterior IOS provided bony support to the orbit and served as a site of attachment for globe-supporting suspensory ligaments. The midportion of the IOS demonstrated a contiguous anatomic relation to the maxillary sinus ostium. The posterior IOS consisted of two components: the intraorbital process of the palatine bone and ethmoidal air cells that extended inferior and posterior to the IOS. Radiographic volumetric analysis demonstrated that there was an average of 2.1 mL of volume available for decompression in the region of the posterior IOS (range, 1.2 to 3.3 mL). CONCLUSIONS: The findings of this anatomic and radiographic study of the inferomedial orbital strut support the concept of a posterior inferomedial orbital decompression. The region of the posterior IOS appears to offer significant volume for axial globe mobilization while minimizing the risk of globe dystopia and/or impairment of the maxillary sinus drainage.
PURPOSE: To study the anatomic and radiographic features of the inferomedial orbital strut (IOS), with particular emphasis on the region of the posterior IOS. METHODS: Cadaver dissection study of the IOS was performed on 20 orbits of 10 fresh-frozen cadaver specimens. Radiographic volumetric analysis was performed on CT scans of 20 orbits to measure the volume available for decompression in the region of the posterior IOS. RESULTS: The anterior IOS provided bony support to the orbit and served as a site of attachment for globe-supporting suspensory ligaments. The midportion of the IOS demonstrated a contiguous anatomic relation to the maxillary sinus ostium. The posterior IOS consisted of two components: the intraorbital process of the palatine bone and ethmoidal air cells that extended inferior and posterior to the IOS. Radiographic volumetric analysis demonstrated that there was an average of 2.1 mL of volume available for decompression in the region of the posterior IOS (range, 1.2 to 3.3 mL). CONCLUSIONS: The findings of this anatomic and radiographic study of the inferomedial orbital strut support the concept of a posterior inferomedial orbital decompression. The region of the posterior IOS appears to offer significant volume for axial globe mobilization while minimizing the risk of globe dystopia and/or impairment of the maxillary sinus drainage.