# The Lower Orbital Septum Revisited: A 3-Dimensional Structure Determines Aesthetic Presentation and Impacts Operative Rejuvenation

## TL;DR

This study examines the structure of the lower orbital septum to better understand eyelid bulging and aging, and how it affects surgical rejuvenation.

## Contribution

The study identifies a 3D structure of the lower orbital septum and its role in aesthetic presentation and surgical outcomes.

## Key findings

- A loose anterior membrane and transverse ligamentous elements were found deep to the postorbicular fascia in both cadavers and patients.
- A posterior septal membrane connects to the anterior membrane at the superior transverse ligament, forming a discrete adipose compartment.
- Variation in fibrous characteristics of the septum correlates with clinical presentation patterns and surgical planning.

## Abstract

The anatomic basis of lower eyelid bulging remains enigmatic, and the concept of compartmentalization is often used to describe bulge location but does not completely explain the cause of periorbital aging.

The authors of this study aim to explore lower septal structure, including the concept of adipose tissue compartmentalization, and assess relevance to aesthetic presentation and operative rejuvenation.

The inferior orbital septa of 10 cadavers (20 lids) were dissected with magnification, with special attention to contiguous tissues, such as orbital fat, orbicularis oculi muscle, tarsus, and inferior oblique muscle. The cadaveric specimens were 71 to 83 years old (mean = 75). Subsequent comparative observations were made in 63 consecutive patients undergoing lower lid blepharoplasty for eyelid distention. The age range was 35 to 82 years (mean = 63).

Both cadavers and patients demonstrated a loose anterior membrane deep to the postorbicular fascia and discrete, transverse ligamentous elements deep to the anterior membrane. In surgical patients, evaluation of the posterior adipose tissue space disclosed a posterior septal membrane that joined the anterior septal membrane at the superior transverse ligament, creating a discrete compartment isolating the adipose tissue from the eyelid protractors and retractors. Variation in the gross fibrous characteristics of septal constituents was observed in both cadavers and operative patients, and this accounted for observed patterns of clinical presentation.

Lower lid topography is predictive of the fibrous character of the underlying septal components, and topography is useful for surgical planning.