Three-dimensional structure of the orbicularis retaining ligament: an anatomical study using micro-computed tomography

The orbicularis retaining ligament (ORL) is an important structure for maintaining the eyelid and cheek skin and contouring the characteristic facial appearance. However, the ORL is a delicate structure that is easily damaged in manual dissection. This study aimed to comprehensively investigate the ORL using a micro-computed tomography (mCT) with phosphotungstic acid (PTA) preparation for the acquisition of its three-dimensional information non-destructively. Twenty-two specimens were obtained from non-embalmed human cadaver (mean age 73.7 years). Multidirectional images of the mCT showed that the ORL consisted of continuous tiny plates with a multilayered plexiform shape. The modified Verhoeff Van Gieson staining and immunofluorescence revealed a ligamentous tissue consisting of multiple fibroelastic bundles. The preorbicularis fibres of the ORL had more layers and a more intricate arrangement than its retro-orbicularis fibres. The number, complexity and ambiguity of the ORL fibres increased in the lateral area and their density and extent increased near the dermis. Its dermal anchorage was shown as a confluence of its fibroelastic tissue into the dermis. The ORL comprises a multilayered meshwork of very thin continuous fibroelastic plates and its related cutaneous deformities might be a complicated outcome of subcutaneous tissue shrinkage, lipid accumulation and ORL retention.