Three-dimensional reconstruction of the suborbicularis oculi fat and the infraorbital soft tissue

Abstract

The aim of this study was to reveal the histomorphological connections among the suborbicularis oculi fat (SOOF), the orbicularis oculi muscle (OOM), the superficial musculoaponeurotic system (SMAS), the infraorbital fat and the skin. Full graft tissue blocks of the infraorbital region with the skin, SMAS, OOM and SOOF were collected post mortem from one female and two male formalin-fixed body donors. Serial histological sections were made, stained and digitized. Digitalization and three-dimensional (3D) reconstruction of the histological meshwork were performed. SOOF was revealed as a fibro-adipose tissue underlying the OOM, which was strictly separated from the intraorbital fat pad by the orbital septum. SOOF, OOM and SMAS were connected by fibrous septa derived from the SOOF, traversing the OOM with division into multiple muscular bundles, continuing above the muscular plane by forming the SMAS and ending with skin insertion. In the infraorbital region, two different types of SMAS bordering the infraorbital fold have been recognized. Muscle cells have been demonstrated in the SMAS fibrous septa of both SMAS types. Together with the OOM, the SMAS and the skin, SOOF forms an anatomical functional unit. Muscular contraction of the OOM could be transferred by the SMAS to the skin level, producing periorbital mimic expression. The 3D reconstruction facilitates the comprehension of the morphological structure, its connections and space correlations in the infraorbital area. The morphological and topographical peculiarities of the infraorbital structures make it possible to conclude that surgical interventions in this area need to be elaborated and individualized.

Keywords: 3D reconstruction; Infraorbital soft tissue; SMAS; SOOF plastic surgery; Subcutaneous musculoaponeurotic system; Suborbicularis oculi fat.

Figure 1

Body donors' sides: a) female and b) male.

Figure 2

Microphotographic overview of the histological section of the a) specimen one and b) specimen two. A = infraorbital area; B = lower eyelid area. The infraorbital fold is marked with an arrow. A change of the SMAS morphology cranial and caudal to the infraorbital fold is visible.

Figure 3

Microphotographic overview of the histological SOOF section lying deep to the OOM from the a) specimen one and b) specimen two. The arrow indicates the septum orbitale.

Figure 4

Microphotographic overview of the connection between SOOF, the OOM and SMAS. The fibrous septa (arrows) divide the OOM belly into several muscular tangles: a) specimen one; b) specimen two.

Figure 5

Microphotographic overview of the histological SMAS section of the infraorbital area: a) specimen one, b) specimen two and lower eyelid regions: c) specimen one, d) specimen two showing the fibro-muscular SMAS septa connecting the OOM fiber bundles to the skin.

Figure 6

Higher magnification of the fiber insertion inferior to the infraorbital fold into the dermis showing muscle cells in the a) specimen one and b) specimen two.

Figure 7

Higher magnification of the fiber insertion inferior to the infraorbital fold into the OOM showing isolated muscle cells in the SMAS septa of the a) specimen one and b) specimen two.

Figure 8

Microphotograph overview of the histological infraorbital fold of the a) specimen one and b) specimen two showing deep cutaneous crinkles.

Figure 9

Microphotograph overview of the histological fibro-vascular connection between the OOM and the infraorbital fold (★) in specimen two.

Figure 10

Higher magnification of the SMAS fiber insertion into the OOM in a) specimen one and b) specimen two donors showing muscular bundles along the fibrous septa.

Figure 11

The 3D reconstruction of the a) specimen one and b) specimen two tissue blocks of the inferolateral side of the orbit. Color map: green—skin; violet—intraorbital fat; light blue—SMAS fibers; pink—OOM; red—SOOF; brown, yellow and orange—SOOF fat pads; arrow—infraorbital fold. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Figure 12

3D reconstruction of the a) specimen one and b) specimen two SOOF fat pads after freezing the shell surrounding the SOOF, demonstrating the connections of the SOOF fat pads. Color map: pink—SOOF shell; brown, yellow and orange—SOOF fat pads. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Figure 13

The three-dimensional reconstruction of the a) specimen one and b) specimen two tissue blocks of the inferolateral side of the orbit demonstrating the fibrous connection between the SOOF and SMAS septa crossing the OOM. Color map: green—skin; violet—intraorbital fat; light blue—SMAS fibers; pink—OOM; red—SOOF; brown, yellow and orange—SOOF fat pads; arrow—infraorbital fold. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)