Strolling under the Skin

The story of the film unfolds about 20 years ago, originating in a university research lab where vascularized tendons were being transferred. The focus was on the intricate vascular network, leading to the discovery of the retrograde flap concept by the Chinese School of Plastic Surgery. A technique was developed to transfer vascularized retrograde tendon flexor transfers onto the cubital pedicle, addressing the challenge of reconstructing flexor tendons.

This new anatomical perspective shed light on the relationships between tendons, sliding sheaths, and vessels, challenging classical theories. Observations during revascularization revealed contradictions to prevailing vascular theories, indicating a continuity between sheaths and tendons despite distension during sliding.

Detailed microscopic analysis using 25-fold video magnification was initiated to understand vessel distribution and mobility. The connective tissue, known as multi-microvascular collagenase absorbing, was explored. It was found to be a chaotic, fractal system crucial for allowing tendon movement without transferring it to surrounding structures. The biomechanical behaviour of this system was compared to a theory of drawers, suggesting a sequential triggering of vacuoles during tendon movement. Computer-synthesized images validated the existence of a sliding system with liquid between vacuoles and an armature of collagen fibres.

The discovery extended beyond tendons; the multi-microvascular collagenase absorbing system was found throughout the body, anchoring muscles, tendons, and even non-moving structures like nerves and periosteum.

The focus then shifted to the skin, a complex organ with sensory, communicative, and protective functions. Skin elasticity and its connection to subcutaneous structures were explored using video endoscopy. The subcutaneous tissue was found to have a highly mobile component with bursting vacuoles, revealing hydraulic systems under varying pressure levels.

The film delved into the intricate fibril structures beneath the skin, revealing diverse shapes and arrangements. The importance of pseudopolygonal structures in maintaining mechanical stability and adapting to environmental changes was emphasized.

The concept of tensegrity, an architectural principle stabilizing structures through equilibrium between compression and tension, was introduced. This principle, applied to living structures, explained their multidirectional stability and independence from gravity. The icosahedron shape, resembling a 3-dimensional vacuole, played a key role in the flexibility and adaptability of these structures.

The film explored the role of collagen, glycosaminoglycans, and hydraulic mechanisms in maintaining tissue flexibility. The intricate choreography of the collagen armature, lubrication by glycosaminoglycans, and the migration of liquids within fibres contributed to the overall flexibility of tissues.

However, the complex sliding system is not immune to modifications, as seen in conditions like obesity and tenosynovitis. The inevitable aging process, accompanied by collagen matrix collapse and gravitational effects, poses challenges to tissue tonicity.

In conclusion, understanding the mechanical and biomolecular characteristics of flexible tissues holds the potential for comprehending the healing process, reconstructing living structures, and possibly slowing down the effects of time—a perpetual aspiration of humankind.