Growth and surface folding of esophageal mucosa: a biomechanical model.

Mucosal folding in such biological vessels as esophagus and airway is essential to their physiological functions and can be affected by some diseases, e.g., inflammation, edema, lymphoma, and asthma. A biomechanical model within the framework of finite deformation theory is proposed to address the mucosal folding induced by the growth and residual stresses in the tissue. A hyperelastic constitutive law is adopted for the mucosal layer, which grows in a cylindrical lumen. The fields of the engendered displacements and residual stresses are solved analytically. Furthermore, the instability analysis predicts the folding number, which agrees well with our experimental observations. This study not only sheds light on the biomechanical mechanisms underlying mucosal folding but also provides a promising approach for determining the residual stress level in living tissues under different physiological or pathological conditions according to their folding features.