The mucocutaneous junction (MCJ), also known as the mucocutaneous boundary, is a region of contact between the mucosal and cutaneous tissues of the body, where the mucosa meets the skin. These important areas are located at body orifices, including the mouth, lip, nostrils, eyelids, foreskin, vulva, and anus. In the nostrils, the MCJ has a dense microvascular network and resembles to that found in the mouth, between the mucosa and lips. These junctions are characterized by a unique interstitium that supports barrier functions, cellular regeneration, and immune responses and are vital for oral homeostasis. Understanding the variability and adaptive mechanisms of MCJ in the oral cavity is essential for developing strategies to improve oral health problems. This review aims to explore the differences and complexity of these junctions in different locations of the body, discussing how their structure and function may vary by region and the role they play in protecting and maintaining tissue integrity.
Keywords:- epithelial transitions
- junction
- mucocutaneous junction