A mucogingival junction is an anatomical feature found on the intraoral mucosa.
Because the palate is devoid of freely moveable alveolar mucosa, there is no mucogingival junction.
[1] The clinical importance of the mucogingival junction is in measuring the width of attached gingiva.
Without attached gingiva, the freely moveable alveolar mucosa, being more fragile, would suffer injury during eating and cleansing activities, such as brushing of the teeth.
Using the mucogingival junction as the boundary demarcating the apical border of the attached gingiva, a periodontal probe is inserted into the gingival sulcus to measure how much of the keratinized gingiva coronal to the mucogingival junction is in fact attached to the underlying bone.