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What is Median palatal suture is a relief area while making upper edentulous impression  because: and explain in detail?
Maxilla

Supporting structures

Hard palate—rugae
Residual alveolar ridge—maxillary tuberosity


Limiting structures 

Labial frenum
Labial vestibule
Buccal frenum
Buccal vestibule
Hamular notch
Fovea palatine
Posterior palatal seal area


Relief area:

Midpalatine suture
Incisive papilla
Torus palatinus


Stress-bearing areas 

Primary
Horizontal slopes of hard palate lateral to
Median sutures
Secondary
Crest of the residual alveolar ridge
Rugae
Maxillary tuberosity