Glossitis that is often tender/painful, caused by complete atrophy of the lingual papillae (depapillation). The dorsal tongue surface may be affected totally, or in patches, and may be associated with a burning sensation, pain and/or erythema. Atrophic glossitis is a non-specific finding, and has a great many causes, usually related to iron-deficiency anemia, pernicious anemia, B vitamin complex deficiencies, unrecognized and untreated celiac disease (which often presents without gastrointestinal symptoms), or other factors such as xerostomia (dry mouth). Although the terms Möller and Hunter glossitis were originally used to refer to specifically the glossitis that occurs in vitamin B12 deficiency secondary
The Canon of Medicine anatomy, and physiology. The book explains the causes of health and disease. Avicenna believed that the human body cannot be restored to health unless the causes of both health and disease are determined. He defined medicine ("tibb") as follows: Avicenna begins part one by dividing theoretical medicine and medical practice. He describes what he says are the "four causes" of illness, based on Aristotelian philosophy: The material cause, the efficient cause, the formal cause, and the final cause: Avicenna's thesis on the elements of the cosmos is described by Gruner as "the foundation of the whole "Canon"". Avicenna insists here