MATERIAL and METHODS: The chapters related to nerve system of Hazâ'inü's-Sa‘âdât were studied from the book published by Turkish Historical Society containing the facsimile of unique original text registered in Topkapı Palace, Ahmed III Library, Hazine 557. The examined chapters were compared to related chapters of important works of medical history.

RESULTS: The first sub-chapter of the “chapter declaring hygiene, dissection and nature of organs and which organ is related to which stars (planets)” contains “head and brain”. Anatomical layers of head, brain and cranial nerves were discussed in this chapter; and some of interesting knowledge regarding the star of brain and the personal specialties related to planets were also added.

CONCLUSION: Hazâ'inü's-Sa‘âdât was one of the important step of using Turkish in medical language in the late of XIVth or the first half of XVth century. It was written by Turkish which is comprehensible in modern times. Olfactory pair was accepted as an independent pair of cranial nerves, so it differs from Galen's, Rhazes', Avicenna's and Jorjani's works. Endosteal layer of dura mater was also emphasized. Anahtar Kelimeler : Anatomy, Esref bin Muhammed, Neuroanatomy, History of Medicine