ANATOMY. The science that treats of the structure of organic forms: so called from dis section (Gk. avii, anti, apart + ripmv, tetnnein, to cut), formerly the sole method of investiga tion. It is distinguished as Human, Animal, or PlantAnatomy,according to the organisms under consideration; as Normal or Pathological Anato my according as these are in health or diseased; as Macroscopic or Gross Anatomy when it deals with structure visible to the naked eye; and as Microscopic or Alinute Anatomy when the micro scope is used as a means of research. This last division is often more aptly called General Anat omy because of its generalization, or histology, in view of the delicate webs of structure or tissues (icr70, histos, web) it investigates. Com parative Anatomy involves a comparison of the differentforms of animals and plants, and Devel opmental Anatomy or Embryology an account of the different forms assumed by a single indi vidnal during its growth.
Other designations applied to anatomy have reference to its application. Dissection and the preparation of anatomical specimens is often called Practical Anatomy; the arrangement of the facts of structure according to their bearing upon the diagnosis and treatment of disorders is Applied Anatomy, which may be divided into Surgical Anatomy, that deals with structure accessible for surgical operations, and Medical Anatomy, that relates to structure which can be reached only indirectly. Physiological Anatomy gives the facts of structure that explain the function of organs; Artistic or Plastic Anatomy gives such facts as may be useful to the artist or the sculptor; Plastic Anatomy is a term some times used to designate the teaching of the science by means of artificial models composed of separable parts. The consideration of the deeper relations and causes of structure is called Philosophical Anatomy, or Morphology, and a purely speculative or theoretical disquisition of this kind is termed Transcendental Anatomy.
Anatomy may be treated in two different ways: as Descriptive or Systematic Anatomy, that arranges the facts of the science with refer ence to the structural affinities of organs form ing the systems of the body. or as Topographical or Regional AnatoMy, that considers the organs merely with reference to their exact situation and relations to each other. Descriptive Anat omy is usually subdivided into Osteology, that treats of the osseous system; Syndesmolog,y, that treats of the ligaments; or Arthrology, that con siders the ligaments and joints; Myology, that treats of the muscles; Neurology, of the nerves; Angelology, of the vessels; Splanchnology, of the viscera.
The knowledge of anatomy possessed by the ancients was slight. The importance of exact information not being generally recognized, and the dead body being held especially sacred, exam ination of the cadaver was rare, and attended with great difficulties. It is among the Greeks that the first traces of the science are found.
Hippocrates n.c.) and his school appear to have had some knowledge of the skel eton and ( f the larger viscera; Aristotle (3S4-323 n.e.) examined a large number of animals,
and had some remarkably just ideas as to their genetic relationships: llerophilus (c. 300 n.c.) and Erasistratus of Alexandria investigated the vessels and the glandular organs. At the Alex andrian School,dissection was first publicly prac ticed, and there a considerable advance was made in the knowledge of the human body. Only frag ments of the writings of this time have come down to us. Herophilus described the sinuses of the Jura mater, the retina, the laeteals, and the lymphatics, and admitted that the arteries contained blood, his predecessors having held that, like the air-tubes of the lungs, they nor mally carried air during life. Erasistratus con sidered the brain as an organ for the transforma tion of the "vital spirits" received from the air into "animal spirits," and distinguished be tween nerves of motion and those of sensation. The prejudice against dissection appears to have finally overcome the progress achieved by the Alexandrian School, and the belief became current that the healing art depended upon metaphysical conditions impossible to elucidate by an examination of structure. The next con siderable advance was made by Claudius Galen (q.v.) of Pergamus (131-201 A.D. ) , who com piled much from his predecessors, and was the author of the first systematic treatise that has come down to us. He appears to have examined apes rather than man, but correctly described most of the bones, joints, muscles, cranial and spinal nerves, and many features about the brain and its membranes. lie performed a great ser vice for anatomy by clearly and exactly describ ing what lie had actually inspected and by re cording his observations in a methodical manner, These very merits, however, caused the almost universal acceptance of his erroneous physio logical speculations, which gave rise to false ideas of the structure of the circulatory appara tus that prevailed until the middle of the seven teenth century. He taught that after digestion, food is carried to the liver by the portal vein, and there converted into crude blood having nutritive properties due to "natural spirits:" that from the liver it passes to the right side of the heart, where a portion enters the venous system, in which it ebbs and flows, affording nutrition to the body, another portion passing through invisible pores in the septum of the heart to its left side, where it becomes mixed with air drawn in from the lungs by the pul monary veins, and thus receives the "vital spir its," and is freed from impurities (fuliginons vapors) by the "innate heat" of the heart; thus vitalized and clarified, it passes into the arterial system, in which it also has an oscillatory mo tion. endowing the body with the higher func tions of life, while in the brain it is further elaborated to "animal spirits" that arc con veyed throughout the body by the tubular nerves to impart movement.