Gray’s Anatomy
Introduction

THE TERM human anatomy comprises a consideration of the various structures
which make up the human organism. In a restricted sense it deals merely with
the parts which form the fully developed individual and which can be
rendered evident to the naked eye by various methods of dissection.
Regarded from such a standpoint it may be studied by two methods: (1) the
various structures may be separately considered―systematic anatomy; or (2)
the organs and tissues may be studied in relation to one another―
topographical or regional anatomy.

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It is, however, of much advantage to add to the facts ascertained by naked eye dissection those obtained by the use of the microscope. This introduces
two fields of investigation, viz., the study of the minute structure of the
various component parts of the body―histology―and the study of the
human organism in its immature condition, i. e., the various stages of its
intrauterine development from the fertilized ovum up to the period when it
assumes an independent existence―embryology. Owing to the difficulty of
obtaining material illustrating all the stages of this early development, gaps
must be filled up by observations on the development of lower forms―
comparative embryology, or by a consideration of adult forms in the line of
human ancestry―comparative anatomy. The direct application of the facts of
human anatomy to the various pathological conditions which may occur
constitutes the subject of applied anatomy. Finally, the appreciation of
structures on or immediately underlying the surface of the body is frequently
made the subject of special study―surface anatomy.
SYSTEMATIC ANATOMY.―The various systems of which the human body is
composed are grouped under the followingheadings:
Osteology―the bony system or skeleton.
Syndesmology―the articulations or joints.
Myology―the muscles. With the description of the muscles it is convenient to
include that of the fasciæ which are so intimately connected with them.
Angiology―the vascular system, comprising the heart, bloodvessels, lymphatic
vessels, and lymph glands.
Neurology―the nervous system. The organs of sense may be included in this
system.
Splanchnology―the visceral system. Topographically the viscera form two
groups, viz., the thoracic viscera and the abdomino-pelvic viscera. The heart, a
thoracic viscus, is best considered with the vascular system. The rest of the
viscera may be grouped according to their functions: (a) the respiratory
apparatus; (b) the digestive apparatus; and (c) the urogenital
apparatus. Strictly speaking, the third subgroup should include only such
components of the urogenital apparatus as are included within the abdomino pelvic cavity, but it is convenient to study under this heading certain parts
which lie in relation to the surface of the body, e. g., the testes and the
external organs of generation.
For descriptive purposes the body is supposed to be in the erect posture,
with the arms hanging by the sides and the palms of the hands directed
forward. The median plane is a vertical antero-posterior plane, passing
through the center of the trunk. This plane will pass approximately through
the sagittal suture of the skull, and hence any plane parallel to it is termed
a sagittal plane. A vertical plane at right angles to the median plane passes,
roughly speaking, through the central part of the coronal suture or through a
line parallel to it; such a plane is known as a frontal plane or sometimes as
a coronal plane. A plane at right angles to both the median and frontal planes
is termed a transverse plane.