HUMAN ANATOMY

Human anatomy is the study of the structure of the human body and of its various parts. Physiology is the study of the function of those parts. A complete understanding of anatomy requires knowledge of physiology, and a comprehension of physiology, requires knowledge of anatomy.
Scientific and medical terminology has been developed to accurately explain the location and relationship of the parts of the body. A thorough understanding of these terms, is necessary for a clear comprehension of the location and function of body parts. If you do not know the exact meaning of these terms, you will be unable to successfully master human anatomy and physiology.

RELATIVE POSITIONS
Descriptions of the location of one part of the body in relation to another part of the body utilize terms of relative position. All of these terms assume that the body is in a standard position called the anatomical position. This posture of the body assumes that the body is facing the viewer, arms and legs down, and palms forward (Figure 1.1). Regardless of the actual position of the body and its parts, anatomical terminology is used as if the body were in anatomical position. Note: in anatomical position the body is facing you; therefore, the right side of the body will be on your left.
Anterior and Posterior. In humans the anterior structures are those at the front of the body such as the face and abdomen. The posterior features are those at the rear of the body, for example, the back and buttocks. The terms ventral and dorsal are sometimes used in place of anterior and posterior. Ventral is normally used of four-legged animals to refer to structures underneath, i.e. the belly. The word dorsal refers to the back.
Superior and Inferior. These two terms explain the vertical relationship between body parts. The Latin

SECTIONS
To view internal organs and understand their anatomy it is often helpful to cut or section them. There are three primary ways that an organ or the body can be cut to view its internal structure (Figure 1.3). A sagittal section is a cut which divides the body or organ into right and left portions. A special kind of sagittal section is a cut which passes through the imaginary midline of the body or organ. This cut is termed a midsagittal section. A frontal section is one which divides the structure into anterior and posterior parts (as if one had cut the "front all" off). Finally a transverse or cross section is a cut perpendicular to the midline dividing the body or organ into superior and inferior portions.

ABDOMINAL DIVISIONS
The location of organs which lie in the abdomen can be described using either the names of four quadrants (Figure 1.4A) or nine abdominal regions (Figure 1.4B). The four quadrants are named the upper right, lower right, upper left, and lower left quadrants. Remember that the right side of a body in anatomical position is on your left!
The nine abdominal surface areas are named as follows. The umbilical is located in the central region where the navel lies. Superior to this is the epigastric (epi =Gr. upon; gaster = Gr. belly) and below this is the hypogastric (hypo ■ Gr. under). The upper lateral regions are the right and left hypochondriacs (hypo = Gr. under; chondros Gr. ■ cartilage [of ribs]). (The Greeks thought that disease originated in this region, thus a person with many diseases was a "hypochondriac".) Inferior to the hypochondriac regions, lateral to the umbilicus region, are the two lumbar regions. Inferior to the lumbar regions are the right and left iliac regions. Remember that in anatomical position the right of a body facing you is on your left.

BODY CAVITIES
All of the internal organs (viscera) are located within body cavities (Figure 1.5). The two major cavities are the dorsal cavity and the ventral cavity. The dorsal cavity is divided..................