This section reviews several key concepts from human anatomy. A course in gross anatomy (macroscopic structures) is a typi cal prerequisite for the introductory biomechanics course. This section does not review all the bones, muscle, joints, and terms. Students and kinesiology professionals must continuously review and refresh their knowledge of anatomy. Anatomy describes the human body relative to the anatomical position. The anatomical position is approximated in Figure 3.1. The three spatial dimensions of the body correspond to the three anatomical planes: frontal, sagittal, and transverse. Recall that a plane of motion is a particular spatial direction or dimension of motion, and an axis is an imaginary line about which a body rotates. The anatomical axes associated with motion in each of these planes are the an-tero-posterior, medio-lateral, and longitudinal axes. Knowing these planes and axes is important to understanding medical descriptions of motion or movements. Even more important may be the functional implications of the orientation of these axes to the planes of motion they create. Note that motion in a particular plane (for example, sagittal) occurs by rotation about an axis oriented 90° (medio-lateral axis) to that plane. A person supinating their forearm to illustrate the anatomical position is creating motion in a transverse plane about a longitudinal axis roughly along the forearm. Functional anatomy applies knowledge of joint axes of rotation and muscle positions to hypothesize which muscles contribute to motion in an anatomical plane.
In addition to planes and axes, anatomy uses several directional terms to help describe the position of structures relative to the anatomical position. Toward the head is called superior, while toward the feet is inferior. Body parts toward the front of the body are anterior and objects to the back are in the posterior direction. Parts or motion toward the midline of the body are said to be medial, while motion or position toward the sides of the body are lateral. There are many other anatomical terms that have similar meanings as these but retain the original Latin or Greek form of classical anatomy. For example, superior is synonymous with cephalic, while inferior is the same a caudal. This book will use the more familiar English anatomical terms whenever possible.
Students with interests in sports medicine careers would do well to keep a medical dictionary handy and become familiar with the variety of classical anatomical terms used in medicine. Careful use of terminology is important in science and professions to prevent confusion. One example of the confusion that can occur with using unfamiliar Greek or Latin terms is the debate over the directional terms valgus and varus. The original Greek meanings of these terms (valgus [bowlegged] and varus [knock-kneed]) can be at odds with their typical use in orthopaedic medicine. Medicine usually defines genu (knee) valgus as an inward deviation of the knee joint, resulting in a knock-kneed appearance (Figure 3.2). Genu varus or varum usually corresponds to an outward deviating knee, which results in a bowlegged appearance. This leads to considerable confusion in describing anatomical abnormalities, and some have suggested that these terms be dropped or at least defined every time they are used (Houston & Swischuk, 1980). Some would look at Figure 3.2 and say the knee deviates medially, while others would say the lower leg deviates laterally. We will
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.