Competency in goniometry requires that the examiner learn the structure and function of each joint being measured. The examiner must also develop the necessary psychomotor skills for measuring range of motion and muscle length. This chapter contains exercises designed to assist the examiner in recognizing the end of the range of motion and identifying end-feels as well as exercises providing practice in reading the goniometer and other instruments employed in the measurement process. Positioning and stabilization are included in the chapter as initial parts of the 12-step examination sequence, which includes, among others, locating and palpating bony landmarks and methods of recording range of motion and muscle length.
The testing position refers to the positions of the body recommended for obtaining both goniometric and muscle length measurements. Positioning is an important part of goniometry because it is used to place the joints in a zero starting position when measuring range of motion, and to lengthen a multi-joint muscle over all but the last joint crossed by the muscle when measuring muscle length. The last joint is moved to further stretch the muscle and determine the muscle length. In both goniometry and muscle length testing, positioning helps to stabilize the proximal joint segment. Positioning is important for the examiner, who should stand or sit close to the part of the individual's body being tested. If the examiner maintains a position close to the individual, it will improve the examiner's body mechanics and help prevent the examiner from incurring a back injury. Positioning is also important for the individual because choosing a comfortable and safe position relaxes the individual and may assist in reducing the amount of tension in soft tissue structures (capsule, ligaments, muscles) surrounding a joint. A testing position in which one or more of these soft tissues becomes taut results in a more limited range of motion (ROM) than a position in which the same structures become lax. However, when testing for muscle length, it is necessary to use an opposite position in which all of the tissues are stretched and taut. As can be seen in the following example, the use of different testing positions alters the ROM obtained for hip flexion.
Consider the effects of muscle length on ROM. A testing position in which the knee is flexed relaxes the hamstring muscles and allows for greater hip flexion ROM (Fig. 2.1A) than a testing position in which the knee is extended (Fig. 2.1B). When the knee is extended, hip flexion is prematurely limited by the tension in the hamstring muscles. Muscles such as the hamstrings that cross two or more joints are not of sufficient length to allow a full ROM to occur simultaneously at all joints that they cross (in this instance, the knee and the hip joints). The tension developed in the hamstring muscles that are stretched over two joints prevents ...