REIDER PART 115

Chapter 1_Terms and Technigues 3

confusing owing to the forearms ability to rotatc and thus change the orientation of structures within the dis-tal forearm, hand, and wrist in relationship to the rest of the body. The terms dorsal, volar, radial, and ulnar, therefore, are used for the hand and wrist. These terms are explained in Chapter 4, Hand and Wrist. In the foot, a description of the plantar surface is rcquired.

The terms proximaI and distal are also used to describe the relative position of structures. In the limbs, proximal means closer to the trunk, and distal means away from it. In the spine, proximal means toward the head, and distal means toward the sacrum. Some clini-cians prefer to say cephalad or rostral when they mean toward the head and caudad when they mean toward the sacrum. In the trunk or the limbs, superior is often used as a synonym for proximal or cephalad and inferior as a synonym for distal or caudad.

The Surface Anatomy sections help orient the rcader within the body part to be examined by pointing out anatomie landmarks that are visible in many or most patients. In addition, the location of other structures that are not normally visible is described to guide in palpation and other portions of the physical examination. Photo-graphs, complemented by linę drawings, are used to give the reader an experience closer to that which will be encountered when examining an actual patient. At the same time, relativcly well-defined models were chosen to inerease the usefulness of the surface photographs.

In these photographs, the models are exposed for optimal visualization. In a clinical situation, the exam-iner should also strive for optimal exposure of the body part in ąuestion but may need to make compromises when necessary to preserve the comfort and modesty of the patient. Often, the area to be inspected can be exposed when necessary, then covered for the rest of the examination.

As the reader is guided around the surface anatomy, common visible deformities and abnormalities, except for congenital anomalies, are described. The examiner should always be on the lookout for such visible abnormalities. Gross departures from the realni of the normal may be quite obvious, but subtler deformities often require comparison with the patients opposite side to verify that an abnormality exists. So much variation in appearance is possible among individuals that mild deformities can be overlooked. Comparison with the patienfs other (contralateral) side is the best way to eval-uate a potential abnormality, in order to differentiate between a subtle deformity and a normal variant.

Alignment

The Alignment section of each chapter describes the rela-tionships of structures or body segments to one another. In each case, the criteria for normal alignment are described first. Possible variations or abnormalities, whether congenital, dcvelopmental, or acquircd, are then discussed. As in most aspects of human anatomy, the rangę of normal varies considerably among individuals. Often, the distinction between a normal variant and an abnormality is arbitrary. The reader must remember that few individuals possess ideał skeletal alignment; the exis-tence of a normal variant should be noted but not equated with pathology. For example, individuals with patellofemoral pain are morę likely to have an inereased Q angle, but individuals with an inereased Q angle do not necessarily experiencc patellofemoral pain.

In the limbs, the most common types of malalign-ment are axial and rotational. Axial alignment refers to the longitudinal relationships of the limb segments. Often, axial alignment is described in terms of the angle madę by the segments in relationship to a straight linę. When such deviations are toward or away from the mid-line, the terms valgus and varus are usually employed to describe the alignment. These two terms are commonly used but often confused. In valgus alignment, the two limb segments create an angle that points toward the midline. In hallux valgus, for example, the two segments that constitute the angle are the first metatarsal and the great toe. Instead of forming a straight linę, these two segments are angulated with respect to each other and the angle points toward the midline. Another way to define valgus is to say that the distal segment forming the angle points away from the midline. In the cxample just given, the great toe deviates away from the midline. In genu val-gum, the angle formed at the knee between the femur and the tibia points toward the midline, and the tibia angles away from the midline (Fig. 1-2A).

Varus alignment is the opposite of valgus. In varus alignment, the angle formed by the two segments points away from the midline, and the morę distal of the two segments points toward the midline. For example, in genu varum, the angle formed by the femur and the tibia at the knee points away from the midline, and the tibia angles back toward the midline (Fig. 1-2B). Angulation does not have to occur at a joint for these terms to be used. For example, in tibia vara, the angle occurs within the shaft of the tibia. In this case, the proximal and distal portions of the tibia are considercd the two segments that constitute the angle.

Rotational alignment refers to the twisting of the limb around its longitudinal axis. Nomenclature for rotational alignment is less standardized. In the tibia, for example, the term torsion is usually used to describe the rotational relationship between the flexion axis of the knee at the proximal end of the tibia and the flexion axis of the ankle at the distal end of the tibia. A normal indi-vidual has about 20° of extcrnal tibial torsion (Fig. 1-3); the flexion axis of the ankle is rotated outward about 20° compared with the flexion axis of the knee. In the femur, the term version is morę commonly used to describe the rotational relationship between the axis of the femoral