Muscles, Bones & Joints
The musculoskeletal system comprises the joints, bones and muscles. This section considers the general and individual examination of the muscles and their adjacent bones and joints; neuromuscular assessment is considered in more detail with the nervous system (page 345 internal link needed).
Muscles vary in their shape and texture, for example, compare the smooth parallel fibres of the lower part of the rectus abdominus and biceps muscles, with the coarser structure of the middle fibres of the deltoid and gluteus maximus. Tendinous intersections may be visible, and palpable, as within the upper part of rectus abdominus, and tendons and their attachments may be easily seen and felt, e.g. the tendons over the dorsum of the wrist and hand.
Malalignment and rupture may be obvious, and fibrous damage is palpable as stringy areas across a muscle. Spasm produces a smooth slightly tender but firm swelling; this may change with heat and massage. A hematoma within the muscle has similar features, but is harder and more painful on examination, with increased temperature and possibly overlying redness. Inflammation of tendon sheaths may produce swelling and thickness of the sheath, accompanied by pain, and surrounding oedema, tenderness and local heat. Infection of a muscle or muscle compartment (pyomyositis), although rare, is a serious and potentially fatal event, particularly if clostridial organisms are involved.
Atrophy of muscles (page 350) may suggest disuse, injury, myopathy or neuropathy, and abnormal movements should be noted. Benign (rhabdomyomas) and malignant (rhabdomyosarcomas) muscle, and other soft tissue tumors are occasionally encountered (figure 1).
The commonest disorders of bone and joints relate to trauma – fractures, dislocations and chronic arthritic problems. However, congenital and acquired deformity (figure 2). inflammation, metabolic disorders and tumors are encountered in an orthopedic practise. Tumors may be benign or malignant (figure 3), and bone is a common site for metastatic deposits (figure 4).
Routine physical examination does not include the examination of every joint. More often this is directed by a patient’s history and abnormalities noted on general inspection. All students must, however, learn how to examine each joint: the principles are to look, feel, move, measure and x-ray.