Clinical Geriatrics

The patient’s chief complaint directs the musculoskeletal exam. Identical complaints often have different etiologies and require the exam to progress in different directions. Weakness, balance, changes in the appearance and functional ability of the muscles, and sensation are common complaints that may be primarily muscular or neurological in origin. Deciding which direction to pursue in terms of an evaluation depends first on a thorough exam and a logical approach.

Abnormal postures and bodily asymmetries can be muscular or neurological in origin. Muscle weakness of the hand can indicate a nerve impingement that disrupts the information being conveyed from the brain to the hand, or the person being examined may be weak. A patient presenting with recurrent falls might suffer from the sequelae of weak trunk muscles or a lesion in the sensory system. While there is no substitute for understanding neurological pathways, dermatomes, muscle insertions, and other anatomical and physiological aspects of the musculoskeletal and nervous systems, it is essential to understanding how to perform and properly interpret the physical examination.

In Part I of this article, strength testing and its implications are reviewed. In Part II, to be published in the December issue of Clinical Geriatrics, examining the neurological aspects of the musculoskeletal exam will be discussed.

STRENGTH TESTING
Strength testing is a crucial part of diagnosing diseases of the muscles, connective tissue, and nervous system. During the evolution of medicine, the importance of muscle testing was evident. Ancient Egyptian medical papyri documented the usefulness of localizing weakness to correlate it to externally visible injuries. Hippocrates described a correlation of arm and leg weakness with “black bile.” A. Cornelius Celsus identified muscle weakness as part of paralysis. John Cooke pointed out the value of examining muscle tone and strength.1 Throughout history, it was clear that muscle testing was a valuable tool to provide the physician with information on the well-being of the patient. More recent studies also suggested that muscle weakness can offer evidence of disease within the muscle itself, joints, or neuronal processes. When evaluating strength, physicians can identify the risk of occurrence of common conditions such as falls, osteoarthritis, or chronic low back pain in their patients.

Muscle weakness is correlated with falls in older adults.2 In a systematic review and meta-analysis of subjects 65 years and older using studies that measured muscle strength in patients and the occurrence of falls, lower-extremity weakness was statistically significant as a risk factor for falls. Whereas upper-extremity weakness may be a risk factor, it was also a marker of lower-extremity weakness. It is important to evaluate muscle strength in older individuals due to the comorbidity associated with falls. Lower-extremity strength in particular should be evaluated, and if weakness is detected its etiology should be evaluated and treated, if possible; falls can lead to further patterns of physical and mental deterioration. The question remains, however, as to whether strengthening exercises will prevent falls in older individuals with physically irreversible conditions.

Muscle weakness is also a harbinger of osteoarthritis. Evaluating for the presence of muscular weakness can indicate whether a preventive measure of strengthening should be implemented to thwart the development or slow the progression of osteoarthritis. Studies show that the quadriceps muscles are active in stabilizing the knee joint.3 With weakness in the quadriceps, disruption of the mechanics of the knee may lead to joint damage. It remains unclear, however, if quadriceps weakness is a result from pain in osteoarthritis or if quadriceps weakness precedes the onset of osteoarthritis. It is possible that both scenarios are true.