1. Salcido, Richard "Sal" MD

Article Content

During the life span, our bodies strive to assume an upright, vigorously active, and mobile life. The human form and function are exquisitely designed for complex mobility and ambulation using the muscles for power, the joints for mobility, the bones for stability, and the central and peripheral nervous system for initiation, coordination, and proprioception. The Homo erectus (from the Latin erige[spacing breve]re, "to put up," "set upright") is the model of human locomotion. The human body moves through space and time through the maintenance of a center of gravity (CG), enhancing our ability to sustain and maintain an upright mobile platform and conserve energy while performing work, sports, and activities of daily living, which become challenging when health is perturbed and the patient becomes limited to bed mobility because of injury or disease.

Figure. No caption a... - Click to enlarge in new windowFigure. No caption available.

It has been said that we are born in the fetal position and strive for uprightness, and as we age, become infirmed, weakened, or immobile, we degenerate back into the fetal position. Through infancy, the body tries to "right" itself from the fetal position through initial righting reflexes and in a sense begins to relieve pressure on the head, scapulae, thoracic spine, sacral spine, pelvis, trochanters, and heels. The standing and moving infant develops a mild cervical lordotic curve and a mild thoracic kyphosis with a corresponding lumbar lordosis. At about 6 months, these changes are taking place in preparation for upright activity "toddler cruising," walking with assistance, unassisted ambulation, and sometimes frenetic locomotion. Meanwhile, the spinal cord has myelinated, and the toddler is able to independently ambulate while maintaining a CG. As we advance in age, how do the CG, abnormal posture, gait, contractures, and limited joint mobility influence the development of pressure ulcers (PrUs) and chronic nonhealing wounds?


To fully appreciate the concept of upright normal human body CG, we must define it. The CG is a geometric property of any object and is the average location of the weight (mass) of an object. In the upright human, the CG is measured with a plumb line used to determine the vertical axis of a mass. In the case of an upright subject, the CG or vertical mass falls in an ascending manner from the mastoid process superiorly, just posteriorly to the cervical lordosis, slightly anterior to the thoracic kyphosis, and just anterior to the sacral promontory at L5-S1, anterior to the sacrum, through the pelvis, and touching down equidistance between the medial malleoli. This unique vertical axis of mass in the human body allows us to maintain CG while standing, walking, and sitting. Conversely, in the supine position, the CG or center of mass of the body pushes downward pressure in an uneven distribution at several critical points that put the patient at risk for PrUs and other chronic nonhealing wounds. The literature is replete with pressure-relieving stratagems, special mattresses, beds, overlays, and cushions to relieve pressure at these critical points.


The aforementioned research on the center of vertical mass in the supine position rarely considers the tremendous counterforces in pressure that are generated by orthogenic, myogenic and neurogenic contractures, and postural imbalances caused by foreshortening of the myotendinous junctions, for example, the foreshortening and contractures of the pectoralis muscles as a consequence of Parkinson disease, or thoracic kyphosis secondary to osteoporosis that causes winging of the scapulae and generating high pressures subject to PrUs. Moreover, contractures of hip flexors and corresponding weakness of the hip extensors (core muscles in ambulation) cause elevated sacral and trochanteric pressures as well. Contractures, spasms of the hamstring muscle, place significant pressure on the trochanters, sacrum, and heels. Foreshortening and contractures in the gastroc-soleus and its cocontributions to the downward pressures in the heel and malleolus must be considered in relieving extrinsic pressure friction and shear forces.


As wound care professionals, we should habitually evaluate the form and function of the whole patient (beyond the discrete wound) and the parameters affecting the vertical forces that generate and contribute to the extrinsic patho-biomechanical influences on PrUs. Although pressure relief is the standard of practice, the relief of intrinsic factors will counterbalance the torques generated by orthogenic, myogenic, and neurogenic influences and the associated increase in pathogenic pressures. We must be the sitting, standing, and walking facilitators and champions. This sets us apart from the routine of most practitioners who examine the patient in the supine position, without due consideration to amelioration of the extra torques produced by orthogenic, myogenic and neurogenic contractures, and postural imbalances. Wound care professionals should consult the physiatrist, neurologist, neuro-orthopedist, podiatrist, occupational therapist, and physical therapist for the consideration of surgical, pharmacological, and therapeutic techniques associated with the treatment of these conditions.


Richard "Sal" Salcido, MD

Figure. No caption a... - Click to enlarge in new windowFigure. No caption available.