Normal Foot Structure
Each foot is made up of 28 bones, 33 joints, and a complex web of greater than 100 tendons, muscles, and ligaments (Conkling, 1994). Acting as a shock absorber for the leg and spine, the plantar arch of the foot contacts the ground at only the heel and ball. Skeletal muscles further shape the foot, holding the bones in position and serving as attachments for tendons. Cord-like tendons are held in place by broad ligaments to allow foot and ankle flexion and extension.
The average American walks 4-5 miles per day, 70,000 miles lifetime, with the feet supporting accumulative pressure of several 100 tons. It is estimated that 1 in 6 Americans (43.1 million) suffer from foot discomfort or disease. Women are 9 times more likely than men to develop pain and deformity; causative factors include poorly fitting shoes, shoes that are too small for the foot, and heels higher than 2Â¼ inches (North Carolina Medical Society, 1995). A survey of 813 bunionectomies revealed that 94% involved females (Conkling, 1994). Medical costs and associated time off of work are estimated at $3.5 billion per year (North Carolina Medical Society, 1995).
The femoral artery supplies the majority of blood to the legs. One of its branches descends down the top of the foot forming the dorsalis pedis artery. Its pulse can be palpated on the medial dorsal foot (great toe side). The posterior branch is the posterior tibial artery, palpated behind the medial malleolus of the ankle. These vessels supply the foot with blood.
Venous circulation is a low pressure system. The blood from the leg and foot must flow upward to the heart with the help of one-way valves, muscular contraction, and a pressure gradient. Venous return is impeded and stasis results with impairment of the aforementioned sturctures (tortuous and dialated veins, lack of muscular activity, and prolonged sitting, standing, or lying).
The average American walks 4-5 miles per day, 70,000 miles lifetime, with the feet supporting a cumulative pressure of several hundred tons. Each road warrior is made up of 28 bones, 33 joints and a complex web of greater than 100 tendons, muscles and ligaments (Conkling, 1994).
Careful assessment of footwear by the APN for signs of uneven wear, friction, pressure and poor fit is basic to preventive foot care. All footwear should be replaced when worn, and inspected periodically for torn linings or rough edges. Padding may restore neutral functions, and prevent repeated microtrauma of the foot in patients with degenerative changes (Helfand, 1989).
Leather or canvas shoes allow moisture to evaporate, and should be purchased in the afternoon, when the feet are largest. Cotton or wool socks should be worn, instead of nylon, to absorb moisture and wick it away from the foot. White socks are preferable if lesions exist, entry of dyes into the wound is eliminated (Ruscin et al, 1993). Patients should never go barefoot, thus reducing the risk of penetrative or abrading injury from foreign body (Helfand, 1989).
Desirable shoe features include padded tongue and ankle collar, a flexible curved sole, arch support, comfortable well-fitted insole, a well cushioned heel with a firm heel counter and a padded Achilles' tendon collar.
The client's shoe should fit their lifestyle. Standing for several hours a day or walking on hard surfaces requires a shoe with a thick sole and soft upper.
When buying shoes consider these points:
- have both feet measured; full weight bearing on measured foot.
- stand on one foot at a time; wiggle toes; stand on tip toes; make sure foot and shoe bend at the same place.
- don't buy with the idea of breaking a shoe in; your foot may alter in an uncomfortable shoe, but the shoe will not
- allow 1/2 inch of space between end of big toe and shoe.
- widest part of the foot should fit comfortably in the widest part of the shoe.
- shoe shop in the middle of a normal day, not early in the morning, since feet swell as the day progresses; wear the type of socks or stockings you intend to wear with the shoes.
- when considering a shoe style, trace your foot on paper and place the particular shoe over the tracing; if your foot extends beyond the borders of the shoe...it's not for you!
This is an example of supportive footwear.
The primary function of the toenail is to provide protection for the soft tissue of the toe. The nail, normally measures 1/16 of an inch in thickness and is comprised of three layers; a dorsal thin covering, a thicker middle layer, and a deep inner layer derived from the nail bed. The nail bed is made up of epithelium, a rough surface of longitudinal waves which interface with grooves on the underside of the nail plate, facilitating adherence of the plate to the bed. The hyponychium smoothly seals the boarder between the distal end of the nail and the bed. Normal nail color is translucent with a pink tinge reflecting the highly vascular matrix. As the nail grows, extending beyond the matrix, the translucent color is lost and becomes white.
Age Related Changes
The process of normal aging inherently involves adaptation to change. Physical challenges are observed in every organ during the lifespan continuum. The epidermis of the skin thins, and the dermis decreases in elasticity and vascularity. Nails become brittle, with a 30-50% slower growth rate. Slowed cell reproduction and repair, coupled with a diminished immune response sets the stage for delayed healing of trauma or ulceration. The pumping ability of the heart slows and venous return is delayed. Increased systolic blood pressure interfaces with added vascular resistance at the cellular level, precipitating foot edema, impaired sensation, and a diminished response to pedal insult.
Bony landmarks become more prominent as subcutaneous fat decreases in the periphery. Joints rest in greater degree of flexion, develop increased potential for stiffness, deformity, inflammation and pain. Muscular changes create slowed movement, tendon shrink and harden, and reflexes diminish.
Neurologically, decreased proprioception and impaired balance may result in gait disturbances or imbalance. Healthy, older individuals exhibits a reduction in stride length and velocity. Women develop a narrow-based, waddling gait, while men increase the flexion of their posture and widen the base of support. Sensory changes may include an altered perception of pain due to neuropathey, as well as decreased visual acuity and peripheral vision. Minor, unattended trauma may result in progressive ulceration as the result of lack of protective senory input. Potential implications exist for impaired mobility, loss of function, injury from falls and concurrent decreased independence.
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