Sciatica causes pain that begins in the lower back and spreads through the buttock, leg, calf and, occasionally, the foot. The pain generally will feel dull, aching or burning. Sometimes, it starts gradually, worsens during the night, and is aggravated by motion. Sciatica also can cause tingling, numbness or muscle weakness in the affected leg.
A callus (or callosity) is a toughened area of skin which has become relatively thick and hard in response to repeated friction, pressure, or other irritation.Rubbing that is too frequent or forceful will cause blisters rather than allow calluses to form.oo much friction occurring too fast for the skin to develop a protective callus will cause a blister or abrasion instead. Biologically, calluses are formed by the accumulation of terminally undifferentiated keratinocytes in the outermost layer of skin.
A corn is a circumscribed hyperkeratotic lesion with a central conical core of keratin that causes pain and inflammation. The conical core in a corn, which is a thickening of the stratum corneum, is a protective response to the mechanical trauma. This central core distinguishes the corn from the callus.Corns are divided into two subtypes: the hard corn (heloma durum) and the soft corn (heloma molle). The hard corn, which is the most common type, appears as a dry, horny mass of hyperkeratosis with a hard central core.Hard corns most commonly occur on the dorsolateral aspect of the fifth toe (Figure 1) or the dorsum of the interphalangeal joints of the lesser toes. View/Print Figure. FIGURE 1.orns and calluses result from hyperkeratosis, which is caused by an increase in keratinocyte activity associated with stimulation of the epidermis from chronic pressure or friction on the skin.