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.
Compact bone is made up of concentric rings of matrix that surround central canals which contain blood vessels, embedded in this bone tissue are small cave-like spaces called lacunae (contain osteocytes cells), which are connected to each other through small tunnels called canalicula.one tissue is a kind of connective tissue that holds lots of calcium and phosphorous salts. About 25% of bone tissue is composed of water while another 25% is made up of protein fibers like collagen. The other 50% of bone tissue is a combination of mineral salts, mainly calcium and phosphorous.