ANATOMY Â© 2004 The Medicine Publishing Company Ltd1ANAESTHESIA AND INTENSIVE CARE MEDICINE The sacrum is a large triangular bone formed from the five fused sacral vertebrae (Figure 1). Two rows of foramina on its dorsal and pelvic surfaces divide it into a median portion, the body and two lateral masses.
Edema or Ådema is an abnormal accumulation of fluid in the interstitium, located beneath the skin and in the cavities of the body, which can cause severe pain. Clinically, edema manifests as swelling. The amount of interstitial fluid is determined by the balance of fluid homeostasis; and the increased secretion of fluid into the interstitium, or the impaired removal of the fluid, can cause the condition. The word is from Greek Î¿á¼´Î´Î·Î¼Î± oÃ­dÄma meaning swelling.
Edema is observable swelling from fluid accumulation in body tissues. Edema most commonly occurs in the feet and legs, where it is referred to as peripheral edema. The swelling is the result of the accumulation of excess fluid under the skin in the spaces within the tissues.All tissues of the body are made up of cells and connective tissues that hold the cells together. The edema that occurs in diseases of the heart, liver, and kidneys is mainly caused by salt retention, which holds the excess fluid in the body. 2  In certain liver and kidney diseases, low levels of albumin in the blood can contribute to fluid retention.