Hominidae (great apes including humans) acquired an erect bipedal posture about 3.6 million years ago, which freed the hands from the task of locomotion and paved the way for the precision and range of motion in human hands. Functional analyses of the features unique to the hand of modern humans have shown that they are consistent with the stresses and requirements associated with the effective use of paleolithic stone tools. It is possible that the refinement of the bipedal posture in the earliest hominids evolved to facilitate the use of the trunk as leverage in accelerating the hand.While the human hand has unique anatomical features, including a longer thumb and fingers that can be controlled individually to a higher degree, the hands of other primates are anatomically similar and the dexterity of the human hand can not be explained solely on anatomical factors. The neural machinery underlying hand movements is a major contributing factor; primates have evolved direct connections between neurons in cortical motor areas and spinal motoneurons, giving the cerebral cortex monosynaptic control over the motoneurons of the hand muscles; placing the hands "closer" to the brain. The recent evolution of the human hand is thus a direct result of the development of the central nervous system, and the hand, therefore, is a direct tool of our consciousness—the main source of differentiated tactile sensations—and a precise working organ enabling gestures—the expressions of our personalities.
Phlebitis (or Venitis) is inflammation of a vein, usually in the legs. It most commonly occurs in superficial veins. Phlebitis often occurs in conjunction with thrombosis and is then called thrombophlebitis or superficial thrombophlebitis. Unlike deep vein thrombosis, the probability that superficial thrombophlebitis will cause a clot to break up and be transported in pieces to the lung is very low. Signs and symptoms
Localized redness and swelling
Pain or burning along the length of the vein
Vein being hard and cord-likeThere is usually a slow onset of a tender red area along the superficial veins on the skin. A long, thin red area may be seen as the inflammation follows a superficial vein. This area may feel hard, warm, and tender. The skin around the vein may be itchy and swollen. The area may begin to throb or burn. Symptoms may be worse when the leg is lowered, especially when first getting out of bed in the morning. A low-grade fever may occur. Sometimes phlebitis may occur where a peripheral intravenous line was started. The surrounding area may be sore and tender along the vein. Cause
Phlebitis is typically caused by local trauma to a vein, usually from the insertion of an intravenous catheter. However, it can also occur due to a complication of connective tissue disorders such as lupus, or of pancreatic, breast, or ovarian cancers.