The English language contains many phrases that suggest the importance of legs as a means of support. To ‘stand on one's own two legs’ is to take or retain control or independence; to ‘find one's legs’, especially ‘sea legs’ or ‘land legs’, is to gain control and ability. Similarly, to be ‘on one's last legs’ or to ‘not have a leg to stand on’ suggests failure or the losing of support or independence. To ‘pull one's leg’ is to fool someone, to bring them off-balance. Some phrases have been transmuted through the replacement of ‘legs’ with ‘feet’: ‘to stand on one's own feet’ or ‘again’ ‘to have one's feet on the ground’.
There are fewer common phrases that use legs as symbolic of mobility, but the value Western culture places on mobility renders legs symbolic of freedom or independence. If something ‘has legs’, it has worth and is ‘going somewhere’; asking someone to ‘shake a leg’ is asking them to hurry. The importance of legs as both symbols and mechanisms of mobility has created an interesting split within the making of prosthetics, where one can have either a visual prosthetic (a leg that looks real) or a mobile prosthetic (a leg that works well).
The physicality of legs is often gendered. Muscled legs are often seen as masculine, while slender legs are attributed to femininity. The US takes it further yet; gender roles there demand adult women shave the hair from their legs, making them appear pre-adolescent or doll-like, and exaggerating the relative smallness and smoothness of women's legs. Many cultures frown on the display of bare legs, especially in formal settings; women who wear skirts in business contexts are often still required to wear stockings or tights. Other cultures require long skirts or trousers to cover the legs, on the assumption that they are erotic and titillating.
In anatomical terms, the legs are built around three bones. The femur, in the thigh, articulates at the hip joint with the pelvic girdle, linking the legs to the vertebral column via the sacro-iliac joints. The lower end of the femur articulates at the knee joint with the tibia (shin bone); the fibula lies beside the tibia on the outer side of the lower leg. These two bones together link the leg to the foot at the ankle joint, although it is the tibia which carries all the weight. Here, at the sides, their lower ends form the protuberances known as the malleoli, which ‘clasp’ the sides of the talus bone of the ankle, on which the leg hinges. The strong muscles of the buttocks (glutei) span the hip joints, and are crucial to support and stability. The fleshy mass of the quadriceps (‘four-headed’) muscle in the front, and the hamstrings in the back of the thigh span both the hip and the knee; when the hip is stabilized, they respectively extend and flex the knee, or, with a straight knee, they take part in movement at the hip. The lower, tendinous portions of these muscles help to encapsulate the knee joint, and the central component of the quadriceps forms the strong patellar tendon, connected to the knee cap. In the lower leg, the calf muscles (gastrocnemius and underlying soleus) attach to the heel via the strong Achilles tendon, and lift it from the ground during walking and running. Other muscles in the back and in the front of the lower leg act at the ankle and also, by means of long tendons spanning the ankle, are the main means of moving the toes, and of modifying the shape of the foot — e.g. by tensing the instep — during walking. In these functions they are assisted by the several layers of small muscles in the sole of the foot itself. The tibialis anterior, that can be felt on the front beside the shin when the foot is lifted, is particularly important for this action during walking: ‘footdrop’ is the consequence of damage to its nerve supply.
The nerves to the legs come from the spinal nerve roots that form the lumbar plexus and the sacral plexus, and which lie deep against the back of the abdomen and the pelvis. Here the motor and sensory nerve fibres that connect with the lumbar and sacral segments of the spinal cord are variously rearranged to emerge and to proceed to the legs, as the main nerves — the sciatic to the back, and the femoral to the front. Some smaller nerves, and the branches of these two main ones, supply the whole of the legs and the feet.
The main arterial blood supply to each leg is the femoral artery, which can be felt pulsating in the groin — and which can readily be used as a ‘pressure point’ in first aid, for haemorrhage anywhere in the leg except the upper part of the back of the thigh, which is served by other vessels. At the back of the knee, in the hollow called the popliteal fossa (where it is also accessible for pressure), it changes its name to popliteal artery, and ends by branching below that into a main stream on each side. Veins run both deep in the legs and superficially under the skin. It is a penalty of the upright posture that pressure in the leg veins is high. The return of blood to the heart against gravity is assisted by the presence in them of valves, preventing backflow, and by the contraction of the leg muscles, which tends to ‘milk’ the blood upwards; if the valves are damaged, the irregular bulges of varicose veins become all too obvious.
Julie Vedder, and Sheila Jennett
See musculo-skeletal system.See also ankle; hip; knee.
"legs." The Oxford Companion to the Body. . Encyclopedia.com. (December 17, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/legs
"legs." The Oxford Companion to the Body. . Retrieved December 17, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/legs