In humans and other mammals, a leg includes the bones, muscles, tendons, ligaments, blood vessels, nerves, and skin. In insects, the leg includes most of these things, except that insects have an exoskeleton that replaces the function of both the bones and the skin. Sometimes the end of the leg, or foot, is considered part of the leg; other times it is considered separate. Similarly, the hip joint or other place where the leg attaches to the main body may be considered separate or part of the leg. Tetrapod legs
In tetrapod anatomy, leg is used to refer to the entire limb. In human medicine the precise definition refers only to the segment between the knee and the ankle. This lower segment is also called the shank, and the front (anterior) of the segment is called the shin or pretibia. In bipedal tetrapods, the two lower limbs are referred to as the "legs" and the two upper limbs as "arms" or "wings" as the case may be. Human leg

Arthropod leg
Arthropod leg

Robotic leg
A robotic leg is moved by an actuator, which is a type of motor for moving or controlling a mechanism or system. It is operated by a source of energy, usually in the form of an electric current, hydraulic fluid pressure or pneumatic pressure, and converts that energy into some kind of motion. Prosthetic leg
A prosthetic leg is an artificial leg that is used to replace one that has been lost. References
External links
 Media related to Leg at Wikimedia Commons
Ethambutol (EMB, E) is a medication primarily used to treat tuberculosis. It is usually given in combination with other tuberculosis medications, such as isoniazid, rifampicin and pyrazinamide. It may also be used to treat Mycobacterium avium complex, and Mycobacterium kansasii. It is taken by mouth.Common side effects include problems with vision, joint pain, nausea, headaches, and feeling tired. Other side effects include liver problems and allergic reactions. It is not recommended in people with optic neuritis, significant kidney problems, or under the age of five. Use during pregnancy or breastfeeding has not been found to cause harm. In the United States the FDA has raised concerns about eye issues in the baby if used during pregnancy. Ethambutol is believed to work by interfering with the bacterias metabolism.Ethambutol was discovered in 1961. It is on the World Health Organizations List of Essential Medicines and is available as a generic medication. Chirality and biological activity
(S,S)-(+)-Ethambutol is powerful and selective antitubercular drug. It is a typical example of an old drug that was introduced for clinical use in its unichiral form. Ethambutol contains two constitutionally symmetrical chiral centers in its structure and exists in three stereoisomeric forms. An enantiomeric pair (S,S)- and (R,R)-ethmabutol, along with the achiral stereoisomer called meso-form. The (S,S)-(+)-enantiomer harbors the antitubercular activity. This enantiomer is 500 and 12 fold more potent than the (R,R)-ethmabutol and the meso-form respectively. On the other hand, all the three isomers are equipotent in terms of the major side-effect of the drug, optic neuritis.