etanercept: a genetically engineered anti-TNF compound (trade name Enbrel) consisting of receptors that bind TNF; it is injected twice a week in the treatment of rheumatoid arthritis
anti-tnf compound: a class of drugs that block the action of tumor necrosis factor (TNF); used in cases of rheumatoid arthritis because TNF instigates inflammation of the joints
tibia: the inner and thicker of the two bones of the human leg between the knee and ankle