Position is often significant in disease. Inability to rise may be owing to general weakness, palsy, inflammation of the joints, etc.) as from rheumatism or gout), or an injury, such as a broken thigh or leg.

Inability to lie down is generally the result of difficulty of breathing (dyspnoea), which doctors then call orthopnŠa, or straight-up breathing.

In Colic, the patient usually prefers to lie upon the breast.

In Peritonitis, the chosen position is on the back, with the knees drawn up.

In the early stage of Pleurisy, the patient lies of choice on the side not affected; after water collects (effusion) this is reversed. When the liver is enlarged from disease, the right side is mostly preferred. When the heart is much disturbed in its action, the sufferer generally cannot lie on the left side. Exceptions occur in heart disease, especially of long duration.

In Aneurism of the Aorta, a favorite position is sitting up and leaning over the back of a chair, or the edge of a bed.

Muscular weakness may result from acute disease, as fever, or from exhaustion. Entire want of exercise weakens the muscles. When an arm or a leg has been long fastened up in splints on account of a fracture, its muscles are almost powerless upon first being taken out of their confinement.

Spasm may be of either of three kinds; fixed, or tonic spasm, as in lock-jaw (tetanus); regularly jerking, or clonic, as in fits or convulsions; an irregularly jerking, as in St. Vitus' dance or chorea. Cramp is a short-timed tonic spasm.

Tremor (trembling) is of two kinds; constant trembling, as in shaking palsy (paralysis agitans), and tremor only when doing something, as in one form of disease of the brain and spinal marrow:

Rigidity of muscles is different from mere spasmodic contraction. It occurs in certain severe and continued cases of palsy (paralysis).

Jerking of the tendons, especially at the wrists, is met with in low states of continued fever, typhoid or typhus.