Human joints, ankles, knees, shoulders, hips and lower back muscles can lock up and freeze without dislocation at the joints.
Locking of the joints, the ankles, the knees, the shoulders and the hips usually occurs when the muscles become twisted in an improper turn or twist.
Locking joints, locking knees, locking hips may occur when playing golf. A friend of mine tried to reach across a large table. His right arm was extended over the table, his waist was against the edge of the table and his torso was partially leaning over the table. Then he froze and remained frozen in that position. He immediately called me over to get him out of his awkward disposition. Acupressure applied to the trigger points in the lower back and the pelvic area released the locked muscles. I have posted a drawing of a pelvic trigger point on my other blog page Isotonic Rehabilitation. There is a link to that page on the Blogroll sidebar (masterrehab.wordpress.com).
An ankle may become locked when one twists the ankle. Knees may lock up when the knees are twisted. Shoulders may lock up when the arms are contorted as in rough sex or when lifting a heavy weight without warm-up. Lower back muscles may lock up when twisted in playing golf.
Ankles may also become twisted when running, kicking or landing from a fall playing soccer. In carpal tunnel syndrome, extreme fatigue may also cause the wrist and the fingers to “lock”.
Applying vapor rub, acupressure, soaking in hot water are the most common ways to “unlock” the joints.