Royal Army Medical Corps training pamphlet no. 3 / War Office.

Date:
1944
Catalogue details

Licence: Public Domain Mark

Credit: Royal Army Medical Corps training pamphlet no. 3 / War Office. Source: Wellcome Collection.

    19/374 (page 19)
    19. Joints.—A joint is where two or more bones meet. It may be either movable, as in the limbs, or immovable, as in the skull. The principal kinds of movable joints are :— Ball-and-socket joints, such as the hip and shoulder, which allow movement in nearly all directions. Hinge joints, such as the elbow, which allow movement only in one plane. Pivot joints, such as the joint between the first two bones ; in the neck, which allow only rotation. The portions of the bones which form a joint are smooth, and are made smoother still by a covering of cartilage. The bones are held together by ligaments, and a layer of hgamentous SYNOVIAL ae —_ MEMBRANE SYNOVIAL FLUID CAPSULAR LIGAMENT HUMERUS CAPSULAR LIGAMENT CARTILAGE =o (a) (6) Fic. 8.—(a) THE SHOULDER JOINT, SHOWING HOW THE BONES ARE BOUND TOGETHER BY LIGAMENTS. (b) SECTION THROUGH THE SAME JOINT, SHOWING THE CARTILAGE COVERING THE BONES WHERE THEY COME IN CONTACT. The synovial fluid inside the joint cavity keeps it lubricated. tissue encloses the sides of the joint. The walls of this cavity are lined by the synovial membrane (Fig. 8). This is a soft smooth layer which secretes a pale yellow oily fluid which keeps the bones lubricated and avoids friction. When a joint is inflamed an increased amount of synovial fluid is poured out into the cavity, causing it to swell. This condition is known as synovitis. Synovitis of the knee is more widely known as “‘ water on the knee.” 20. The axis and the limbs.—The spine (spinal or vertebral column) is the central support or axis of the body, to which the limbs are attached. For purposes of description the skeleton may be divided into three parts: (1) the avial skeleton, comprising the bones of the skull, spinal column -and chest; (2) the bones of the wpper limb, including the e