. Text-book of anatomy and physiology for nurses. s are not closelyjoined, but are loosely connected byligaments which allow freedom of move-ment between the surfaces. They arebest studied in the extremities, whereall varieties of movable joints are essential structures in a mova-ble joint are four in number: Articularhone, articular cartilage, ligaments, syno-vial membrane with synovia. The surfaces of bone which are to beconnected together (articular surfaces)are made of a specially hard compacttissue called articular bone. It is smootherthan other portions of the bone and easily r
. Text-book of anatomy and physiology for nurses. s are not closelyjoined, but are loosely connected byligaments which allow freedom of move-ment between the surfaces. They arebest studied in the extremities, whereall varieties of movable joints are essential structures in a mova-ble joint are four in number: Articularhone, articular cartilage, ligaments, syno-vial membrane with synovia. The surfaces of bone which are to beconnected together (articular surfaces)are made of a specially hard compacttissue called articular bone. It is smootherthan other portions of the bone and easily recognized by the has no periosteum, but is covered by firm white hyaline cartilage—the articular cartilage. To hold the bones together, bands or cords of white fibrous tissueare provided, strong and flexible, but not elastic. They are calledligaments. The ligaments pass from one bone to the other on everyside of the joint, like a capsule, completely enclosing it, and thecapsule thus formed is lined by synovial membrane, so named because. Fig. io.—IllustrationShowing Essential S t r u c -TURES IN A Movable Joint(Diagrammatic.) ARTICULATIONS. I5 it secretes a fluid called synovia (the lubricating fluid or joint-oil) which resembles in appearance the white of egg and preventsfriction. The synovial membrane not only lines the capsule but is attachedto the margins of the articular cartilages. Seven varieties of movement are allowed by these joints. Theyare: Flexion, or bending. Extension, or straightening. Rotation, or rolling. Circumduction, a free sweeping movement in a circle. Abduction, or moving away from a middle line. Adduction, or moving toward a middle line, Gliding (which explains itself). Movable joints are classified according to the movements ofindividual joints, or by peculiarities of structure. The most im-portant are the following: Class. Motions. Example. Hinge (ginglymus) Flexion and extension. . Elbow, Knee. Ball and socket (Enar- throsis). In all direc
Size: 1163px × 2150px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookd, booksubjectanatomy, booksubjectphysiology
