Volume 2

General and descriptive anatomy of the domestic animals / by John Gamgee and James Law.

Date:
1861-1862
Catalogue details

Licence: Public Domain Mark

Credit: General and descriptive anatomy of the domestic animals / by John Gamgee and James Law. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    ARTICULATIONS. Mixed joints; their mode of union. Structure of moveable joints. Divisible into four varieties. Gliding joints. Ball-and- socket joints, their move- ments. MIXED ARTICULATIONS—AMPHIARTHROSIS—SYMPHYSIS. Amphiarthrosis (aycpi, on all sides; apdpov, a joint), or symphysis, includes those joints in which smooth, and even rough and indented surfaces are connected together at all parts by interposed fibro-cartila- ginous discs, as in the union of the bodies of the vertebral; also such as are covered by fibro-cartilage, lined to a small extent by synovial membrane, as in the sacro-iliac articulation. Both these varieties are commonly provided with external ligaments. The first resembles the synarthrodial joints by the continuity of the surfaces and the absence of a synovial membrane; the last, the diarthrodial, by the converse of these characters. When the external ligaments are wanting, the former class is only distinguishable from synarthrosis by the greater freedom of motion. MOVEABLE ARTICULATIONS.— DIARTHROSIS. In diarthrosis (Sia, through; apdpov, a joint), or moveable joints, two contiguous bony surfaces are encrusted with cartilage, retained in contact by ligaments, and surrounded by synovial membrane. Their connection is further strengthened by surrounding muscles, as is well seen in shoulder-slip, when, from sprain of the muscles occu- pying the dorsum scapulas, these are thrown out of use, and the head of the humerus rolls outward at every step. The moveable joints are divisible into four varieties, according to the motions they respectively possess, and are designated: arthrodia, or gliding joints; enarthrosis, or ball-and-socket joints; ginglymus, or hinge joints; and diarthrosis rotatorius, or pivot joints. Arthrodia (apdpov, a joint; apco, to adapt) is that form of joint in which a slight gliding motion only is allowed. It is formed by the apposition of plain surfaces, or of one slightly con- vex and the other correspondingly concave, their movements on each other being limited by surrounding ligaments or osseous prominences. The best examples of this joint are found between the articulating processes of the vertebrae and between the bones composing the two rows of the carpus and tarsus. Enarthrosis (ev, in; apdpov, a joint), or the ball-and-socket joint, is formed by the reception of a globular head in a cup-shaped cavity, the parts being connected by capsular and other ligaments, and strengthened in most cases by enveloping tendons. This joint is possessed of the most varied movements, flexion, extension, adduction, abduction, circumduction, and rotation, are all performed within certain limits. We have examples of this