. The anatomy of the human body. Human anatomy; Anatomy. ARTICULATIONS OF THE ELBOW. Ill Fig. 71. Fig. 72. Rotation.—In this movement the humerus does not turn upon its own, but upon an imaginary axis, directed from the head of the humerus to the epi-trochlea, parallel to the bone. The manner in which the rotatory muscles embrace the head of the humerus is highly favourable to this motion, by compensating for the shortness of the neck, which serves as a lever for the rotatory movements. The Humero-cubital , or Elbow-joint {figs. 71 and 72). Preparation.—1. Remove carefully the bra
. The anatomy of the human body. Human anatomy; Anatomy. ARTICULATIONS OF THE ELBOW. Ill Fig. 71. Fig. 72. Rotation.—In this movement the humerus does not turn upon its own, but upon an imaginary axis, directed from the head of the humerus to the epi-trochlea, parallel to the bone. The manner in which the rotatory muscles embrace the head of the humerus is highly favourable to this motion, by compensating for the shortness of the neck, which serves as a lever for the rotatory movements. The Humero-cubital , or Elbow-joint {figs. 71 and 72). Preparation.—1. Remove carefully the brachialis anticus muscle ; 2. Detach the ten- don of the triceps from above downward, without opening the synovial capsule ; 3. Re- move the muscles which are attached to the internal and external tuberosities, keeping in mind that the lateral ligaments are intimately connected with the tendons of these miiscles. This articulation belongs to the class of trochlear joints (angular ginglymi). Articular Surfaces.—On the humerus we find, 1. An almost perfect trochlea or pulley, presenting two edges, of which the internal is the more prominent, so that, when the end of the bone rests upon a horizontal plane, its shaft is directed very obliquely from above downward and inward; 2. The small head, or articular condyle, separated from the trochlea by a furrow, which is also articular ; 3. Two cavities, a pos-^ terior, which is very deep, and is intended to receive the olecranon process, and an anterior, which is shal- lower, and receives the coronoid. The articular surfaces of the forearm are, 1. The greater sigmoid cavity of the ulna, which exactly em- braces the trochlea ;* 2. The glenoid cavity of the ra- dius, which receives the small head of the humerus. The means of union consist of four hgaments, two lateral, an anterior, and a posterior. 1. The external lateral ligament {a, figs. 71, 72) is blended with the ten- don of the supinator brevis ; it is of a triangular form, and s
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