. Cunningham's Text-book of anatomy. Anatomy. MUSCLES OF THE SHOULDER 375 Serratus anterior .Subscapulars Supraspinatus Pectoralis MINOR Coracoid process Triceps brachii (long head) the horizontal position. In this movement it is aided by the supraspinatus and infraspinatus. The anterior (clavicular) portion of the muscle assists the pectoralis major in drawing the arm forwards, while the posterior portion draws it backwards. M. Supraspinatus.—The supraspinatus arises by fleshy fibres from the supra- spinous fossa (except near the neck of the bone) and from the deep fascia over it (Fig. 329, p
. Cunningham's Text-book of anatomy. Anatomy. MUSCLES OF THE SHOULDER 375 Serratus anterior .Subscapulars Supraspinatus Pectoralis MINOR Coracoid process Triceps brachii (long head) the horizontal position. In this movement it is aided by the supraspinatus and infraspinatus. The anterior (clavicular) portion of the muscle assists the pectoralis major in drawing the arm forwards, while the posterior portion draws it backwards. M. Supraspinatus.—The supraspinatus arises by fleshy fibres from the supra- spinous fossa (except near the neck of the bone) and from the deep fascia over it (Fig. 329, p. 368). It is directed laterally under the trapezius muscle, the acromion and coraco- acromial ligament, to be inserted by a broad thick tendon into the most proximal facet on the larger tubercle of the humerus, and into the capsule of the shoulder- joint (Fig. 336, p. 376). Nerve-Supply. — The muscle is supplied by the supra-scapular nerve (C. 5. 6.). Action.—The supraspin- atus assists the deltoid in ab- ducting the arm from the side. M. Infraspinatus.—The infraspin- atus arises from the infra-spinous fossa of the scapula (excepting near the neck of the bone and the fiat surface along the axillary margin) and from the thick fascia over it (Fig. 337, p. 376). The fibres of the muscle converge to the neck of the scapula; and are inserted by tendon into the middle facet on the larger tubercle of the humerus, and into the capsule of the shoulder-joint (Fig. 336, p. 376). A bursa separates the muscle from the neck of the scapula, and in a minority of cases communicates with the synovial cavity of the shoulder-joint. The supraspinatus and the upper part of the infraspinatus muscles are concealed by the trapezius, acromion, and deltoid. They cover the neck of the scapula, the transverse scapular artery, and supra- scapular nerve, and the capsule of the shoulder-joint. Nerve-Supply. —Supra-scapular nerve. Action.—The muscle assists the deltoid in abducting and drawing bac
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
