Stretching and strengthening exercises: their effect on three-dimensional scapular kinematics.

OBJECTIVE: To quantitatively evaluate the effects of commonly used shoulder exercises on shoulder kinematics and resting posture. STUDY DESIGN: A repeated-measures design was used with measurements performed before and after a 6-week exercise program. METHOD: Twenty asymptomatic subjects with forward shoulder posture were recruited. Stretching exercises for the pectoral muscles and resisted strengthening exercises for the scapular retractors and elevators and the glenohumeral abductors and external rotators were performed three times per week for 6 weeks. A three-dimensional electromechanical digitizer was used to measure thoracic inclination and scapular orientation and position. These measurements were taken with the arm (1) at the side, (2) abducted to 90 degrees, and (3) at maximal abduction. The isometric force of glenohumeral external and internal rotation and horizontal abduction and adduction were measured with a hand-held dynamometer. All subjects were tested before and after the 6-week exercise program. Hotelling's T2 and paired t tests were used for data analysis. RESULTS: The strength of horizontal abduction and internal and external rotation increased after exercise (p < .01). The anterior inclination of the thoracic spine decreased, and the glenohumeral contribution to arm elevation increased (p < .01). Resting scapular posture did not change. As the arm was abducted to 90 degrees, the scapula showed less upward rotation and less superior translation after the exercise program (p < .01). CONCLUSION: The exercise program improved muscle strength, produced a more erect upper trunk posture, increased scapular stability, and altered scapulohumeral rhythm.

Neurovascular entrapment in the regions of the shoulder and posterior triangle of the neck.

The purpose of this article is to provide information that facilitates the critical evaluation of the thoracic outlet syndrome and other nerve entrapment syndromes in the regions of the posterior cervical triangle and the shoulder. General comments regarding entrapment are followed by discussions of specific entrapment sites. Each discussion stresses the anatomic view and includes comments on causes, symptoms, diagnostic tests, and management.

Cytoplasmic crystalloids in irradiated rat parotid glands.

Cytoplasmic crystalloids were found in parotid acinar cells of rats given a large (6400 R) single exposure of X-rays to the head and neck. The crystalloids were first observed 1 day after irradiation and became numerous at 3-4 days. They were associated with autophagic vacuoles, which were seen in acinar cells as early as 3-6 h. Crystalloids sometimes appeared to be forming within autophagic vacuoles, which also contained membranous residues and apparently degenerating secretory material. They were bounded by a single smooth membrane and had a substructure consisting of dense, parallel longitudinal striations. They crystalloids were also seen in macrophages associated with the basal surface of acinar cells. At 3-4 days macrophages were numerous and many contained crystalloids, degenerated secretory droplets, and other cellular debris, which they apparently had phagocytosed. By 6-8 days crystalloids and macrophages were seen infrequently. Regarding mode of formation, removal by macrophages, and ultrastructure, the crystalloids resembled those described by others after ethionine intoxication. Ethionine-induced crystalloids have cytochemical characteristics consistent with a lysosomal identity. The crystalloids in irradiated parotid glands probably reflect a variant type of lysosome, which is a nonspecific manifestation of severe cellular injury and can be elicited by a variety of injurious agents.

Isoproterenol in comparison to WR-2721 as a chemoradioprotector of the rat parotid gland.

A comparison was made of the radioprotective abilities of the chemoradioprotector WR-2721, an amino-thiol, and the beta-sympathomimetic secretogogue isoproterenol on the rat parotid gland. Using the dose-response curve of WR-2721 for gland weights as a basis for comparison, isoproterenol was found to offer significant and equal protection during both the acute (DMF, 2.5) and the chronic (DMF, 2.3) periods.