. American practice of surgery ; a complete system of the science and art of surgery . ines offorce of the two muscles ap-proach ope another, the deltoidis able to\ obtain a fulcrum onthe glenoids- Jn normal action,the glenoid beai\ all the weight,and the power o*^ the supraspi-natus keeps the-tuberosity fromseeking a fulcrum on the acro-mion and coraco-iicromial liga-ment. The fune|io:i of the bursais to prevent friction at this in the region of the bursa or in that of the tendinous insertion of thesupraspinatus, throws the latter out of action, and the deltoid alone cannotperf
. American practice of surgery ; a complete system of the science and art of surgery . ines offorce of the two muscles ap-proach ope another, the deltoidis able to\ obtain a fulcrum onthe glenoids- Jn normal action,the glenoid beai\ all the weight,and the power o*^ the supraspi-natus keeps the-tuberosity fromseeking a fulcrum on the acro-mion and coraco-iicromial liga-ment. The fune|io:i of the bursais to prevent friction at this in the region of the bursa or in that of the tendinous insertion of thesupraspinatus, throws the latter out of action, and the deltoid alone cannotperform abduction. (Figs. 29 and 30.) Pathology.—The important point in the pathology of this affection is thatthe spot on the greater tuberosity where the tendon of the supraspinatus isusually found damaged, is the point which acts as a fulcrum on the acromion,when the supraspinatus is not doing its work. Partial rupture at the insertionof this tendon may occur from muscular violence alone, during the period ofabduction when the burden of overcoming inertia is suddenly thrown on the. Fig. 27.—Diagram from a Frozen Section. (Dr. E. ) Notice the deltoid and its origin from tlie edgeof the acromion. Notice also tlie subdeltoid or subacro-mial bursa with its roof made by the under surface ofthe acromion and by the fascia beneath the upper portionof the deltoid. Its base is on the greater tuberosity andthe tendon of the supraspinatus, which separates it likean interarticular fibrocartilage from the true joint. Ifthe surfaces of the bursa between the points A and Bwere adherent, it would be impossible for the joinl to passinto the position shown in Fig. 28. 46 AMERICAN PRACTICE OF SURGERY. supraspinatus. Unless this musclo is on the qui vive, the j)o\verful contractionof the deltoid tends to force the tuberosity to gain a fulcrum on the acromion,and this jams the tendinous expansion of the supraspinatus between the twobones. (Figs. 31, 32, and 33.) Sympto?ns.—The clinical
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectsurgery, bookyear1906
