The Medical and surgical reporter . mechanical considera- tract: the result is shown in Fig. 2, and maybe expressed, in general terms, by saying thatthere are pronation and flexion of the also, in general, it may be stated, that anymuscle passing obliquely across the quadrangleof the forearm, from one angle to the other, ornearly in that direction, when contracting, willcause, or tend to cause, both pronation and flex-ion of the forearm. The force of pronation maybe greater, or the force of flexion may be greater. In the next place let me direct your attentionto the distribution an
The Medical and surgical reporter . mechanical considera- tract: the result is shown in Fig. 2, and maybe expressed, in general terms, by saying thatthere are pronation and flexion of the also, in general, it may be stated, that anymuscle passing obliquely across the quadrangleof the forearm, from one angle to the other, ornearly in that direction, when contracting, willcause, or tend to cause, both pronation and flex-ion of the forearm. The force of pronation maybe greater, or the force of flexion may be greater. In the next place let me direct your attentionto the distribution and function of the musclesacting on the forearm :— 1. The pronator quadratus is a simple pro-nator. 2. The pronator radii teres can pronate andflex the forearm. I. The brachialis anticus flexes the forearm. 4. The biceps brachii flexes and pronates theforearm and supinates the radius. The pro-nating force acts through the semilunar fasciaand the fascia enveloping the pronator radiiteres and the carpo-radial flexor. The semi- . 1.:. tion that will aid you in understanding thefunctions of the forearm. Let a and 6, in , be two rigid bars, attached to H, anotherrigid bar, in such a manner as to be moved likethe bones of the forearm. Let p m c representthe pronator radii teres: c the origin, m thecontractile substance, and p the insertion of themuscle. When a muscle contracts, it will bring,or tend to bring, the origin and insertion nearertogether. Now let the pronator radii teres con- ^.^0 lunar fascia acts as a tendon: the biceps is,therefore, a bi-ped. 5. The flexor longus pollicis is a simple flexor. 6. The flexor carpi ulnaris is a simple flexor. 7. The flexor carpi radialis can flex and pro-nate the forearm. 8. The palmar is longus may tend to pronatethe forearm. 9. The flexor sublimis digitorum acts, to acertain extent, as a pronator of the forearm :—- Sept. 14, Lecture. 223 The pronator radii teres tends more to prona-tion than flexion. The carpo-radial flexor
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