. Cunningham's Text-book of anatomy. Anatomy. THE ULNA. 213 posterior surface is subdivided by a faint longitudinal ridge, the bone between which and the interosseous crest furnishes origins for the abductor pollicis longus, extensor pollicis longus, and extensor indicis proprius muscles, in order proximo- distally. The surface of bone between the dorsal margin and the afore-mentioned longitudinal line is smooth and overlain by the extensor carpi ulnaris muscle, which does not arise from it. The distal extremity of the ulna presents a rounded head (capitulum ulnse), from which, on its medial a
. Cunningham's Text-book of anatomy. Anatomy. THE ULNA. 213 posterior surface is subdivided by a faint longitudinal ridge, the bone between which and the interosseous crest furnishes origins for the abductor pollicis longus, extensor pollicis longus, and extensor indicis proprius muscles, in order proximo- distally. The surface of bone between the dorsal margin and the afore-mentioned longitudinal line is smooth and overlain by the extensor carpi ulnaris muscle, which does not arise from it. The distal extremity of the ulna presents a rounded head (capitulum ulnse), from which, on its medial and dorsal aspect, there projects distally a cylindrical pointed process called the styloid process. To the extremity of this latter is attached the ulnar collateral ligament of the carpus, whilst on the volar aspect it has connected with it the antero-medial portion of the capsule of the wrist-joint. The antero-lateral half of the circumference of the head is furnished with a smooth narrow convex articular surface, which fits into the ulnar notch of the radius. Its distal surface, flat and semilunar in shape, and separated from the root of the styloid process by a well-marked groove, rests on the upper surface of the triangular articular disc of the wrist, the apex of which is attached to the groove just mentioned. The margins of the head, to the volar side and dorsal to the radial articular surface, have attached to them the volar and dorsal inferior radio- ulnar ligaments. The dorsal and medial surface of the styloid process is channelled by a groove which separates it from the dorsal surface of the head, and extends proximally some little way upon the dorsal surface of the distal end of the shaft. In this is lodged the tendon of the extensor carpi ulnaris muscle. The pro- portionate length of the ulna to the body height is as 1 is to 6'26-6-66. Nutrient Foramina.âA foramen, having a proximal direction, for the nutrient artery of the shaft oj)ens on the volar surface of the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
