Licence: Public Domain Mark
Credit: Practical anatomy. Source: Wellcome Collection.
Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.
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![The position of the ulnar artery, between the tendon of the flexor carpi ulnaris and the innermost tendon of the flexor sublimis in the lower half of the forearm, is now to be noticed, and by a slight separation of the tendons the ulnar nerve can be seen lying close to the ulnar side of the artery. This is the point where the ulnar artery is usually tied. The flexor sublimis is now to be divided near its origins and turned down without injuring the median nerve, from which a branch may be traced to the deep surface of the muscle. The Deep Muscles (Fig. 12), of the forearm are the flexor longus pollicis to the radial side, the flexor pro- fundus digitorum to the ulnar side, and the pronator quad- ratus, a small square muscle with transverse fibres, to be seen above the carpus by drawing aside the tendons. These are now to be cleaned, all vessels and nerves being carefully preserved. The Flexor Longus Pollieis (Fig. 12. 5) arises from the whole of the anterior surface of the radius between the oblique line and the attachment of the pronator quad- ratus, and from the outer half of the interosseous mem- brane in nearly its whole length. It very generally has a small additional origin, by a slip of very variable size, from the outer side of the coronoid process of the ulna. A single round tendon passes beneath the annular ligament and through the palm of the hand [between the two heads of the flexor brevis pollicis] to be inserted into the terminal phalanx of the thumb. The Flexor Profundus Digitorum (perforans) (Fig. 12, 4) arises from the anterior surface of the ulna between the coronoid process (which it embraces) and the origin of the pronator quadratus, and from the adjacent half of the interosseous membrane; also from the upper two-thirds of the inner surface of the ulna, extending to the olecranon process and the posterior border of the bone, to which an aponeurosis is attached from which some of the fibres arise. The muscle ends in four tendons (of which the outermost alone is quite separate in the forearm), which pass beneath the annular ligament, and after giving attachment [origin] to the lumbricales muscles in the palm, pierce the tendons of the flexor sublimis [opposite the first phalanges], and are inserted into the bases of the third phalanges of the four fingers. The two preceding muscles are direct flexors of](https://iiif.wellcomecollection.org/image/b21020735_0060.jp2/full/800%2C/0/default.jpg)
