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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![turned outwards. The position of the radial nerve to the outer side [in the middle third] is to be borne in mind and the ligature passed from it. The pronator teres is to be divided about its middle, without in- juring the median nerve or the origin of the muscle from the ulna, which can now be thoroughly seen; and the flexor carpi radialis and palmaris longus are to be divided so as to expose thoroughly the flexor sublimis. which is to be cleaned. [The rule (p. 16) for divid- ing the muscles at different levels, where there are many muscles to- gether, in order to match the two ends which belong together, is to be borne in mind.] The skin of the front of one of the lingers is to be carefully removed without interfering with the palm, and the sheath of the tendons dissected out. [Fig. 11.] The Flexor Sublimis Digitorum (perforatus) (Fig. 11, 16) is the only muscle of the forearm which has an origin from the three bones of the arm. It arises from the internal conctyle of the humerus and slightly from the internal lateral ligament of the elbow; from the intermus- cular septa between it and the more superficial muscles ; from the inner side of the coronoid process of the ulna above the pronator teres ; and from the whole of the oblique line on the front of the radius. Between the origins from the humerus and the radius is the median nerve. The muscle ends in four tendons, of which the two to the second and third fingers lie in front of those to the first and fourth fingers ; all pass under the annular ligament and through the palm of the hand to the second phalanges of the four fingers. The sheath of the finger which is exposed [Fig. 11] should be laid open along the centre, when it will be found to be thick opposite each phalanx, but thin at each joint. [The sheaths are attached to the lateral ridges on the phalanges and with the palmar fascia act as pulleys, preventing the tendons from assuming a straight line, and thus obliterat- ing the palm.] The tendon of the flexor sublimis (perfo- ratus) will be seen to be flattened on the first phalanx and split to give passage to the tendon of the flexor profundus (perforans), the two slips of the flexor sublimis being in- serted into the sides of the second phalanx, and the tendon of the flexor profundus into the base of the third phalanx. The flexor sublimis is a flexor of the [second] phalanges and then [secondarily] of the carpus, and is supplied by the median nerve. 5](https://iiif.wellcomecollection.org/image/b21020735_0059.jp2/full/800%2C/0/default.jpg)
