364 



FORE- ARM. 



is a branch of the ulnar artery, and not unfre- 

 quently is of large size, though usually of a 

 calibre about intermediate to the two last men- 

 tioned. It arises from the ulnar artery where 

 that vessel is covered by the pronator radii 

 teres, and descending towards the interosseal 

 ligament reaches that structure a little below 

 the tendon of the biceps. It is accompanied 

 by a branch of the median nerve in its course 

 downwards ; lies between the interosseous liga- 

 ments and the external edge of the flexor com- 

 munis digitorum profundus ; it terminates by 

 dividing into two branches, of which one 

 passes backwards through the interosseal liga- 

 ment, anastomosing with the posterior inter- 

 osseal, and the other, a small branch , descends 

 over the wrist-joint into the palm of the hand, 

 where it anastomoses with the deep palmar arch. 

 In the posterior region of the fore-arm we 

 meet with only one vessel of any size ; this 

 is the posterior interosseal artery, a branch 

 from the anterior interosseal, which passes 

 through the interosseal ligament opposite the 

 tubercle of the radius; its course is not so 

 straight and uniform as the anterior, its distri- 

 buent branches are larger and more numerous, 

 and it may be said to ramble down between 

 the extensor muscles and the interosseal liga- 

 ment, though it does not lie so immediately in 

 contact with the ligament as the anterior inter- 

 osseal. It terminates by anastomosis with the 

 vessels about the wrist-joint. 



Such is the usual distribution of these ves- 

 sels ; they are, nevertheless, subject to every 

 kind of variety, and the operator previously to the 

 commencement of an operation ought always 

 carefully to examine the course of these vessels 

 in order to detect any anormal arrangement 

 either in relation to their size or distribution. 



The arteries of the fore-arm are more ex- 

 posed to accidents from cutting instruments 

 than most other vessels in the body ; and the 

 usual plan of securing the vessel in these cases 

 is to apply two ligatures on the wounded 

 trunk, one above and the other below the orifice, 

 the latter being required in consequence of the 

 free anastomosis of the vessels in the hand. 



But the fore-arm is occasionally wounded by 

 sharp penetrating instruments, which passing 

 deeply into the fleshy mass, the vessel which 

 has been wounded is not immediately indicated, 

 and the surgeon is consequently at a loss to 

 discover which of the three main trunks requires 

 the application of a ligature. 



An examination through the wound would 

 tend to aggravate the mischief, and besides, 

 the search is often attended with difficulty, and 

 often unsatisfactory. 



In such cases it will be found far more 

 advantageous to arrest the hemorrhage by pres- 

 sure on the brachial artery, at the same time 

 allaying the local inflammation by due attention 

 to the position of the arm, and the usual 

 antiphlogistic remedies, a plan which I have 

 seen adopted with great success by Mr. Tyrrell, 

 at St. Thomas's Hospital.* 



* Sec St. Thomas's Hospital Reports, edited by 

 John F. South, No. i. p. 25. 



There are some cases, however, which im- 

 peratively require the application of ligatures, 

 as for instance, when either of these vessels is 

 opened by sloughing of the tissues from phleg- 

 monous inflammation, or from aneurism in the 

 fore-arm or hand. In the first of these cases, 

 patients have frequently been lost from the 

 temporary suspension of the hemorrhage by 

 the use of cold applications or accidental 

 circumstance, and its occurring again suddenly 

 during the absence of the surgeon. 



In the performance of the operation of tying 

 the radial artery the supinator radii longus 

 muscle affords an unerring guide throughout 

 the fore-arm, but the surgeon must remember 

 that the inner edge of this muscle is not on the 

 outer side of the fore-arm, but as nearly in the 

 centre as possible. The needle must be passed 

 from without inwards, in order to avoid wound- 

 ing the nerve. 



The ulnar artery cannot be secured in the 

 upper third of the arm, it lies so completely 

 covered by most of the flexors arising from the 

 inner condyle ; as soon as the vessel has gained 

 its position between the flexor carpi ulnaris 

 and the flexor digitorum communis, it may be 

 easily reached, the former muscle overlapping 

 it, and therefore forming an excellent guide. 

 The needle in this operation must be passed 

 from within outwards, as the nerve lies to the 

 ulnar side of the artery. 



The bones of the fore-arm are not unfre- 

 quently fractured, either singly or together, but 

 the radius, from its external position and strong 

 connection with the bones of the hand, is more 

 frequently fractured than the ulna. The injury 

 generally takes place a little above the middle 

 of the bone. 



When both bones are fractured, the accident 

 is frequently occasioned by the passage of a 

 heavy weight over the limb, the violence acting 

 immediately on the injured portions. In child- 

 hood these bones are sometimes bent instead of 

 being broken, and as the deformity is slight, 

 though the effect altogether very serious, the 

 nature of the accident is not very readily de- 

 tected. 



" When these bones are fractured near their 

 inferior extremities," says M. Boyer,* " the in- 

 flammatory swelling might render the diagnosis 

 difficult, and cause the fracture to be mistaken 

 for a luxation of the hand. But the two cases 

 may be distinguished by simply moving the 

 hand ; by the motion, if there be luxation with- 

 out fracture, the styloid processes of the radius 

 and ulna will not change their situation ; but 

 if a fracture do exist, these processes will follow 

 the motion of the hand." 



If the radius be fractured a little below the 

 head and above the tubercle, that is, through 

 the neck, and the annular ligament remain en- 

 tire, the deformity is so slight that there is great 

 difficulty in detecting the nature of the injury, 

 especially if there be much swelling and effu- 



* Lectures of Boyer upon Diseases of the Bones, 

 arranged by M. Richerand. translated by M. Far- 

 rell, vol.i. p. 161. 



