Obturator and internal circumflex with anastomotica and superior internal articular.
Note.—The importance of the articular branches of the popliteal explain the danger of gangrene after a sudden rupture or increase in size of a popliteal aneurism.
Ligature of the Innominate.—The performance of this extremely dangerous, in fact almost hopeless operation, is by no means so difficult as might be expected.
The patient lying down with the shoulders raised and head thrown well back, the sternal attachment of the right sterno-mastoid must be very freely exposed. This may be done by an incision ([Plate I.] fig. 7) along its anterior edge from the upper edge of the sternum, as far as may be necessary; another about the same length along the upper edge of the clavicle, will meet the former at an acute angle, and will include a triangular flap of skin, which must be carefully dissected up. The sternal, and probably a portion of the clavicular attachment of the right sterno-mastoid, must then be cautiously divided. This being done, the sterno-hyoid and sterno-thyroid muscles require division immediately above their sternal attachments.
A dense process of cervical fascia (just becoming thoracic) now covers the vessel, binding it on the right side to the right innominate vein, and on the left maintaining the relation of the innominate artery to the trachea. The inferior thyroid veins lie on this fascia, and must be drawn aside, not cut. The fascia is then to be scraped through very cautiously, exposing the root of the right carotid, which, being traced downwards, will lead to the innominate. The following parts lie in close relation to the vessel at the point of ligature, and must be avoided:—1. The left innominate vein crosses the artery in front from left to right, and must be drawn down. 2. The right innominate vein and right pneumogastric are in close contact with the artery on the right side; to avoid them the aneurism-needle must be entered on the outside (right of the vessel). 3. The apex of the right pleura and the trachea are in close contact behind, requiring the point of the needle to be kept close to the artery in bringing the thread round.
It might have been expected that the sudden arrest of so large a proportion of the vascular supply of the body, so very near the heart, would cause serious, or even fatal symptoms; this, however, is not the case, no serious inconvenience of this sort being experienced; yet hitherto every case has proved fatal, either from secondary hæmorrhage or inflammation of lungs and pleura.
In fifteen well-authenticated, and in three more doubtful cases, the ligature has been applied; all of these died at periods varying from twelve hours (as in Hutin's case), to forty-two days as in Thomson's, and sixty-seven days (Graefe's).[11]
A successful case of ligature of the innominate along with the right carotid and (after secondary hæmorrhage) the right vertebral, in a mulatto aged thirty-two, for a subclavian aneurism, has been put on record by Dr. Smyth of New Orleans, in the American Journal of Medical Science for July 1866.
And here we may also note that Mr. Heath has lately treated a case of innominate aneurism by simultaneous ligature of the third part of the subclavian and the carotid. Both ligatures separated on the eighteenth day, and the tumour was much smaller some months afterwards.[12]