the director should be used to break away the cellular tissue behind the sterno-clavicular joint, and to search between it and the mesial line for the innominate artery; should the subclavian or carotid trunks come into view, they will be recognised respectively by their direction, and they may be made use of as guides to the situation of the innominate, around which the ligature should be passed from without inwards.

The common carotids, in the study of operative anatomy, may be considered to have the same course and relations on both sides of the body; as that part of the left carotid which differs from the right is beyond the reach of the ligature. We may therefore consider that the carotid commences behind the sterno-clavicular joint, and extends as high in the neck as the upper border of the thyroid cartilage. Its course is indicated by a line drawn from between the angle of the jaw and the mastoid process, to a point half an inch external to the sternal end of the clavicle; the best line to follow, however, in making incisions for exposing the vessel, is that of the anterior border of the sterno mastoid. The vessel in the lower half of its course lies deeply and is overlapped by the sterno mastoid, its sternal origin, the sterno-hyoid, and thyroid muscles, besides the various layers of cervical fascia; after a short distance these muscles diverge, and it pursues its course more superficially to its termination; at a variable distance above the clavicle, the omohyoid muscle crosses the artery obliquely from without inwards. In the upper part of the neck the vessel is only separated from the integuments by the platysma, cervical fascia, and its own sheath; in front of its sheath is found the descendens noni nerve, with its communicating branches, while within the sheath, on the outer side of the artery, are the pneumogastric nerve and internal jugular vein.

Internally are found the trachea and larynx, and occasionally the lateral lobe of the thyroid body overlaps the artery in the middle of its course. A ligature may be applied to this vessel in any part of its course between the above-mentioned limits; but that part which lies opposite to the cricoid cartilage is usually selected as the most convenient point to expose the artery.

To tie the carotid at this point, make an incision along the anterior border of the sterno-mastoid, about three inches in length, and after dividing the platysma and thè superficial and deep cervical fascia, the omohyoid will generally come into view; push this to the outer side and open the sheath of the carotid on the director, taking care not to injure the descendens noni nerve. With the point of the director separate the artery from the vein and vagus nerve on its outer side, and pass the ligature around it from without inwards, to avoid injuring the nerve. performing this operation on the dead body, it is not uncommon for the internal jugular to be mistaken for the carotid sheath, and to be laid open on the director; though there is but little danger of this, except when the vein is flaccid and empty, and overlaps the artery.

In

The external carotid, extending from opposite the upper border of the thyroid cartilage to the interval between the jaw and the mastoid process, lies superficially in that part of its course which concerns us. The anterior border of the sterno-mastoid marks its direction and serves as a guide in making our incisions. The only structures covering the artery are the integument, platysma, and cervical fascia: it is crossed from without inwards by the hypoglossal nerve, and lies side by side with the internal carotid, which latter is on its outer and posterior aspect. The two vessels may best be distinguished, besides by their position, by the latter being without branches and larger

than the former. The point usually selected for ligature of this vessel, is just beyond its origin, and here it may be tied by an incision made over the anterior margin of the mastoid, commencing opposite the hyoid bone and running upward for about two inches; the skin, platysma, and cervical fasciæ being divided, the director should be used to clear the vessel, care being taken to avoid injuring the hypoglossal and descendens noni nerves. The internal jugular vein will be found on the outer side of the artery, and separated from it by the hypoglossal nerve. The ligature should be passed from without inwards.

The internal carotid only admits of being ligatured within a short distance of its origin; subsequently its course lies so deeply among the important structures, that an attempt to expose it would be unjustifiable. The various steps for exposing this vessel in the first part of its course are precisely those that are described above as necessary for ligaturing the external carotid. The ligature should be passed from without inwards to avoid the risk of injuring the vagus nerve, or the internal jugular vein.

The lingual artery, after leaving the external carotid, runs upwards and inwards beneath the posterior belly of the digastricus and stylo-hyoideus, to the upper border of the greater cornu of the hyoid bone, along which it pursues its course, lying on the middle constrictor muscle, and beneath the hyoglossus.

The portion of the artery with which we have to deal, is that lying beneath the last-named muscle. Here the vessel is covered by the skin, platysma, superficial and deep cervical fascia and hyoglossus muscles.

The anterior and posterior bellies of the digastricus at their divergence below, form with the hypoglossal nerve above, and the mylo-hyoidens on the inner side, a small space with its apex at the hyoid bone and its base above,

The floor of the space is covered by the hyoglossus muscle, and immediately beneath this will be found the lingual artery, the course of which is indicated by a dotted line in fig. 10.

To expose the artery, throw the head back, and turn the chin to the opposite side, and make a slightly curved

incision about two inches in length, commencing at the

small cornu of the hyoid bone, and extending outwards and upwards along the upper border of its greater cornu. The skin, platysma, and cervical fascia being divided, the submaxillary gland will most likely come into view; this being turned upwards, until the hypoglossal nerve is seen, the

junction of the bellies of the digastricus must be sought, and the hyoglossus muscle divided transversely on the director, at the point before indicated: the artery will now be plainly seen, and the ligature can be placed around it.

The lingual artery may be exposed by other methods, but we have selected that operation which we have personally found most convenient and certain of success.

We shall omit any description of the course of the facial artery; as the only point at which its ligature is attempted, is where it crosses the lower jaw, at the anterior border of the masseter muscle. It is exposed by an incision an inch in length, parallel to the body of the lower jaw; crossing the anterior margin of the masseter muscle at the lowest point of its insertion. The skin, platysma, and fasciæ must be divided, and the artery carefully separated from its vein. The direction of the vessel will, of course, be at right angles to that of the wound.

The temporal artery.—The main trunk of this artery, after leaving the parotid gland, passes upwards over the zygoma, just in front of the pinna of the ear. To tie the vessel, an incision should be made an inch in length, just in front of the antitragus, and crossing the zygoma at right angles; the skin and fasciæ must be divided, and the ves sel sought for in the dense cellular tissue which is found at this spot.

We propose to proceed with the ligature of the vessels of the trunk and lower extremities, in order, from above downwards, commencing with the common iliac artery.

The common iliac arteries, commencing at the bifurcation of the aorta on the left side of the fourth lumbar vertebra, extend downwards and outwards, diverging from each other, until just short of the sacro-iliac joint, where they give off the external and internal iliac trunks. The artery of the right side is thus rather longer than that of