the excessive length the cervical loop of the internal portion of the pelvis floor segment of the utero-ovarian artery enables the gynecologist to avoid ligating or wounding the ureter. The length of the cervical loop is responsible for the safety from ligature or wounds of numerous ureters.

The finger is around the cervical loop (2, 3, 4). The lateral cervical triangle is formed by 2, the distal arterio ureteral crossing; (4) the internal os and (19) the vesicle orifice of the ureter. The cervical loop (2, 3, 4) forms the proximal side, the ureter (2, 19) forms the distal side and the lateral border of the cervix and vagina (4 to 19) forms the median side of the lateral cervical triangle. 3a shows the cervical loop forming the distal instead of the proximal side of the cervical triangle, which is reversed during vaginal hysterectomy. 1, origin of the pelvic floor segment of the utero-ovarian artery; 2, the distal arterio-ureteral crossing (also the ureteral loop and distal arteria ureterica). 3, cervical loop; 4, internal os; 19, ureter penetrating bladder wall; 22, ramus cervicis; 23, rami corporis; UT, uterus; ves, bladder; A, finger hooked around the cervical loop 3a; B, traction forceps; c. the uterus drawn distalward in the vagina; Rec, rectum.

Little is found in medical literature on what I term the cervical loop of the uterine artery as practically the utero-ovarian artery itself has no literature, yet the cervical loop is plain in vaginal hysterectomy, in dissections, and in the exact non-personal equation of the X-ray. The descending arm of the cervical loop passes distalward along the internal and posterior border of the ureter while the ascending arm of the loop passes

proximalward along the lateral border of the vaginal formix and cervix. During pregnancy the cervical loop doubles in length and size in the first

three months.

The cervical loop has marked age and functional relations.

In fetal life and childhood it is short, small and straight. At puberty it springs into active life, becoming flexed and large. At the menstrual period it enlarges, its pulse beat is vigorous and it elongates. In gestation it enormously develops, trebles in length and caliber, shows a mighty cervical loop-in the form of two spiral arms, which fill the space between the lateral cervical border and the ureter, and during the later part of gestation the cervical loop extends, unfolds proximalward, becoming almost a straight line. In senility it atrophies, shortens in length, decreases in caliber, thickens, calcifies in its walls, and again becomes almost straight in outline, losing its flexosity, as in childhood.

THE CERVICAL LOOP OR THE INTERNAL PORTION OF THE PELVIC FLOOR SEGMENT OF THE UTERO-OVARIAN ARTERY.

Extends from the distal arterio-ureteral crossing to the lateral border of the os uteri internum. It is an exceeding important vessel in gynecology, on account of its frequent ligation. It is the internal one-third of the pelvic floor segment. It is from one to one and one-half, or even two inches in length, slightly flexous in childhood, senility and the nullipara, but very flexous in the multipara and early gestation.

Its flexosity is increased in myoma or other uterine growths. It lies at or partly in the base of the ligamentum latum in an extensive bed of yielding, elastic, areolar tissue which facilitates extensive motion.

From the distal arterio-ureteral crossing the internal portion mounts proximalward over the lateral vaginal fornix, after which it departs slightly from the cervix and lateralward, and passes proximalward again to the distal portion of the corpus. In some cases it makes a distinct circular loop at the os uteri internum (see Figs. ).

The abundant strong white connective tissue, fibres, bands and planes which surrounds the cervical loop, or the internal portion of the pelvic floor are so intimately interwoven about the spiral cords of the artery, that it will not easily elongate in a straight line without complete removal by dissection of the areolar tissue. The cervical loop, internal portion of the pelvic floor segment, sends off some very important branches. The cervical loop or horizontal, subligamentary portion, of the pelvic floor segment extends from the descending portion to the lateral border of the cervix. Practically the artery does not lie within the blades of the ligamentum latum. Here the horizontal portion of the plevic floor segment should not be termed the intra-ligamentary portion.

The cervical loop, the internal portion of the pelvic floor segment is the most mobile and free part of the utero-ovarian artery, besides being practically the chief surgical segment. Dissections and the X-ray shows that the cervical loop terminates about one-fifth to two-thirds of an inch from the lateral border of the os uteri internum in a vast bed of white cellular tissue (whence by cervical lacerations infective germs gain access,

FIG. 4.-A CUT TO ILLUSTRATE THE CERVICAL LOOP AND LATERAL CERVICAL TRIANGLE DURING OPERATION.

The cervical loop (2, 3, 4). The lateral cervical triangle (2, 3, 4; 2, 19; 4, 19). The cervical (2, 3. 4) loop is drawn distalward by the finger (A) becoming, 3a, ready for ligation. c, is the uterus drawn distalward in the vagina by traction forceps. B. traction forcep. 1, Middle arterio ureteral crossing: 2, distal arterio-ureteral crossing; 3, cervical loop (also distal ureteral spindle); 4, internal os: 5. external, and 6 internal iliac: 8, superior gluteal; 10, inferior gluteal: 13, vesicle arteries; 16, hypogas tric: 17. obturator; 18, uterus; 19, bladder at vesicle orifice; 20, rectum; 21, 22, 23, sacral plexus: A. pelvic floor segment of the utero-ovarian artery with its usual concavity dorsalward. Observe that the situation of the ureters and trigone remain the same during the operation.

FIG. 5.-A CUT TO ILLUSTRATE THE CERVIAL LOOP (2, 3, 4) AND LATERAL CERVICAL TRIANGLE (2, 4, 19) NORMALLY AND DURING OPERATION REVERSED.

The cervical loop (2, 3, 4). The lateral cervical triangle (2, 19; 2, 3, 4; 4, 19). 1, origin of pelvic floor segment; 2, distal arteria ureteral crossing (also arterio-ureteral loop and distal arteria ureterica); 3, cervical loop; 4, internal os; 5, uterine segment; 6, middle bifurcation of the utero-ovarian artery; 7, ramus ovarii; 8, ramus oviductus; 9, junction of oviducal and ovarian segments (also proximal bifurcation||of utero-ovarian artery); 10, ovarian segment; 19, vesicle orifice of ureter; 22, ramus cervicis; 23 ramus corporis; 24, rami fundi; 31, 32, 33, oviduct; A, finger hooked around the cervical loop; B, traction forceps drawing the left half of the uterus distalward into the vagina; B, traction forceps drawing the uterus Cinto vagina; 13, 14, 15, round ligament segment; 21, deep epigastric.

Observe that the ureters and trigone remain in situ, normally during the operation, especially after the uterus and bladder are separated from each other. This is easily noted in figure C.

producing cellulitis, and consequent vascular compromizations). The cervical loop crosses the lateral vaginal fornix by mounting proximally over it.

In some dissections and several X-rays I found a branch about the size of the distal arteria ureterica, springing from the pelvic floor segment immediately internal to the distal arterio-ureteral crossing. It is very large. especially (see Fig.) making extra-vascular arches with the oviducal segment. It supplies the mesometrium. Except the cervico-vaginal and the above branch the cervical loop lying between the distal arterio-ureteral crossing and the lateral cervical border sends off only very fine spiral

FIG. 6.-A CUT TO ILLUSTRATE THE LATERAL CERVICAL TRIANGLE REVERSED DURING OPERATION BY DRAWING THE CERVICAL LOOP DISTALWARD (2, 3, 4).

The cervical loop (2, 3, 4). The lateral cervical triangle (2, 19; 2, 3, 4; 4, 19). 1, origin of pelvic floor segment; 2, distal arterio-ureteral crossing (also arterio-ureteral loop and distal arteria ureterica; 3, cervical loop; 4, internal os; 5, uterine segment; 6, middle bifurcation of the utero-ovarian artery); 7, ramus ovarii; 8, ramus oviductus; 9, junction of oviducal and ovarian segments (also proximal bifurcation of utero-ovarian artery); 10, ovarian segment; 19, vesicle orifice of ureter; 22, ramus cervicis; 23, ramus corporis; 24, rami fundi; 31, 32, 33, oviduct; A, finger hooked around the cervical loop; B, traction forceps drawing the right half of the uterus distalward in the vagina. Note that the normal position of the ureters and trigone remains while the operation proceeds.

twigs to the mesometrium. The cervico-vaginal branch courses to the lateral border of the cervix, thence distalward on the vagina, dividing in several branches which pass to the anterior and posterior surfaces of the cervix, in order either to end there or to pass to the anterior and posterior vaginal walls.

In the ligamentary portion the cervical loop is accompanied by large adjacent veins which being injected obscure the artery. It is here surrounded by a resisting envelope of cellular tissue; the same as surrounds