This document summarizes the anatomy of major arteries in the pelvis, including the common iliac arteries, internal iliac artery, and branches such as the internal pudendal artery. It describes the origins, courses, branching patterns, and relationships to surrounding structures of these arteries. Key points include that the common iliac arteries arise from the abdominal aorta and bifurcate into the external and internal iliac arteries, and the internal iliac artery further divides into anterior and posterior trunks which give rise to branches supplying the pelvic viscera and walls.

1. THECOMMONANDINTERNALILIACARTERIES.BLOODSUPPLY
LYMPHO-ANDVENOUSOUTFLOWFROMWALLSANDORGANSOF
THESMALLPELVIS.
By Kritika and Ishita
Group 47

2. Common iliac arteries
◦ The abdominal aorta divides, on the left side of the body of the fourth lumbar vertebra, into the
two common iliac arteries. Each is about 5 cm. in length. They diverge from the termination of
the aorta, pass downward and lateralward, and divide, opposite the intervertebral fibrocartilage
between the last lumbar vertebra and the sacrum, into two branches, the external iliac and
hypogastric arteries; the former supplies the lower extremity; the latter, the viscera and parietes
of the pelvis.
◦ The right common iliac artery is somewhat longer than the left, and passes more obliquely
across the body of the last lumbar vertebra. In front of it are the peritoneum, the small
intestines, branches of the sympathetic nerves, and, at its point of division, the ureter. Behind, it
is separated from the bodies of the fourth and fifth lumbar vertebræ, and the intervening
fibrocartilage, by the terminations of the two common iliac veins and the commencement of the
inferior vena cava. Laterally, it is in relation, above, with the inferior vena cava and the right
common iliac vein; and, below, with the psoas major. Medial to it, above, is the left common iliac
vein.

3. Common iliac arteries
◦ The left common iliac artery is in relation, in front, with the peritoneum, the small intestines,
branches of the sympathetic nerves, and the superior hemorrhoidal artery; and is crossed at its
point of bifurcation by the ureter. It rests on the bodies of the fourth and fifth lumbar vertebræ,
and the intervening fibrocartilage. The left common iliac vein lies partly medial to, and partly
behind the artery; laterally, the artery is in relation with the Psoas major.

4. …
◦ Branches.—The common iliac arteries give off small branches to the peritoneum, Psoas major, ureters,
and the surrounding areolar tissue, and occasionally give origin to the iliolumbar, or accessory renal
arteries.
◦ Peculiarities.—The point of origin varies according to the bifurcation of the aorta. In three-fourths of a
large number of cases, the aorta bifurcated either upon the fourth lumbar vertebra, or upon the
fibrocartilage between it and the fifth; the bifurcation being, in one case out of nine, below, and in
one out of eleven, above this point. In about 80 per cent. of the cases the aorta bifurcated within 1.25
cm. above or below the level of the crest of the ilium; more frequently below than above.
◦ Collateral Circulation.—The principal agents in carrying on the collateral circulation after the
application of a ligature to the common iliac are: the anastomoses of the hemorrhoidal branches of
the hypogastric with the superior hemorrhoidal from the inferior mesenteric; of the uterine, ovarian,
and vesical arteries of the opposite sides; of the lateral sacral with the middle sacral artery; of the
inferior epigastric with the internal mammary, inferior intercostal, and lumbar arteries; of the deep
iliac circumflex with the lumbar arteries; of the iliolumbar with the last lumbar artery; of the obturator
artery, by means of its pubic branch, with the vessel of the opposite side and with the inferior
epigastric.

5. Internal iliac artery
◦ The internal iliac artery supplies the walls and viscera of
the pelvis, the buttock, the generative organs, and the
medial side of the thigh. It is a short, thick vessel, smaller
than the external iliac, and about 4 cm. in length. It arises
at the bifurcation of the common iliac, opposite the
lumbosacral articulation, and, passing downward to the
upper margin of the greater sciatic foramen, divides into
two large trunks, an anterior and a posterior. Relations.—
It is in relation in front with the ureter; behind, with the
internal iliac vein, the lumbosacral trunk, and the
Piriformis muscle; laterally, near its origin, with the
external iliac vein, which lies between it and the Psoas
major muscle; lower down, with the obturator nerve.

6. …
◦ In the fetus, the internal iliac artery is twice as large as the external iliac, and is the direct
continuation of the common iliac. It ascends along the side of the bladder, and runs upward on
the back of the anterior wall of the abdomen to the umbilicus, converging toward its fellow of
the opposite side. Having passed through the umbilical opening, the two arteries, now termed
umbilical, enter the umbilical cord, where they are coiled around the umbilical vein, and
ultimately ramify in the placenta.
◦ At birth, when the placental circulation ceases, the pelvic portion only of the artery remains
patent and constitutes the internal iliac and the first part of the superior vesical artery of the
adult; the remainder of the vessel is converted into a solid fibrous cord, the lateral umbilical
ligament (obliterated internal iliac artery) which extends from the pelvis to the umbilicus.

7. Length and place of division
◦ n two-thirds of a large number of cases, the length of the internal iliac varied between 2.25 and
3.4 cm.; in the remaining third it was more frequently longer than shorter, the maximum length
being about 7 cm. the minimum about 1 cm.
◦ The lengths of the common iliac and internal iliac arteries bear an inverse proportion to each
other, the internal iliac artery being long when the common iliac is short, and vice versa.
◦ As Regards its Place of Division.—The place of division of the internal iliac varies between the
upper margin of the sacrum and the upper border of the greater sciatic foramen.
◦ The right and left internal iliac arteries in a series of cases often differed in length, but neither
seemed constantly to exceed the other.

8. …
◦ Collateral Circulation.—The circulation after ligature of the internal iliac artery is carried on by
the anastomosis of the uterine and ovarian arteries; of the vesical arteries of the two sides; of the
hemorrhoidal branches of the internal iliac with those from the inferior mesenteric; of the
obturator artery, by means of its pubic branch, with the vessel of the opposite side, and with the
inferior epigastric and medial femoral circumflex; of the circumflex and perforating branches of
the profunda femoris with the inferior gluteal; of the superior gluteal with the posterior
branches of the lateral sacral arteries; of the iliolumbar with the last lumbar; of the lateral sacral
with the middle sacral; and of the iliac circumflex with the iliolumbar and superior gluteal.

9. Branches

10. Branches
◦ The superior vesical artery (a. vesicalis superior) supplies numerous branches to the upper part of the
bladder. From one of these a slender vessel, the artery to the ductus deferens, takes origin and
accompanies the duct in its course to the testis, where it anastomoses with the internal spermatic
artery. Other branches supply the ureter. The first part of the superior vesical artery represents the
terminal section of the pervious portion of the fetal hypogastric artery.
◦ The middle vesical artery (a. vesicalis medialis), usually a branch of the superior, is distributed to the
fundus of the bladder and the vesiculæ seminales.
◦ The inferior vesical artery (a. vesicalis inferior) frequently arises in common with the middle
hemorrhoidal, and is distributed to the fundus of the bladder, the prostate, and the vesiculæ
seminales. The branches to the prostate communicate with the corresponding vessels of the opposite
side.
◦ The middle hemorrhoidal artery (a. hæmorrhoidalis media) usually arises with the preceding vessel. It
is distributed to the rectum, anastomosing with the inferior vesical and with the superior and inferior
hemorrhoidal arteries. It gives offsets to the vesiculæ seminales and prostate.

11. …
◦ The uterine artery (a. uterina) springs from the anterior division of the
hypogastric and runs medialward on the Levator ani and toward the cervix uteri;
about 2 cm. from the cervix it crosses above and in front of the ureter, to which it
supplies a small branch. Reaching the side of the uterus it ascends in a tortuous
manner between the two layers of the broad ligament to the junction of the uterine
tube and uterus. It then runs lateralward toward the hilus of the ovary, and ends by
joining with the ovarian artery. It supplies branches to the cervix uteri and others
which descend on the vagina; the latter anastomose with branches of the vaginal
arteries and form with them two median longitudinal vessels—the azygos arteries
of the vagina—one of which runs down in front of and the other behind the
vagina. It supplies numerous branches to the body of the uterus, and from its
terminal portion twigs are distributed to the uterine tube and the round ligament of
the uterus.

12. …
◦ The vaginal artery (a. vaginalis) usually corresponds to the inferior vesical in the
male; it descends upon the vagina, supplying its mucous membrane, and sends
branches to the bulb of the vestibule, the fundus of the bladder, and the contiguous
part of the rectum. It assists in forming the azygos arteries of the vagina, and is
frequently represented by two or three branches.
◦ The obturator artery (a. obturatoria) passes forward and downward on the lateral
wall of the pelvis, to the upper part of the obturator foramen, and, escaping from
the pelvic cavity through the obturator canal, it divides into an anterior and a
posterior branch. In the pelvic cavity this vessel is in relation, laterally, with the
obturator fascia; medially, with the ureter, ductus deferens, and peritoneum; while
a little below it is the obturator nerve.

13. …
◦ Branches.—Inside the pelvis the obturator artery gives off iliac branches to the iliac fossa, which
supply the bone and the Iliacus, and anastomose with the ilio-lumbar artery; a vesical branch,
which runs backward to supply the bladder; and a public branch, which is given off from the
vessel just before it leaves the pelvic cavity. The pubic branch ascends upon the back of the
pubis, communicating with the corresponding vessel of the opposite side, and with the inferior
epigastric artery.
◦ Outside the pelvis, the obturator artery divides at the upper margin of the obturator foramen,
into an anterior and a posterior branch which encircle the foramen under cover of the Obturator
externus.

14. …
◦ The anterior branch runs forward on the outer surface of the obturator membrane and then curves downward
along the anterior margin of the foramen. It distributes branches to the Obturator externus, Pectineus, Adductores,
and Gracilis, and anastomoses with the posterior branch and with the medial femoral circumflex artery.
◦ The posterior branch follows the posterior margin of the foramen and turns forward on the inferior ramus of the
ischium, where it anastomoses with the anterior branch. It gives twigs to the muscles attached to the ischial
tuberosity and anastomoses with the inferior gluteal. It also supplies an articular branch which enters the hip-joint
through the acetabular notch, ramifies in the fat at the bottom of the acetabulum and sends a twig along the
ligamentum teres to the head of the femur.
◦ Peculiarities.—The obturator artery sometimes arises from the main stem or from the posterior trunk of the
hypogastric, or it may spring from the superior gluteal artery; occasionally it arises from the external iliac. In about
two out of every seven cases it springs from the inferior epigastric and descends almost vertically to the upper part
of the obturator foramen. The artery in this course usually lies in contact with the external iliac vein, and on the
lateral side of the femoral ring; in such cases it would not be endangered in the operation for strangulated femoral
hernia. Occasionally, however, it curves along the free margin of the lacunar ligament, and if in such circumstances
a femoral hernia occurred, the vessel would almost completely encircle the neck of the hernial sac, and would be in
great danger of being wounded if an operation were performed for strangulation.

15. Internal pudendal artery
◦ The internal pudendal artery (a. pudenda interna; internal pudic artery) is the smaller of the two
terminal branches of the anterior trunk of the hypogastric, and supplies the external organs of
generation. Though the course of the artery is the same in the two sexes, the vessel is smaller in the
female than in the male, and the distribution of its branches somewhat different. The description of
its arrangement in the male will first be given, and subsequently the differences which it presents in
the female will be mentioned.
◦ The internal pudendal artery in the male passes downward and outward to the lower border of the
greater sciatic foramen, and emerges from the pelvis between the Piriformis and Coccygeus; it then
crosses the ischial spine, and enters the perineum through the lesser sciatic foramen. The artery now
crosses the Obturator internus, along the lateral wall of the ischiorectal fossa, being situated about 4
cm. above the lower margin of the ischial tuberosity. It gradually approaches the margin of the
inferior ramus of the ischium and passes forward between the two layers of the fascia of the
urogenital diaphragm; it then runs forward along the medial margin of the inferior ramus of the
pubis, and about 1.25 cm. behind the pubic arcuate ligament it pierces the inferior fascia of the
urogenital diaphragm and divides into the dorsal and deep arteries of the penis.

16. Branches
Branches.—The branches of the internal
pudendal artery are:
Muscular. Artery of the Urethral Bulb.
Inferior Hemorrhoidal. Urethral.
Perineal. Deep Artery of the Penis.
Dorsal Artery of the Penis.

17. The Muscular Branches consist of two
sets: one given off in the pelvis; the other, as the
vessel crosses the ischial spine. The former
consists of several small offsets which supply
the Levator ani, the Obturator internus, the
Piriformis, and the Coccygeus. The branches
given off outside the pelvis are distributed to
the adjacent parts of the Glutæus maximus and
external rotator muscles. They anastomose with
branches of the inferior gluteal artery.
The Inferior Hemorrhoidal Artery (a.
hæmorrhoidalis inferior) arises from the internal
pudendal as it passes above the ischial
tuberosity. Piercing the wall of Alcock’s canal it
divides into two or three branches which cross
the ischiorectal fossa, and are distributed to the
muscles and integument of the anal region, and
send offshoots around the lower edge of the
Glutæus maximus to the skin of the buttock.
They anastomose with the corresponding
vessels of the opposite side, with the superior
and middle hemorrhoidal, and with the perineal
artery

18. …
◦ The Perineal Artery (a. perinei; superficial perineal artery) arises from the internal pudendal, in front of
the preceding branches, and turns upward, crossing either over or under the Transversus perinæi
superficialis, and runs forward, parallel to the pubic arch, in the interspace between the
Bulbocavernosus and Ischiocavernosus, both of which it supplies, and finally divides into several
posterior scrotal branches which are distributed to the skin and dartos tunic of the scrotum. As it
crosses the Transversus perinæi superficialis it gives off the transverse perineal artery which runs
transversely on the cutaneous surface of the muscle, and anastomoses with the corresponding vessel
of the opposite side and with the perineal and inferior hemorrhoidal arteries. It supplies the
Transversus perinæi superficialis and the structures between the anus and the urethral bulb. The
Artery of the Urethral Bulb (a. bulbi urethræ) is a short vessel of large caliber which arises from the
internal pudendal between the two layers of fascia of the urogenital diaphragm; it passes medialward,
pierces the inferior fascia of the urogenital diaphragm, and gives off branches which ramify in the
bulb of the urethra and in the posterior part of the corpus cavernosum urethræ. It gives off a small
branch to the bulbo-urethral gland.

19. …
◦ The Urethral Artery (a. urethralis) arises a short distance in front of the artery of the urethral bulb. It
runs forward and medialward, pierces the inferior fascia of the urogenital diaphragm and enters the
corpus cavernosum urethræ, in which it is continued forward to the glans penis.
◦ The Deep Artery of the Penis (a. profunda penis; artery to the corpus cavernosum), one of the
terminal branches of the internal pudendal, arises from that vessel while it is situated between the
two fasciæ of the urogenital diaphragm; it pierces the inferior fascia, and, entering the crus penis
obliquely, runs forward in the center of the corpus cavernosum penis, to which its branches are
distributed.
◦ The Dorsal Artery of the Penis (a. dorsalis penis) ascends between the crus penis and the pubic
symphysis, and, piercing the inferior fascia of the urogenital diaphragm, passes between the two
layers of the suspensory ligament of the penis, and runs forward on the dorsum of the penis to the
glans, where it divides into two branches, which supply the glans and prepuce. On the penis, it lies
between the dorsal nerve and deep dorsal vein, the former being on its lateral side. It supplies the
integument and fibrous sheath of the corpus cavernosum penis, sending branches through the sheath
to anastomose with the preceding vessel.

20. …
The inferior gluteal artery (a. glutæa inferior; sciatic arter, the larger of
the two terminal branches of the anterior trunk of the hypogastric, is
distributed chiefly to the buttock and back of the thigh. It passes
down on the sacral plexus of nerves and the Piriformis, behind the
internal pudendal artery, to the lower part of the greater sciatic
foramen, through which it escapes from the pelvis between the
Piriformis and Coccygeus. It then descends in the interval between the
greater trochanter of the femur and tuberosity of the ischium,
accompanied by the sciatic and posterior femoral cutaneous nerves,
and covered by the Glutæus maximus, and is continued down the
back of the thigh, supplying the skin, and anastomosing with branches
of the perforating arteries.
Inside the pelvis it distributes branches to the Piriformis, Coccygeus,
and Levator ani; some branches which supply the fat around the
rectum, and occasionally take the place of the middle hemorrhoidal
artery; and vesical branches to the fundus of the bladder, vesiculæ
seminales, and prostatate

21. Branches
Muscular. Anastomotic.
Coccygeal. Articular.
Comitans Nervi
Ischiadici.
Cutaneous.
The Muscular Branches supply the Glutæus maximus, anastomosing
with the superior gluteal artery in the substance of the muscle; the
external rotators, anastomosing with the internal pudendal artery; and
the muscles attached to the tuberosity of the ischium, anastomosing
with the posterior branch of the obturator and the medial femoral
circumflex arteries.
The Coccygeal Branches run medialward, pierce the sacrotuberous
ligament, and supply the Glutæus maximus, the integument, and other
structures on the back of the coccyx.
The Arteria Comitans Nervi Ischiadici is a long, slender vessel, which
accompanies the sciatic nerve for a short distance; it then penetrates it,
and runs in its substance to the lower part of the thigh.
The Anastomotic is directed downward across the external rotators, and
assists in forming the so-called crucial anastomosis by joining with the
first perforating and medial and lateral femoral circumflex arteries.
The Articular Branch, generally derived from the anastomotic, is
distributed to the capsule of the hip-joint.
The Cutaneous Branches are distributed to the skin of the buttock and
back of the thigh.

22. …
◦ The Lumbar Branch (ramus lumbalis) supplies the Psoas major and Quadratus lumborum,
anastomoses with the last lumbar artery, and sends a small spinal branch through the intervertebral
foramen between the last lumbar vertebra and the sacrum, into the vertebral canal, to supply the
cauda equina.
◦ The Iliac Branch (ramus iliacus) descends to supply the Iliacus; some offsets, running between the
muscle and the bone, anastomose with the iliac branches of the obturator; one of these enters an
oblique canal to supply the bone, while others run along the crest of the ilium, distributing branches
to the gluteal and abdominal muscles, and anastomosing in their course with the superior gluteal,
iliac circumflex, and lateral femoral circumflex arteries.
◦ The lateral sacral arteries (aa. sacrales laterales) arise from the posterior division of the hypogastric;
there are usually two, a superior and an inferior.
◦ The superior, of large size, passes medialward, and, after anastomosing with branches from the
middle sacral, enters the first or second anterior sacral foramen, supplies branches to the contents of
the sacral canal, and, escaping by the corresponding posterior sacral foramen, is distributed to the
skin and muscles on the dorsum of the sacrum, anastomosing with the superior gluteal.

23. The arteries of the gluteal and posterior
femoral regions
◦ The inferior runs obliquely across the front of the Piriformis and the sacral nerves to the medial
side of the anterior sacral foramina, descends on the front of the sacrum, and anastomoses over
the coccyx with the middle sacral and opposite lateral sacral artery. In its course it gives off
branches, which enter the anterior sacral foramina; these, after supplying the contents of the
sacral canal, escapes by the posterior sacral foramina, and are distributed to the muscles and
skin on the dorsal surface of the sacrum, anastomosing with the gluteal arteries.
◦ The superior gluteal artery (a. glutæa superior; gluteal artery) is the largest branch of the
hypogastric, and appears to be the continuation of the posterior division of that vessel. It is a
short artery which runs backward between the lumbosacral trunk and the first sacral nerve, and,
passing out of the pelvis above the upper border of the Piriformis, immediately divides into a
superficial and a deep branch. Within the pelvis it gives off a few branches to the Iliacus,
Piriformis, and Obturator internus, and just previous to quitting that cavity, a nutrient artery
which enters the ilium.

24. …
◦ The superficial branch enters the deep surface of the Glutæus maximus, and divides into
numerous branches, some of which supply the muscle and anastomose with the inferior gluteal,
while others perforate its tendinous origin, and supply the integument covering the posterior
surface of the sacrum, anastomosing with the posterior branches of the lateral sacral arteries.
◦ The deep branch lies under the Glutæus medius and almost immediately subdivides into two. Of
these, the superior division, continuing the original course of the vessel, passes along the upper
border of the Glutæus minimus to the anterior superior spine of the ilium, anastomosing with
the deep iliac circumflex artery and the ascending branch of the lateral femoral circumflex
artery. The inferior division crosses the Glutæus minimus obliquely to the greater trochanter,
distributing branches to the Glutæi and anastomoses with the lateral femoral circumflex artery.
Some branches pierce the Glutæus minimus and supply the hip-joint.