Block 7 Anatomy Perineum Pelvis BRS W Exp Prt 3

The bladder is situated in the anterior part of the pelvic cavity. Thus, a stab
wound superior to the pubic symphysis would injure the bladder

The cardinal (transverse cervical) ligament provides the major ligamentous
support for the uterus. The sphincter ani externus does not support the uterus. The broad and
round ligaments of the uterus provide minor supports for the uterus. The suspensory ligament of
the ovary does not support the uterus.

Lymphatic vessels from the testis and epididymis ascend along the testicular
vessels in the spermatic cord through the inguinal canal and continue upward in the abdomen
to drain into the upper lumbar nodes. The lymph from the other structures drains into
the superficial inguinal lymph nodes.

Cancer cells from the rectal cancer are likely to metastasize to the liver via
the superior rectal, inferior mesenteric, splenic, and portal veins. Cancer cells are not directly
spread to the other organs listed. The spleen and duodenum drain their venous blood to the portal
venous system and the kidney and suprarenal gland empty into the caval (inferior vena cava)
system.

The ischiorectal fossa lies in the anal triangle and is bound laterally by the
obturator internus with its fascia and superomedially by the levator ani and external anal sphincter.
It contains the inferior rectal vessels. Thus, hemorrhage occurs in the ischiorectal fossa when
it is ruptured.

The sphincter urethrae is found in the deep perineal space, whereas the
other structures are located in the superficial perineal space.

The lumbosacral trunk is formed by part of the ventral ramus of the fourth
lumbar nerve and the ventral ramus of the fifth lumbar nerve. This trunk contributes to the formation
of the sacral plexus by joining the ventral ramus of the first sacral nerve in the pelvic cavity
and does not leave the pelvic cavity. All other nerves leave the abdominal and pelvic cavities.
The ilioinguinal nerve accompanies the spermatic cord or the round ligament of the uterus, continues
through the inguinal canal, and emerges through the superficial inguinal ring. The genitofemoral
nerve divides into a genital branch, which enters the inguinal canal through the deep
inguinal ring and exits through the superficial inguinal ring and supplies the cremaster muscle
and the scrotum or labium majus, and a femoral branch, which passes deep to the inguinal ligament
and enters the femoral triangle. The femoral nerve enters the femoral triangle deep to the
inguinal ligament and lateral to the femoral vessels and divides into numerous branches. The lateral
femoral cutaneous nerve runs in front of the iliacus and behind the inguinal ligament and
innervates the skin of the anterior and lateral thigh.

The mucous membrane and the circular smooth muscle layer of the rectum
form three transverse folds; the middle one is called Houston's valve. The venous blood returns
to the portal venous system via the superior rectal vein.

The external iliac artery becomes the femoral artery immediately after passing
the inguinal ligament. Therefore, ligation of the external iliac artery reduces blood pressure
in the femoral artery.

The seminal vesicle is a lobulated glandular structure and produces the alkaline
constituent of the seminal fluid, which contains fructose and choline. Fructose, which is
nutritive to spermatozoa, also allows forensic determination of rape, whereas choline crystals are
the preferred basis for the determination of the presence of semen.

The obturator foramen transmits the obturator nerve and vessels. Therefore,
the knife wound in this foramen injures the obturator nerve and vessels.

The answer is B. The obturator internus muscle and its fascia form the lateral wall of the ischiorectal
fossa. This muscle is innervated by the nerve to the obturator internus, which passes
through the greater and lesser sciatic foramen.

An obstetrician should avoid incising the levator ani and the external anal
sphincter. The levator ani is the major part of the pelvic diaphragm, which forms the pelvic floor
and supports all of the pelvic organs. None of the other choices applies here.

Of all the arteries listed, the uterine artery remains within the pelvic cavity.

All of the listed structures do not cross the pelvic brim except the lumbosacral
trunk, which arises from L4 and L5, enters the true pelvis by crossing the pelvic brim,
and contributes to the format ion of the sacral plexus. The deep dorsal vein of the penis enters the
pelvic cavity by passing under the symphysis pubis between the arcuate and transverse perineal
ligaments.

The scrotum is innervated by branches of the ilioinguinal, genitofemoral,
pudendal, and posterior femoral cutaneous nerves. The scrotum receives blood from the posterior
scrotal branches of the internal pudendal arteries and the anterior scrotal branches of the external
pudendal arteries, but it does not receive blood from the testicular artery. Similarly, the scrotum
is drained by the posterior scrotal veins into the internal pudendal vein. The lymph vessels
from the scrotum drain into the superficial inguinal nodes, whereas the lymph vessels from the
testis drain into the upper lumbar nodes. The dartos tunic is continuous with the membranous
layer of the superficial perineal fascia (Colles' fascia).

The sacrospinous ligament forms a boundary of the lesser sciatic foramen.
The pubic arcuate ligament, tip of the coccyx, ischial tuberosities, and sacrotuberous ligament all
form part of the boundary of the perineum

In females, the urethra extends from the bladder, runs above the anterior
vaginal wall, and pierces the urogenital diaphragm to reach the urethral orifice in the vestibule
behind the clitoris. It is about 4 cm long. In males, the urethra is about 20 cm long.

The greater trochanter provides an insertion site for the obturator internus
muscle.

The vagina is the genital canal in the female, extending from the vestibule
to the uterine cervix. The vagina transmits the products of menstruation and receives the penis
in copulation.