Download 1. The boundaries of the perineum include all the following except

1. The boundaries of the perineum include all the following except:
Ischiopubic rami
Ischial tuberosity
Tip of the coccyx
Sacrotuberal ligament
Sacrospinal ligament
2. A condensation of fibrous tissue in the female located at the center
of the posterior border of the perineal membrane is the:
Frenulum
Posterior labial commissure
Perineal body
Anococcygeal ligament
Pubovesical ligament
3. The artery which supplies blood to the major erectile body in both
the male and female is the:
Artery of the bulb
Dorsal artery of the penis/clitoris
Deep artery of the penis/clitoris
Posterior labial/scrotal artery
Superficial external pudendal artery
4. The vestibular bulbs/bulb of the corpus spongiosum are firmly
attached to the:
Perineal membrane
Superior pubic rami
Ischiopubic rami
Pubic symphysis
Ischial tuberosities
5. The part of the male reproductive tract which carries only semen
within the prostate gland is the:
Prostatic urethra
Membranous urethra
Seminal vesicle
Ductus deferens
Ejaculatory duct
6. Which of the following developmental processes is least likely to
be involved in the differentiation of male external genitalia from the
indifferent state?
Descent of the gonads into the labio-scrotal folds
Fusion of the urogenital folds
Elongation of the phallus
Formation of new erectile bodies
7. An intrahepatic blockage of the portal venous outflow may cause
intestinal blood to drain via portal-systemic anastomoses into the:
Superior gluteal vein
Middle rectal vein
Splenic vein
Renal vein
Inferior phrenic vein
8. What part of the ischioanal (ischiorectal) fossa extends deep to the
sacrotuberal ligament?
Anterior recess
Genital hiatus
Posterior recess
Pudendal canal
9. The perineum is bounded by all of the following skeletal elements
except:
coccyx
ischiopubic ramus
spine of ischium
symphysis pubis
10.
A 6 mo. old male was brought to the pediatric clinic by his
parents because of leakage of urine from the ventral surface of his
penis. This congenital condition, hypospadias, is due to incomplete
ventral closure of a component of the penis. Which of the below
structures would be partially open for urine to take such a course?
Shaft of corpus cavernosum
Membranous urethra
Glans
Shaft of corpus spongiosum
11.
During childbirth a bilateral pudendal nerve block may be
performed to provide anesthesia to the majority of the perineum
and the lower one fourth of the vagina. To do this an anesthetic
agent is injected near the pudendal nerve as it passes from the
pelvic cavity to the perineum. The physician inserts a finger into
the vagina and presses laterally to palpate what landmark?
Arcus tendineus levator ani
Coccyx
Ischial spine
Lateral fornix
Obturator foramen
12.
During a vaginal delivery, a surgeon performed median
episiotomy in which he cut too far (i.e., through the perineal body
into the structure immediately posterior). Which perineal structure
did he cut?
Bulbospongiosis muscle
External anal sphincter muscle
Ischiocavernosis muscle
Sacrospinous ligament
Sphincter urethrae
13.
During a prostatectomy, the surgeon attempts to protect the
prostatic plexus of nerves which contains nerve fibers that
innervate penile tissue to cause erection. From which nerves do
these fibers originate?
Deep perineal
Dorsal nerve of the penis
Genitofemoral
Pelvic splanchnics
Pudendal
14.
If the venous drainage of the anal canal above the pectinate
line is impaired in a patient with portal hypertension, there may be
an increase in blood flow downward to the systemic venous
system via anastomoses with the inferior rectal vein, which is a
tributary of the:
External iliac
Inferior gluteal
Inferior mesenteric
Internal iliac
Internal pudendal
15.
A patient complains of a boil located on her labia majora.
Lymphatic spread of the infection would most likely enlarge which
nodes?
Lumbar nodes
Sacral nodes
External iliac nodes
Superficial inguinal nodes
Internal iliac nodes
16.
In order to perform an episiotomy prior to childbirth, the
perineum must be anesthetized. By inserting a finger in the vagina
and pressing laterally, what palpable bony landmark can be used
as the posterior limit of the pudendal canal?
Coccyx
Ischial tuberosity
Ischiopubic ramus
Obturator groove
Ischial spine
1. The correct answer is:
sacrospinal ligament
The sacrospinal ligament connects the sacrum to the ischial spine.
Together with the sacrotuberous ligament, it converts the greater and
lesser sciatic notches into greater and lesser sciatic foramina. However,
it is not near the perineum--it is more important as a landmark that
creates the greater and lesser sciatic foramina which helps to organize
the structures exiting the pelvis.
The bounderies of the perineum are as follows. Anterior: pubic
symphysis; Anterolateral: ischiopubic rami; Lateral: ischial tuberosities;
Posterolateral: sacrotuberous ligament; Posterior: tip of the coccyx.
These boundaries create two triangles in the perineum: the urogenital
triangle and the anal triangle. The urogenital triangle is the anterior
subdivision, bounded by the pubic symphysis, ischiopubic rami, and the
posterior margin of the perineal membrane, which corresponds to an
imaginary line between the two ischial tuberosities. The anal triangle is
the posterior division of the perineum. It starts off where the urogenital
triangle ends: at the posterior margin of the perineal membrane. Then, it
is bounded by the sacrotuberous ligament and the tip of the coccyx.
It's important to look at these triangles and orient yourself to them using
the bones in your bone set--you'll realize that the perineum is not
contained in one flat plane; instead, the triangles are at angles to each
other.
2. The correct answer is:
perineal body
The perineal body is an irregular fibromuscular mass located at the
center of the posterior border of the perineal membrane. It is the site
where many muscles converge, including bulbospongiosus, external
anal sphincter, and the superficial and deep transverse perineal
muscles. This is found only in females; the male homolog for this
structure is the central tendinous point.
Frenulum is a word that refers to a small fold, and there are two in the
female perineum, so this isn't even specific enough to be a good answer.
The frenulum of the clitoris is a structure lying deep to the clitoris, formed
by the deep labia minora. This structure is not near the posterior border
of the perineal membrane; it is clearly in the urogenital triangle. There is
also a frenulum of the labia minora which is just anterior to the perineal
body, also in the urogenital triangle. Although the frenulum of the labia
minora is sort of superficial to the center of the posterior border of the
perineal membrane, the question is asking for a structure that is closely
associated with the perineal membrane. This means that structures of
the external genitalia will be wrong answers. The posterior labial
commissure is another structure of the external genitalia which is located
over the posterior border of the perineal membrane, and it's also a
wrong answer for the same reason. The anococcygeal ligament is a
ligament that attaches the external anal sphincter to the coccyx. It is
located in the anal triangle. The pubovesicular ligament attaches the
bladder to the pubic bone. It is more associated with the pelvic viscera
as opposed to the perineum.
3. The correct answer is:
deep artery of the penis/clitoris
The deep artery supplies the corpus cavernosum of the penis/clitoris,
which is the major erectile body. It is one of the two terminal branches of
the internal pudendal artery, with the other one being the dorsal artery of
the penis/clitoris. This artery supplies superficial structures. The artery of
the bulb supplies blood to the bulb of the penis and the bulb of the
vestibule. Although the bulbs are erectile tissue, the corpus cavernosum
is the main erectile body. The posterior labial/scrotal artery supplies
exactly what you would guess--the posterior labia or scrotum. It is a
branch of the perineal artery. Finally, the superficial external pudendal
artery supplies the skin and superficial fascia of the upper medial thigh,
as well as the skin of the pubic region. It is a superficial branch of the
femoral artery.
4. The correct answer is:
perineal membrane
The bulbs of the vestibule/bulb of the corpus spongiosum are pieces of
erectile tissue that attach to the perineal membrane. They are covered
by the bulbospongiosis muscle. The ischiopubic rami, pubic symphysis,
and ischial tuberosities are bony structures important for defining the
boundaries of the perineum. The crura of the corpora cavernosa attach
to the ischiopubic rami and the perineal membrane.
5. The correct answer is:
ejaculatory duct
The ejaculatory duct is a duct which courses through the prostate gland
and contains only semen. Remember, semen is the combination of
sperm from the ductus deferens, seminal fluid from the seminal vesicle,
and secretions of the prostate gland. The ejaculatory duct is formed by
the union of the duct of the seminal vesicle and the ampulla of the
ductus deferens, and it is the site where sperm and seminal fluid mix.
The prostatic urethra is also contained in the prostate gland, and it
carries semen, but it also carries urine out of the bladder. The
membranous urethra is the continuation of the prostatic urethra outside
of the prostate gland, and it carries both semen and urine as well. The
seminal vesicle is a structure on the posterior surface of the bladder that
produces seminal fluid. The ductus deferens is a passageway that
carries sperm from the epididymis to the ejaculatory duct.
6. The correct answer is:
formation of new erectile bodies
Males and females have analogous erectile bodies. The three main
erectile bodies in males are 2 corpus cavernosa and a corpus
spongiosum. Females have 2 corpus cavernosa plus 2 vestibular bulbs
which are analogs to the corpus spongiosum. So, females actually have
more erectile bodies than males. Development differs, however, in many
other ways. Remember: the gubernaculum pulls the testes to descend
into the scrotum, but the ovaries stop their descent and remain in the
pelvis. The urogenital folds fuse in males to create the raphe of the
penis. However, they stay open in females to create the labial minora
and perineal raphe. Finally, the phallus elongates in males but not in
females.
7. The correct answer is:
middle rectal vein
There are four portal-caval anastomoses in the body. First, between the
superior rectal veins in the portal system and the middle and inferior
rectal veins in the caval system. Second, between the esophageal veins
that go to the left gastric vein (portal) and the esophageal veins that go
to the azygos system (caval). Third, between the paraumbilical veins of
the portal system and the veins of the anterior abdominal wall that drain
into the inferior vena cava. Fourth, between the colic veins of the portal
system and the retroperitoneal veins of the caval system. So middle
rectal is the right answer. The superior gluteal vein, renal vein, and
inferior phrenic vein are all part of the caval system; the splenic vein is
part of the portal system.
8. The correct answer is:
posterior recess
The ischioanal fossa is a space found on both sides of the anal canal. It
is bounded laterally by the obturator internus, superiorly by the pelvic
diaphragm, and medially by the pelvic diaphragm and anus. It is the area
that is lateral to the anal canal and inferior to the pelvic diaphragm. The
anterior recesses are the parts of the ischioanal fossa that extend above
the perineal membrane, and the posterior recesses extend deep to the
sacrotuberal membrane and superior to the gluteus maximus. The
genital hiatus is the place where the pelvic diaphragm splits to allow the
urethra/vagina and anus to pass through. The pudendal canal travels
from the lesser sciatic foramen, where its contents enter the perineum. It
contains the internal pudendal artery, internal pudendal vein, and
pudendal nerve.
9. The correct answer is:
spine of the ischium
The bounderies of the perineum are as follows. Anterior: pubic
symphysis; Anterolateral: ischiopubic rami; Lateral: ischial tuberosities;
Posterolateral: sacrotuberous ligament; Posterior: tip of the coccyx. The
spine of the ischium, which projects into the pelvis toward the lateral
pelvic wall, does not make up a boundary of the perineum
10. The correct answer is:
shaft of the corpus spongiosum
Since the urine is leaking through the ventral side of the penis, it must be
leaking through a defect in the spongy urethra. The spongy urethra is
contained in the corpus spongiosum, so it follows that the corpus
spongiosum must be open. The membranous urethra is a brief portion of
the urethra extending from the bottom of the prostate to the top of the
corpus spongiosum. A defect here would not cause leakage on the
ventral surface of the penis. The corpora cavernosa are erectile bodies
that lie beside the corpus spongiosum. They are not involved with the
flow of urine or the urethra. The glans of the penis is at the tip - if this
structure failed to close, there would be abnormal leakage from the tip of
the penis, not the ventral surface.
11. The correct answer is:
Ischial spine
When performing a transvaginal pudendal nerve block, the ischial spine
is palpated through the wall of the vagina and the needle is then passed
through the vaginal mucous membrane toward the ischial spine.
Eventually, the needle pierces the sacrospinous ligament, at which point
the pudendal nerve is bathed with anesthetic. Remember--the pudendal
nerve is within the pudendal canal, and it wraps around the ischial spine
before it delivers its branches. So, administering the nerve block at the
ischial spine allows a physician to anesthetize all the branches of the
pudendal nerve. This is a very important landmark that you want to
remember!
Also remember--the pudendal nerve block does not need to be
administered transvaginally. In a perineal pudendal nerve block, the
ischial tuberosity is palpated through the buttock and the needle is
inserted into the pudendal canal about one inch deep medial to the
ischial tuberosity. The anesthetic can then be injected to bathe pudendal
nerve. In this case, a different anatomical landmark, the ischial
tuberosity, is used to deliver the nerve block
Arcus tendineus levator ani is the origin for levator ani. It is a
specialization of the fascia of obturator internus which runs from the
spine of the ischium to the superior pubic ramus. The coccyx is the most
inferior portion of the vertebral column--it is found on the posterior wall of
the pelvis. The lateral fornix of the vagina is the space found lateral to
the cervix as it protrudes into the vagina. The obturator foramen is a
large foramen on the anterior side of the pelvis, formed by the pubic and
ischial rami. It is a site of attachment for obturator externus and internus.
None of these structures are appropriate landmarks to use when
performing a pudendal nerve block.
12. The correct answer is:
External anal sphincter muscle
An episiotomy is an incision made in the perineum to enlarge the distal
end of the birth canal and to prevent serious damage to the perineal
structures. This procedure is often performed when there is a risk of
tearing the birth canal due to a breech or forceps delivery. When
performing a median episiotomy, a cut is made immediately posterior to
the vagina, through the perineal body. If this cut went too far, the
physician might cut through the external anal sphincter or the rectum.
So, external anal sphincter is the correct answer.
It's important to remember that episiotomies are often made in the
posterolateral direction, not on the midline. If the incision tears further
during the delivery, a median incision is more likely than a posterolateral
incision to extend posteriorly through the external anal sphincter, and the
rectum. Consequently, a posterolateral incision is considered safer by
some.
The bulbospongiosus muscle, ischiocavernosus muscle, and sphincter
urethrae are anterior to the area that is cut during an episiotomy. The
sacrospinous ligament extends from the sacrum to the ischial spine--it is
deep to the perineum and should not be involved with this procedure.
13. The correct answer is:
Pelvic splanchnics
Erection is mediated by parasympathetic nerves, and the pelvic
splanchnic nerves are the parasympathetic nerves that innervate the
smooth muscle and glands of all pelvic viscera. So, the pelvic splanchnic
nerves are the nerves contributing the fibers to the prostatic plexus
which innervate penile/clitoral erectile tissue to cause erection.
None of the other listed nerves carry parasympathetic fibers which could
innervate the penis and cause erection. Additionally, none of these other
nerves contribute to the prostatic plexus, which is an extension of the
inferior hypogastric plexus. The deep perineal nerve is the a branch of
the perineal nerve that innervates all the muscles of the urogenital
triangle. The dorsal nerve of the penis/clitoris is a branch of the
pudendal nerve that provides sensory innervation to the skin of the shaft
of the penis/clitoris. The genitofemoral nerve provides motor innervation
to the cremaster muscle and sensory innervation to the skin of the
anterior scrotum/labium majus and the upper medial thigh. Finally, the
pudendal nerve is the major nerve of the perineal region. Its branches
include the inferior rectal nerve, perineal nerve, and the dorsal nerve of
the penis/clitoris.
14. The correct answer is:
Internal pudendal
The rectal venous plexus is one of the four portal/systemic
anastomoses. Blood from the portal system can flow into the venous
system at this junction. This means that portal blood, from the superior
rectal vein, could flow through the rectal venous plexus, into the inferior
rectal vein and into the systemic venous drainage. Now, you just need to
figure out what the inferior rectal vein drains into. And it drains into the
internal pudendal vein, so that's the answer. See Netter plate 370 for a
picture illustrating this concept of the portal/systemic anastomosis in the
rectum.
The external iliac vein is one of the two branches of the common iliac
vein (along with the internal iliac vein). However, the internal iliac vein
and its tributaries (including the pudendal vein) are much more important
in draining the pelvic structures. The inferior gluteal vein is a branch of
the anterior division of the internal iliac vein--it drains gluteus maximus.
The inferior mesenteric vein is part of the portal venous system--it gives
rise to the superior rectal veins, but not the inferior rectal veins!
15. The correct answer is:
Superficial inguinal lymph nodes
The perineum and the external genitalia, including the labia majora and
scrotum, drain to the superficial inguinal lymph nodes. However, in the
male, remember that the testes do not drain to the superficial inguinal
lymph nodes! The lymphatic vessels for testes travel in the spermatic
cord and drain the testes into the lumbar nodes (ovaries also drain to
lumbar nodes).
The lumbar nodes drain the internal pelvic organs; the sacral nodes
drain the prostate gland, uterus, vagina, rectum, and posterior pelvic
wall; the external iliac nodes drain the lower limb; the internal iliac nodes
drain the pelvis and gluteal region.
16. The correct answer is:
Ischial spine
The pudendal canal travels from the lesser sciatic foramen to the deep
transverse perineus muscle. The ischial spine marks the posterior limit of
the pudendal canal, so that's the correct answer. If you weren't sure
about that, you might also notice that the physician here is trying to
perform a transvaginal pudendal nerve block. This means that the
physician will be using the ischial spine as a landmark and inserting the
needle near this prominence, coating the pudendal nerve with
anesthesia before it gives off its branches.
The coccyx is the inferior end of the vertebral column; it is on the
posterior wall of the pelvis. The ischial tuberosity (not to be confused
with the ischial spine!) protrudes posteroinferiorly from the body of the
ischium. It is the attachment for the sacrotuberous ligament. The
ischiopubic ramus is the articulation between the ischial ramus and the
inferior pubic ramus in the anterior pubis. The obturator groove is a
groove on the inferior surface of the superior pubic ramus. It marks the
area of passage of the obturator vessels and nerve in the obturator
canal.