Anatomy Perineum –pelvis BRS - Part 2
.JPG "Anatomy Perineum pelvis BRS - Part 2 - Quiz")
Questions and Answers
- 1.
A 22-year-old victim of an automobile accident has received destructive damage to structures that form the boundary of the perineum. Which of the following structures is spared?
- A.
Pubic arcuate ligament
- B.
Tip of the coccyx
- C.
Ischial tuberosities
- D.
Sacrospinous ligament
- E.
Sacrotuberous ligament
Correct Answer
D. Sacrospinous ligamentExplanation
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 perineumRate this question:
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- 2.
A 32-year-old man undergoes vasectomy as a permanent birth control. A physician performing the vasectomy by making an incision on each side of the scrotum should remember which of the following statements is most applicable to the scrotum?
- A.
It is innervated by the ilioinguinal and genitofemoral nerves
- B.
It receives blood primarily from the testicular artery
- C.
Its venous blood drains primarily into the renal vein on the left
- D.
Its lymphatic drainage is primarily into upper lumbar nodes
- E.
Its dartos tunic is continuous with the perineal membrane
Correct Answer
A. It is innervated by the ilioinguinal and genitofemoral nervesExplanation
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).Rate this question:
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- 3.
A 37-year-old woman complains of a bearing-down sensation in her womb and an increased frequency of and burning sensation on urination. On examination by her gynecologist, she is diagnosed with the uterine prolapse. Which of the following structures provides the primary support for the cervix of the uterus?
- A.
External anal sphincter
- B.
Broad ligament of the uterus
- C.
Cardinal (transverse cervical) ligament
- D.
Round ligament of the uterus
- E.
Suspensory ligament of the ovary
Correct Answer
C. Cardinal (transverse cervical) ligamentExplanation
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.Rate this question:
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- 4.
A woman is delivering a breech baby. The obstetrician decides it is best to perform a mediolateral episiotomy. Which of the following structures, should the obstetrician avoid incising?
- A.
Vaginal wall
- B.
Superficial transverse perineal muscle
- C.
Bulbospongiosus
- D.
Levator ani
- E.
Perineal membrane
Correct Answer
D. Levator aniExplanation
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.Rate this question:
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- 5.
During pelvic surgery, a surgeon notices severe bleeding from the artery that remains within the true pelvis. Which of the following arteries is most likely to be injured?
- A.
Iliolumbar artery
- B.
Obturator artery
- C.
Uterine artery
- D.
Internal pudendal artery
- E.
Inferior gluteal artery
Correct Answer
C. Uterine arteryExplanation
Of all the arteries listed, the uterine artery remains within the pelvic cavity.Rate this question:
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- 6.
A neurosurgeon performs surgical resection of a rare meningeal tumor in the sacral region. He tries to avoid an injury of the nerve that arises from the lumbosacral plexus and remains within the abdominal or pelvic cavity. To which of the following nerves should he pay particular attention?
- A.
Ilioinguinal nerve
- B.
Genitofemoral nerve
- C.
Lumbosacral trunk
- D.
Femoral nerve
- E.
Lateral femoral cutaneous nerve
Correct Answer
C. Lumbosacral trunkExplanation
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.Rate this question:
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- 7.
After repair of a ruptured diverticulum, a 31-year-old patient begins to spike with fever and complains of abdominal pain. An infection in the deep perineal space would most likely damage which of the following structures?
- A.
Ischiocavernosus muscles
- B.
Superficial transverse perineal muscles
- C.
Levator ani
- D.
Sphincter urethrae
- E.
Bulbospongiosus
Correct Answer
D. Sphincter urethraeExplanation
The sphincter urethrae is found in the deep perineal space, whereas the
other structures are located in the superficial perineal space.Rate this question:
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- 8.
A radiologist interprets a lymphangiogram for a 29-year-old patient with metastatic carcinoma. Upper lumbar nodes most likely receive lymph from which of the following structures?
- A.
Lower part of the anal canal
- B.
Clitoris
- C.
Labium majus
- D.
Testis
- E.
Scrotum
Correct Answer
D. TestisExplanation
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.Rate this question:
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- 9.
A 49-year-old woman has a large mass on the pelvic brim. Which of the following structures was most likely compressed by this mass when crossing the pelvic brim?
- A.
Deep dorsal vein of the penis
- B.
Uterine tube
- C.
Ovarian ligament
- D.
Uterine artery
- E.
Lumbosacral trunk
Correct Answer
E. Lumbosacral trunkExplanation
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.Rate this question:
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- 10.
A 26-year-old man comes to a hospital with fever, nausea, pain, and itching in the perineal region. On examination by an urologist, he is diagnosed as having infected bulbourethral (Cowper's) glands. Which of the following structures is affected by this infection?
- A.
Superficial perineal space.
- B.
Sphincter urethrae.
- C.
Production of sperm.
- D.
Testis
- E.
Seminal vesicles
Correct Answer
B. Sphincter urethrae.Explanation
The bulbourethral glands lie on either side of the membranous urethra, embedded
in the sphincter urethrae. Their ducts open into the bulbous part of the penile urethra.
Semen—a thick, yellowish white, viscous, spermatozoa-containing fluid—is a mixture of the secretions
of the testes, seminal vesicles, prostate, and bulbourethral glands. Sperm, or spermatozoa,
are produced in the seminiferous tubules of the testis and matured in the head of the epididymis.
The seminal vesicles are lobulated glandular structures, produce the alkaline constituent
of the seminal fluid that contains fructose and choline, and lie inferior and lateral to the ampullae
of the ductus deferens against the fundus (base) of the bladder.Rate this question:
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- 11.
A 21-year-old man is involved in a highspeed motor vehicle accident. As a result, he has extensive damage to his sphincter urethrae. Which of the following statements best explains the injured sphincter urethrae?
- A.
Smooth muscle
- B.
Innervated by the perineal nerve
- C.
Lying between the perinea] membrane and CoIles' fascia
- D.
Enclosed in the pelvic fascia
- E.
Part of the pelvic diaphragm
Correct Answer
B. Innervated by the perineal nerveExplanation
The sphincter urethrae is striated muscle that lies in the deep perineal space
and forms a part of the urogenital diaphragm but not the pelvic diaphragm. It is not enclosed in
the pelvic fascia. It is innervated by a deep (muscular) branch of the perineal nerve.Rate this question:
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- 12.
An obstetrician is about to perform a pudendal block so a woman can experience less pain when she delivers her child. He recalls what he learned in medical school about this nerve:
- A.
It passes superficial to the sacrotuberous ligament
- B.
It innervates the testis and epididymis in a male
- C.
It provides motor fibers to the coccygeus
- D.
It can be blocked by injecting an anesthetic near the inferior margin of the ischial spine
- E.
It arises from the lumbar plexus
Correct Answer
D. It can be blocked by injecting an anesthetic near the inferior margin of the ischial spineExplanation
The pudendal nerve, which arises from the sacral plexus, provides sensory
innervation to the labium majus (or scrotum in a male). It leaves the pelvis through the greater
sciatic foramen and enters the perineum through the lesser sciatic foramen near the inferior margin
of the ischial spine. Therefore, it can be blocked by injection of an anesthetic near the inferior
margin of the ischial spine.Rate this question:
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- 13.
A trauma surgeon in the emergency room at a local center examines a 14-year-old boy with extensive pelvic injuries after a hit and run accident. The surgeon inspects the ischiorectal fossa because it:
- A.
Accumulates urine leaking from rupture of the bulb of the penis
- B.
Contains the inferior rectal vessels
- C.
Has a pudendal canal along its medial wall
- D.
Is bounded anteriorly by the sacrotuberous ligament
- E.
Contains a perineal branch of the fifth lumbar nerve
Correct Answer
B. Contains the inferior rectal vesselsExplanation
The ischiorectal fossa is bounded posteriorly by the gluteus maximus and
the sacrotuberous ligament. It contains fat, the inferior rectal nerve and vessels, and perineal
branches of the posterior femoral cutaneous nerve. The pudendal canal runs along its lateral wall.
Urine leaking from a ruptured bulb of the penis does not spread into the ischiorectal fossa because
Scarpa's fascia ends by firm attachment to the fascia lata of the thigh.Rate this question:
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- 14.
An elderly man with prostatitis is seen at an internal medicine clinic. The seminal colliculus of his prostate gland is infected, and its fine openings are closed. Which of the following structures is most likely to be disturbed?
- A.
Ducts of the prostate gland
- B.
Prostatic utricle
- C.
Ducts of the bulbourethral glands
- D.
Ejaculatory ducts
- E.
Duct of the seminal vesicles
Correct Answer
D. Ejaculatory ductsExplanation
The ejaculatory ducts, which open onto the seminal colliculus, may be
injured. The prostate ducts open into the urethral sinus, the bulbourethral ducts open into the
bulbous part of the penile urethra, and the ducts of the seminal vesicle join the ampulla of the
ductus deferens to form the ejaculatory duct. The prostatic utricle is a minute pouch on the summit
of the seminal colliculus.Rate this question:
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- 15.
A general surgeon is giving a lecture to a team of surgery residents. She describes characteristics of structures above the pectinate line of the anal canal, which include
- A.
Stratified squamous epithelium
- B.
Venous drainage into the caval system
- C.
Lymphatic drainage into the superficial inguinal nodes
- D.
Visceral sensory innervation
- E.
External hemorrhoids
Correct Answer
D. Visceral sensory innervationExplanation
The pectinate line is a point of demarcation between visceral and somatic
portions of the anal canal. Characteristics above the pectinate line include columnar epithelium,
venous drainage into the portal system, lymphatic drainage into the internal iliac nodes, visceral
sensory innervation, and internal hemorrhoids.Rate this question:
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- 16.
A 78-year-old man has carcinoma of the rectum. The cancer is likely to metastasize via the veins into which of the following structures?
- A.
Spleen
- B.
Kidney
- C.
Liver
- D.
Duodenum
- E.
Suprarenal gland
Correct Answer
C. LiverExplanation
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.Rate this question:
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- 17.
Which structure extends between the vestibule and the cervix of the uterus and serves as the excretory channel for the products of menstruation?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
D. DExplanation
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.Rate this question:
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- 18.
Which structure in the female that is much shorter than that in the male?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
A. AExplanation
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.Rate this question:
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- 19.
Into which structure does hemorrhage occur after injury to the inferior rectal vessels?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
E. EExplanation
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.Rate this question:
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- 20.
Which structure has Houston's valve or fold, with its venous blood drained by the portal venous system?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
C. CExplanation
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.Rate this question:
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- 21.
Which structure is innervated by the nerve passing through both the greater and lesser sciatic foramina?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
B. BExplanation
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.Rate this question:
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- 22.
Which structure, when fractured, results in paralysis of the obturator internus muscles?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
E. EExplanation
The greater trochanter provides an insertion site for the obturator internus
muscle.Rate this question:
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- 23.
Which structure secretes fluid containing fructose, which allows for forensic determination of rape?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
B. BExplanation
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.Rate this question:
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- 24.
In which structure would ligation of the external iliac artery reduce blood pressure?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
A. AExplanation
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.Rate this question:
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- 25.
A knife wound to the obturator foramen might injure which structure?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
E. EExplanation
The obturator foramen transmits the obturator nerve and vessels. Therefore,
the knife wound in this foramen injures the obturator nerve and vessels.Rate this question:
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- 26.
A stab wound immediately superior to the pubic symphysis on the anterior pelvic wall would most likely injure which visceral organ first?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
C. CExplanation
The bladder is situated in the anterior part of the pelvic cavity. Thus, a stab
wound superior to the pubic symphysis would injure the bladderRate this question:
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.JPG "Which structure in the female that is much shorter than that in the male?")
.JPG "Into which structure does hemorrhage occur after injury to the inferior rectal vessels?")
.JPG "Which structure has Houston's valve or fold, with its venous blood drained by the portal venous system?")
.JPG "Which structure is innervated by the nerve passing through both the greater and lesser sciatic foramina?")
.JPG "Which structure, when fractured, results in paralysis of the obturator internus muscles?")
.JPG "Which structure secretes fluid containing fructose, which allows for forensic determination of rape?")
.JPG "In which structure would ligation of the external iliac artery reduce blood pressure?")
.JPG "A knife wound to the obturator foramen might injure which structure?")
.JPG "A stab wound immediately superior to the pubic symphysis on the anterior pelvic wall would most likely injure which visceral organ first?")
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