Block 7 Anatomy BRS Pretest Pelvis - Pt2

. (Moore and Dalley, p 387. Sadler, p 235.) Partial or complete duplication of the ureters is a fairly common (1 in 125 births) occurrence. While the OB carefully identified both a right and left ureter and spared them during the clamping and removal of the uterine arteries the duplicated ureter on the left side most likely was not noticed and thus damaged. The pain is most likely due to a collection of urine or an “urinoma.” Duplicated ureters are at greater risk since they are often smaller than normal ureters. If the site of damage could be identified, then the duplicated left ureters could be connected above the damage to the undamaged ureter and may preserve full kidney function. While a pyelogram
(answer a) does require injection of an iodine based dye that can cause some kidney damage, this should not cause damage specifically to the inferior half of the left kidney. Renal failure following anesthesia (answer c) is relatively rare. The development of the kidney stone (answer d) within one of the left duplicated ureters would be unlikely, but if present then the stone should be evident on the pyelogram images. Thus, “answer d” is a good second choice answer.

Moore and Dalley, pp 413, 426–427.) Endoscopic exploration to rule out ectopic pregnancy. The positive pregnancy test, the blood in the cul-de-sac of Douglas and the mass in the uterine tube all suggest ectopic pregnancy. All the other possible answers (answers a, c, d, and e) do not fit with a positive pregnancy test and are much lower frequency events.

(Moore and Dalley, pp 387–388.) The uterine artery (answer a) crosses anterior and superior to the ureter near the lateral fornix of the vagina and is deliberately clamped and removed during a hysterectomy. Some clinicians and anatomists once referred to the uterine artery as “the bridge over troubled waters.” Because of its close proximity to the artery, the ureter may be accidentally ligated or severed while tying off of the artery. Of course, the bladder (answer c) and the kidney (answer e) are large structures and should not be mistakenly clamped. The urethra (answer d) should be far out of the operating field.

(Moore and Dalley, pp 422–423, 465–466.) The pudendal nerve serves the skin around the posterior/ lateral entrance of the vagina; the nerve wraps around the ischial spine, which is used as a landmark; transvaginal administration is less painful since the upper portion of the vagina has fewer pain receptors. The pudendal nerve serves the skin around the posterior/lateral entrance of the vagina; the nerve wraps around the ischial spine, which is used as a landmark; transvaginal administration is less painful since the upper portion of the vagina has fewer pain receptors [thus none of the other (answers a, c, and d) are correct].

(Moore and Dalley, p 400.) Cystocele. Bulges in the anterior wall of the vagina are most likely due to the bladder falling posteriorly into the anterior vaginal wall. A bulge on the posterior wall of the vagina would most likely be a rectocele (answer b). Cervical cancer (answer c) generally would not present as described. A didelphic uterus (answer d) is a duplication of the uterus as result of failure of the right and left paramesonephric ducts to fuse in the midline. An indirect inguinal hernia (answer e) would generally present as a mass within the labia major.

(Moore and Dalley, pp 228–229.) A dark mass within the scrotum would most likely be one of two things: varicocele or indirect inguinal hernia. Varicoceles are a stasis of blood within the
pampiniform plexus and occur most frequently on the left side because the testicular vein on the left drains into the higher pressure left renal vein, whereas the right testicular vein drains into the inferior vena cava. The presence of a varicocele is associated with reduced fertility. A femoral hernia (answers c and d) would not end up in the scrotum, rather within the thigh. Cryptorchidism (answer a), that is an undescended testicle, on the right side does not fit the physical examination findings. The right side is
normal [thus not (answer e)].

. (Moore and Dalley, pp 359–360.) The sacrococcygeal joint. The indicated line represents the sacroiliac joint. These structures are seen bilaterally between the alae of the sacrum and the ilia. The body of the sacrum (answer a) is in the midline and normal. The sacroiliac ligaments might have been sprained by the trauma of the fall. The pathway for spinal nerves (answer c) is through foramina of the sacrum, not through long bony canals. Similarly, the pathway for the gluteal arteries
(answers d and e) is through the greater sciatic foramen between the ilium and the sacrum.

(Moore and Dalley, p 424.) Ampulla of the oviduct. Fertilization normally occurs in the ampulla of the oviduct within 24 hours of the egg’s release from the ovary. The wall of the uterine cavity (answer b) is the normal site of implantation about 4 days later. Fertilization normally does not occur either in the infundibulum (answer c) nor isthmus of the oviduct (answer d). Sperm must pass through cervical (answer e) mucous to reach the uterus.

(Moore and Dalley, pp 436, 438.) Vaginal wall, bulbospongiosus, and superficial transverse perineal muscles. Both the pubococcygeus and iliococcygeus muscle (answers a and b) are part of the pelvic diaphragm and are much deeper muscles and thus would not be cut. The prepuce and rectus abdominis muscle (answer d) are superior and lateral to the vagina and an episiotomy is performed in a posterior mediolateral direction, not anterior mediolateral direction. Both the sacrospinous
and sacrotuberous ligaments (answer e) are much deeper structures, which stabilize the pelvis and never cut during an episiotomy.

(Moore and Dalley, pp 399, 425, 432.) Postsynaptic sympathetic neurons destined for the skin lie in the ganglia of the sympathetic chain. Although the preganglionic fibers arise between T1 and L2, each of the sacral ganglia has a gray ramus that brings postganglionic fibers to the associated spinal nerve. These sympathetic neurons mediate sweating (sudomotor), vasoconstriction (vasomotor), and piloerection (pilomotor) in dermatomes S1–S5. Male ejaculation is practically mediated by skeletal muscle (contraction of the bulbospongiosus muscle innervated by superficial perineal nerves, branches of the pudendal nerve.) Ejaculation also requires sympathetic discharge to keep the internal urethral sphincter closed, preventing so called retroejaculation into the bladder. Emission (rapid contraction of the vas deferens) is mainly mediated by sympathetic, but mainly by lumbar splanchnic nerves, thereby bypassing the sympathetic chain ganglia. Erection in both male and female (answers c and d)
is mainly mediated by parasympathetic nerves. Bladder contraction (answer a) is also mainly controlled by parasympathetic nerves.

(Moore and Dalley, pp 422–424, 493.) Caudal analgesia can be induced by an injection of anesthetic through the sacral hiatus into the sacral epidural space of the vertebral canal well caudal to the termination of the dural sac (answer b). The sacral hiatus represents the absence of a complete neural arch of the fifth sacral vertebra. The four anterior (answer a) and posterior (answer d) sacral foramina on either side of the midline join the intervertebral foramen (answer c) and provide egress for the anterior and posterior primary rami of the sacral spinal nerves. The level to which the anesthesia blocks the spinal nerves is a function of the amount of anesthetic delivered.

(Moore and Dalley, pp 449–451.) Pus from the abscessed diverticuli in that space can extend anteriorly deep to the perineal membrane, but inferior to the urogenital diaphragm. The ischioanal fossa (asterisk on CT accompanying the question) is a fat-filled space [thus not muscle (answer b)] that extends from below the levator ani muscle (puborectalis, pubococcygeus, and iliococcygeus muscles). It also extends anteriorly in the area between the pelvic diaphragm (superiorly) and the perineal membrane (inferiorly). It cannot extend superiorly above the pelvic diaphragm [thus not (answer c)] and, therefore, cannot extend superiorly anterior to the sacrum (answer d). The paracolic gutter (answer a) in not on the image.

(Moore and Dalley, pp 428–429.) The mesosalpinx (answer b), mesovarium (answer c), and suspensory ligament are all continuous with the broad ligament (answer a), which is a reflection of peritoneum over the female reproductive organs. The mesovarium attaches the ovary to the broad ligament. The suspensory ligament of the ovary runs from the pelvic brim to the lateral pole of the ovary. It contains the ovarian artery, ovarian vein, ovarian lymphatics, and ovarian nerves (ovarian neurovascular bundle). Volvulus of the ovary (usually associated with an ovarian tumor) may constrict the neurovascular bundle with ovarian infarct and pain referred to the inguinal and hypogastric regions. The base of the broad ligament has the transverse cervical ligament (answer e).

Moore and Dalley, p 387.) The obturator usually arises from the anterior trunk of the internal iliac artery. However, in 25% of the population, it arises from the inferior epigastric or the external iliac artery. There is considerable variation as to the origins of the branches of the posterior and anterior trunks of the internal iliac artery. The internal pudendal artery (answer a), umbilical artery (answer d), and uterine artery (answer e) almost always arise from the anterior trunk. The superior
gluteal artery (answer c) usually arises from the posterior trunk.

(Moore and Dalley, p 449.) The bulbospongiosus muscle is innervated by the pudendal nerve (S2–S4) and its contraction helps to keep blood within the shaft of the penis. Contraction of the internal urethral sphincter is under control of the sympathetic nervous system [thus not (answer a)]. Concomitant with dilation of the helicine arteries under parasympathetic innervation [thus not (answers b and c)], which allows increased blood to flow into the cavernous spaces, contraction of the bulbospongiosus and ischiocavernosus muscles at the base of the cavernous bodies reduce blood from leaving, resulting in engorgement and penile or clitoral erection. Emission of seminal fluid, prostatic secretions, and sperm from the vas deferens is due to contraction of smooth muscle under sympathetic
control [thus not (answer d)].

(Moore and Dalley, pp 424, 469.) Peritoneal cavity. The purpose of performing a hysterosalpingogram is to determine if the fallopian tubes are open and thus potentially capable of transporting sperm and eggs for conception. The dye is generally introduced via a catheter placed through the cervix and injected into the uterus. In this case it seems as if dye is spilling into the peritoneal cavity at ends of each fallopian tube. The dye would pass the isthmus of the oviduct next to the body of the uterus. Within the image (E) is the vagina, (D) is the isthmus of the cervix, (B) is the body of the uterus, and A is the ampulla of the oviduct just proximal to the infundibulum out of which dye is flowing as curling wisps.

(Moore and Dalley, pp 362–363.) The transverse midplane diameter is measured between the ischial spines. It can be approximated by the somewhat greater transverse diameter measured between the ischial tuberosities (answer b). The distance from the lower margin of the pubic symphysis to the sacroiliac joint (answer c) defines the sagittal diameter, which is usually the greatest dimension and, therefore, unimportant. The measurement from the sacral promontory to the inferior margin of the pubic symphysis (answer d) is the diagonal conjugate, an estimate of the pelvic inlet

(Moore and Dalley, pp 392–393, 431, 452.) Lymph drains from the testicles to preaortic nodes, because remember that the blood supply for the testicles comes directly off the abdominal aorta, where the testicles first develop, prior to their inferior migration into the scrotum.
All the other pelvic structures: penis (answer a), scrotum (answer b), anus (answer d), and epididymides (answer e) can drain lymphatics to the superficial inguinal nodes. The anus and rectum have drainage to three sites: superficial inguinal nodes, internal iliac nodes, and inferior mesenteric preaortic nodes.

not-available-via-ai