Anatomy Exam Ii I Don't Know

Front 1

Sympathetic fibers in the greater thoracic splanchnic nerve arise from neuron cell bodies found in the:

Back 1

The sympathetic fibers in the greater thoracic splanchnic nerve are preganglionic sympathetic fibers that have left the sympathetic chain and are going to synapse in an abdominal ganglia. These preganglionic sympathetic fibers originate in the lateral horn of the spinal cord grey matter. The celiac ganglia and the superior mesenteric ganglia are the two ganglia where the fibers from the greater thoracic splanchnic nerve can go to synapse. Finally, remember that these fibers did not originate in the chain ganglia--the fibers from there are the postganglionic sympathetic fibers.

Front 2

Which nerve fiber would have its cell body in the lateral horn of the spinal cord at segmental level T1?

Back 2

Efferent fibers to the skin of the forehead might have their cell bodies located in the lateral horn of the T1 level. Because these fibers are at the superior edge of the thoracolumbar outflow (located from T1 to L2), they might go up the chain, synapse at a higher ganglion, and provide sympathetic innervation to the head and face. Afferent fibers would not have their cell bodies located in the lateral horn--afferent sensory fibers have cell bodies in dorsal root ganglia. Efferent fibers to the sweat glands of the lumbar region would be sympathetic fibers, but these cell bodies would be located at the T12, L1, or L2 levels--not at T1. T1 is too high for the lumbar region! Finally, parasympathetic fibers to the heart come from the vagus nerve.

Front 3

Gray rami communicantes contain postganglionic sympathetic fibers that innervate which of the following structures in the thoracic region?

Back 3

Sympathetic fibers innervate sweat glands by synapsing in the sympathetic chain, jumping on the grey rami to rejoin the spinal nerve, and heading for the periphery. The sympathetic nerves to the heart, aorta, lungs, and bronchi are carried in the cardiac and pulmonary plexuses. These fibers are not found in spinal nerves.

Front 4

Which structure contains postganglionic sympathetic fibers?

Back 4

White rami communicantes carry presynaptic sympathetic fibers to the sympathetic trunk. When a presynaptic nerve fiber reaches the sympathetic chain, there are three things that can happen. First, the nerve fibers can enter a ganglia, synapse at that level, and rejoin the spinal nerve via the grey rami communicantes. Second, the preganglionic nerve fibers can travel up and down the trunk, synapse in a ganglia at another level, and then rejoin a spinal nerve. This is how sympathetic fibers join spinal nerves at the cervical and lumbar levels, which are above and below the lateral horn. Third, some preganglionic fibers do not synapse in the trunk and, instead, form splanchnic nerves. These nerves descend into the abdomen and synapse in other ganglia.

The greater thoracic splanchnic nerve contains preganglionic fibers that are destined to synapse in the celiac plexus. The recurrent laryngeal nerve provides motor and sensory innervation to the upper esophagus and pharynx. Finally, the vagus nerve is a mixed nerve that carries preganglionic parasympathetic fibers. None of these nerves carry postganglionic sympathetic fibers.

The ulnar nerve innervates muscles of the hand and forearm, and provides some sensory innervation to skin of the hand. The ulnar nerve is derived from ventral primary rami, all of which carry postganglionic sympathetic fibers (to innervate vascular smooth muscle, arrector pili muscles, and sweat glands).

Front 5

Most of the drainage of the thoracic body wall reaches the superior vena cava via the azygos vein. A notable exception is the left superior intercostal vein, which normally drains into the:

Back 5

The left superior intercostal vein drains intercostal spaces 2-4, and then drains into the left brachiocephalic vein. See Netter Plate 231 for a picture of this relationship. The left bronchial vein is a small vein that removes venous blood from the lungs--it drains into the accessory hemiazygos vein. The left pulmonary veins carry oxygenated blood from the lung to the left atrium of the heart. The left subclavian vein is a continuation of the left brachiocephalic vein--this vein drains blood from the arm into the left brachiocephalic vein. The superior vena cava is formed by the junction of the left and right brachiocephalic veins; it delivers blood to the right atrium.

Front 6

You are observing a physician perform a thoracoscopic procedure. She pushes the deflated lung anteroinferiorly and points out a nervous structure lying across the heads of the ribs. You identify this structure as the

Back 6

The sympathetic trunk can be found on the posterior wall of the thorax, lying on the heads of the ribs. It contains the cell bodies of postganglionic sympathetic fibers. When a nerve fiber reaches the sympathetic chain, there are three things that can happen. First, the nerve fibers can enter a ganglia in the trunk, synapse at that level, and rejoin the spinal nerve via the grey rami communicantes. Second, the preganglionic nerve fibers can travel up and down the trunk, synapse in a ganglia at another level, and then rejoin a spinal nerve. This is how sympathetic fibers join spinal nerves at the cervical and lumbar levels, which are above and below the lateral horn. Third, some preganglionic fibers do not synapse in the trunk and, instead, form splanchnic nerves. These nerves descend into the abdomen and synapse in other ganglia. You really need to understand all three of these possibilities!

The greater thoracic splanchnic nerve is one of the splanchnic nerves that is carrying preganglionic fibers away from the trunk. It lies medial to the trunk, on the vertebral bodies, and carries fibers to the celiac plexus. The phrenic nerve travels through the anterior thorax to innervate the diaphragm--it's not found near the heads of the ribs. The pulmonary plexus is located along the pulmonary vessels and primary bronchi in the root of the lung--it carries both sympathetic and parasympathetic fibers to the lungs.The vagus nerve is the major nerve carrying parasympathetic fibers in the thorax and to the abdomen. It begins in the anterior portion of the thorax, then enters the posterior mediastinum and forms the esophageal plexus covering the esophagus.

Front 7

During a procedure to harvest lymph nodes in the posterior mediastinum, the thoracic duct is accidentally cut. The resulting accumulation of lymph in the pleural cavity is referred to as:

Back 7

A chylothorax is a pleural effusion composed of lymphatic fluid due to disruption of the thoracic duct. Pleurisy refers to the inflammation of the pleura with exudation into the pleural cavity. A pyothorax is an infection that occurs in the pleural space, where pus accumulates within the pleural cavity. A hemothorax involves the accumulation of blood in the pleural space. Finally, lymphedema is a swelling in a body part cause by the obstruction of lymphatic flow or the removal of the lymphatic vessels in a region.

Front 8

An enlarging lymph node gradually constricts the flow of blood in the azygos venous arch. Which vessel would enlarge as a result of collateral drainage?

Back 8

The internal thoracic vein would provide a collateral route for drainage if the azygos vein was obstructed. In the case of an obstruction, blood could flow from the posterior intercostal veins (which usually drain into the azygos) into the anterior intercostal veins, enter the internal thoracic vein, and drain into the right brachiocephalic vein. This would allow the blood to bypass the blockage. The right brachiocephalic vein would be receiving more blood due to this blockage, but it wouldn't be the vessel that would enlarge--the internal thoracic vein would become distended. The superior epigastric vein is an inferior extension of the internal thoracic vein--it is too inferior to assist with collateral circulation.

Front 9

A cancerous growth from the body of the 9th thoracic vertebra exerts pressure anterolaterally. Which structure lies in direct contact with this growth?

Back 9

The thoracic splanchnic nerves lie on the anterior surfaces of the vertebral bodies. Remember, the splanchnic nerves lie medial to the sympathetic trunk, which is lying on the heads of the ribs. The vagus nerve lies in the anterior chest and eventually forms the esophageal plexus, covering the esophagus. The phrenic nerve innervates the diaphragm--it is not near the posterior wall of the thorax. Intercostal nerves run in the intercostal groove at the posterior border of the rib--they are not near the vertebral bodies.

Front 10

A 45-year-old female patient complains of excessive sweating on the right side of the face and neck and in the right armpit region, where it leaves her clothing constantly stained with moisture. It is now such a terrible social embarrassment that she has become withdrawn and self-conscious. Since no medical treatment has proven effective, she is considering surgical denervation of the sweat glands in the affected areas. Which structure(s) might be removed or cut in order to alleviate her condition?

Back 10

The cervicothoracic ganglion is a sympathetic ganglion, formed by the fusion of the inferior cervical sympathetic ganglion and the T1 ganglion of the sympathetic trunk. The postsynaptic sympathetic fibers from this ganglia innervate the vascular smooth muscle and sweat glands of the C8 & T1 cutaneous distribution on chest & upper limb. Since the sweat glands in the right armpit are innervated by fibers coming from the stellate ganglion, this ganglion might need to be removed or cut to alleviate the patient's condition.

The dorsal roots of cervical spinal nerve carry afferent, sensory fibers. These sensory fibers are not involved in innervation to glands. The greater thoracic splanchnic nerve carries preganglionic sympathetic fibers to the abdomen, where they synapse in the celiac ganglion. The lumbar sympathetic trunk is involved with sympathetic innervation in the abdomen--it is far from the area where this patient is experiencing problems. Finally, the vagus nerve carries parasympathetic fibers to the thorax and abdomen; it does not innervate sweat glands.

Front 11

Following pregnancy and delivery, a 32-year-old woman continued to have problems with urinary incontinence which developed during pregnancy. Her obstetrician counseled her to strengthen the muscle bordering the vagina and urethra, increasing its tone and exerting pressure on the urethra. This physical therapy was soon adequate to restore urinary continence. What muscle was strengthened?

Back 11

Puborectalis is the part of levator ani that is closest to the vagina and urethra. This muscle may be injured during a difficult childbirth. By doing Kegel exercises, where women contract and relax the pelvic floor, these injured muscles may be strengthened and urinary continence may be improved. Besides levator ani, coccygeus is the second muscle that makes the pelvic floor. However, it extends between the ischial spine and the side of the coccyx/lower sacrum, so it is not next to the vagina and urethra and is not important for maintaining urinary continence. Ischiocavernosus compresses the corpus cavernosum. It is closely applied to the crus penis/clitoris in the perineum. Obturator internus and piriformis laterally rotate and abduct the thigh. Although these muscles originate in the pelvis, they are functionally more important to the lower limb.

Front 12

Preganglionic parasympathetic nerve fibers within the pelvic (inferior hypogastric) plexus arise from S2, 3, 4 and enter the plexus via:

Back 12

Pelvic splanchnic nerves carry parasympathetic fibers from the lateral horn of the spinal cord at the S2, 3, and 4 levels. They can be seen coming off of the ventral primary rami of S2, 3, and 4 and going to the inferior hypogastric plexus. These nerves provide parasympathetic innervation to the pelvic viscera and the GI tract distal to the left colic flexure. (Remember, the vagus gives parasympathetic innervation to the rest of the gut.) Sacral splanchnic nerves come off the sacral sympathetic chain ganglia, carrying sympathetic fibers that will go to the inferior hypogastric plexus. To remember the difference between the pelvic and sacral splanchnics, just remember that the sacral splanchnics are named after a spinal cord segment, just like the thoracic, lumbar, and cervical splanchnics that you know and love. These all carry sympathetic fibers. Pelvic splanchnics are not named after a spinal cord segment and they're different--they carry parasympathetic fibers.

The grey rami communicantes are structures that postganglionic sympathetic neurons travel on to get out of the sympathetic trunk and rejoin a spinal nerve. There are gray rami in the pelvis. The white rami communicantes are structures that preganglionic sympathetic fibers use to get out of a spinal nerve to enter the sympathetic trunk. White rami are seen between the T1 to L2 levels, but not in the pelvis. Finally, the hypogastric nerves carry postganglionic sympathetic nerves from the superior hypogastric plexus to the inferior hypogastric plexus.

Front 13

While performing a hysterectomy, the resident must ligate the uterine artery. To avoid iatrogenic injury to the ureters, she must be aware that the ureter passes ___________ the artery at the level of the ______________.

Back 13

Under; cervix
Remember--the ureter passes under the uterine artery, in the inferior portion of the mesometrium, near the cervix! This is a very important relationship--see Netter Plate 370 for a picture.

Front 14

A caudal epidural block is a form of regional anesthetic used in childbirth. Within the sacral canal, the anesthetic agent bathes the sacral spinal nerve roots which would anesthetize all of the following nerves except:

Back 14

The sacral splanchnic nerves do not come out of the sacral nerve roots--instead, these nerves come from the sacral sympathetic ganglia. So, anesthesia bathing the sacral nerve roots would not affect the sacral splanchnic nerves, which are coming from the sympathetic trunk. The sacral splanchnic nerves contribute to the inferior hypogastric plexus and provide sympathetic innervation to the vascular smooth muscle of the pelvic viscera.

The pelvic splanchnic nerves are comprised of fibers from S2, 3, and 4, and pudendal nerve is made of the ventral primary rami of S2-4. These nerves would be numbed if the sacral nerve roots were anesthetized. Finally, the S2 dorsal root and S2 ventral primary ramus would also be anesthetized by the caudal epidural block.

Front 15

Blood supply to the superior portions of the bladder typically arises from the ____________ arteries.

Back 15

The umbilical artery supplies the superior part of the bladder by giving off the superior vesical arteries. In males, this artery supplies the ductus deferens via the artery of the ductus deferens. Distal to those branches, the umbilical artery is not patent, and it becomes the medial umbilical ligament. The middle rectal artery supplies blood to the middle of the rectum, while the obturator artery supplies blood to the medial thigh and hip. The inferior gluteal artery supplies blood to gluteus maximus, and the uterine artery supplies blood to the uterus.

Front 16

The pelvic splanchnic nerves primarily carry ____________ to the _____________ plexus.

Back 16

preganglionic parasympathetics--inferior hypogastric
Although all the other splanchnic nerves carry sympathetic fibers, the pelvic splanchnic nerves transmit preganglionic parasympathetic fibers from S2, 3, and 4. These fibers are carried to the inferior hypogastric plexus. The parasympathetic fibers from the inferior hypogastric plexus supply the smooth muscle of the pelvic viscera, while the sympathetic fibers from the inferior hypogastric plexus supply vascular smooth muscle of vessels supplying the pelvic viscera. The superior hypogastric plexus is a continuation of the intermesenteric plexus--it contributes sympathetic fibers to the inferior hypogastric plexus through hypogastric nerves.

Front 17

The arcus tendineus levator ani is a thickening of fascia of the:

Back 17

The fascia of obturator internus has two specializations. First, there is a strong band on the medial edge of obturator internus that stretches between the spine of the ischium and the superior pubic ramus. This is the arcus tendineus levator ani, which gives origin to the levator ani muscles. The other specialization is the obturator membrane, which nearly covers the entire obturator foramen, only leaving space for the obturator nerves and vessels to exit. Coccygeus is a muscle that elevates the pelvic diaphragm--it is found posterior to levator ani. Obturator externus is not found it the pelvis--it takes origin from the external surface of the obturator membrane and inserts on the femur. It is an important muscle for laterally rotating the thigh. The piriformis muscle takes origin from the anterior surfaces of S2 to S4, both between and lateral to the sacral foramina. It exits the pelvis via the greater sciatic foramen, inserting on the greater trochanter of the femur in order to rotate the thigh laterally.

Front 18

The sacral outflow of the parasympathetic (craniosacral) system enters the pelvic plexus via:

Back 18

Pelvic splanchnic nerves
Pelvic splanchnic nerves come from the anterior branches of S2 through S4. These are parasympathetic nerves, which send parasympathetic neurons to the hypogastric plexus, and therefore the pelvic viscera and distal colon. Hypogastric nerves are from the superior hypogastric plexus. These nerves transmit sympathetic neurons to the hypogastric plexus, and therefore the pelvic viscera. The pudendal nerve is a branch of the sacral plexus. It provides motor innervation to the muscles of the perineum, and it is the primary sensory innervation to the genitalia. Sacral splanchnic nerves are from the second and/or third ganglia of the sacral sympathetic trunk. These provide a secondary way for sympathetic neurons to reach the hypogastric plexus, and therefore the pelvic viscera.

Front 19

The artery which supplies blood to the major erectile body in both the male and female is the:

Back 19

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.

Front 20

The part of the male reproductive tract which carries only semen within the prostate gland is the:

Back 20

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.

Front 21

An intrahepatic blockage of the portal venous outflow may cause intestinal blood to drain via portal-systemic anastomoses into the:

Back 21

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.

Front 22

What part of the ischioanal (ischiorectal) fossa extends deep to the sacrotuberal ligament?

Back 22

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.

Front 23

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?

Back 23

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.