Abdomen and Pelvis Flashcards

Question

Regarding the relationship of the 4 parts of the duodenum, which is correct? A The first part runs to the right, upwards and forwards form the pylorus B The second part is covered in front by peritoneum and crossed by the attachment of the transverse mesocolon C The third part lies at the hilum of the right kidney D The fourth part lies on the left psoas muscle and left sympathetic trunk, to reach the lower border of the spleen

Answer 1

B Explanation The first part of the duodenum runs to the right, upwards and backwards form the pylorus. The second part is covered in front by peritoneum and crossed by the attachment of the transverse mesocolon. The second part curves downwards over the hilum of the right kidney. The third part curves forward from the right paravertebral gutter over the slope of the right psoas muscle and passes over the forwardly projecting inferior vena cava and aorta to reach the left posas muscle. The fourth part ascends to the left of the aorta to lie on the left psoas muscle and left sympathetic trunk, to reach the lower border of the pancreas In the old text, it stated that the hilum of each kidney lie at the plane, the right just below it and the left just above. The third part of the duodenum (transverse part) runs at L3 level, below the hilum of the right kidney. Some newer sources report that the TL runs through the hilum of the left kidney

Answer 2

A Explanation The answer is taken form Last's anatomy The duodenum is supplied by the superior and inferior pancreaticoduodenal arteries, but the first 2cm of the duodenum-the usual site of ulceration, receives blood from the hepatic, gastroduodenal, supraduodenal, right gastric and right gastroepiploic arteries. Venous drainage is to tributaries of the superior mesenteric and portal veins

Answer 3

C Explanation They ureters are approximately 25-30cm long. Note: some texts say the urters are 25cm exactly. In males the ureter lies posteriolateral to the ductus deferensand enters the posterior superior angle of the bladder. In females it passes close to the lateral part of the fornix of the vagina and enters the posterior superior angle of the bladder. Nerve innervation includes sympathetic fibres from T10 (some sources T11)-L2 and parasympathetic splanchnic nerves. Intact innervation of the renal pelvis or ureter is not necessary for the initiation or propogation of peristalsis form the calycael pacemakers Note: Nerve innervation can be a bit confusing. Different sources have different opinions: CM: Receives pain fibers from sympathetic T11 to L2. “visceral afferent fibres conveying pain sensation follow the sympathetic fibres retrograde to the spinal ganglia and cord segments T11-L2”. Web: preganglionic sympathetic neurons that supply the uretersare located in segments of T10-L1 of the spinal cord

Answer 4

D Explanation The lumbar plexus of nerves is formed anterior to the lumbar transverse processes, within the proximal attachment of psoas major. The nerve network is composed of the anterior rami of L1 to L4. The plexus innervates part of the lower abdominal wall, but is mainly concerned in supplying skin and muscle in the lower limb. It reinforces the sacral plexus, which is the true plexus of the lower limb. Last's anatomy does not include the lumbosacral trunk as part of the lumbar plexus. Branches of the lumbar plexus: (femoral, obturator & lumbosacral trunk are the largest) Ilioinguinal and iliohypogastric nerves (L1) Genitofemoral nerve (L1 L2) Lateral cutaneous nerve of the thigh (L2 L3) Accessory obturator nerve (L3 L4) Femoral nerve (L2-L4) Obturator nerve (L2-L4) Lumbosacral trunk (L4 L5) Note: a cute (but inappropriate) mnemonic "Interested In Getting Laid On Friday Larry" Extra: The anterior rami of lumbar spinal nerves L1 to L4. It also receives contributions from the T12 nerve, the last spinal nerve arising from the thoracic segments of the spinal cord. The fifth lumbar nerve (L5) does not participate in the formation of the lumbar plexus. Rather, it joins communicating branches from the L4 nerve to form the lumbosacral trunk. Source: brainmadesimple.com

Answer 5

D Explanation The abdominal aorta is approximately 13cm in length. Begins at the aortic hiatus of the diaphragm (T12 vertebral level) and ends at vertebral level L4 and divides into the left and right common iliac arteries. The abdominal aorta extends from 2.5cm superior to the transpyloric plane to a point inferior and to the left of the umbilicus at the level of the supracristal plane (plane of the highest point of the iliac crests). The abdominal aorta descends anterior to the vertebral bodies of T12-L4. The left lumbar veins pass posterior to the aorta to reach the IVC. On the right, the aorta is related to the azygous vein, cisternal chyi, thoracic duct, right crus of the diaphragm and right celiac ganglion. On the left, the aorta is related to the left curs of the diaphragm and the left celiac ganglion. From superior to inferior, the important anterior relations of the abdominal aorta are: celiac plexus and ganglion, body of pancreas and splenic vein, left renal vein, horizontal part (3rd) of the duodenum and coils of small intestine.

Answer 6

D Explanation The transpyloric plane bisects the body between the jugular notch superior and the pubic crest inferiorly. This level is approximately midway between the superior borders of the manubrium of the sternum and the pubic symphysis (typically the L1 level). It cuts each costal margin at the tip of the ninth costal cartilage, which is at the lateral border of rectus abdominus. Deep to this point on the right side lies the fundus of the gallbladder. The plane passes through the lower border of the first lumbar vertebra (L1), where the spinal cord ends at the conus medullaris. The plane passes through the pylorus and along the head, neck and body of the pancreas just above the attachment of the transverse mesocolon. The supracolic compartment, containing liver, spleen and fundus of the stomach, lies above the plane, and the infracolic compartment, containing the colon and small intestine, lies below it. Note: In most texts the spleen is included in the plane. Other texts do not. More recent texts point out that the tips of the 8th costal cartilages are bisected. While others say the 9th costal cartilage Extra: the SMA leaves the aorta, and the splenic vein joins the SMV to form the portal vein at this level. The hilum of each kidney lies at the plane, the right just below and the left just above it.

Answer 7

D Explanation The spleen is ovoid, purplish, pulpy mass. The spleen is usually the size of ones fist but can vary considerably. The approximate size is 12cm long and 7 cm wide. The diaphragmatic surface of the spleen is convexly curved to fit the concavity of the diaphragm. The anterior and superior borders of the spleen are sharp and often notched whereas the inferior and posterior borders are rounded. The spleen is seldom palpable through the anterolateral abdominal wall unless it is enlarged. The relations of the spleen: anterior=stomach, posterior=left part of the diaphragm, inferiorly=left colic flexure and medially=left kidney. The arterial supply of the spleen is from the splenic artery, the largest branch of the celiac trunk. Venous drainage is via the splenic vein, which joins the superior mesenteric vein to form the portal vein. Lymph drainage=pancreaticosplenic nodes. Nerve supply is derived from the celiac plexus and is vasomotor in function.

Answer 8

A Explanation Characteristics of Inguinal hernias: Direct: Acquired weakness of the anterior abdominal wall, less common than indirect, exits from abdominal cavity through peritoneum plus transversalis fascia, passes through the or around inguinal canal, via superficial ring, lateral cord, rarely enters scrotum. Direct hernias herniate medially to the inferior epigastric artery Direct inguinal hernias RIP through Hasselbach's triangle (R - rectus abdominis, I - inferior epigastric artery, P - Puopart's ligament = inguinal ligament). Indirect: Congenital weakness-patency of the process vaginalis, more common than direct hernias (2/3 or 3/4 of all inguinal hernias), exits from the abdominal cavity through peritoneum of persistent process vaginalis plus all 3 fascial coverings of cord/round ligaments, traverses inguinal canal within process vaginalis via superficial ring inside cord, commonly passing into scrotum/labium majora. Remember indirect hernias herniate laterally to the inferior epigastric artery

Answer 9

D Explanation The cervix is the least mobile part of the uterus because of the passive support provided by the attached condensations of the endopelvic fascia (ligaments), which may also contain smooth muscle. The ligaments are the cardinal (transverse cervical) and the utero sacral. Cardinal ligament: extends form the supravaginal cervix and lateral parts of the fornix of the vagina to the lateral wall of the pelvis. Uterosacral ligaments: pass superiorly and slightly posteriorly from the sides of the cervix to the middle of the sacrum

Answer 10

C Explanation The Celiac trunk arises form the abdominal aorta, after a short antero-inferior course, bifurcates into splenic and common hepatic arteries. The distribution of supply is to the esophagus, stomach, proximal duodenum, liver/biliary apparatus and pancreas

Answer 11

D Explanation Visceral referred pain from a gastric ulcer is referred to the epigastric region because the stomach is supplied by pain afferents that reach the T7 and T8 spinal sensory ganglia and spinal cord segments through the greater splanchnic nerve. The brain interprets the pain as though the irritation occurred in the skin of the epigastric region, which is also supplied by the same sensory ganglia and spinal cord segments.

Answer 12

A Explanation Visceral referred pain from a gastric ulcer is referred to the epigastric region because the stomach is supplied by pain afferents that reach the T7 and T8 spinal sensory ganglia and spinal cord segments through the greater splanchnic nerve. The brain interprets the pain as though the irritation occurred in the skin of the epigastric region, which is also supplied by the same sensory ganglia and spinal cord segments.

Answer 13

D Explanation Note that this question is referring to the deep inguinal ring specifically, not the inguinal canal. The deep inguinal ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal. COA: - The deep (internal) inguinal ring is the entrance to the inguinal canal. It is located superior to the middle of the inguinal ligament and lateral to the inferior epigastric artery. It is the beginning of an evagination in the transversalis fascia that forms an opening like the entrance to a cave. Through this opening, the extraperitoneal ductus deferens (vas deferens) and testicular vessels in males (or round ligament of the uterus in females) pass to enter the inguinal canal. The transversalis fascia itself continues into the canal, forming the innermost covering (internal fascia) of the structures traversing the canal. - The superficial (external) inguinal ring is the exit by which the spermatic cord in males, or the round ligament in females, emerges from the inguinal canal. The superficial ring is a split that occurs in the diagonal, otherwise parallel fibers of the external oblique aponeurosis just superolateral to the pubic tubercle. The parts of the aponeurosis that lie lateral and medial to, and form the margins of, the superficial ring are crura (L. leg-like parts). The lateral crus attaches to the pubic tubercle, and the medial crus attaches to the pubic crest. Fibers of the superficial layer of investing (deep) fascia overlying the external oblique muscle and aponeurosis, running perpendicular to the fibers of the aponeurosis, pass from one crus to the other across the superolateral part of the ring. These intercrural fibers help prevent the crura from spreading apart (i.e., they keep the “split” in the aponeurosis from expanding).

Answer 14

B Nerve innervation of the ureters is via renal, gonadal and hypogastric plexuses. Sensory fibres enter the cord at T11-L2.

Answer 15

B Explanation The vascular supply of the gut – the 3 major arteries below come directly off the aorta: Celiac axis – supplies the stomach (also supplies the common hepatic and splenic arteries) Superior Mesenteric Artery – supplies the entire small intestine and about 2/3 of the transverse colon Inferior Mesenteric Artery – supplies distal transverse colon, descending colon, and sigmoid colon (Rectal arteries come off of the internal iliac artery) Extensive collateral circulation exists between the systems, with the major weaknesses being the so-called “watershed” areas between the SMA and IMA (splenic flexure), and IMA and rectal arteries (recto-sigmoid junction). Acute Mesenteric Ischemia of the Small IntestineThis is the most feared form of mesenteric ischemia, which carries a >60% mortality rate.Clinical presentation is classically that of acute onset of severe periumbilical pain that is out of proportion to physical exam findings, +/- nausea/vomiting. Peritoneal signs and sepsis indicate bowel infarction. It is important to note that in nonocclusive disease, ~25% of patients may have no abdominal pain Mesenteric Artery Embolism – ~50% of cases, e.g. from A-fib, endocarditis, LV thrombus, etc. The SMA is most anatomically predisposed, due to its large caliber and narrow take-off angle from the aorta. The IMA is rarely affected due to its small caliber. The most commonly involved segment is the middle of the jejunum, as this is the most distant from collateral circulation of the celiac axis and IMA. Source: Stanford school of medicine Watershed areas of the colon are the locations of termination of primary arterial supply and rely more on collateral vessels. In the colon these include the splenic flexure (terminations of SMA/IMA) and the rectosigmoid colon (terminations of IMA, pudendal, and internal iliac).

Answer 16

A The main blood supply to the pancreas is via the splenic artery. The head is supplied by superior and inferior pancreaticoduodenal arteries.

Answer 17

D Explanation Superior to the pectinate line, the lymphatic vessels drain deeply into the internal iliac lymph nodes and through them into the common iliac and lumbar lymph nodes. Inferior to the pectinate line, the lymphatic vessels drain superficially into the superficial inguinal lymph nodes, as does most of the perineum.

Answer 18

D Explanation Torsion of the spermatic cord is a surgical emergency because necrosis of the testis may occur. The torsion obstructs the venous drainage, with resultant edema and haemorrhage, and subsequent arterial obstruction. The twisting usually occurs just above the upper pole of the testis.

Answer 19

D Explanation Just distal to the perineal membrane, the spongy urethra is well covered inferiorly and posteriorly by erectile tissue of the bulb of the penis; however, a short segment of the intermediate part of the urethra is unprotected. Because the urethral wall is thin and the angle that must be negotiated to enter the intermediate part of the spongy urethra, the wall is vulnerable to rupture during the insertion of urethral catheters and sounds. Source: Morre 8th edition. pg 653: clinical box: urethral catheterization

Answer 20

D Explanation Weak areas of the pelvis, where fractures often occur, are the pubic rami, the acetabula (or the area immediately surrounding them), the region of the sacro-iliac joints, and the alae of the ilium.