Abdo_wall

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Abdominal Wall 1. The terminal ends of the ilioinguinal nerves in the female are referred to as: A. Anterior cutaneous branches B. Anterior labial C. Cremasterics D. Iliohypogatrics 2. The usual location for an appendectomy incision is the: A. left lower quadrant B. left upper quadrant C. right lower quadrant D. right upper quadrant 3. The inferior border of the rectus sheath posteriorly is called the: A. Falx inguinalis B. Inguinal ligament C. Internal inguinal ring D. Arcuate line E. Linea alba 4. A medical student was asked by her preceptor to palpate the margin of the superficial inguinal ring of a healthy male patient. After passing her finger down the edge of the medial crus of the superficial inguinal ring, she felt a bony protuberance deep to the medial edge of the spermatic cord, which she correctly identified as the : A. pecten pubis B. pubic symphysis C. pubic tubercle D. iliopubic eminence E. iliopectineal line 5. You were asked to assist in a surgical operation on a young patient to treat an ulcer in the first part of the duodenum. You would expect that the surgeon will approach the ulcer by doing an anterior abdominal wall incision in the following region: A. Epigastric B. Left inguinal C. Left lumbar D. Right hypochondrial E. Hypogastric

6. Following an emergency appendectomy your patient complained of having paraesthesia (numbness) of the skin at the pubic region. The most likely nerve that has been injured during the operation is: A. Genitofemoral B. Iliohypogastric C. Subcostal D. Spinal nerve T10 E. Spinal nerve T9 7. An obstetrician decides to do a Caesarean section on a 25-year-old pregnant woman. A transverse suprapubic incision is chosen for that purpose. All of the following abdominal wall layers will be encountered during the incision EXCEPT the: A. Anterior rectus sheath B. Posterior rectus sheath C. Rectus abdominus muscle D. Skin and subcutaneous tissue E. Transversalis fascia, extraperitoneal fat, and peritoneum 8. In order to reduce a hernia (return it to the abdominal cavity), a surgeon finds it necessary to ligate an artery in the extraperitoneal connective tissue (preperitoneal fat) running vertically just medial to the bowel as the bowel passes through the abdominal wall. This artery is the: A. Deep circumflex iliac B. Inferior epigastric C. Superficial circumflex iliac D. Superficial epigastric E. Superficial external pudendal 9. The posterior layer of the rectus sheath ends inferiorly at the A. Arcuate line B. Intercrestal line C. Linea alba D. Pectineal line E. Semilunar line

Dr: Ahmed Nawaz Jamali

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10. Surgical approaches to the abdomen sometimes necessitate a midline incision between the two rectus sheaths, i.e., through the: A. Linea aspera B. Arcuate line C. Semilunar line D. Iliopectineal line E. Linea alba 11. The internal thoracic artery is sometimes surgically cut near the caudal end of the sternum and used to supply blood to a region of the heart. In these cases, maintenance of adequate blood flow to the rectus abdominis may be dependent on increased flow through which artery? A. Superficial epigastric B. Inferior epigastric C. Umbilical D. Superficial circumflex iliac E. Deep circumflex iliac 12. The normal pattern of venous and lymphatic drainage of the superficial tissues of the anterior abdominal wall is arranged around a horizontal plane. Above that plane, drainage is in a cranial direction; below the plane drainage is in a caudal direction. This reference plane corresponds to: A. Transpyloric plane B. Level of anterior superior iliac spines C. Transtubercular line D. Level of arcuate line E. Level of umbilicus

Answers 1. B. The ilioinguinal nerves supply motor and sensory fibers to the abdominal wall inferior to the umbilicus. What differentiates these nerves from the iliohypogastric

nerves is that the ilioinguinal nerves also innervate the scrotum or labia by passing through the inguinal canal. These branches are called the anterior scrotal or labial nerves. Anterior cutaneous branches pretty much describes what these branches are, but there's an answer here that is a little more specific. The genital branch of the genitofemoral nerve innervates the cremaster muscle. 2. C. Since the appendix is located in the right lower quadrant, you would probably want to make your incision there to remove it! The appendix is the terminal portion of the cecum which has a small, dead-end lumen. It is located just behind the cecum in the right internal iliac fossa. Where are incisions made for other procedures? For a cholecystectomy (gall bladder removal), there is an incision in the right upper quadrant. (Or, this surgery can be performed laproscopically.) For a caesarian, a transverse suprapubic incision (also called a Pfannenstiel incision) is used. A midline incision, through the linea alba, may be used to repair an aortic aneurysm. 3. D. rectus sheath is a tough, tendinous sheath over the rectus abdominis muscle. It covers the entire anterior surface of the rectus abdominis. However, on the posterior side of the muscle, the sheath is incomplete-- it ends inferiorly at the arcuate line. Below the arcuate line, the rectus abdominis is covered by transversalis fascia, not the rectus sheath! The linea alba is also related to the rectus abdominis--it is a ligament that runs down the middle of the abdomen, bisecting the rectus abdominis. It is made by the intermingling of the aponeuroses of the external oblique, internal oblique, and transversus abdominis. It's a good place to make a vertical incision. All of the other answer choices are related to the inguinal

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canal. The falx inguinalis (sometimes called the inguinal falx or conjoint tendon), is the inferomedial attachment of transversus abdominis with some fibers of internal abdominal oblique--it contributes to the posterior wall of the inguinal canal. The inguinal ligament is the ligament that connects the anterior superior iliac spine with the pubic tubercle--it makes the floor of the inguinal canal. The internal (deep) inguinal ring is the entrance to the inguinal canal, where the transversalis fascia pouches out and creates an opening through which structures can leave the abdominal cavity. 4. C. The pubic tubercle is a bony process that would be felt lateral to the edge of the spermatic cord at the superficial inguinal ring. (This is really the only answer choice that could feel like a bony prominence when palpated.)The pubic tubercle serves as the point of attachment for the inguinal ligament, which makes up the floor of the inguinal canal. The pectin pubis is the ridge on the superior surface of the superior pubic ramus. This is the place where you find the pectineal ligament, a thickining of fascia on the pecten of the pubis. The pectineal ligament is a good place to put sutures when doing surgery. The pubic symphysis is the joint between the two pubic bones. The iliopubic eminence is a bony process on the pubis found near its articulation with the ilium. The iliopectineal line is a line formed by the arcuate line of the ilium and the pectinate line of the pubis. This line forms a plane that marks the transition between the abdominal and pelvic cavity.

5. A. The epigastric region is one of the nine regions of the abdomen. It contains the duodenum, part of the stomach, part of the liver, and the pancreas. This is the region that the surgeon would need to enter to

reach the ulcer in the first part of the duodenum. The left inguinal region contains the sigmoid colon. The left lumbar region contains the descending colon and kidney. The right hypochondrial region contains part of the liver and the gall bladder. Finally, the hypogastric region contains the bladder and rectum. For a good picture of this, see the dissector answer 1 for this lab. 6. B. The iliohypogastric nerve is a branch of the lumbar plexus. It provides sensory innervation to the skin of the lower abdominal wall, upper hip and upper thigh. This is the region where the patient is experiencing parasthesia, so this nerve must be injured . The genitofemoral nerve is another nerve from the lumbar plexus. It provides sensory innervation to the skin of the anterior scrotum or labia majora and upper medial thigh. The subcostal nerve is the ventral primary ramus of T12--it is the equivalent of an intercostal nerve at a higher thoracic level. It provides sensory innervation to the anterolateral abdominal wall, but in an area superior to the pubic region. A spinal nerve would not have been injured in the operation. Remember--the spinal nerve is just that small segment of nerve that exists once the dorsal and ventral rootlets come together, before the dorsal and ventral primary rami branch off. In any case, the T9 and T10 dermatomes are superior to the area where the patient is experiencing parasthesia. 7. B. Remember--the transverse suprapubic incision (also called the Pfannenstiel incision) is made below the arcuate line. So, there is no longer a posterior layer of the rectus sheath, and the inner surface of the rectus abdominus is lined only with transversalis fascia. When making this incision, the abdominal wall layers are incised as follows: skin, superficial fascia (fatty and

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membranous), deep fascia, anterior rectus sheath, rectus abdominis muscle, transversalis fascia, extraperitoneal connective tissue, and peritoneum. 8. B. The inferior epigastric vessels are found in the preperitoneal fat of the abdomen. They lie just superficial to the peritoneum and form the lateral umbilical fold. Hernias may pass lateral or medial to these vessels. If the hernia is lateral to the vessels (which is what happened in this case), it is an indirect inguinal hernia. If the hernia is medial to these vessels, it is an indirect inguinal hernia. The deep circumflex artery courses along the iliac crest on the inner surface of the abdominal wall. This artery is very lateral on the abdominal wall, and hernias would pass medial to this vessel. The superficial circumflex iliac, superior epigastric, and superficial external pudendal arteries are all superficial arteries that arise from the femoral artery. They are all found in the superficial fascia--not in the preperitoneal fat.

9. A. The arcuate line is an anatomical feature on the inner surface of the abdominal wall. It is the point at which the posterior lamina of the rectus sheath ends, and transversalis fascia lines the inner surface of rectus abdominis. The intercrestal line is an imaginary line drawn in the horizontal plane at the upper margin of the iliac crests. It is a landmark used to find the L4 vertebra, which is useful when performing a spinal tap. Linea alba is an aponeurotic band on the midline of the anterior abdominal wall, which extends from the xiphoid process to the pubic symphysis. It is formed by the combined abdominal muscle aponeuroses, and it provides a useful site for a midline incision in the abdomen. The pectineal line is a structural feature of the pubic bone. It is an oblique ridge on the lateral

part of the superior ramus. Finally, the semilunar line is the lateral margin of the rectus abdominus, formed by the fused aponeuroses of the abdominal wall muscles at the lateral margin of the rectus sheath. 10. E. The linea alba is an aponeurotic band on the midline of the anterior abdominal wall, which extends from the xiphoid process to the pubic symphysis. It is formed by the combined abdominal muscle aponeuroses. Because there are no major arteries or nerves running in the linea alba, it provides a useful site for a midline incision in the abdomen. The linea aspera is a vertical ridge on posterior surface of the femur. The arcuate line is the point at which the posterior lamina of the rectus sheath ends, and transversalis fascia lines the inner surface of rectus abdominis. The semilunar line is the lateral margin of the rectus abdominus, formed by the fused aponeuroses of the abdominal wall muscles. The iliopectineal line is a line on the pelvic bones, formed by the arcuate line of the ilium and the pectineal line of the pubis. (Note--the arcuate line of the ilium is totally different than the arcuate line of the rectus sheath!) This line is important because it marks the boundary between the abdominal cavity and the pelvic cavity. 11. B. If the internal thoracic artery was ligated, blood would no longer flow to the superior epigastric artery, which is the branch of the internal thoracic that supplies blood to rectus abdominus. However, the superior epigastric artery communicates with the inferior epigastric artery, a branch of the external iliac artery. This means that blood could flow from the external iliac, to the inferior epigastric, to the superior epigastric and the rectus abdominus. The superficial epigastric and superficial circumflex iliac arteries are two superficial branches of the femoral

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artery. They do not supply deep structures in the abdomen. The umbilical arteries are obliterated in adults--they form the medial umbilical folds. The deep circumflex iliac artery courses along the iliac crest on the inner surface of the abdominal wall. It is too lateral to supply blood to rectus abdominus. 12. E. The umbilicus is an important landmark for venous and lymphatic drainage of the abdominal wall. Above the umbilicus, lymphatics drain into the axillary lymph nodes and the venous blood drains into the superior epigastric vein, which drains to the internal thoracic vein. Below the umbilicus, lymphatics drain into the superficial inguinal lymph nodes, while venous blood drains into the inferior epigastric vein and the external iliac vein.

Dr: Ahmed Nawaz Jamali