WBR0941
| Author | PageAuthor::William J Gibson (Reviewed by Serge Korjian) |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Anatomy |
| Sub Category | SubCategory::Gastrointestinal |
| Prompt | [[Prompt::A 70-year-old man presents to his primary care physician for a bulge in his right groin that becomes more prominent when coughing and standing up. Ultrasound of the region reveals a hernia that protrudes medial to the inferior epigastric vessels and lateral to the rectus abdominus. The inferior border of this hernia is bounded by a tissue formed from the aponeurosis of which of the following?]] |
| Answer A | AnswerA::Internal abdominal oblique |
| Answer A Explanation | [[AnswerAExp::The internal abdominal oblique lies deep to the external abdominal oblique and superficial to the transversus abdominis. It is responsible for rotation and side-bending of the trunk. In males, the cremaster muscle is attached to the internal abdominal oblique.]] |
| Answer B | AnswerB::External abdominal oblique |
| Answer B Explanation | AnswerBExp::The aponeurosis of the external abdominal oblique gives rise to the inguinal ligament. |
| Answer C | AnswerC::Transversus abdominus |
| Answer C Explanation | AnswerCExp::The transversus abdominis is forms the innermost layer of the abdominal muscles, found deep to the internal abdominal oblique muscle. Its aponeurosis gives rise to the line alba. |
| Answer D | AnswerD::Linea alba |
| Answer D Explanation | AnswerDExp::The linea alba is the fibrous band that runs down the midline of the abdomen atop the rectus abdominus. |
| Answer E | AnswerE::Spermatic cord |
| Answer E Explanation | AnswerEExp::The spermatic cord travels through the inguinal canal and contains the vas deferens and essential neurovascular structures for the scrotum. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient in this vignette has a direct inguinal hernia, in which the contents of the abdomen protrude through a weakened area in the transversalis fascia. This region lies superior to the inguinal ligament, medial to the inferior epigastric vessels and lateral to the rectus abdominus. It is often referred to as Hesselbach’s triangle. The inferior border of the Hesselbach triangle, the inguinal ligament, is formed by the external abdominal oblique aponeurosis. Direct hernias are capable of exiting via the superficial inguinal ring but, unlike indirect inguinal hernias, they cannot move into the scrotum. Direct inguinal hernias occur 10x more often in males than in females. In contrast, indirect hernias protrude lateral to the inferior epigastric vessels and passes through the deep inguinal ring into the scrotum. The pathophysiology of indirect hernias is due to failure of closure of the processus vaginalis, and outpouching of the peritoneum into the scrotum. Educational Objective: The aponeurosis of the external abdominal oblique gives rise to the inguinal ligament. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Abdomen, WBRKeyword::Anatomy, WBRKeyword::Inguinal, WBRKeyword::Ligament, WBRKeyword::Hernia, WBRKeyword::Musculoskeletal |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |