SBA — Single Best Answer · Review
Question 9
Anatomy → Blood vessels and nerves
Classification
Question
SSBAQuestion Header
A superficial cutaneous lesion of the anterior abdominal wall lies well below the umbilicus. Which lymph-node group is the principal destination for lymph following the superficial epigastric vessels from this region?
Question Stem
A) Parasternal lymph nodes
B) Axillary lymph nodes
C) Superficial inguinal lymph nodes
D) External iliac lymph nodes
E) Posterior mediastinal lymph nodes
B) Axillary lymph nodes
C) Superficial inguinal lymph nodes
D) External iliac lymph nodes
E) Posterior mediastinal lymph nodes
Options
A
Parasternal lymph nodes
B
Axillary lymph nodes
C
Superficial inguinal lymph nodes
D
External iliac lymph nodes
E
Posterior mediastinal lymph nodes
Explanation
Superficial lymphatic vessels of the anterior abdominal wall follow the subcutaneous blood vessels. Lymphatics from infraumbilical skin run with the superficial epigastric vessels and ultimately drain to the superficial inguinal lymph nodes. In contrast, the supraumbilical region drains principally towards axillary and parasternal nodes. External iliac nodes receive important deep lymphatic drainage from the lower abdominal wall, particularly along deeper vessels such as the inferior epigastric and deep circumflex iliac arteries. Posterior mediastinal and lateral aortic nodes are associated with deeper lateral lymphatic pathways that accompany intercostal, subcostal or lumbar vessels. The superficial versus deep distinction is therefore essential when predicting abdominal-wall lymphatic spread.
Option Validity
A) Parasternal nodes contribute to supraumbilical rather than infraumbilical superficial drainage.
B) Axillary nodes receive superficial lymph from the upper abdominal wall rather than the infraumbilical region described.
D) External iliac nodes are principally part of the deep lower abdominal-wall drainage pathway.
E) Posterior mediastinal nodes are associated with deeper lateral lymphatics, not superficial infraumbilical skin.
Further Reading
Part 1 MRCOG Revision Notes and Sample SBAs. Cambridge University Press, 2020. Section 1: Anatomy, Chapter 1. https://doi.org/10.1017/9781108644396