Anatomy Lecture Notes

Abdominal Wall and Inguinal Canal

Abdominal Wall Muscles

External Obliques

• Most superficial of the anterolateral abdominal wall muscles.
• Muscle fibers run in a similar direction to external intercostal muscles (hands in front pockets direction).

Internal Oblique and Transversus Abdominis

• Located deeper than the external obliques.
• Not required to be identified in the current scope.

Rectus Sheath

• Formed by the tendons (aponeurosis) of the oblique muscles and transversus abdominis.
• Robust, dominant white structure in the anterior abdominal wall.
• Contains the linea alba (white line) as medial attachment point of abdominal muscles.

Rectus Abdominis

• Located beneath the anterior portion of the rectus sheath.
• Extends from xiphoid process to pubic symphysis.
• Contains tendinous intersections (typically 3).

Arcuate Line

• Found about three-fourths of the way down the rectus abdominis.
• Below this line, the rectus sheath is incomplete, leaving only transversalis fascia.

Inguinal Canal

Overview

• Traditionally complex and difficult to dissect.
• Extends from the deep inguinal ring (not visible superficially) to the superficial inguinal ring (visible in dissection).

Superficial Inguinal Ring

• Exit of the inguinal canal.
• Formed by the external oblique aponeurosis.
• Structures such as the round ligament of the uterus and the spermatic cord exit here.

Round Ligament of the Uterus

• Connects the uterus to the labia majus.
• Appears as a tubular collection of adipose tissue and is sometimes difficult to differentiate from surrounding tissue.
• Identified by ilioinguinal nerve running superficial to it.
• Remnant of the gubernaculum.

Spermatic Cord

• Seen exiting the superficial inguinal ring.
• Composed of multiple structures, including nerves, vessels, and vas deferens.
• Discussed in detail in reproductive anatomy session.

Inguinal Ligament

• Floor of the inguinal canal.
• Extends from anterior superior iliac spine to pubic tubercle.
• Made of external oblique aponeurosis.

Deep Surface of the Anterior Abdominal Wall

Prominent Features

• Inferior epigastric vessels (veins and artery).
• Round ligament of the uterus entering the deep inguinal ring.
• Relationship of the deep inguinal ring (entrance to inguinal canal) to the inferior epigastric vessels.

Diaphragm

• Left and right hemidiaphragms (Liver under right, stomach under left).
• Three openings for the esophagus, inferior vena cava, and aorta.

Summary

• Understanding of abdominal wall musculature, inguinal canal structures, and the deep anatomy.
• Importance of identifying structures and knowing their relationships (e.g., hernias).

Notes:

• Review these structures carefully.
• Reach out with any questions.

Have a great day!