The arcuate line of the rectus sheath--does it exist?

Area of Science:

• Anatomy
• Surgical anatomy

Background:

• The anterior abdominal wall's rectus sheath anatomy is conventionally described with a distinct arcuate line.
• Variations in this anatomy can impact surgical procedures and understanding.

Purpose of the Study:

• To investigate the anatomical variations in the lower anterior abdominal wall, specifically the rectus sheath.
• To describe the transition of aponeurotic fibers and the presence/absence of the arcuate line.

Main Methods:

• Dissection of the lower anterior abdominal wall in 40 human cadaveric specimens.
• Observation and documentation of anatomical features, including fiber orientation and sheath composition.

Main Results:

• Significant variability was observed, differing from the standard anatomical description.
• Aponeurotic fibers shifted from posterior to anterior rectus sheath inferiorly, leading to arcuate line absence.
• Observed variations included a thinned/complete posterior rectus sheath (PRS), ill-defined/double arcuate lines, or transverse aponeurotic bands.

Conclusions:

• The conventional arcuate line is frequently absent in the lower anterior abdominal wall due to fiber migration.
• Anatomical variations in the rectus sheath are common and necessitate consideration in surgical approaches.
• The posterior rectus sheath (PRS) and transverse aponeurotic bands represent common alternative findings.