Rectus Sheath

Original Editor - lucinda hampton

Top Contributors - Lucinda hampton and Kim Jackson  

Introduction

The Rectus Sheath is a multilayered aponeurosis, being a durable, resilient, fibrous compartment that contains both the rectus abdominis muscle and the pyramidalis muscle.

It covers the anterior and posterior surfaces of the upper three-quarters of the rectus abdominis muscle, and the lower quarter of its anterior surface. The lower quarter of the posterior surface of the rectus abdominis muscle isn’t covered with rectus sheath at all, but rather lays directly on the transversalis fascia.

Image 1: Dissection of a human Rectus abdominis sheath

Key Facts

Definition	Multilayered aponeurosis that encloses the rectus abdominis and pyramidalis muscles
Walls of upper three-quarters	Anterior wall: Aponeurosis of external abdominal oblique muscle and aponeurosis of internal abdominal oblique muscle Posterior wall: Aponeurosis of internal abdominal oblique muscle and aponeurosis of transversus abdominis muscle
Walls of lower quarter	Anterior wall: As above Posterior wall: Absent
Function	Protection of anterior abdominal muscles and vessels. Provides maximal compression and support of abdominal organs.

Contents

1. 

   Rectus abdominis and Pyramidalis muscles
2. Lower 6 thoracic nerves and accompanying branches of the posterior intercostal vessels
3. Superior and inferior epigastric vessels

Image 3: Figure 2: Rectus sheath (Gray's illustrations)