Rectus sheath is contributed by?
**Core Concept**
The rectus sheath is a fibrous compartment that encloses the rectus abdominis muscle in the abdominal wall. It is formed by the aponeuroses of the external and internal oblique and transversus abdominis muscles.
**Why the Correct Answer is Right**
The rectus sheath is formed by the aponeuroses of the three flat abdominal muscles - external oblique, internal oblique, and transversus abdominis. These aponeuroses merge in front of the rectus abdominis muscle to form the anterior layer of the rectus sheath. The posterior layer is formed by the transversalis fascia. This anatomical arrangement provides a protective covering for the rectus abdominis muscle.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the correct muscles contributing to the rectus sheath.
**Option B:** Incorrect because it is incomplete - only two of the three muscles are mentioned.
**Option C:** Incorrect because it is incomplete - the aponeuroses of the external and internal oblique muscles, but not the transversus abdominis, are mentioned.
**Clinical Pearl / High-Yield Fact**
The rectus sheath is an important landmark for surgical incisions and muscle dissections in the abdominal wall. Knowledge of its anatomy is crucial for avoiding injury to the rectus abdominis muscle and its surrounding structures.
**Correct Answer:** D. All the above (External oblique, Internal oblique, and Transversus abdominis).