28. Boundaries of Rectus sheath
The rectus sheath is a fibrous compartment enclosing the rectus abdominis and pyramidalis muscles, formed by the aponeuroses of the oblique and transversus abdominis muscles. Its boundaries consist of the medial linea alba (where sheaths meet) and lateral linea semilunaris (where fascia splits), extending from the pubic symphysis inferiorly to the costal cartilages (5th-7th) superiorly-PKK