Semilunar line
Linea semilunaris
- Latin eponym: Linea Spigeli
- Eponym: Van den Spieghel's line; Spighel's line
- Related terms: Linea semilunaris
Definition
The semilunar lines (a.k.a. the linea semilunares) are curved tendinous lines located along the lateral borders of the rectus abdominis muscles. They represent the sites where the aponeurosis of the internal abdominal oblique splits into anterior and posterior layers to enclose the rectus abdominis within the rectus sheath, above the arcuate line.
The semilunar lines extend from the costal margin to the pubic tubercle and mark the transition between the flat muscles of the lateral abdominal wall and the rectus sheath medially.
References
Nassereddin A, Sajjad H. Anatomy, Abdomen and Pelvis: Linea Semilunaris. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555983/
