semilunaris

Semilunaris is the Latin term meaning crescent-shaped, used in anatomy to describe structures that have a crescent or half-moon outline. In English, semilunar is more common as an adjective, while semilunaris appears in Latinized phrases and in older texts. The term is most often encountered in names of crescent-shaped anatomical features.

One well-known example is linea semilunaris, the semilunar line of the abdominal wall. Each semilunar line marks the lateral border of the rectus abdominis where the aponeuroses of the abdominal muscles transition to form the rectus sheath. The lines are curved and extend from the costal margin to the pubic crest on each side, serving as anatomical landmarks for the lateral abdominal wall.

In the knee, the term appears in reference to the semilunar cartilages, the crescent-shaped fibrocartilages that are better known today as the medial and lateral menisci. These structures cushion and stabilize the knee joint by distributing load and guiding motion.

Other historical or less common uses of semilunaris exist in anatomical literature to describe various crescent-shaped structures, but linea semilunaris and the semilunar cartilages are among the best-known examples. Overall, semilunaris denotes crescent-shaped morphology across different anatomical contexts.