The aesthetic feature popularly known as the “V-line” or “Adonis Belt” is a pair of shallow, diagonal indentations that descend from the hip bones toward the groin area. This visual characteristic is often viewed as a symbol of peak physical conditioning. The structure itself is a specific and universally present anatomical landmark.
The Proper Anatomical Terminology
The term that most accurately describes the indentation of the V-line is the Iliac Furrow, though it is sometimes referred to as the Inguinal Furrow. Non-clinical nicknames, such as the “Adonis Belt,” “Apollo’s Belt,” or “V-Cut,” are aesthetic descriptors used to describe this feature.
The Musculature and Connective Tissue Involved
The indentation that forms the V-line is fundamentally a visual representation of the inguinal ligament, a dense band of connective tissue. This ligament is not a muscle; it is the thickened, rolled-under lower border of the aponeurosis of the external oblique muscle. The inguinal ligament runs obliquely from the anterior superior iliac spine, a bony projection of the hip, down to the pubic tubercle near the groin. The V-shape is created where this ligament delineates the boundary between the lower abdominal wall and the upper thigh. The adjacent musculature, particularly the external oblique muscles, provides the prominent edges that frame the indentation.
When these surrounding muscles are well-developed, they create contrast, making the depression of the inguinal ligament more noticeable. The external oblique is the largest and most superficial of the three flat muscles in the abdominal wall, and its aponeurosis extends downward to form the inguinal ligament. The visible V-line is a combination of the connective tissue of the ligament itself and the defined borders of the muscle where its tendon attaches to the pelvis.
Why the V-Lines Become Visible
The primary factor determining the visibility of the iliac furrow is the level of subcutaneous body fat. The inguinal ligament and surrounding structures are typically covered by adipose tissue, which obscures the groove in most individuals. For the V-line to become prominent, the body fat percentage must be significantly low, often falling into the range of 6 to 13 percent.
This low level of body fat allows the skin to lie close to the underlying connective tissue, revealing the path of the inguinal ligament. Without this low body fat, even highly developed abdominal muscles will not make the furrow visible. A secondary factor that enhances the contrast is the development of the adjacent musculature, including the external obliques and the deep transverse abdominis. Building the size and definition of these muscles creates a deeper and more pronounced border around the inguinal ligament, making the V-shape appear more dramatic.