Linea semilunaris | |
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![]() The obliquus externus abdominis. (Linea semilunaris labeled vertically at center, at border between brown and gray.) | |
![]() Linea semilunares are at lateral borders of rectus abdominis. | |
Identifiers | |
TA98 | A04.5.01.025 |
TA2 | 2380 |
FMA | 19929 |
Anatomical terminology |
The linea semilunaris (also semilunar line or Spigelian line) is a curved line found on either side of the rectus abdominis muscle.
The linea semilunaris was first described by Adriaan van den Spiegel. [1] [2] [3]
There are two commonly used definitions identifying the linea semilunaris. [4] [1] [5] The first is defined as corresponding with the lateral border of the rectus sheath. [1] [6] [7] [8] [9] In this definition, it is formed by the aponeurosis of the internal oblique at its line of division to enclose the rectus. [9] [10] This is reinforced anteriorly by the external oblique, and posteriorly by the transversus abdominis above the arcuate line. [11] [10] [9] The second definition identifies it as the line forming and marking the transition from muscle to aponeurosis in the transversus abdominis muscle, known as the spigelian aponeurosis. [1] [12] [13] [14] In both definitions, it extends from the cartilage of the ninth rib to the pubic tubercle. [4] [6] [7] The terms spigelian fascia and spigelian aponeurosis have also been used to define the linea semulunaris. [5] In this definition it refers to the aponeuroses of the lateral abdominal muscles lateral to the rectus muscle. [5] In other definitions the spigelian aponeurosis/spigelian fascia is the aponeurosis of the transverse abdominal muscle medial to the linea semilunaris and lateral to the rectus muscle. [15] [14]
A hernia through the linea semilunaris is called a Spigelian hernia. [16] [17] This usually occurs at the meeting point of the linea semilunaris with the arcuate line and the lateral border of the rectus abdominis muscle. [16]
. [Paul] Barbette did not in fact explicitly mention the linea semilunaris but described an abdominal hernia 'under and beside the umbilicus, way above the groin.' The linea semilunaris was first described by Adriaan van den Spiegel, De humāni corporis fabrica libri decern (Venice: Ev. Deuchenius, 1627), p. 118. Quoted by Gerrit A. Lindeboom, Adriaan van den Spiegel (Amsterdam: Rodopi, 1978), p. 68. Spiegel made no mention of any hernia.
Linea semilunaris à Spigelio dicta, circa quam tendines obliquorum abdominis musculorum incipiunt.
In previous reports there appears to be some difference of opinion as to what exactly constitutes Spiegel's line. Watson (1948) defines it as the line which represents the point of division of the internal oblique aponeurosis to enclose the rectus muscle. River (1942) defines it as the line of transition between the muscle bundles and aponeurosis of the transversus. This lies for the greater part at some distance lateral to the edge of the rectus sheath, but the muscle-fibres of the internal oblique extend right up to the edge of the sheath.
The semilunar line that marks the lateral border of the rectus sheath streches from the tip of the ninth rib cage to the pubic tubercle
The linea semilunaris is a curved depression which extends from the tip of the ninth costal cartilage to the symphysis pubis. It marks the lateral edge of the rectus sheath
We remind the reader that the convex linea semilunaris (semilunar line of Spieghel) is pro- duced by and marks the site of transition from the aponeurotic part to the muscular part of the transverse abdominal muscle.