What Is the Linea Semilunaris?

The rectus abdominis sheath sheaths rectus abdominis. It covers the anterior oblique muscle and the anterior layer of the oblique tendon and the anterior oblique tendon. The posterior layer is healed with the transverse abdominal aponeurosis. Below 4-5cm below the umbilicus, the posterior layer of the intraabdominal oblique tendon and the transverse abdominis constituting the posterior layer of the sheath are completely transferred to the front of the rectus abdominis and participate in the anterior layer of the sheath, so there is no sheath here. Back layer. When the rectus abdominis sheath is viewed from the rear, it can be seen that the free lower edge of the posterior layer is an arc line protruding upward, which is called an arched line (half-circle line). The rectus abdominis below this line is directly attached to the transverse abdominal fascia.

The rectus abdominis sheath sheaths rectus abdominis. It covers the anterior oblique muscle and the anterior layer of the oblique tendon and the anterior oblique tendon. The posterior layer is healed with the transverse abdominal aponeurosis. Below 4-5cm below the umbilicus, the posterior layer of the intraabdominal oblique tendon and the transverse abdominis constituting the posterior layer of the sheath are completely transferred to the front of the rectus abdominis and participate in the anterior layer of the sheath, so there is no sheath here. Back layer. When the rectus abdominis sheath is viewed from the rear, it can be seen that the free lower edge of the posterior layer is an arc line protruding upward, which is called an arched line (half-circle line). The rectus abdominis below this line is directly attached to the transverse abdominal fascia.

Chinese name

Rectus sheath

Foreign name

sheath of rectus abdominis

Nature

Wrapped rectus abdominis

Attributes

The aponeurosis of the three flat muscles of the outer abdominal wall

Composition of rectus sheath

In the anatomy of 14 straight abdominal sheaths, we found that 4 cases had obvious double half-circles (one case was only left, one case was right, one case was present on both sides; one was present on both sides). The rest are single semi-circle lines. From the cross section of each specimen, the typical arrangement above the middle section was observed, and the abdominal abdominal muscle bonds and the transverse abdominal muscle fibers at the near half-circle line were difficult to separate from each other. This fact is consistent with the observations of BJAsnon and CBMcVay It is impossible to judge with naked eyes whether the strokes of the various layers of the push rods are crossed. Therefore, a tissue section must be used for confirmation.

Classification of rectus sheaths

The rectus abdominis sheath is divided into two leaves.

The anterior lobe is formed by the aponeurosis, but its thickness changes in 3 localities. The thinnest sheath in the upper part is composed of only one layer of the external oblique tendon; the thickest part is composed of three layers of flat tendons; the middle part is the true two layers of aponeurosis.

The posterior leaf is formed by 4 different tissues in 4 different planes. In the plane around the umbilicus, the two layers of aponeurosis form the same structure as the anterior sheath; in the plane between the umbilicus and the xiphoid process, part of the transverse abdominal muscle is added; in the plane below the xiphoid process, the cartilage (costal cartilage and xiphoid ); The plane below the umbilical and pubic symphysis, the aponeurosis migrates in the anterior lobe while forming an arcuate line, and the posterior lobe is composed of a ventral transverse fascia.

A white line (linea alba) is formed on the inside of the muscle sheath. The white line below the umbilicus is a veritable line. The white line above the umbilicus forms a band, about half an inch or more wide.

Linea semilunaris are formed on the outer side of the sheath, and are on the same vertical line as the lumbar vertebra process and the ureter.