Lumbocostal Triangle

The lumbocostal triangle (Latin trigonum lumbococcstale, English lumbar triangle) is an important element of the chest, performing two functions: respiratory and protective. Breathing movements involve the muscles of the diaphragm, chest wall and abdominal wall.

The lumbocostal triangles make up four points: the posterior inferior iliac tuberosity. The apex of the right triangle coincides with the anterior superior iliac spine, and the anterior inferior iliac suture is located at the posterior end of the XIII thoracic vertebra. The posterior inferior iliac tuberosity is in contact with the bodies of the two lower thoracic vertebrae and its apex passes along the line of convergence of the twelfth rib with the cartilages of the posterior sections of the XI, X and IX costal arches. The upper point is located at the intersection of the twelfth fissure (superior aperture of the chest) and the anterior fissure of the spine. There are ribs at the bottom of the triangles. The upper triangular section is formed by the diaphragm, the lateral part of the posterior wall of the chest cavity and the pelvic diaphragm. The inferior and lateral triangular sections are formed by the lower abdominal cavity, the anterior pelvis and the inner surface of the anterior chest wall in an adult.

Between the upper and lower triangular cells is the middle part of the body from bottom to top. The peritoneum forms two rows of structures, at the top called the transversalis fascia, which fixes the rectus abdominis muscle and the fibers of the femoral nerve; from below - the deep fascial system for the transverse abdominal muscle. A direct continuation of the transverse layer of the body is the transversalis fascia.

**Lumbo-Rib Triangle** - (trigonun lumboscostale)

***This triangle is formed by the anterior surface of the I and XII ribs, the dorsal edge of the vertebral bodies of the Duodenum and the cartilages of the VIII-X ribs.*** The inner surface of the triangle **is the site of anatomical and topographical relationships in which special care is required due to danger causing injury to the capsules of the intervertebral joints, sacrospinalis or ostiomotorus muscles.**

The medial border of the triangle passes through the anterior surface of the II-VI costal cartilages, the anterior one along the cartilage of the VIII rib, the lower border along the lower boundary lines of the vertebral bodies of the lumbar and sacral spine and upward along the tissue of the anterolateral surface of the pelvis. The lateral border is formed by the dorsal edges of the bodies of the 2-4 lumbar vertebrae. The height of the triangle is 6-12 cm.

***Anatomical landmarks are the anterior angles of the lumbar and sacral vertebral bodies, the bodies of the lumbar segments along which vessels and nerves pass, the lower transverse processes of the 3-4 lumbar bodies and the L1 vertebral body, as well as the days of the semi-inferior vertebral bodies and the apex of the sacrum, on which projected by the anterior angles of the upper and lower caudal vertebrae.***

**The greater lumbar nerve (L1-L2) exits the spine under the transverse process of the LV lumbar vertebra to its left. The lesser lumbar nerve emerges from the right leg of this (D3V) transverse