Serratus posterior inferior muscle
Encyclopedia
The Serratus posterior inferior muscle (or posterior serratus) is a muscle
of the human body
.
It is situated at the junction of the thoracic and lumbar regions: it is of an irregularly quadrilateral form, broader than the serratus posterior superior muscle
, and separated from it by a wide interval.
It arises by a thin aponeurosis
from the spinous processes of the lower two thoracic and upper two or three lumbar vertebræ, and from the supraspinal ligament.
Passing obliquely upward and lateralward, it becomes fleshy, and divides into four flat digitations, which are inserted into the inferior borders of the lower four ribs, a little beyond their angles.
The thin aponeurosis of origin is intimately blended with the lumbodorsal fascia, and aponeurosis of the Latissimus dorsi.
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
of the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
.
Origin and insertion
The muscle lies at the junction of the thoracic and lumbar regions. The origin arises from the vertebrae T11 through L2. The muscle's insertion is the lower border of the 9th through 12th ribs.It is situated at the junction of the thoracic and lumbar regions: it is of an irregularly quadrilateral form, broader than the serratus posterior superior muscle
Serratus posterior superior muscle
The Serratus posterior superior is a thin, quadrilateral muscle, situated at the upper and back part of the thorax.It arises by a thin and broad aponeurosis from the lower part of the ligamentum nuchae, from the spinous processes of the seventh cervical and upper two or three thoracic vertebræ and...
, and separated from it by a wide interval.
It arises by a thin aponeurosis
Aponeurosis
Aponeuroses are layers of flat broad tendons. They have a shiny, whitish-silvery color, are histologically similar to tendons, and are very sparingly supplied with blood vessels and nerves. When dissected, aponeuroses are papery, and peel off by sections...
from the spinous processes of the lower two thoracic and upper two or three lumbar vertebræ, and from the supraspinal ligament.
Passing obliquely upward and lateralward, it becomes fleshy, and divides into four flat digitations, which are inserted into the inferior borders of the lower four ribs, a little beyond their angles.
The thin aponeurosis of origin is intimately blended with the lumbodorsal fascia, and aponeurosis of the Latissimus dorsi.