The linea alba (Latin for: white line) is a strong fibrous midline structure
of the
anterior abdominal wall
In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls.
There is a common set of layers covering and forming all the walls: the deepest being the v ...
situated between the two
recti abdominis muscles (one on either side). The umbilicus (navel) is present on the linea alba through which foetal umbilical vessels pass before birth.
The linea alba is formed by the union of
aponeuroses
An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...
(of the muscles of the
anterior abdominal wall
In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls.
There is a common set of layers covering and forming all the walls: the deepest being the v ...
) that collectively make up the
rectus sheath
The rectus sheath (also called the rectus fascia.) is a tough fibrous compartment formed by the aponeuroses of the transverse abdominal, transverse abdominal muscle, and the internal oblique, internal and external oblique muscles. It contains the ...
. The linea alba attaches to the
xiphoid process superiorly, and to the
pubic symphysis inferiorly. It is narrow inferiorly where the two recti abdominis muscles are in contact with each other posterior to it, and broadens superior-ward from just inferior to the umbilicus.
The name means ''white line'' as it is composed mostly of
collagen
Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...
connective tissue, which has a white appearance.
In sufficiently muscular individuals, its presence can be seen on the
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different ...
, forming the depression between the left and right halves of a "
six pack".
Function
The linea alba stabilizes the anterior abdominal wall, as it balances contractile forces from the muscles attached to it.
Clinical significance
An abnormal widening of the linea alba is known as
diastasis recti.
During pregnancy, the linea alba usually darkens due to hormonal changes whereupon it becomes known as the
linea nigra. The linea nigra sometimes also occurs in either sex outside the context of pregnancy.
A median incision through the linea alba is a common
surgical approach for
abdominal surgery
The term abdominal surgery broadly covers surgical procedures that involve opening the abdomen (laparotomy). Surgery of each abdominal organ is dealt with separately in connection with the description of that organ (see stomach, kidney, liver, e ...
. This is because it consists of mostly
connective tissue
Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesod ...
, and does not contain any primary
nerve
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...
s or
blood vessel
Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...
s.
Additional images
File:Gray_abdomen_front_surface_en.png, Surface anatomy of the front of the thorax and abdomen.
File:Linea alba.jpg, Linea alba
See also
*
Linea alba (cheek)
*
Linea nigra
References
External links
*
* (before removing skin)
* (after removing skin)
*
{{Authority control
Abdomen