Pyramidalis muscle

Last updated
Pyramidalis muscle
Gray397.png
Muscles at the front of the abdomen, showing the pyramidalis at the bottom centre.
Details
Origin Pubic symphysis and pubic crest
Insertion Linea alba
Artery Inferior and superior epigastric arteries
Nerve Subcostal nerve (T12)
Actions Tensing the linea alba
Identifiers
Latin musculus pyramidalis
TA98 A04.5.01.007
TA2 2363
FMA 15568
Anatomical terms of muscle

The pyramidalis muscle is a small triangular muscle, anterior to the rectus abdominis muscle, and contained in the rectus sheath.

Contents

Structure

The pyramidalis muscle is part of the anterior abdominal wall. [1] Inferiorly, the pyramidalis muscle attaches to the pelvis in two places: the pubic symphysis and pubic crest, arising by tendinous fibers from the anterior part of the pubis and the anterior pubic ligament.

Superiorly, the fleshy portion of the pyramidalis muscle passes upward, diminishing in size as it ascends, and ends by a pointed extremity which is inserted into the linea alba, midway between the umbilicus and pubis.[ citation needed ]

Nerve supply

The pyramidalis muscle is innervated by the ventral portion of T12.

Blood supply

The inferior and superior epigastric arteries supply blood to the pyramidalis muscle.[ citation needed ]

Variation

The pyramidalis muscle is present in 80% of human population. [2] [ unreliable source? ] It may be absent on one or both sides; the lower end of the rectus then becomes proportionately increased in size.

Occasionally, it is doubled on one side, and the muscles of the two sides are sometimes of unequal size.[ citation needed ] It may also extend higher than the usual level.[ citation needed ]

Function

The pyramidalis muscle tenses the linea alba when contracting.[ citation needed ]

Clinical significance

While making the longitudinal incision for a classical caesarean section, the pyramidalis muscle is used to determine midline and location of the linea alba.[ citation needed ]

Additional images

Related Research Articles

<span class="mw-page-title-main">Pubic symphysis</span> Cartilaginous joint between the front of the left and right hip bones

The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubic symphysis. In females, the pubic symphysis is attached to the suspensory ligament of the clitoris. In most adults, it can be moved roughly 2 mm and with 1 degree rotation. This increases for women at the time of childbirth.

<span class="mw-page-title-main">Linea alba (abdomen)</span> Fibrous structure of the abdomen

The linea alba is a strong fibrous midline structure of the anterior abdominal wall situated between the two recti abdominis muscles. The umbilicus (navel) is a defect in the linea alba through which foetal umbilical vessels pass before birth. The linea alba is formed by the union of aponeuroses that collectively make up the rectus sheath. 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.

<span class="mw-page-title-main">Rectus abdominis muscle</span> Paired straight muscle

The rectus abdominis muscle, also known as the "abdominal muscle" or simply the "abs", is a pair of segmented skeletal muscle on the ventral aspect of a person's abdomen. The paired muscle is separated at the midline by a band of dense connective tissue called the linea alba, and the connective tissue defining each lateral margin of the rectus abdominus is the linea semilunaris. The muscle extends from the pubic symphysis, pubic crest and pubic tubercle inferiorly, to the xiphoid process and costal cartilages of the 5th–7th ribs superiorly.

<span class="mw-page-title-main">Inguinal ligament</span> Band running from the pubic tubercle to the anterior superior iliac spine

The inguinal ligament, also known as Poupart's ligament or groin ligament, is a band running from the pubic tubercle to the anterior superior iliac spine. It forms the base of the inguinal canal through which an indirect inguinal hernia may develop.

<span class="mw-page-title-main">Transverse abdominal muscle</span> Muscle of the abdominal area

The transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral abdominal wall, deep to the internal oblique muscle. It is thought by most fitness instructors to be a significant component of the core.

<span class="mw-page-title-main">Abdominal internal oblique muscle</span> Muscle in the abdominal wall

The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle.

<span class="mw-page-title-main">Abdomen</span> Part of the body between the chest and pelvis

The abdomen is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods, it is the posterior tagma of the body; it follows the thorax or cephalothorax.

<span class="mw-page-title-main">Inferior epigastric artery</span> Blood vessel

In human anatomy, the inferior epigastric artery is an artery that arises from the external iliac artery. It is accompanied by the inferior epigastric vein; inferiorly, these two inferior epigastric vessels together travel within the lateral umbilical fold The inferior epigastric artery then traverses the arcuate line of rectus sheath to enter the rectus sheath, then anastomoses with the superior epigastric artery within the rectus sheath.

<span class="mw-page-title-main">Pubis (bone)</span> Most forward-facing of the three main regions making up the os coxa

In vertebrates, the pubis or pubic bone forms the lower and anterior part of each side of the hip bone. The pubis is the most forward-facing of the three bones that make up the hip bone. The left and right pubic bones are each made up of three sections; A superior ramus, inferior ramus, and a body.

<span class="mw-page-title-main">Conjoint tendon</span> Medial part of the posterior wall of the inguinal canal

The conjoint tendon is a sheath of connective tissue formed from the lower part of the common aponeurosis of the abdominal internal oblique muscle and the transversus abdominis muscle, joining the muscle to the pelvis. It forms the medial part of the posterior wall of the inguinal canal.

<span class="mw-page-title-main">Transversalis fascia</span> Aponeurosis between the transverse abdominal muscle and the extraperitoneal fat

The transversalis fascia is the fascial lining of the anterolateral abdominal wall situated between the inner surface of the transverse abdominal muscle, and the preperitoneal fascia. It is directly continuous with the iliac fascia, the internal spermatic fascia, and pelvic fascia.

<span class="mw-page-title-main">Pelvic cavity</span> Body cavity bounded by the pelvic bones

The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet. Its lower boundary is the pelvic floor.

<span class="mw-page-title-main">Arcuate line of rectus sheath</span> Line of demarcation in the human abdomen

The arcuate line of rectus sheath is a line of demarcation corresponding to the free inferior margin of the posterior layer of the rectus sheath inferior to which only the anterior layer of the rectus sheath is present and the rectus abdominis muscle is therefore in direct contact with the transversalis fascia. The arcuate line is concave inferior-wards.

<span class="mw-page-title-main">Linea semilunaris</span>

The linea semilunaris is a curved tendinous intersection found on either side of the rectus abdominis muscle.

<span class="mw-page-title-main">Rectus sheath</span> Laminas around abdominal muscles

The rectus sheath is a tough fibrous compartment formed by the aponeuroses of the transverse abdominal muscle, and the internal and external oblique muscles. It contains the rectus abdominis and pyramidalis muscles, as well as vessels and nerves.

<span class="mw-page-title-main">Tendinous intersection</span>

The rectus abdominis muscle is crossed by three fibrous bands called the tendinous intersections or tendinous inscriptions. One is usually situated at the level of the umbilicus, one at the extremity of the xiphoid process, and the third about midway between the two.

<span class="mw-page-title-main">Aponeurosis of the abdominal external oblique muscle</span> Membranous structure

The aponeurosis of the abdominal external oblique muscle is a thin but strong membranous structure, the fibers of which are directed downward and medially.

<span class="mw-page-title-main">Hip bone</span> Bone of the pelvis

The hip bone is a large flat bone, constricted in the center and expanded above and below. In some vertebrates it is composed of three parts: the ilium, ischium, and the pubis.

In surgery, a surgical incision is a cut made through the skin and soft tissue to facilitate an operation or procedure. Often, multiple incisions are possible for an operation. In general, a surgical incision is made as small and unobtrusive as possible to facilitate safe and timely operating conditions.

<span class="mw-page-title-main">Pelvis</span> Lower torso of the human body

The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.

References

  1. Shapiro, L. E.; Kim, J. H.; Lee, S. J.; Yoo, J. J.; Atala, A.; Ko, I. K. (2016-01-01), Lee, Sang Jin; Yoo, James J.; Atala, Anthony (eds.), "Chapter 16 - In Situ Volumetric Muscle Repair", In Situ Tissue Regeneration, Boston: Academic Press, pp. 295–312, ISBN   978-0-12-802225-2 , retrieved 2021-01-23
  2. "7 Vestigial Features of the Human Body". Encyclopedia Britannica. Retrieved 2017-11-09.