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Transversus Abdominis Muscle Anatomy

Quick Overview View Flashcards
Origin
  • Costal cartilages of the seventh to twelfth ribs
  • Thoracolumbar fascia
  • Iliac crest
  • Inguinal ligament
Insertion
  • Linea alba
  • Pubic crest via conjoint tendon
  • Pectineal line of the pubis (pecten pubis) via conjoint tendon
Action
  • Provides structural support to adjacent abdominal structures
  • Compresses the abdomen and increases intra-abdominal pressure
Innervation
  • Intercostal nerves (T7-T11)
  • Subcostal nerve (T12)
  • Iliohypogastric nerve (L1)
  • Ilioinguinal nerve (L1)
Blood Supply
  • Lower posterior intercostal artery
  • Subcostal artery
  • Superficial and deep circumflex iliac arteries
  • Inferior and superior epigastric arteries
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Location & Overview

The transversus abdominis (sometimes abbreviated as ‘TVA’) is one of the five abdominal muscles. The other four are the external oblique, internal oblique, rectus abdominis, and the pyramidalis. The transversus abdominis muscle is the deepest among the anterolateral abdominal muscles, with its fibers running transversely and extending to the linea alba at the abdomen’s midline. It is primarily responsible for providing structural support to the adjacent abdominal structures. The transversus abdominis is also one of the three muscles that form the rectus sheath. Composed of the aponeuroses of the internal oblique, external oblique, and transversus abdominis muscles, the rectus sheath envelops the rectus abdominis and pyramidalis muscles. These two muscles reside within the rectus sheath, much like a sword housed within its scabbard (also known as a sheath), hence the sheath’s name.[1,2,3]

transversus abdominis anterior view
Here we can see the transversus abdominis from an anterior view.
transversus abdominis anterolateral view
Here we can see the transversus abdominis from an anterolateral view.
transversus abdominis lateral view
Here we can see the transversus abdominis from a lateral view.
transversus abdominis posterior view
Here we can see the transversus abdominis from a posterior view.
transversus abdominis muscle highlighted in red
This image distinctly highlights the transversus abdominis in red, amidst the other muscles of the body. Other abdominal muscles are selectively concealed to allow clear viewing of the transversus abdominis, considering its position as the deepest of all abdominal muscles.
transversus abdominis and internal oblique
This image again showcases the transversus abdominis, highlighted in red, but this time it is partially obscured by the internal oblique muscle. While other abdominal muscles are still hidden, this image shows the transversus abdominis relative to the internal oblique muscle.
transversus abdominis and aponeurosis
Here we can see the transversus abdominis muscle with the aponeurosis attached and connecting to the linea alba.

Origin & Insertion

The transversus abdominis muscle originates from the costal cartilages of the seventh to twelfth ribs, thoracolumbar fascia, iliac crest, and inguinal ligament. It then inserts into the linea alba. It also inserts onto the pubic crest and pectineal line of the pubis via the conjoint tendon. The pectineal line is also known as the pecten pubis. The conjoint tendon is formed by the lower sections of the aponeurosis of the transversus abdominis and the internal oblique.[2,3]

transversus abdominis origin ribs costal cartilages
Here we can see the first origin point of the transversus abdominis on the costal cartilages of the 7th to 10th ribs, highlighted in red.
transversus abdominis origin ribs 11 and 12
Next, we can see the final two rib origin points of the transversus abdominis on the posterior aspect of the skeleton, located on ribs 11 and 12 and highlighted in red.
transversus abdominis origin inguinal ligament
Moving inferiorly toward the pelvis, we can see another origin point at the inguinal ligament, highlighted in red.
transversus abdominis origin thoracolumbar fascia
Finally, the last point of origin is the thoracolumbar fascia, highlighted in green in the lower back region.
transversus abdominis insertion linea alba
The first point of insertion of the transversus abdominis muscle is the linea alba, which you can see highlighted in blue.
transversus abdominis insertion pubic crest and pectineal line
The last points of insertion are on the pubic crest and pectineal line (via conjoint tendon). The points of insertion are highlighted in blue.

Action & Function

The role of the transversus abdominis muscle is to compress the abdominal contents and provide structural support. This compression of the abdominal area can increase intra-abdominal pressure. Furthermore, this compression can draw the belly button inward and is involved in the ‘vacuum exercise’. The compression of the abdomen can also assist in forced expiration.[3,4]

Innervation

The transversus abdominis muscle is innervated by the intercostal nerves (T7-T11), subcostal nerves (T12), iliohypogastric nerves (L1), and ilioinguinal nerves (L1).[3,5]

intercostal nerves
Here we can see the intercostal nerves highlighted in red. These nerves innervate the transversus abdominis muscle.
subcostal nerve
Here we can see the subcostal nerve highlighted in red. The subcostal nerve innervates the transversus abdominis muscle.
iliohypogastric and ilioinguinal nerves
Here we can see the iliohypogastric and ilioinguinal nerves labeled. These nerves innervate the transversus abdominis muscle. The iliohypogastric and ilioinguinal nerves originate from the lumbar plexus, with both nerves arising primarily from the anterior rami of the first lumbar nerve (L1). Sometimes, the iliohypogastric nerve also receives contributions from the twelfth thoracic nerve (T12). The iliohypogastric nerve has two branches, the lateral cutaneous branch and the anterior cutaneous branch. The anterior branch in this picture is the one going around to the front of the body.

Blood Supply

The transversus abdominis muscle receives its blood supply from the lower posterior intercostal artery, subcostal artery, superficial and deep circumflex iliac arteries, and inferior and superior epigastric arteries.[3,5]

References

  1. [1] Varacallo M, Scharbach S, Al-Dhahir MA. Anatomy, Anterolateral Abdominal Wall Muscles. (Updated 2021 Jul 31). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470334/
  2. [2] Flynn W, Vickerton P. Anatomy, Abdomen and Pelvis, Abdominal Wall. (Updated 2021 Jul 31). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551649/
  3. [3] Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincott Williams & Wilkins; 2017.
  4. [4] Hides J, Wilson S, Stanton W, McMahon S, Keto H, McMahon K, Bryant M, Richardson C. An MRI investigation into the function of the transversus abdominis muscle during “drawing-in” of the abdominal wall. Spine (Phila Pa 1976). 2006 Mar 15;31(6):E175-8. doi: 10.1097/01.brs.0000202740.86338.df. PMID: 16540858.
  5. [5] Seeras K, Qasawa RN, Ju R, et al. Anatomy, Abdomen and Pelvis, Anterolateral Abdominal Wall. (Updated 2021 Jul 26). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525975/

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