|Origin||Costal cartilages of the seventh to twelfth ribs|
Pubic crest via conjoint tendon
Pectineal line of the pubis (pecten pubis) via conjoint tendon
|Action||Provides structural support to adjacent abdominal structures|
Compresses abdomen and increases intrabdominal pressure
|Nerve||Intercostal nerves (T7-T11)|
Subcostal nerve (T12)
Iliohypogastric nerve (L1)
Ilioinguinal nerve (L1)
|Artery||Lower posterior intercostal artery|
Superficial and deep circumflex iliac arteries
Inferior and superior epigastric arteries
Location & Overview
The transversus abdominis (sometimes abbreviated as ‘TVA’) is one of the five abdominal muscles. The other four include 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 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   .
Origin & Insertion
The transversus abdominis muscle originates from the costal cartilages of 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.  .
The role of the transversus abdominis muscle is to compress and provides structural support to adjacent abdominal structures. This compression of the abdominal area can increase intrabdominal pressure. Furthermore, this compression can draw the belly button inwards and is involved in the ‘vacuum exercise’. The compression of the abdomen can also assist in forced expiration  .
The transversus abdominis muscle is innervated by the intercostal nerves (T7-T11), subcostal nerves (T12) iliohypogastric nerves (L1) and ilioinguinal (L1) nerves  .
The transversus abdominis muscle gets its blood supply from the lower posterior intercostal artery, subcostal artery, superficial and deep circumflex iliac arteries, and inferior and superior epigastric arteries  .
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Transversus Abdominis Flashcards
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|↑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, ↑4||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, ↑5, ↑6, ↑8, ↑10||Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.|
|↑7||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.|
|↑9, ↑11||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/|