Transversus Abdominis Muscle Anatomy

Overview
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 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
Subcostal artery
Superficial and deep circumflex iliac arteries
Inferior and superior epigastric arteries

Location & Overview

The transversus abdominis (sometimes abbreviated to ‘TVA’) is one if 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 of the anterolateral abdominal muscles. Its fibres run transversely and continue to the linea alba at the midline of the abdomen. The transversus abdominus is also one of the three muscles which form the rectus sheath. The rectus sheath is comprised of the internal oblique and external oblique muscles in addition to the transversus abdominis. The rectus sheath surrounds the rectus abdominis muscle and the pyramidalis muscle. They both sit within the rectus sheath like how a sword would be kept in a sheath (which is the reason for its name) [1] [2] [3].

transversus abdominis without its aponeurosis

Here we can see the transversus abdominis muscle in isolation without its aponeurosis.

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 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 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. [4] [5].

transversus abdominis origin ribs costal cartilages

Here we can see the first origin point of the transversus abdominis on the 7th to 10th rib’s costal cartilages 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 of the skeleton. Located on ribs 11 and 12 and highlighted in red.

transversus abdominis origin inguinal ligament

Moving inferiorly towards the pelvis we can see another origin point at the inguinal ligament highlighted in red.

transversus abdominis origin thoracolumbar fascia

Finally, our 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.

Actions

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 [6] [7].

Innervation

The transversus abdominis muscle is innervated by the intercostal nerves (T7-T11), subcostal nerves (T12) iliohypogastric nerves (L1) and ilioinguinal (L1) nerves [8] [9].

Blood Supply

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 [10] [11].

Want some flashcards to help you remember this information? Then click the link below:
Transversus Abdominis Flashcards

References

References
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/