Transverse Abdominal Muscle

Transverse Abdominal Muscle is the innermost of the three flat abdominal muscles. It is positioned immediately deep to the internal oblique muscle. The three flat muscles are the external oblique, internal oblique, and transversus abdominis.

Transverse Abdominal Muscle also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle.

The fibers of the transversus abdominis run more or less transversally, except for the inferior ones, which run parallel to those of the internal oblique. This transverse, circumferential orientation is ideal for compressing the abdominal contents, increasing intra-abdominal pressure. The fibers of the transversus abdominis muscle also end in an aponeurosis, which contributes to the formation of the rectus sheath.

See Also: Internal Oblique Muscle

Transverse Abdominal Muscle Anatomy

Origin

The transverse abdominis has multiple origins:

• Internal surfaces of costal cartilages of ribs 7-12,
• Thoracolumbar fascia,
• Anterior two thirds of iliac crest,
• Iliopectineal arch

Insertion

• Linea alba,
• Aponeurosis of internal abdominal oblique muscle;
• Pubic crest,
• Pectinal line of pubis.

See Also: Abdominal Rectus Muscle

The lower fibers of which curve inferomedially together with those of the internal oblique muscle insert into the crest of the pubis and pectineal line, forming the inguinal conjoint tendon also called the aponeurotic falx.

Innervation

• Intercostal nerves (T7-T11),
• Subcostal nerve (T12),
• Iliohypogastric nerve (L1),
• Ilioinguinal nerve (L1)

Blood Supply

• Lower posterior intercostal and subcostal arteries,
• Superior and inferior epigastric arteries,
• Superficial and deep circumflex arteries,
• Posterior lumbar arteries

Action

• Bilateral contraction: Compresses abdominal viscera, expiration
• Unilateral contraction: Trunk rotation (ipsilateral)

References & More

1. Clinically Oriented Anatomy – 8th Edition
2. De Troyer A, Estenne M, Ninane V, Van Gansbeke D, Gorini M. Transversus abdominis muscle function in humans. J Appl Physiol (1985). 1990 Mar;68(3):1010-6. doi: 10.1152/jappl.1990.68.3.1010. PMID: 2140344. Pubmed
3. Selkow NM, Eck MR, Rivas S. TRANSVERSUS ABDOMINIS ACTIVATION AND TIMING IMPROVES FOLLOWING CORE STABILITY TRAINING: A RANDOMIZED TRIAL. Int J Sports Phys Ther. 2017 Dec;12(7):1048-1056. doi: 10.26603/ijspt20171048. PMID: 29234556; PMCID: PMC5717480. Pubmed