The transversus abdominis is a muscle of the anterior abdominal wall. It is the deepest of the flat abdominal wall muscles.
- Attachments: Originates from the inguinal ligament, costal cartilages 7-12, the iliac crest and thoracolumbar fascia. It inserts onto the conjoint tendon, xiphoid process, linea alba and the pubic crest.
- Actions: Compression of abdominal contents.
- Innervation: Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) and branches of the lumbar plexus.
- Blood supply: Lower posterior intercostal and subcostal arteries, superior and inferior epigastric arteries, superficial and deep circumflex arteries, posterior lumbar arteries.
By OpenStax [CC BY 4.0], via Wikimedia Commons
Fig 1 – The muscles of the anterolateral abdominal wall. Note how the flat muscles form aponeuroses medially.
