Transversus Abdominis Detail

musculus transversus abdominis detail

The deepest flat abdominal muscle with transverse fibres. It is the primary spinal stabiliser, contracting prior to limb movement in healthy individuals, and the first muscle targeted in lumbar rehabilitation.

Nerve: Ventral rami of T7-T12, iliohypogastric and ilioinguinal nerves… Blood Supply: Lower posterior intercostal arteries Region: Abdomen

Anatomical Data

Origin, Insertion & Supply

Origin	Thoracolumbar fascia, inner iliac crest, lateral inguinal ligament, inner surfaces of lower 6 costal cartilages
Insertion	Linea alba, pubic crest, pectineal line via conjoint tendon
Nerve Supply	Ventral rami of T7-T12, iliohypogastric and ilioinguinal nerves (L1)
Blood Supply	Lower posterior intercostal arteries

Biomechanics

Function & Actions

Actions	Increases intra-abdominal pressure — primary abdominal compression muscle; Thoracolumbar fascial tension for lumbar stabilisation; Main muscle of forced expiration and coughing

Clinical Relevance

Clinical Notes

Delayed transversus abdominis activation is a key feature of chronic LBP. Ultrasound biofeedback is used in physiotherapy for TA activation training. The TAP block targets the TA-internal oblique plane for post-operative abdominal analgesia.

Palpation

Not directly palpable individually — assessed by real-time ultrasound.

Pathology

Common Injuries & Conditions

Delayed TA Activation in Chronic Low Back Pain

Absent anticipatory TA contraction before limb movement, producing lumbar instability, targeted by motor control rehabilitation with ultrasound biofeedback.