| Latin | Musculus transversus abdominis |
|---|---|
| Origin |
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| Insertion |
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| Action |
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| Nerve | Thoracoabdominal nerves, subcostal nerve, iliohypogastric nerve and ilioinguinal nerve (T7–L1) |
| Name | Latin transversus, 'lying across' — its fibres run horizontally around the waist like a belt. |
Palpation
- Direct palpation of transversus abdominis is not practical at Cert IV level, because it lies under both obliques and you cannot feel it separately.
- Instead, work the surface area over it; client supine with a bolster under the knees.
- Place a flat hand on the lower abdomen, about 2 cm inside and below the ASIS, where the overlying muscle is thinnest.
- Ask the client to gently draw the navel in towards the spine without holding the breath; you may feel a slight tensing under your fingers, which is mainly transversus abdominis.
Transversus abdominis is the innermost of the three flat abdominal muscles, under the Internal oblique and External oblique. Its fibres run horizontally, so when it contracts it narrows the waist like a corset. It is often talked about in Pilates and rehabilitation as a “core” muscle that works with Multifidus and the Diaphragm to support the lower back. In breathing it opposes the diaphragm: the diaphragm pushes the abdominal contents down on the in-breath, and transversus draws the abdominal wall in for a forced out-breath.
In a massage you treat it indirectly, through the layers above it, using gentle pressure. Slow, broad effleurage over the whole abdomen lets the client relax the abdominal wall. Work clockwise (as you look down at the abdomen), which follows the colon up the client’s right side, across under the ribs and down the left side.
Sources differ slightly on its nerve supply. The Wikipedia infobox lists the thoracoabdominal nerves from T6, while its text (and most textbooks) give T7–T11, plus the subcostal (T12), iliohypogastric and ilioinguinal (L1) nerves. This note uses T7–L1.