Trunk (thorax, abdomen, back)
Subcostales
Musculi subcostales
- Origin
- Inner surface of the lower ribs, near the costal angle
- Insertion
- Inner surface of the 2nd or 3rd rib below
- Function
- Assists expiration, together with the internal intercostal muscles
- Innervation
- Intercostal nerves
- Movement & chain
- Variably developed muscle bundles, functionally comparable to the deeper layer of the internal intercostal muscles.
- Palpation
- Lies on the inner surface of the lower ribs near their angles; cannot be palpated from the body surface.
- Clinical
- Depress the ribs during forced expiration; involuntarily contracted in pleurisy and painful lower rib injuries.
- Segmental innervation
- Intercostal nerves at that level (lower segments).
- In clinical practice
- Skin and pressure point inspection; maintain comfortable positioning and proper body mechanics during patient handling and daily care.
- Region in the model
- Trunk (thorax, abdomen, back)