where do you think the serratus posterior inferior muscle would be located?

The serratus posterior inferior muscle is located in the lower part of the back, at the junction between the lower thoracic spine and the upper lumbar spine, running from those vertebrae out to the lower ribs.

Basic location

• This muscle stretches from the spinous processes of vertebrae T11 to about L2 (sometimes L3) to the inferior borders of ribs 9–12.

• On the surface map of the body, it sits in the mid‑ to low‑back region, just above the waistline and beneath the lower part of the rib cage.

Relation to other back muscles

• It lies deep to the latissimus dorsi (that big superficial “V” back muscle) and superficial to the erector spinae muscles and thoracolumbar fascia.

• Anatomically it is part of the “intermediate” layer of extrinsic back muscles, together with the serratus posterior superior higher up.

Shape and orientation

• The muscle is thin and broad, with a somewhat quadrilateral, serrated appearance where it attaches to ribs 9–12.

• Its fibers run superolaterally (upward and outward) from the lower spine toward the lower ribs, forming a subtle V‑shape in the lower back.

Functional context

• Functionally it assists in controlling the movement and position of the lower ribs, often described as helping with forced expiration and stabilizing the thoracolumbar junction during trunk movements.

• Because of this position, trigger points in this muscle can refer pain to the area between the lower ribs and the top of the hip, especially with twisting, bending, or overhead reaching.

Information gathered from public forums or data available on the internet and portrayed here.