Intercostales Intimi #anatomy #anatomyshorts #muscleoftheday #kinesiology

Added: 2026-06-02

[00:00:00]Everyone knows your ribs have muscles between them, and they're called the intercostals, and they help you to breathe. But, how many muscle layers are there? You have the external and internal, which is two, but there's actually a third layer that you may not know about. This is the internal costal intimii muscles, or also called the innermost intercostals. And the function is to assist with that forced expiration by helping depress the ribs. It also helps to stabilize the intercostal space during breathing, and it works alongside the external and internal intercostals.

[00:00:33]Now, the origin is going to be the superior border of the rib below, and then the insertion is going to be the inferior border of the rib above it.

[00:00:42]The innervation is the intercostal nerves, which is going to the anterior rami of the thoracic spinal nerves T1 to T11. This is Daily Anatomy, one muscle at a time.