The infamous rectus abdominis muscle
There is definitely a fascination with the rectus abdominis muscle. Popularly people often call it “the six-pack muscle”, even though there are technically eight sections within this muscle. How this muscle is related to the idea of the core is still under debate. Research is inconclusive about whether or not strength in this muscle is related to back pain. If you’ve been curious about this muscle, read on. Because, in this post we look at the muscle along with its attachments and actions.
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What does the name rectus abdominis muscle mean?
Rectus is the Latin word for straight. Abdominis of course, refers to the abdomen. The rectus abdominis, specifically, is the straight abdominal muscle that we’re all familiar with.
Where does the rectus abdominis muscle attach?
It’s important to recognize that the origin and insertion of the rectus abdominis can change depending on the movement. Because of the long area it covers and the strength necessary, it’s compartmentalized into little packets. This is what we refer to as the six-pack. Technically there are four compartments on each side.
Origin
It originates on the pubic symphysis.
Insertion
It inserts onto the costal cartilages 5, 6, & 7 and the xiphoid process.
What actions does the rectus abdominis muscle do?
The rectus abdominis acts to flex the trunk and compress the abdominal contents. In the case of these abdominal muscles, stabilization is a key function.
Poses where this muscle contracts
In a posture such as navasana, all of the abdominals do an isometric contraction in order to help stabilize the trunk.
A posture such as parighasana requires lateral flexion of the spine. So, as we lean over our left leg, the left side contracts.
Poses where this muscle is lengthened
In a posture such as urdhva dhanurasana the abdominal muscles lengthen as the rib cage and the pelvis move apart.
In a posture such as parighasana, when we lean over our left leg, the right side of the body lengthens.