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Pyramidalis Muscle; Origin, Nerve Supply, Function

Last updated: February 7, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 3 min read

Pyramidalis Muscle is a small triangular muscle, anterior to the rectus abdominis muscle, and contained in the rectus sheath. Pyramidalis muscles are small triangular-shaped muscles that lie between the anterior surface of the rectus abdominus and the posterior surface of the rectus sheath. The precise function of pyramidal muscles is unclear, but together the muscles are thought to tense the linea alba. The muscles are not always present, or are often unilateral, and vary greatly in size. Their wider inferior margins attach to the pubic symphyses and pubic crests, whereas their narrow superior margins attach to the linea alba.

Anatomy of Pyramidalis Muscle

  • Inferiorly, the pyramidal attaches to the pelvis in two places: the pubic symphysis and pubic crest, arising by tendinous fibers from the anterior part of the pubis and the anterior pubic ligament.
  • Superiorly, the fleshy portion of the pyramidalis passes upward, diminishing in size as it ascends, and ends by a pointed extremity which is inserted into the linea alba, midway between the umbilicus and pubis.
  • The pyramidalis muscle is present in 80% of the human population.[rx] This muscle may be absent on one or both sides; the lower end of the rectus then becomes proportionately increased in size.
  • Occasionally it is double on one side, and the muscles of the two sides are sometimes of unequal size. It may also extend higher than the usual level.

Pyramidalis Muscle; Origin, Nerve Supply, Function

Origin of Pyramidalis

  • Pyramidalis originates inferiorly by tendinous fibers from symphysis pubis and pubic crest.

Insertion of Pyramidalis

  • The fleshy portion of the muscle passes upward, diminishing in size as it ascends, and ends by a pointed extremity which is inserted into the linea alba, midway between the umbilicus and pubis.


Nerve supply of Pyramidalis Muscle

  • The pyramidalis is innervated by the ventral portion of T12. Pyramidalis is innervated by the terminal branches of the subcostal nerve (the anterior ramus of 12th thoracic nerve).

Blood supply

  • The inferior and superior epigastric arteries supply blood to this muscle.
  • The major portion of the blood supply of pyramidalis comes from the inferior epigastric artery. Some contribution is made by the deep circumflex iliac artery.

Function of Pyramidalis Muscle

  • The pyramidalis, when contracting, tenses the linea alba. Pyramidalis has a function of tensing the linea alba, however, the physiologic significance is doubtful.

References


Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.