Section 01 of 20
Introduction
Rectus abdominis is a long, flat, strap-like muscle on each side of the midline of the front of the abdomen. It runs from the pubic bone up to the lower rib cartilages and the xiphoid process. The two muscles are separated by a fibrous seam called the linea alba and are enclosed in a tough sleeve called the rectus sheath.
The muscle is crossed by three or four tendinous intersections, which divide it into segments. These give the well-known "six-pack" appearance in lean, well-trained people. The muscle works with the oblique and transversus muscles as part of the abdominal wall.
Section 02 of 20
Origin
| Origin | The pubic crest and the front of the pubic symphysis (the pubic bones at the lower midline). |
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An anatomical image for this section will be added when verified source media becomes available.
Section 03 of 20
Insertion
| Insertion | The xiphoid process of the sternum and the costal cartilages of ribs 5–7. |
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An anatomical image for this section will be added when verified source media becomes available.
Section 04 of 20
Actions
No dedicated action video is currently available. This movement is explained below and video will be added when verified source media becomes available.
| Primary action | Flexion of the trunk. |
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| Secondary actions | Posterior pelvic tilt, abdominal compression, and trunk stabilization. |
| Movement at the joint | Lumbar and lower thoracic spine (and the pelvis). |
| Heads / fiber groups | Single paired muscle divided by tendinous intersections. |
| Functional examples | Sit-ups and crunches; sitting up from lying; lifting; coughing and forced exhalation; bracing the trunk. |
Trunk flexion
Curls the trunk forward, as in a sit-up or crunch.
Posterior pelvic tilt
Tilts the pelvis backward, flattening the low back.
Abdominal compression
Compresses the abdomen for forced exhalation, coughing, and bearing down.
Trunk stability
Resists over-arching of the spine and helps brace the trunk during lifting.
Section 05 of 20
Nerve Innervation
| Nerve | Thoracoabdominal nerves (anterior rami of T7–T11) and the subcostal nerve (T12). |
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The epigastric vessels run inside the rectus sheath, so severe abdominal wall pain with a swelling after a cough or strain may reflect a hematoma, not muscle tightness. Pain over the abdomen can also come from the organs beneath it.
Section 06 of 20
Blood Supply
| Blood | The superior epigastric artery (from the internal thoracic) and the inferior epigastric artery (from the external iliac), which join within the muscle, with contributions from the deep circumflex iliac artery. |
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Section 07 of 20
Pictures and Visual Anatomy
An anatomical image for this section will be added when verified source media becomes available.
Section 08 of 20
Functional Movement
Rectus abdominis is used when sitting up from lying, bending forward, lifting, coughing, laughing, and bracing the trunk during exercise. It also limits over-arching of the low back when the arms or legs move.
Section 09 of 20
Synergists and Antagonists
Synergists: the external and internal obliques and transversus abdominis (compression and trunk flexion), with iliopsoas assisting flexion when the legs are fixed. Antagonists: the erector spinae and quadratus lumborum (trunk extension) and the hip flexors and back muscles for pelvic tilt.
Section 10 of 20
Palpation and Location
Client position and technique
Position the client supine with the knees bent and supported and the abdomen relaxed. Locate the pubic bone, the xiphoid process, and the linea alba at the midline, then feel the firm vertical band of muscle on each side. Ask for a small head lift or curl to feel the muscle and its tendinous intersections tighten.
Protect nearby structures
Obtain clear consent and use secure draping. The abdominal organs, aorta, and hernia sites lie beneath or beside the muscle. Use light, flat-hand pressure, never press on a lump, a pulsating area, or a painful spot, and avoid the area entirely in pregnancy and after recent abdominal surgery.
Section 11 of 20
Massage Therapy Relevance
Rectus abdominis is central to core strength and posture. Weakness or overuse may be associated with low back pain and poor posture, and abdominal wall tension is common after surgery or with stress, but abdominal pain can also come from many non-muscular causes.
Section 12 of 20
Dysfunction: What Happens When Movement Goes Wrong
Changes in how a muscle works can change how a joint moves. The points below describe possibilities that may be associated with altered muscle function; they are not diagnoses, and one muscle is never assumed to be the sole cause of a problem.
When the muscle is weak
Weakness may reduce trunk stability and may be associated with an increased low back arch and more load on the lumbar spine.
When it is tight or shortened
Tightness may be associated with a rounded posture, limited trunk extension, and a pulled-down feeling in the rib cage.
When it is overused
Repeated flexion and heavy lifting may overload the muscle and may contribute to abdominal wall pain.
When it is strained
A strain may cause abdominal wall pain with sitting up, coughing, or laughing; hernia and visceral causes can look similar.
When it is inhibited or others compensate
Reduced activation may be associated with poor core control and more work by the hip flexors and the low back muscles.
When it does not coordinate well with synergists and antagonists
Poor coordination with the obliques, transversus abdominis, and the diaphragm may alter trunk control and may be associated with low back or abdominal symptoms.
Section 13 of 20
Conditions, Pathologies, and Pain Relationships
Rectus abdominis strain
Sudden trunk flexion, heavy lifting, twisting, and forceful sit-ups may strain the muscle and cause pain that is worse when sitting up, coughing, or laughing.
Diastasis recti
Separation of the two muscle bellies along the linea alba, common in and after pregnancy, may be associated with a midline bulge and reduced core support.
Hernia
Umbilical, epigastric, and incisional hernias occur through weak points of the abdominal wall and need medical assessment; they are not a massage problem.
Differential considerations
Gastrointestinal conditions, gallbladder or pancreatic disease, urinary and gynecologic problems, and referred pain from the spine can all cause abdominal pain.
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Example Clinical Relationship
A client several months after pregnancy reports a soft bulge along the midline when sitting up and a weak, aching low back. The rectus abdominis and the linea alba may be involved, and the pattern may be associated with diastasis recti, but hernia and pelvic floor problems can look similar. Gentle, consented work on nearby muscles may support comfort, while a painful or non-reducible bulge needs referral.
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Massage and Treatment Approaches
For healthy, non-acute tissue with clear consent, position the client supine with the knees supported. Begin with light effleurage over the abdomen in the direction of the colon, then use very gentle kneading over the muscle, always working with the client's breathing and within comfort.
| Movement | Use slow diaphragmatic breathing and gentle pelvic tilts within comfort; do not force stretch into trunk extension. |
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| Regional work | Consider the obliques, the diaphragm, the hip flexors, and the lumbar erector spinae when assessment supports it. |
| Avoid | Deep pressure on the abdomen, over a hernia, scar, or diastasis, over any pulsation, or at any tender point. |
Section 16 of 20
Precautions and Contraindications
Precautions and contraindications
- Pregnancy (especially after the first trimester), recent abdominal surgery, or a known hernia or diastasis recti.
- Use caution with inflammatory bowel disease, abdominal pain of unknown cause, or after a full meal.
- Use caution with anticoagulant use or easy bruising; avoid deep pressure over a known aortic aneurysm.
- Always obtain explicit consent and use secure draping.
Section 17 of 20
Red Flags and When to Refer
Red flags and referral
- Severe or worsening abdominal pain, fever, vomiting, or a rigid abdomen.
- A new, painful, or non-reducible bulge in the abdominal wall or groin.
- A pulsating abdominal mass, blood in the stool or vomit, or black stool.
- Abdominal pain with chest pain, shortness of breath, or unexplained weight loss.
Section 18 of 20
Study Summary
Attachments
Origin: pubic crest and symphysis. Insertion: xiphoid process and costal cartilages of ribs 5–7.
Actions
Trunk flexion, posterior pelvic tilt, and abdominal compression.
Supply
T7–T12 anterior rami; superior and inferior epigastric arteries.
Section 19 of 20
Instructor Narration
Open narration transcript
Rectus abdominis is the paired vertical muscle at the front of the abdomen. Tendinous intersections divide it into segments.
It arises from the pubic crest and the pubic symphysis, and inserts on the xiphoid process and the costal cartilages of ribs 5 to 7.
It flexes the trunk, tilts the pelvis backward, and compresses the abdomen. The obliques and transversus abdominis help it, and the erector spinae oppose it.
The thoracoabdominal nerves from T7 to T11 and the subcostal nerve supply it, and the superior and inferior epigastric arteries provide its blood.
Palpate with the client supine and the knees bent, feel the vertical band beside the linea alba, and ask for a small head lift. Obtain consent, drape securely, and use light pressure only.
Strain, diastasis recti, hernia, and organ problems can overlap. Refer severe or worsening abdominal pain, a new painful bulge, a pulsating mass, or bleeding.
Remember: pubic crest and symphysis to the xiphoid and ribs 5 to 7; trunk flexion; T7 to T12.
Section 20 of 20