Rectus Abdominis Muscle
Origin: The fifth to seventh costal cartilages, and the inferomedial costal margin and posterior aspect of the xiphoid process of the sternum
Insertion: Pubic crest and the pubic symphysis
Actions: Flexion of the vertebral column
Innervation: Ventral Primary rami of (T7 to T12)
Blood Supply: Branches from the musculophrenic artery, the lower two or three posterior intercostal arteries, the subcostal artery and branches from the superficial epigastric artery.
Primary Actions of the Rectus Abdominis
1. Flexion of the thoracic spine when acting bilaterally
Agonists: None
Antagonists:
- Iliocostalis cervicis
- Iliocostalis thoracics
- Iliocostalis lumborum
- Longissimus cervicis
- Longissimus thoracics
- Spinalis thoracics
- Semispinalis cervicis
Note: Internal oblique, external oblique, and psoas major assist with flexion of the thoracic spine.
2. Flexion of the lumber spine when acting bilaterally
Agonists: None
Antagonists:
- Iliocostalis lumborum
- Longissimus thoracics
- Spinalis thoracics
Note: Internal oblique, external oblique, and psoas major assist with flexion of the thoracic spine.
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Secondary Actions of the Rectus Abdominis
1. Assists with forced expiration
Agonists:
- Serratus posterior inferior
- Transversus Abdominis
Antagonists:
- Serratus posterior superior
- Levatores costarum breve
- Levatores costarum longi
Note: The internal and external obliques also assist with forced expiration.
Muscle Pain Information: The rectus abdominis muscle contributes to pain in the abdominals, mid and low back, heartburn and testicular game.
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For beginning and intermediary anatomy . Muscle overlays on the human body. Excellent visuals!