Musculus rectus abdominis
The rectus abdominis originates from the ventral surfaces of costal cartilages 4-9 and the sternum and inserts on the prepubic tendon and cranial pubis. Its actions include flexing the trunk, supporting the abdominal organs, assisting expiration, and contributing to abdominal press during defecation, urination, and parturition. It also helps tilt the pelvis during collection. It contains approximately ten transverse tendinous inscriptions. An accessory ligament from the prepubic tendon attaches to the head of the femur and helps stabilize the hip joint. It is innervated by ventral branches of thoracic and lumbar spinal nerves.
Origin: Ventral surfaces of costal cartilages 4-9 and the sternum
Insertion: Prepubic tendon and cranial pubis
Action: Flexes the trunk; supports abdominal organs; assists expiration; tilts pelvis during collection
Innervation: Ventral branches of thoracic and lumbar spinal nerves
Strain or trauma can contribute to abdominal wall weakness or hernias. Relevant in evaluations of abdominal pain, colic recovery, and core stability. The tendinous inscriptions are normal anatomical features and should not be mistaken for pathology.
## Overview Prepubic tendon rupture is a catastrophic tearing of the tendon that supports the abdominal wall, most often in late-gestation mares carrying heavy foals, twins, or with hydrops. The abdo
## Overview Core weakness and back pain frequently coexist and reinforce each other. Pain inhibits muscle activation, leading to atrophy; weak muscles then fail to stabilize the spine, increasing pai
Visible asymmetry or swelling of the abdominal wall, or persistent difficulty with collection or core engagement, should be evaluated.
## Overview Prepubic tendon rupture is a catastrophic tearing of the tendon that supports the abdominal wall, most often in late-gestation mares carrying heavy foals, twins, or with hydrops. The abdomen drops dramatically, severe ventral edema develops from the udder forward, and the mare is reluctant to move and in pain. Complete rupture cannot be surgically repaired and often requires euthanasia. Partial tears are managed supportively. ## Causes Excessive abdominal weight in late pregnancy, especially in older multiparous or draft mares. ## Diagnosis Clinical appearance of a dropped abdomen and rapidly progressive edema, plus ultrasound. ## Treatment Supportive care with belly bandages and pain relief for partial tears. Induction or cesarean section if near term. Complete rupture has a poor prognosis. ## Recovery and Prognosis Poor for complete rupture. Guarded for partial tears with intensive support. ## Prevention Monitoring of high-risk mares. No proven prevention. Signs include: severe ventral edema from the udder forward; dramatically dropped abdomen; reluctance to move; pain; inability to foal normally
## Overview Core weakness and back pain frequently coexist and reinforce each other. Pain inhibits muscle activation, leading to atrophy; weak muscles then fail to stabilize the spine, increasing pain. Breaking the cycle requires both pain management and targeted strengthening. ## Causes Primary back pathology, limb lameness, or training imbalances. ## Diagnosis Combined lameness/back evaluation and muscle assessment. ## Treatment Analgesia or joint therapy as needed plus progressive core rehabilitation. ## Recovery and Prognosis Favorable when both components are addressed. ## Prevention Early intervention for back discomfort and inclusion of core exercises. Signs include: back pain or sensitivity; poor muscling; hollow posture; reduced performance; reluctance to engage the hindquarters
Strain or trauma can contribute to abdominal wall weakness or hernias. Relevant in evaluations of abdominal pain, colic recovery, and core stability. The tendinous inscriptions are normal anatomical features and should not be mistaken for pathology.
Visible asymmetry or swelling of the abdominal wall, or persistent difficulty with collection or core engagement, should be evaluated.
See the Rectus Abdominis on our interactive 3D horse model. Open 3D Model