Equine Rectal Prolapse and Rectal Tear – NAVLE Study Guide

Overview and Clinical Importance

Rectal prolapse and rectal tears are significant emergency conditions in equine practice that carry substantial morbidity and mortality. Rectal tears are particularly notable as a common source of veterinary malpractice litigation. Understanding the classification, immediate management, and prognosis of these conditions is essential for board examinations and clinical practice.

Part 1: Rectal Anatomy Review

Understanding rectal anatomy is essential for comprehending tear classification and surgical management.

Rectal Wall Layers (from innermost to outermost)

• Mucosa: Innermost layer; columnar epithelium; produces mucus for lubrication
• Submucosa: Connective tissue layer containing blood vessels and nerves; highly vascular
• Muscularis: Smooth muscle layer; inner circular and outer longitudinal fibers
• Serosa: Outermost layer (ventral and lateral); continuous with peritoneum
• Mesorectum: Attaches rectal wall dorsally; no serosa present dorsally; contains blood supply from caudal mesenteric artery

Part 2: Rectal Tears

Etiology and Risk Factors

Most rectal tears are iatrogenic, occurring during rectal palpation for breeding management or colic examination. Tears typically occur when the examiner palpates during a peristaltic wave, when the animal strains, or when the horse moves abruptly.