• The best site for a biopsy is midway between the tuber ischii and the origin of the Achilles tendon at about the level of the vulvar lips. Avoid tendinous insertions.
  • This site hides scarring under tail hairs and is easily treated if dehiscence occurs


  • Tranquilize the horse and wrap the tail
  • Lidocaine subcutaneously (7-ml) (not in muscle itself)
  • 1.5 inch vertical incision
  • Incise skin, subcutaneous tissue
  • Vertical incision through fascia (leave and suture fascia to prevent unsightly herniation of muscle)
  • Undermine the fascia on one side
  • Make two parallel vertical incisions, one-half inch apart
  • Hold muscle in one place with forceps then transect dorsally
  • Free biopsy one-half inch deep, then transect ventrally ¾ inch length
  • Close dead space with subcutaneous layers
  • Close skin with simple interrupted sutures or staples
  • Small scar may remain
  • Good subcutaneous closure is the most important technique to prevent wound dehiscence.