How to Approach the Equine Pelvis Ultrasonographically?

Introduction
Injuries of the equine pelvis are frequent causes of hindlimb lameness. Ultrasonography (US) has already been proven to be useful for the diagnosis of pelvic fractures and hip joint pathology. However, performing an US examination of the equine pelvis requires a systematic approach and an adequate knowledge of the anatomy.
The aim of this presentation is:

• To describe and illustrate the anatomy and corresponding reference ultrasongraphic images.
• To propose a standardised US protocol for the examination of the equine pelvis.

Anatomy of the equine pelvis and reference images
A two-step tour is proposed as a practical protocol for a standardised US examination of the equine pelvis, based on a systematic approach. A dorsal approach (step I) is followed by a transrectal approach (step II). Both approaches are performed with the legs in weight bearing position.
The dorsal approach is performed with a convex or phased array 2-6 MHz transducer. The transrectal approach is performed with a linear rectal 5-7 MHz transducer. The dorsal area is properly prepared by clipping the hair, washing the skin with hot water and soap and by applying acoustic gel. Through every step, the movement of the transducer is described using typical anatomical landmarks. The entire pelvis is checked in all cases. Both bony and soft tissue structures are evaluated. The dorsal aproach is performed in two perpendicular planes. Transrectally only one approach (craniocaudal dirrection) is possible because of technical restrictions: the linear transducer can hardly be rotated inside the rectum. The use of a (micro)convex of phased array transducer may be a possible sollution to overcome this problem. [...]