Fig. 4. Cranial-caudal view of the left testis. The height of the testis is measured by placing the ultrasound probe ventrally with the beam directed dorsally. The length is measured by placing the probe caudally and directing the beam cranially. Notice the slight rotation of the testis to an upward position and the position of the cauda epididymis.
the clinician to angle the probe caudally so that the cross-section of the testis appears round rather than elliptical.
b. Width: The opposite testis should be pushed dorsally so that the testis of interest is al- lowed to occupy the scrotum without being compressed or distorted, which will alter (i.e., reduce) the width measure (Figs. 6 and 7). Avoid grabbing the neck of the scrotum to force the testis into the scrotum similar to the technique recommended for measuring the circumference of the bull testes. This can cause strong contractions of the cremas- ter muscle making the testis even harder to manipulate. The probe should be posi- tioned laterally on the scrotum, approxi- mately one-third of the distance from the cranial scrotum. This is usually the widest portion of the testis. The shape of the tes- tis should be approximately round and oblique sections should be avoided.
c. Length: Similar to the height measure the testis should hang in situ without being ma- nipulated. The US probe is placed on the most caudal aspect of the scrotum and di- rected cranially to include the greatest cau- dal-cranial distance. If the tail of the epididymis is included in the image (Fig. 4) it should not be included as part of the mea- sure (Figs. 4 and 8). To avoid “off center” images, the probe should be rotated verti- cally approximately 30° to visualize the greatest length.
304 2014 Vol. 60 AAEP PROCEEDINGS
Fig. 5. Lateral-medial view of the left testis. The width of the testis is measured by placing the ultrasound probe laterally at the widest point of the testis with the beam directed medially.
d. A minimum of two measurements/dimen- sion are taken and repeated until they are within 3 to 5 mm of each other.
9. After both testes have been measured, the cli- nician should do a thorough manual as well as
Fig. 6. Shown is the relationship between total testicular vol- ume (TTV) and daily sperm output (DSO, mean SD).
