Torsion of the testis or, strictly speaking, torsion of the spermatic cord has been a recognized surgical emergency since Delasiauve first described a case affecting an undescended testis in 1839 at Hôtel Dieu in Paris. The usual causes are high investment of the tunica vaginalis which allows the testicle to hang like a bell clapper inside the tunica and so predispose to rotation of the testicle and spermatic cord within the tunica.

Torsion may occur at any age but is most common around puberty. Various investigative techniques, including colour Doppler ultrasound, may be helpful in the diagnosis but if there is any doubt at all the testicles should be explored (Fig. 1) 1613. As the abnormality is bilateral it is imperative that the contralateral testicle is fixed at the same time. This subject is discussed in more detail in Chapter 36 203.