The appendix testis (or hydatid of Morgagni) is a vestigial remnant of the Müllerian duct, present on the upper pole of the testis and attached to the tunica vaginalis. It is present about 90% of the time.[citation needed]
| Appendix of testis | |
|---|---|
 The right testis, exposed by laying open the tunica vaginalis (appendix of testis is labeled at right) | |
| Details | |
| Precursor | Müllerian duct |
| Artery | Testicular artery |
| Vein | Testicular vein, pampiniform plexus |
| Identifiers | |
| Latin | appendix testis |
| TA98 | A09.3.02.010 |
| TA2 | 3612 |
| FMA | 19846 19846, 19846 |
| Anatomical terminology | |
Clinical significance
Torsion
The appendix of testis can, occasionally become twisted, causing acute one-sided testicular pain and may require surgical excision to achieve relief. One third of patients present with a palpable "blue dot" discoloration on the scrotum. This is nearly diagnostic of this condition. If clinical suspicion is high for the serious differential diagnosis of testicular torsion, a surgical exploration of the scrotum is warranted. Torsion of the appendix of testis occurs at ages 0–15 years, with a mean at 10 years, which is similar to that of testicular torsion.[1]