Editing Male genitals (section)

== '''Testes''' ==

* '''Embryology'''
** Develop in retroperitoneum      below the kidneys at week 7, initially with mesonephric duct (Wolffian      duct - see kidney embryology) attached
*** Paramesonephric (Mullerian)       duct forms appendix testis and prostatic utricle in men
** Gubernaculum forms between      testis and abdominal wall muscles
** Processus vaginalis forms in      the abdominal wall as an evagination
*** Fibres of the internal       oblique become cremasteric fibres
*** Fibres of EO become       external spermatic fascia
** 3 months gestation: testes      lie at internal ring
** 7-9 months gestation:      descent to scrotum, accompanied by shortening of gubernaculum, pushing      fascial structures ahead of it
**
** A peritoneal evagination      covers the testis, called processus vaginalis, which is usually      obliterated during first year of life (except around the testis where it      persists as a double layer (tunica vaginalis) which permits movement)
*** The connection to       peritoneal cavity is thus removed - if it persists, the boy will have a       hernia or congenital hydrocoele (see separate topic)
* '''Coverings''' (Some Days Eddie Can Irritate     People Very Thoroughly)
** Skin
** Dartos
** External spermatic fascia
** Cremasteric fascia (no      muscle at this level)
** Internal spermatic fascia
** Tunica vaginalis (anterior      and lateral - residual peritoneum)
** Tunica vasculosa (filmy coat      with blood vessels)
** Tunica albuginea (dense,      whitish-blue coat)
*** Thickest posteriorly, where       it penetrates into testis as mediastinum testis
* '''Arterial     supply'''
** Testicular arteries      originate high up in retroperitoneum from just below renal arteries      (predominant supply)
** Anastomosis with deferential      artery and cremasteric artery lower down in cord - it is therefore      uncommon for significant ischaemia of the testis to occur with division      of the testicular artery within the peritoneal cavity, although will      usually get some degree of atrophy
* '''Venous'''
** Testis and epididymis drain      into a plexus, which lies mainly anterior to vas. Ascend in the cord as      ~2 veins, then enter abdomen as one or two veins.
** Testicular veins drain into      renal vein on left and IVC on right
** Can get varicocoele,      especially on left - see separate topic
* '''Lymphatics'''
** Lymphatic drainage also      follows this route to para-aortic nodes