The ischiourethralis is considered the male counterpart of the female compressor urethrae, originating from the ischial rami and inserting on the membranous urethra and perineal membrane. It forms part of the striated urethral sphincter mechanism in the male, working alongside the rhabdosphincter to provide voluntary urethral closure below the prostate.
| Origin | Ischial rami |
|---|---|
| Insertion | Urethra and perineal membrane in males |
| Nerve Supply | Pudendal nerve (S2-S4) |
| Blood Supply | Internal pudendal artery |
| Actions | Male equivalent of the compressor urethrae; contributes to urethral closure and assists ejaculation |
|---|
The male external urethral sphincter complex, incorporating the rhabdosphincter and ischiourethralis, is the structure that must be preserved during radical prostatectomy to maintain post-operative continence. The sphincter lies at the prostatic apex, immediately below the prostate, and its intact neuromuscular function is the primary determinant of early continence recovery after prostatectomy. Nerve-sparing techniques, urethral length preservation, and precise anastomosis all contribute to continence outcomes by protecting this muscle.
Not directly palpable; assessed by urethral pressure profilometry and electromyographic recording from perineal electrode placement.
Transection or denervation of the ischiourethralis and rhabdosphincter at the prostatic apex during radical prostatectomy causes stress urinary incontinence, the severity of which is proportional to the degree of sphincter damage; managed by pelvic floor rehabilitation and, for persistent incontinence, by artificial urinary sphincter implantation.
