The anatomy of the external striated urethral sphincter

Sant, Grannum R.

doi:10.1038/sc.1972.25

Cited by 13 publications

(5 citation statements)

References 6 publications

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“…On the other hand, with the descent of the bladder neck during micturition, those circular fibers assume an oblique direction (2). The circular layer of smooth muscle is prominent in the regions of the prostate base and middle prostate, while the longitudinal layer is more evident in the distal portion (18). In our study we have observed a circular smooth muscle layer localized mainly at the prostate base, while the longitudinal muscle layer was more evident at the prostate apex.…”

Section: Commentssupporting

confidence: 52%

Disposition of the striated urethral sphincter and its relation to the prostate in human fetuses

et al. 2007

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Objective: To describe the arrangement of the muscle fibers of the striated urethral sphincter and its relationship with the prostate during the fetal period in humans. Materials and Methods:We analyzed 17 prostates from well preserved fresh human fetuses ranging in age from 10 to 31 weeks postconception (WPC). Transversal sections were obtained and stained with Gomori's trichrome and immunolabeled with anti alpha-actin antibody. Results: We found that the urethral striated sphincter (rabdosphincter) is located on the periphery of the smooth muscle and there was no merge between striated and smooth muscle fibers in any fetal period. In the prostate apex, the striated sphincter shows a circular arrangement and covers completely the urethra externally, whereas adjacent to verumontanum, it looks like a "horseshoe" and covers only the anterior and lateral surfaces of the urethra. Near the bladder neck, in fetuses younger than 20 WPC, we have found striated muscle fibers only at the anterior surface of the prostate, while in fetuses older than 20 WPC, the striated muscle covers the anterior and lateral surfaces of the prostate. Conclusions: The urethral sphincter muscle covers the anterior and lateral surfaces of the urethra in all fetuses older than 20 WPC, close to the bladder neck and at the distal prostate. In the region of the prostate apex, the urethral sphincter covers completely the urethra circularly. The knowledge of the normal anatomy of the urethral sphincter in fetuses could be important to understand its alterations in congenital anomalies involving the base of the bladder, the bladder neck and the proximal urethra.

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Section: Commentssupporting

confidence: 52%

Disposition of the striated urethral sphincter and its relation to the prostate in human fetuses

et al. 2007

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“…Contrary to most other authors who recommend a bilateral sphincterotomy, we support the contention of Madersbacher and Scott (1 976) that the anteromedian incision is sufficient and measurable. Oelrich (1964) and Sant (1972) have demonstrated that the circular striated muscle fibres around the membranous urethra and the longitudinally oriented fibres of the external sphincter are greatest anteriorly. Also, the neurovascular anatomy of the urogenital diaphragm clearly shows the bilateral course of the internal pudendal vessels and nerves at this level (Fig.…”

Section: Resultsmentioning

confidence: 99%

Experience with Anteromedian (12 O'Clock) External Urethral Sphincterotomy in 100 Male Subjects with Neuropathic Bladders

Whitmore¹,

Fam²,

Yalla³

1978

British Journal of Urology

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One hundred male spinal cord injured patients have now undergone anteromedian (12 o'clock) external urethral sphincterotomy alone or in combination with transurethral incision or resection of the bladder neck. The functional affect of this procedure has been documented by voiding cystourethrogram and urodynamic studies. The morbidity and clinical results including blood loss and loss of reflex erection are reviewed. The short-term clinical results suggest that this is the best of currently available techniques to lower external urethral sphincter resistance.

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“…In contrast to pudendal neurectomy, sphincterotomy interrupts the submucosal elastic ring of the membranous urethra described by Gil Vernet (1953), Pennington and Lund (1960), as well as the circular smooth muscle fibres of the membranous urethra (Gil Vernet, 1968). In view of the sacral segmental interplay which exists not only between the detrusor and the striated muscles of the pelvic floor, but also between the pelvic floor muscles themselves (Bors, Comarr and Moulton, 1950;Bors, Rossier and Sullivan, 1962;Rossier and Bors, 1964), sphincterotomy may have an effect on a possible spastic component of the striated muscles of the pelvic floor and/or on the striated muscular fibres running from the external sphincter up to the bladder neck and trigone (Beneventi and Marshall, 1956;Bors, Comarr and Reingold, 1954;Manley, 1966;Sant, 1972;Young and Wesson, 1921).…”

Section: Discussionmentioning

confidence: 99%

Urinary Manometry in Spinal Cord Injury: a Follow‐up Study. Value of Cysto‐Sphincterometrography as an Indication for Sphincterotomy

Rossier

Ott²

1974

British Journal of Urology

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Two factors may intervene in the failure of the neurogenic bladder to empty: lack of co-ordination and contraction of the detrusor, and increased urethral resistance. Increase in urethral resistance may be due to inadequate opening of the bladder neck, the external sphincter, or both.Dysfunction of the external sphincter may be due to one of the following: spasticity of the sphincter, part of a general spasticity of the muscles of the pelvic floor; hyperreflexia of the sphincter (Bors, 1964), which responds spasmodically to exteroceptive stimuli from the bladder, urethral, and anal mucosa (Rossier and Bors, 1964); bladder-sphincter into-ordination (loss of reflex inhibition of the sphincter at the moment of detrusor contraction); reflex contraction of the sphincter in response to increased intra-abdominal pressure (Newman, 1949) or the Credt manoeuvre (Rossier, 1964); or fibrotic stenosis of the sphincter, in cases of long standing spinal cord injury (Cukier et al., 1971). Pudendal nerve section, which denervates the pelvic floor muscles, except the levator anii, has given satisfactory results, but has certain disadvantages : the operation is technically difficult, and because of the frequent anatomical variations, is occasionally incomplete. Both bilateral and unilateral pudendal neurectomy may result in loss of erection. Section of the pudendal nerve naturally has no effect on a sclerosed sphincter.Since Cosbie Ross, Damanski and Gibbon (1957) proposed transurethral sphincterotomy, many others have published results of this procedure: therapeutic success seems to be of the order of 50% to 60% (Currie et al., 1970; Cosbie Ross, Gibbon and Damanski, 1963; Tsuji et al., 1965) and up to 87 % in the small series reported by Smythe (1966). Malament (1972), O'Flynn (1972) Retief (1970), Cosbie Ross (1968 and Tsuji et al. (1967), have reported 87 % to 100 o/n "satisfactory" results, without, however, defining their criteria of success. We felt, therefore, that a more precise analysis was in order, of the results obtained in 28 of our patients.

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The anatomy of the external striated urethral sphincter

Cited by 13 publications

References 6 publications

Disposition of the striated urethral sphincter and its relation to the prostate in human fetuses

Disposition of the striated urethral sphincter and its relation to the prostate in human fetuses

Experience with Anteromedian (12 O'Clock) External Urethral Sphincterotomy in 100 Male Subjects with Neuropathic Bladders

Urinary Manometry in Spinal Cord Injury: a Follow‐up Study. Value of Cysto‐Sphincterometrography as an Indication for Sphincterotomy

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