The corporo-glans ligament: description and functional significance of a ligament connecting the corpora cavernosa to the glans penis

The two corpora cavernosa (CC) end blindly under cover of the glans penis (GP). The method of attachment of the CC to the GP could not be traced in the literature. The current communication investigated the hypothesis of a ligamentous attachment existing between the two corporal ends and the GP. In all, 18 male cadaveric specimens were studied by direct dissection and histologically. Six were neonates and 12 adults (mean age 32.3+/-10.6 s.d. y). After examining and photographing the connection between the CC and GP, sagittal, parasagittal, and coronal sections of the connection were stained and studied microscopically. A triangular fibrous tissue band connected the distal blind ends of the two CC with the GP. The base of this band was attached to the tunica albuginea of the two CC, while the apex was continuous with the fibrous septa between the sinusoids of the cavernous tissue of the GP. Microscopically, the ligament consisted of collagen and elastic fibers; in some sections, the collagen fibers of the tunica albuginea were continuous with those of the band. A band of collagen and elastic fibers could be identified connecting the two CC to the GP; we term it the 'corporo-glans ligament'. This ligament presumably affords the connection with rigidity, flexibility, and tissue strength. We suggest that it firmly connects the GP to the CC during penile thrusting. Further studies are required to assess the possible role of this ligament in erectile dysfunction.     

Colosigmoid junction: a study of its functional activity with identification of a physiologic sphincter and involvement in reflex actions.

The colosigmoid junction (CSJ) marks the termination of the descending colon (DC) and the beginning of the sigmoid colon (SC); it is a fixed area in the retroperitoneum. At this site where two functionally different areas meet, we hypothesized the presence at the CSJ of a physiologic sphincter that regulates the passage of gut contents from the DC to the SC. This hypothesis was investigated for this communication. Eight subjects (mean age 36.6 +/- 4.7 SD years, 6 women) were studied during surgical repair of incisional hernia or laparotomy. The pressure responses of the CSJ to individual distension of the DC and SC were recorded. A balloon-ended tube was introduced per annum to lie in the DC or SC, and the pressure in the DC, CSJ, and SC was measured by saline-perfused catheters. To study whether the CSJ response to individual DC or SC distension was a direct or reflex action, the test was repeated in six of eight patients after separate anesthetization of the DC, CSJ, and SC. The CSJ had a higher pressure than that of the DC or SC; the high-pressure zone measured a mean of 2.1 +/- 0.9 cm. High-volume DC distension effected a significant DC pressure rise (p <.001) and a CSJ pressure decline (p <.05), which lasted a mean of 7.2 +/- 1.2 s. In contrast, the CSJ responded to big volume SC distension by significant pressure elevation (p <.001) which was also momentary. Small volume distension of the DC or SC effected no significant CSJ pressure response (p >.05). The CSJ pressure did not respond to distension of the anesthetized DC or SC. Likewise, the anesthetized CSJ did not react to DC or SC distension. When the test was repeated using saline instead of xylocaine, the CSJ pressure response was similar to that without saline injection. The CSJ is a high pressure zone with a measurable length. It reacts to DC or SC balloon distension by dilatation or narrowing, respectively. These findings presumably denote the existence of a "physiologic sphincter" at the CSJ, which appears to regulate the passage of colonic contents to the SC. We postulate that the CSJ pressure response to DC or SC distension is reflex and mediated through the "colosigmoid reflexes." The role of the colosigmoid sphincter and reflexes in colonic motility disorders remains to be investigated.     

Effect of straining on perineal muscles and their role in perineal support: identification of the straining-perineal reflex

OBJECTIVE: The functional activity of the superficial (STPM) and deep (DTPM) transverse perineal muscles is poorly addressed in the literature. We investigated the hypothesis that these muscles act to support the perineum during increased intraabdominal pressure (IAP). METHODS: 46 healthy volunteers (mean age 30.4 +/- 1.2 y, 20 nulliparous women) were studied. The IAP was recorded by a manometric catheter introduced into the rectum. The response of the perineal muscles to straining (sudden by coughing and slow by Valsalva's maneuver) was registered by a needle electrode inserted into the STPM and DTPM separately. The response was recorded again after individual anesthetization of the perineal muscles and rectum using Xylocaine. The test was repeated using saline instead of Xylocaine and was performed on both sides. RESULTS: Straining (sudden or slow sustained) effected increase of the rectal pressure and the motor unit action potentials of both perineal muscles. The higher rectal pressure was increased by straining, the higher the motor unit action potentials increased MUAPs. The latency showed a gradual decrease upon incremental rectal pressure elevation. The perineal muscles did not respond to straining after individual anesthetization of the rectum and perineal muscles, but did respond to saline administration. The response was similar from muscles on both sides. CONCLUSIONS: Perineal muscle contraction on straining postulates a reflex relationship that we call the "straining-perineal reflex." We suggest that this reflex, which results in perineal muscle contraction, supports the perineum against the increased IAP induced by straining and the tendency of the perineum to descend. The results warrant further study of the role of the straining-perineal reflex in the genesis of perineal functional disorders.     

Effect of perineal compression on vesical motor activity

OBJECTIVE: It has been reported that digital pressure on the perineum inhibits bladder contraction; however, the mechanism is not fully understood. We investigated the hypothesis that this mechanism may be reflex in nature. MATERIAL AND METHODS: A total of 21 healthy volunteers (13 males; mean age 42.3 +/- 11.8 years) were studied. A barostat system consisting of a balloon-ended catheter connected to a strain gauge and air-injection system was used to assess vesical tone. The catheter was introduced into the urinary bladder and the balloon was inflated with 150 ml of air. Digital pressure was exerted on the perineum and the vesical tone was simultaneously assessed by recording the balloon volume variations, expressed as the percentage change from the baseline volume. The test was repeated after separate anesthetization of the perineum and bladder with xylocaine and after using normal saline instead of xylocaine. RESULTS: Digital pressure on the perineum effected a significant decrease in vesical tone, which ranged from 42% to 84% (mean 67.5% +/- 12.5%) of the baseline value. The mean latency was 18.6 +/- 2.6 ms. There was no significant difference between men and women in terms of vesical tone response to perineal pressure. Digital perineal pressure applied 20 min after individual anesthetization of the perineum and bladder produced no significant changes in vesical tone. The response returned after the anesthetic effect had waned. The vesical tone response following saline administration was similar to that before administration. CONCLUSIONS: Vesical tone decrease in response to digital pressure on the perineum suggests a reflex relationship which was absent on individual anesthetization of the two possible arms of the reflex arc: the perineal skin and urinary bladder. We call this relationship the "perineovesical reflex". This reflex may have the potential to be used as an investigative tool in the diagnosis of vesical motor disorders.     

Transverse folds of rectum: anatomic study and clinical implications

There are controversies with respect to the location, number, and function of the transverse folds of the rectum (TFR), probably because their physioanatomic aspects have not been fully investigated. The purpose of this communication was to study the anatomic and histologic structure of the TFR aiming at elucidation of their function in the light of their structure. The TFR were studied morphologically and histologically in 18 cadavers (10 male, 8 female) with a mean age of 36.6 +/- 10.4 (SD) years. Barium enema studies were also performed in 36 volunteers (20 male, 16 female; mean age 38.6 +/- 15.2 [SD] years). The number of TFR varied, the commonest findings being two and three. In a few cases, TFR were absent or exceeded three in number. Most folds extended beyond the middle of the rectal lumen; a few were narrow. They were thick at the base and tapered gradually. Microscopically, the TFR contained circular and longitudinal smooth muscle fibers; they were rarely purely mucosal. TFR varied in location dividing the rectum into compartments; an alternating side-to-side arrangement allows for a wavy movement of the stool in the rectum. The wavy movement, compartmental division, and the shelving action of the TFR are suggested to retard stool movement in the rectum so as to allow time for fecal sampling (stool or gas) and for impulses to reach the conscious level to decide whether or not to defecate. Further studies are needed to investigate the role of the TFR in clinical practice.     

Effect of pelvic floor muscle contraction on vesical and rectal function with identification of puborectalis-rectovesical inhibitory reflex and levator-rectovesical excitatory reflex

 The effects of pelvic floor muscle contraction on rectal and vesical function were studied in 19 healthy volunteers with the aim of shedding light on some of the hitherto vague aspects of the mechanisms involved in micturition and defecation and their disorders. Rectal and vesical pressures were recorded during puborectalis (PR) and levator ani (LA) muscle stimulation with the rectum or urinary bladder empty and full. Muscle stimulation was effected by needle EMG electrode. The pressure responses to stimulation of the PR and LA muscles were also recorded with these muscles and the rectum and urinary bladder individually anesthetized in 12 of the 19 subjects. The test was repeated using saline instead of xylocaine. PR and LA muscle stimulation produced no pressure response in the empty rectum or bladder. Upon rectal balloon distension with a mean of 156.6 ± 34.2 ml of carbon dioxide the mean rectal pressure was 64.6 ± 18.7 cm H₂O, the subject felt the urge to evacuate and the balloon was expelled to the exterior. On PR muscle stimulation at rectal distension with the above volume, the subject did not feel the urge to evacuate, the rectal pressure was 8.2 ± 1.6 cm H₂O and the balloon was not expelled. Upon LA stimulation at the same volume, the urge persisted, the rectal pressure was higher and the balloon was expelled. Vesical filling with a mean of 378.2 ± 23.6 ml of saline initiated the urge to urinate and elevated the vesical pressure. PR muscle stimulation at this volume aborted the urge and pressure elevation, while LA stimulation caused more elevation of the vesical pressure and spontaneous micturition. Bladder filling with a mean of 423.6 ± 38.2 ml produced high vesical pressure and spontaneous urination, both of which were prevented by PR muscle stimulation but not by LA muscle stimulation. Stimulation of the PR and LA muscles during individual anesthetization of the rectum, bladder or PR and LA muscles resulted in no significant rectal or vesical pressure changes. Repetition of the test using saline instead of xylocaine resulted in rectal and vesical pressure responses similar to those without the use of saline. In conclusion, the decline in rectal and vesical responses upon PR muscle contraction indicates a reflex relationship which we term `puborectalis rectovesical inhibitory reflex'. This reflex is suggested to abort the urge to defecate or urinate. In contrast, LA muscle contraction produced rectal and vesical pressure elevation which is suggested to be mediated through the `levator rectovesical excitatory reflex'. `This reflex is probably evoked to promote rectal and vesical evacuation.     

Occupational stress in naval personnel

Introduction: Increased stress levels have been reported and it has been implicated for mental illness amongst service personnel. However no study has been reported among Indian naval sailors.     

Role of the Enteric Nervous Plexus in Rectal Motile Activity: An Experimental Study

The gut innervation is formed by an intrinsic and an extrinsic component. The former is responsible for the intestinal contractions that occur in the total absence of extrinsic innervation. We hypothesize that the intrinsic plexuses do not produce local contraction, but mediate reflex actions of the gut musculature. This hypothesis was investigated in the rectum of the experimental animal. In 16 anesthetized mongrel dogs, the rectum was exposed, and 3 monopolar silver-silver chloride electrodes were sutured serially to the rectal wall and connected to a rectilinear pen recorder. The rectal electric activity was recorded at rest and on rectal inflation while the anal pressure was synchronously registered. The tests were repeated after separate drug administration using phentolamine, propranolol (adrenoceptor blocking agents), atropine (cholinergic blocking agent), drotaverine (direct smooth muscle relaxant), and nitroglycerine. (NO donor, inhibitory noncholinergic, nonadrenergic mediator). Slow waves or pacesetter potentials (PPs) and action potentials (APs) were recorded from the three electrodes. Rectal balloon distension caused an increase of frequency, amplitude, and conduction velocity of these waves, as well as a decrease of anal pressure. Repetition of the test after administration of phentolamine, propranotol, and atropine effected no change in rectal electromyelographic (EMG) activity or anal pressure, while drotaverine and nitroglycerine administration aborted both the electric activity and the anal pressure response. We conclude that the rectal electric activity, presumably responsible for rectal motility, was not aborted by enteric nervous plexus block but by direct muscle relaxant. This suggests that the enteric plexus has no direct action on the rectal motile activity but mediates the rectal reflex actions. This concept might explain some of the hitherto unknown mechanisms of rectal dyssynergia syndromes.