[The pelvic diaphragm, clitoris and vaginal vestibule of the bitch. I. The pelvic diaphragm. 2. The clitoris and vaginal vestibule].
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PURPOSE: We present a comprehensive account of clitoral anatomy, including its component structures, neurovascular supply, relationship to adjacent structures (the urethra, vagina and vestibular glands, and connective tissue supports), histology and immunohistochemistry. We related recent anatomical findings to the historical literature to determine when data on accurate anatomy became available. MATERIALS AND METHODS: An extensive review of the current and historical literature was done. The studies reviewed included dissection and microdissection, magnetic resonance imaging (MRI), 3-dimensional sectional anatomy reconstruction, histology and immunohistochemical studies. RESULTS: The clitoris is a multiplanar structure with a broad attachment to the pubic arch and via extensive supporting tissue to the mons pubis and labia. Centrally it is attached to the urethra and vagina. Its components include the erectile bodies (paired bulbs and paired corpora, which are continuous with the crura) and the glans clitoris. The glans is a midline, densely neural, non-erectile structure that is the only external manifestation of the clitoris. All other components are composed of erectile tissue with the composition of the bulbar erectile tissue differing from that of the corpora. The clitoral and perineal neurovascular bundles are large, paired terminations of the pudendal neurovascular bundles. The clitoral neurovascular bundles ascend along the ischiopubic rami to meet each other and pass along the superior surface of the clitoral body supplying the clitoris. The neural trunks pass largely intact into the glans. These nerves are at least 2 mm in diameter even in infancy. The cavernous or autonomic neural anatomy is microscopic and difficult to define consistently. MRI complements dissection studies and clarifies the anatomy. Clitoral pharmacology and histology appears to parallel those of penile tissue, although the clinical impact is vastly different. CONCLUSIONS: Typical textbook descriptions of the clitoris lack detail and include inaccuracies. It is impossible to convey clitoral anatomy in a single diagram showing only 1 plane, as is typically provided in textbooks, which reveal it as a flat structure. MRI provides a multiplanar representation of clitoral anatomy in the live state, which is a major advantage, and complements dissection materials. The work of Kobelt in the early 19th century provides a most comprehensive and accurate description of clitoral anatomy, and modern study provides objective images and few novel findings. The bulbs appear to be part of the clitoris. They are spongy in character and in continuity with the other parts of the clitoris. The distal urethra and vagina are intimately related structures, although they are not erectile in character. They form a tissue cluster with the clitoris. This cluster appears to be the locus of female sexual function and orgasm.
PURPOSE: Endogenous or exogenous testosterone exposure to the fetus during gestation may result in masculinization of the external genitalia. Surgical correction requires a clear understanding of normal female anatomy. We report observations from our anatomical dissections on which we base our approach to reduction clitoroplasty. MATERIALS AND METHODS: A total of 14 normal human fetal clitoral specimens at 8 to 24 weeks of gestation were serially sectioned after formalin fixation. Every tenth section was stained with Masson's trichrome, smooth muscle alpha-actin and the neuronal markers PGP 9.5 or S-100. Computer reconstruction using imaging software permitted 3-dimensional analysis of the nerves, corporeal bodies and glans clitoris. These specimens were compared with 2 obtained postnatally at feminizing genitoplasty. RESULTS: The normal fetal clitoris consists of 2 corporeal bodies with a midline septum. The ultrastructure of the female corporeal bodies is similar to that of the male counterpart. The glans clitoris forms a cap on top of the distal end of the narrowed corporeal bodies. There is a midline septum starting on the ventral aspect and extending approximately halfway into the glans. Large bundles of nerves course along the corporeal bodies with the highest density on the dorsal aspect or top. No nerves were noted at the 12 o'clock position, although nerves extend completely around the tunica in a fashion similar to that of the fetal penis. Glans innervation is provided by multiple perforating branches entering at the dorsal junction of the corporeal body and glans. The lowest density of nerves in the glans is on the ventral aspect in juxtaposition to the glans septum. In surgical specimens obtained from patients with congenital adrenal hyperplasia nerves were adjacent to the excised tunica of the corporeal bodies, especially on the lateral aspect. CONCLUSIONS: A clear understanding of the anatomy of the human clitoris is important for surgical reconstruction. As in the human penis, nerves in the clitoris form an extensive network around the tunica of the corporeal body with a nerve-free zone at the midline 12 o'clock position. Care should be taken to preserve all nerves. Reduction of the glans clitoris should not violate the extensive innervation that predominates on the dorsal aspect of the glans. The normal clitoris has corporeal bodies that are smaller but analogous to those of the penis. One may consider their function when extensive resection is considered.
We evaluated possible morphological alteration in clitoris and vagina from spontaneous hypertensive rats (SHR) and normotensive WKY rats. Clitoris and vagina were processed by Masson's trichrome, anti-alpha-smooth-muscle actin, anticollagen type I (COL I) and type III (COL III), and anti-TGFbeta(1). SHR presented higher amount of clitoral cavernous smooth muscle (CSM), vascular smooth muscle; TGFbeta(1) in clitoral vessel wall; higher wall/lumen ratio in both vaginal and clitoral vessels; and remarkable interstitial fibrosis, expressed by a higher amount in interstitial COL I and III in both clitoris and vagina, compared to WKY rats. Nerve fibers from clitoral and vaginal tissue in SHR showed important fibrosis at perineurium. SHR showed positive correlation between systolic blood pressure (SBP) and clitoral CSM; SBP and fibrosis in clitoris; and SBP and COL I and III in clitoris, respectively. Similar findings were observed between SBP and COL I and III in vagina. In conclusion, SHR present morphologic changes in clitoral vessels as well as in clitoral cavernous space, which have a high positive correlation with the high blood pressure level. Moreover, the increase in extracellular matrix affects not only the clitoral and vaginal interstitium but also the nerve structures from both clitoris and vagina.
PURPOSE: Our aim was to identify and localize nitric oxide synthase isoforms in the human clitoris in support of the hypothesis that nitric oxide mediates erectile function in this organ. MATERIALS AND METHODS: Nitric oxide synthase immunohistochemistry studies specific for neuronal, inducible and endothelial isoforms of the enzyme were performed on human clitoral tissue obtained from 4 patients (3 with female pseudohermaphroditism and 1 with true hermaphroditism) at feminizing genitoplasty and from 1 phenotypically normal woman at autopsy. RESULTS: Neuronal nitric oxide synthase immunoreactivity was detected in nerve bundles and fibers coursing within the glans clitoris and corpora cavernosa of the clitoris, predominating in the latter tissue. Specific inducible nitric oxide synthase immunoreactivity was not identified. Endothelial nitric oxide synthase immunoreactivity was detected in vascular and sinusoidal endothelium of these tissues with a predominance in the glans clitoris. CONCLUSIONS: The presence and anatomical localizations of nitric oxide synthase isoforms in the human clitoris indicate that nitric oxide is generated in this organ. These data suggest that nitric oxide may be involved in the erectile physiology of the clitoris as a modulator of clitoral smooth muscle activity. Functional studies are required to support this hypothesis.
We aimed to define the gross anatomy of the supporting structures of the clitoris. We performed a dissection of the perineum of a series of 22 female and four male cadavers. Specific dissection of the clitoral and penile suspensory ligament complex was performed in four female and two male cadavers. Serial written observations and photography were used to document the findings. Our findings were then compared with the anatomical description of these structures in the historical and current anatomical literature. The suspensory ligament of clitoris consistently displayed two components: a superficial fibro-fatty structure extending from a broad base within the mons pubis to converge on the body of the clitoris and extending into the labia majora: in addition there is a deep component with a narrow origin on the symphysis pubis extending to the body and the bulbs of the clitoris. The supporting structures of the clitoris are more substantial and complex than previously described. Their shape, extent, and orientation are different from analogous structures of the penis, the suspensory ligament of which was found as described in the literature.
In the present study, the distributions of neuropeptides in the normal human clitoris and in a clitoris from an adrenogenital syndrome (AGS) was demonstrated by immunohistochemistry (IHC). Immunohistochemical screening detected a complex network of nerve fibers containing vasoactive intestinal polypeptide (VIP), peptide histidine methionine (PHM), neuropeptide tyrosine (neuropeptide Y), C-flanking peptide of neuropeptide Y (CPON), calcitonin gene-related peptide (CGRP) and substance P immunoreactivities. Special attention was given to the VIP-related peptide helospectin, that has been detected in neuronal elements in the clitoris. No visible differences between the localization and distribution of peptidergic nerve fibers of normal and hypertrophic clitoris from AGS have been observed. Co-localization studies showed the co-existence of VIP, PHM and partly helospectin and neuropeptide Y with CPON within nerve fibers in the cavernous tissue and substance P and CGRP co-expression in nerve fibers especially underneath and within the glans clitoris.
BACKGROUND: Isolated absence of the clitoris is a rare entity with medical and sexual implications for patients. CASE: As part of an examination for alleged sexual abuse, a 13-year-old female was noted to have an apparent absence of the clitoris. Congenital absence of the clitoris was felt to be the most likely diagnosis. The differential diagnosis and medical implications are reviewed. CONCLUSION: Isolated absence of the clitoris is a rare entity. When faced with the finding, a detailed medical evaluation should be performed to clarify the nature of the finding, rule out other potential anomalies and help in the counseling of the patient.
We report a case of painful priapism of the clitoris lasting 24 hours, which was believed to be pathophysiologically associated with the administration of trazodone hydrochloride. Drug-induced unusual erectile activity in the clitoris has been described previously. However, to our knowledge this is the first reported case of drug-induced priapism of the clitoris. Management involved discontinuation of the offending agents and administration of adrenergic agonists to induce clitoral smooth muscle contraction. Clitoral function, proposed to be the ability to engorge and enable extrusion of the glans clitoris, was not obviously adversely affected by the priapistic episode.
BACKGROUND: Nevus lipomatosus cutaneous superficialis (NLCS) is a relatively rare condition. Although NLCS can affect any region of the entire body, no case of NLCS in the clitoris has ever been reported. OBJECTIVE: To report a case of NLCS of the clitoris that presented manifestations that were similar to female pseudohermaphrodism. METHODS: This is a case report and review of the literature. RESULTS: A congenital, soft, skin-colored lesion of the clitoris in a 1-year-old girl resembled female pseudohermaphrodism. It was resected, and the histologic diagnosis was NLCS. Postoperatively, there was no subsequent change in the lesion during the 3-year follow-up period. CONCLUSION: We reported a case of congenital solitary NLCS of the clitoris. Although NLCS might be a relatively rare condition, we should consider it in the differential diagnosis of female pseudohermaphrodism.
PURPOSE: Female sexual dysfunction is a common disorder but there are few objective measures of female genital function. We present a novel technique to record electrical activity of the female genital erectile tissue. MATERIALS AND METHOD: We placed concentric needle electrodes in the right clitoral crus and the bulb of 22 healthy women. Following spontaneous activity recording we stimulated the median nerve to activate the sympathetic nervous system. We simultaneously measured evoked activity in the clitoris and bulb, and hand sympathetic skin responses (SSRs). RESULTS: Spontaneous electrical activity of the clitoris and bulb was present in 13 subjects. A total of 21 subjects had evoked activity in the bulb, while 18 had evoked activity in the clitoris. All subjects had hand SSRs. Evoked genital response latencies were similar to hand SSR latency (p > 0.05). Evoked electrical activity was recordable in the clitoris and bulb but it was more easily performed in the bulb. CONCLUSIONS: Evoked electrical activity is more consistently obtained than spontaneous activity. These tests represent possible objective measures of female genital autonomic innervation, which may have relevance to female sexual function.
In 29 rats, responses evoked by pelvic and hypogastric nerve stimulation were recorded from postganglionic nerves to bladder and penis (clitoris). Responses to pelvic nerve stimulation had nonsynapsing and synapsing components. The nonsynapsing component was relatively large in main nerve to penis and small in lateral nerve to penis and nerves to bladder. Pelvic nerve fiber synapsing on pelvic ganglion neurons to bladder had a large subliminal fringe, while fibers synapsing on neurons supplying penis (clitoris) had a small subliminal fringe. Recruitment was greater in nerves to bladder and lateral nerve to penis (clitoris) compared to main nerve to penis (clitoris), indicating more synapsing fibers in the former nerves. Almost all hypogastric fibers to bladder were direct. A small subliminal fringe was demonstrated for hypogastric fibers synapsing on neurons supplying penis. No subliminal fringe was evident for the bladder. Pelvic and hypogastric nerve interaction on pelvic ganglion neurons could not be demonstrated with either single shock or tetanic trains of conditioning stimuli. With antidromic stimulation, conduction velocities of afferent fibers in pelvic nerve ranged from 0.15 m per sec to 2.9 m per sec. In hypogastric nerve they ranged from 0.35 m per sec to 2.8 m per sec.
Clitoral reduction, especially in an adult, is a rare procedure which often leaves the glans clitoris without the capacity for tactile sensation. We present the case of a 34-year-old woman with symptomatic clitoromegaly since puberty who underwent a clitoral reduction procedure designed to preserve the neurovascular supply of the glans clitoris. The surgical technique presented here removes the corpora cavernosa of the clitoris, but conserves important neurovascular attachments. While this procedure was done on an adult, it could just as easily be performed on children or adolescents with clitoromegaly, typically the at-risk group for this condition.
Vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and angiotensin 2 are key neuropeptides that innervate the sexual organs. For further understanding of neuropeptide involvement in female sexual function, we investigated peptide receptor mRNA expression using reverse transcription-polymerase chain reaction (RT-PCR) in the rat vagina and clitoris, and alteration during the shift from the proestrus to the estrus phase. VIP, angiotensin 2 and CGRP receptor subtypes transcripts were found to be expressed in the vagina and the clitoris. Significantly increased levels of angiotensin 2 and CGRP receptor subtypes transcripts were observed in the vagina as compared to the clitoris. Significant increases in the expression of the VIP receptor type 2 (VPAC2) mRNA and parallel increases in a novel VIP responsive gene, activity-dependent neuroprotective protein (ADNP) mRNA were detected in the rat vagina during the estrus phase. The expression pattern of neuropeptide receptors in the female sexual organs suggest an intimate involvement of the corresponding neuropeptides in female sexual function.
A 23-year-old female polar bear (Ursus maritimus) killed in an Inuit hunt in East Greenland on July 9, 1999 had a significantly enlarged clitoris resembling, in size, form and colour, those of previously reported 'pseudohermaphroditic' polar bears from Svalbard. It has been suggested that an enzyme defect (21-hydroxylase deficiency), androgen producing tumour or high exposure to organochlorines during the foetal stage or early development could be the reason for the supposed pseudohermaphroditism observed for Svalbard bears. Except for the enlarged clitoris, all dimensions of the external and internal reproductive organs of the present were similar to a reference group of 23 normal adult female polar bears from East Greenland collected in 1999-2002. The aberrant bear was a female genotype, and macroscopic examination of her internal reproductive organs indicated that she was reproductively functional. A histological examination of the clitoral enlargement in the present East Greenland specimen allows a first-time histological evaluation of the earlier macroscopic field diagnosis from Svalbard. This examination revealed intense chronic ulcerative and perivascular clitoriditis similar to "acral lick dermatitis" frequently seen in domestic dogs (i.e., we did not find any signs of pseudohermaphroditic hyperplasia of clitoral tissue due to androgenic or antiestrogenic endocrine disruption). The levels of organohalogens and TEQ values were lower than concentration thresholds of toxicological risk. It is hence possible that the previously reported adult female polar bear pseudohermaphrodites from Svalbard are in fact misdiagnoses. Therefore, future studies examining pseudohermaphroditism in wildlife should consider that certain occurrences are natural events, e.g., enlarged clitoris in the present East Greenland polar bear. Furthermore, caution should be exercised in suggesting linkages of such inflammatory abnormalities with correlations to anthropogenic pollutant exposures.
Current surgical procedures that are utilized in the management of patients with an enlarged clitoris are both complex and challenging. We report a new method of concealing the hypertrophied clitoris between the labia majora instead of resorting to the more difficult clitoral amputation or recession. This concealment of the clitoris is simple, may be done on an outpatient basis, and accomplishes the goal of creating normal-appearing female external genitalia.
BACKGROUND: Hair tourniquet syndrome involves fibers of hair or thread wrapped around an appendage producing tissue necrosis. Appendages commonly involved include the toe, finger, and penis. We report a hair tourniquet resulting in amputation of the clitoris. CASE: An adolescent presented with a 4-year history of intermittent genital pain that increased in severity over the preceding 5 days. Physical examination revealed a necrotic clitoris surrounded by a black hair. During the examination, the tissue fell off resulting in immediate improvement in the patient's pain. CONCLUSION: We report a case of a clitoral hair tourniquet syndrome leading to autoamputation of the clitoris. A high index of suspicion for this condition is important because of the potential consequences of delayed treatment.