[Anatomical variations of the gallbladder].
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Gallbladder↗
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Results for “Anatomic Variation”
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Arachnoid granulations in the transverse and sigmoid sinuses: CT, MR, and MR angiographic appearance of a normal anatomic variation.
PURPOSE: To investigate the imaging characteristics, prevalence, and clinical significance of arachnoid granulations in the transverse and sigmoid venous sinuses. METHODS: We reviewed the imaging findings, clinical signs and symptoms, final diagnoses, and follow-up studies of 32 patients with 41 probable arachnoid granulations. RESULTS: On CT scans, arachnoid granulations appear as well-defined filling defects, wholly or partly within a venous sinus, with the same density as cerebrospinal fluid. MR images show these entities as largely isointense with cerebrospinal fluid in all sequences. Linear variations of signal intensity within the granulations are thought to be fibrous septa or vessels. Calcification was present in 3 granulations and altered both CT density and MR signal intensity. The granulations appear as filling defects at MR angiography and at digital subtraction angiography. In some oblique MR angiographic projections, they appear elliptical and could be mistaken for thrombus. No clinical significance could be given to the existence of any of these arachnoid granulations. They occur in 0.3 to 1 of 100 adults in the population. CONCLUSION: Arachnoid granulations in the transverse and sigmoid venous sinuses are common findings seen with thin-section imaging and are usually of no significance.
Adult↗
[Anatomic variations of the coronary arteries].
PURPOSE: To study the coronary arteries and their main branches showing the aspects of source, trajectory and anastomoses of these vessels at the subepicardial level. METHODS: The study was carried out on 110 adult human hearts, of both sexes, fixed in 10% formaldehyde solution. The pericardium was removed to expose the coronary arteries and their branches at the subepicardial level. RESULTS: In 38.18% of the cases the left coronary artery presented a trifurcation into anterior interventricular, circunflex and left marginal branches (35.70%) and into anterior interventricular, circunflex and lateral branches (64.30%). In 60% of the hearts examined, the left coronary artery presented a bifurcation into anterior interventricular and circunflex branches. In 1.82% of the cases these two branches arise directly from the aorta. An anastomosis, at the subepicardial level, between the anterior and posterior interventricular branches was observed in 56.36% of the hearts. In 88.18% the posterior interventricular branch arised from the right coronary artery, whereas in 11.82% this vessel arises from the circunflex branch. Anastomoses between the right coronary artery and the circunflex branch were found in 10% of the hearts (crux cordis). The dominance of the right coronary artery was present in 69.09% of the cases, of the left coronary artery in 11.82% and in 19.09% of the hearts had balanced distribution. CONCLUSION: The coronary arteries and their main branches present a great quantity of variations with regard to source, trajectory and anastomoses. This knowledge is important for the interpretation of coronary angiography and surgical myocardial revascularization.
Adult↗
Anatomic variation in pediatric chronic sinusitis: a CT study.
The diagnosis of pediatric chronic sinusitis is problematic in very young children who have several of the symptoms consistent with chronic sinusitis. This article addresses only the issues surrounding the imaging, and particularly computed tomographic scanning, of chronic sinusitis in the pediatric population.
Adolescent↗
Transient colonic ischaemia: consequence of a rare anatomical variation of the mesenteric arteries.
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Adult↗
Anatomical variations of the middle turbinate.
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Ethmoid Bone↗
An anatomic variation of the stylomastoid foramen.
During the examination of cranial bones, we observed an abnormality in one of the right temporal bones. In this variation, the stylomastoid foramen was not completely formed on the temporal bone and instead of a foramen, there was a sulcus in its localization on the bone. The articulation with the occipital bone transformed this sulcus into a foramen. This variation was not reported in the literature.
Humans↗
Evaluation of some important anatomical variations and dangerous areas of the paranasal sinuses by CT for safer endonasal surgery.
The purpose of this study is to determine some important variations and dangerous areas carrying risks for major complications, in the routine CT examination. We also made specific measurements to evaluate the individual differences. This prospective study consisted of 111 patients (222 sides). Eighty patients underwent coronal, and the rest coronal and axial CT. The depth of lamina cribrosa, its distance to the inferior turbinate, and the distance of anterior ethmoidal artery (AEA) either to the orbital roof or inferior turbinate were measured. Variations of the upper attachment of uncinate process were encountered in 23%. AEA coursed freely within ethmoidal cells in 43%. Anterior clinoid aeration was seen in 14%, optic canal bulging into the sphenoid sinus in 13% and an extreme medial course of the carotid canal in 12% of the patients. The mean depth of lamina cribrosa was 5.9 mm, and its mean distance to the inferior turbinate was 25.7 mm. The mean distance of AEA to the orbital roof was 13.7 mm, and to the inferior turbinate 30.05 mm. Anterior clinoid aeration correlated well with the variations of carotid and optic canals, statistically (p < 0.01). A detailed CT study will provide important information on the areas carrying risks of complications and the size of the area to be worked on.
Adolescent↗
Variations of anatomical elements contributing to subtalar joint stability: intrinsic risk factors for post-traumatic lateral instability of the ankle?
Ankle sprains are frequently followed by chronic lateral instability, often with talar hypermobility. This might be due to subtalar instability. Among intrinsic risk factors, anatomical variants are generally overlooked. In the subtalar region, anatomical variation is particularly frequent. On the talus as well as on the calcaneus, the anterior articular facets may be missing or fused with the medial facets, giving rise to three subtalar joint configurations: a three-joint configuration, a fused configuration with a relatively large anteromedial joint, and a two-joint configuration without anterior joint. Osteometry was performed on these joint facets (134 calcanei, 122 tali), demonstrating significant differences in the surface of these configurations and the existence of a supplementary supporting surface with grossly transverse orientation in the three-joint configuration. There are also several variants of stabilizing ligaments within the sinus tarsi. Some of these configurations might expose to increased risk of associated subtalar lesions, resulting in subtalar instability. A systematic look for these variants is recommended in order to evaluate the associated risk factors, eventually resulting in a better understanding, prevention and cure of sequellae.
Ankle Injuries↗
[Anatomic variants of paranasal sinuses].
During the last 15 years period, the development of functional endoscopic sinus surgery underlines the needs of a better knowledge of sinonasal anatomy and consequently, of sinonasal anatomic variations. These anatomic variations are widely spread into the population and commonly encountered in daily CT practice. The difference of anatomic landmarks during endoscopic surgery can result in bony transgression and increase the difficulties of the surgery. In fact, functional endoscopic surgery is a blind surgery leading to severe complications with medico-legal impact. Therefore, the anatomic sinonasal variations should be depicted in all sinonasal CT imaging studies irrespective of the indications. Moreover, some anatomical variants may cause certain symptoms.
Endoscopy↗
Superior laryngeal nerve identification and preservation in thyroidectomy.
BACKGROUND: Injury to the external branch of the superior laryngeal nerve (EBSLN) can result in detrimental voice changes, the severity of which varies according to the voice demands of the patient. Variations in its anatomic patterns and in the rates of identification reported in the literature have discouraged thyroid surgeons from routine exploration and identification of this nerve. Inconsistent with the surgical principle of preservation of critical structures through identification, modern-day thyroidectomy surgeons still avoid the EBSLN rather than identifying and preserving it. OBJECTIVES: To describe the anatomic variations of the EBSLN, particularly at the junction of the inferior constrictor and cricothyroid muscles; to propose a systematic approach to identification and preservation of this nerve; and to define the identification rate of this nerve during thyroidectomy. MATERIALS AND METHODS: A retrospective review of thyroid lobectomies and total thyroidectomies performed between 1978 and 1997 was carried out. A total of 884 patients were included, with 1057 EBSLNs explored. Intraoperative findings of identification of the EBSLN were recorded and compared on an annual basis for both benign and malignant disease. Overall results were also compared with those found in previous series identified through a 50-year literature review. RESULTS: The 3 anatomic variations of the distal aspect of the EBSLN as it enters the cricothyroid were encountered and are described. The total identification rate over the 20-year period was 900 (85.1%) of 1057 nerves. Operations performed for benign disease were associated with higher identification rates (599 [86.1%] of 696) as opposed to those performed for malignant disease (301 [83.4%] of 361). Operations performed in recent years have a higher identification rate (over 90%). CONCLUSIONS: Understanding the 3 anatomic variations of the distal portion of the EBSLN and its relation to the inferior constrictor muscle allows for high rates of identification of this nerve. The EBSLN should be explored during thyroid surgery and identification is possible in most cases. Preservation of the EBSLN maintains optimal function of the larynx.
Humans↗
Topographic variations in anatomical structures of the anterior neck of children: an ultrasonographic study.
OBJECTIVE: Tracheostomies in children are frequently used for temporary airway support during surgical procedures. In pediatric patients with congenital craniofacial malformations, preoperative assessment of the delicate anatomy of the airway is necessary. The purpose of this study was to assess the ultrasonographic anatomy of the anterior neck with regard to the performance of tracheostomy. STUDY DESIGN: Ultrasonographic investigation was done in 50 pediatric patients (age range, 6 to 15 years) to analyze the relationships among the anatomical structures that are of practical interest with respect to tracheostomy. RESULTS: The data reveal that information concerning variations in anatomical structures lying in the immediate vicinity of the tracheostomy site was readily obtainable with the techniques used. CONCLUSIONS: In pediatric patients requiring tracheostomy for surgical treatment of severe congenital craniofacial malformations, preoperative ultrasonography may be used to diagnose individual anatomical variations at the tracheostomy site.
Adolescent↗
A variation of coeliac trunk.
The anatomical variations of the coeliac trunk are due to developmental changes in the ventral splanchnic arteries. This report describes a case in which the left inferior phrenic artery and left gastric artery arose from the long coeliac trunk (4.3 cm.) via a common trunk. The arterial variations, like other anatomical variations, cannot be ignored during the operative procedures in abdomen. Therefore the different forms of variations concerning the coeliac trunk should be kept in mind during both surgical and non-surgical evaluations.
Aged↗
Iliolumbar veins have a high frequency of variations.
The spectrum of individual anatomic variations of the vascular structures are broad, however, the exact incidence of variations of the lumbosacral vein is obscure. In the current study, 38 iliolumbar veins were dissected from 19 formaldehyde-preserved male cadavers. The drainage pattern of the iliolumbar vein was determined. The diameter and the length of the iliolumbar vein were measured, and the relationships of the iliolumbar vein with the lumbosacral trunk, obturator nerve, and iliolumbar artery were ascertained. Means and standard deviations were used as descriptive measures to define variations among the cases. The iliolumbar vein or veins were detected in both sides of all 19 cadavers. Five drainage patterns were seen between the iliolumbar vein and the lumbosacral major veins. In only five cadavers, symmetric drainage patterns were seen on the left and the right sides. In our study, two drainage patterns were seen that were not previously reported. Anatomic variations of the iliolumbar vein are numerous and should be considered to avoid complications when doing surgery.
Cadaver↗
Root canal treatment in mandibular canines with two roots: a report of two cases.
AIM: To highlight anatomical variation in the mandibular canine. SUMMARY: Two clinical case reports are presented to illustrate anatomical variation in the human mandibular canine. Endodontic treatment may sometimes fail because morphological features of the tooth adversely affect the treatment procedures. Many investigators have reported the anatomical variations associated with mandibular canines. Mandibular canines are recognized as usually having one root and one root canal in most cases, although approximately 15% may have two canals or sometimes two roots. This paper describes two clinical cases of mandibular canines with two roots and two canals. KEY LEARNING POINTS: Failure to control infection in the root canal system has an adverse impact on outcome. Clinicians should be aware of anatomical variations in the teeth they are managing, and should never assume that canal systems are simple. The majority of mandibular canines have one root and root canal, but 15% may have two canals, and a smaller number may have two distinct roots.
Cuspid↗
[Application of an image-guidance system in endoscopic sinus surgery].
OBJECTIVE: To evaluate the advantages of image-guidance system in endoscopic sinus surgery. METHODS: Twenty-eight endoscopic sinus surgery procedures were performed with the help of image-guidance system. There were 11 cases of chronic sinusitis with/or without nasal polyps, 4 juvenile nasopharyngeal angiofibromas, 6 pituitary adenomas, 3 ethmoid ossifying fibromas, 2 nasopharyngeal mixed tumors, 1 nasal leiomyoma, 1 fungal sinusitis, and 1 inverted papilloma. RESULTS: In all cases, the preoperative operation would take 15-30 minutes, the registration rate was 1.3-2.0, the localization accuracy was within 1 mm. Compared with the traditional endoscopic sinus surgery, the operative time did not differ obviously. No complication occurred. CONCLUSIONS: The image-guidance system could identify the operative borders and critical anatomical structures together with the corresponding CT data, especially in cases with anatomical variations, unidentified anatomical landmarks, and intranasal or anterior skull base tumors. Endoscopic sinus surgery, combined with the image-guidance system, provided accurate tumor resection while preserving normal tissue. It could increase surgical effectiveness and decrease overall surgical complications. We believe that the image-guidance system is a useful tool for endoscopic sinus surgery.
Adolescent↗
Intravenous cholangiography is superfluous prior to laparoscopic cholecystectomy.
OBJECTIVE: Intravenous cholangiography (IVC) re-introduced into the preoperative diagnostic work-up of cholecystectomy after the change to the laparoscopic technique, was suggested to detect anatomical anomalies and bile duct stones. The value of IVC in this context was to be evaluated by this study. DESIGN: Prospectively controlled study. IVC findings were controlled by intraoperative imaging techniques such as laparoscopic sonography and intraoperative cholangiography. SETTING: Surgical unit of a university hospital. SUBJECTS: One hundred patients underwent laparoscopic cholecystectomy between January 1992 and January 1993. Eighty-five of these patients had both IVC and intraoperative cholangiography (IOC). There were nine technical failures for IVC and five for IOC. MAIN OUTCOME MEASURES: Anatomical variations and previously unsuspected common duct stones. RESULTS: Anatomical variations of the biliary tree and the hepatic vessels were detected by IVC in only three cases while IOC demonstrated 31 biliary and vascular anomalies in 28 patients. IVC demonstrated bile duct stones in one and IOC in two cases. CONCLUSIONS: We conclude that IVC is of little help in the diagnosis of anatomical variations of the biliary tree and should be omitted from the preoperative diagnostic work-up of laparoscopic cholecystectomy.
Adult↗
Apical anatomy in mesial and mesiobuccal roots of permanent first molars.
The purpose of this in vitro study was to investigate the canal configuration types, and the prevalence and location of anatomical variations in the mesiobuccal (MB) and mesial roots of permanent maxillary and mandibular first molars after instrumentation. The number and the type of canals were determined before instrumentation using conventional methods. All root canals from the 47 MB roots and 42 mesial roots were then instrumented to size #30 with ProFile .04 taper rotary instruments in a crown-down method and then filled with a single gutta-percha cone and sealer. Transverse 1 mm-thick cross-sections at 2, 3, 4, and 5 mm from the apex were obtained, stained and examined using a stereomicroscope. The canal configuration types and the prevalence and location of isthmi and accessory canals in roots with two canals were evaluated. The prevalence of two canals was 80.8% in the maxillary MB roots and 95.2% in the mandibular mesial roots. There were six types of canal configurations in the instrumented root apices. The prevalence of anatomical variations was highest at the apical 4 mm level, and was more frequent in mandibular first molars, and in roots with Weine type III canal. chi test showed that the prevalence of the anatomical variations was statistically higher in the maxillary MB roots with Weine type III canals than in those with Weine type II canals (p < 0.05). Different canal configurations were often found at different levels in the same root. The results indicate that anatomical variations persist following instrumentation of roots with two canals in first molars. These anatomical variations should be considered during surgical or nonsurgical endodontic procedures of the permanent first molars.
Chi-Square Distribution↗