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Results for “Anatomic Variation”

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PubMed1999

[Anatomic variations of the ostiomeatal complex and their correlation with chronic sinusitis: CT evaluation].

OBJECTIVE: To explore the relationship between anatomic variations in the ostiomeatal complex (OMC) and chronic sinusitis. METHODS: Coronal plane CT scans of the paranasal sinuses showing the ostiomeatal complex including the middle turbinate, uncinate, ethmoid bulla, agger nasi and Haller cell were analyzed in 297 individuals (594 sides). Statistical analyses were carried out with SPSS 5.0. RESULTS: There were 81.14% of OMC noted to have at least one variation. The anatomic variations included paradoxical curvature of the middle turbinate (13.97%), the pneumatized middle turbinate (34.85%), uncinate hyperplasia(19.36%), deviation of uncinate (45.27%), large ethmoidal bulla (30.30%), large agger nasi (0.70%) and Haller cell (1.00%). The correlation between variations and chronic sinusitis was significant (P < 0.01). CONCLUSION: The occurrence of OMC variation is common. The variations may be one of the causes of chronic sinusitis. Therefore, properly handling the variations was important in the endoscopic sinus surgery.

Adolescent↗

PubMed2000

Anatomic variations of the radial artery in patients undergoing transradial coronary intervention.

Anatomic variations of the radial artery and their effect on the use of the radial artery as a route for transradial coronary intervention (TRI) were studied. Ultrasonography of the radial artery was performed prospectively in 115 patients selected to undergo elective TRI. Anatomic variations were observed in 11 of 115 patients (9.6%). Variations included six tortuous configurations (5. 2%), two stenoses (1.7%), two hypoplasias (1.7%), and one radioulnar loop (0.9%). The hypoplastic radial arteries and the radioulnar loop were inaccessible for catheterization, and coronary intervention was planned via the femoral artery. The transradial approach was attempted in the remaining 112 patients (97.4%) with only one instance of access failure, in a patient who had a stenotic vessel. These findings indicate that anatomic variations of the radial artery is not rare, and that preoperative ultrasound examination may help to exclude patients with inaccessible arteries and those at high risk for access failure.

Aged↗

PubMed2004

The incidence of anatomic variations and sinus opacities in pediatric patients with chronic sinonasal symptoms.

OBJECTIVES: In this study, our purpose was to determine the incidence of paranasal sinus anatomic variations and their relationship with sinus opacities in pediatric patients. PATIENTS AND METHODS: A total of 44 children (age range 3 to 16 years) unresponsive to maximum medical therapy were evaluated with coronal paranasal sinus computed tomography. RESULTS: Computed tomographic evaluations revealed that 70.5% (31/44) of the patients had at least one anatomic variation, the most common being septal deviation, followed by concha bullosa and agger nasi cells. Sinus opacities were found in 81.8% (36/44) of the patients, of whom 9 had single and 27 had multiple involvement of sinus groups. The most commonly involved sinuses were anterior ethmoids and maxillary sinuses, followed by posterior ethmoids, sphenoid and frontal sinuses. Patients with single, multiple, and no anatomic variations had 78.9% (15/19), 83.3% (10/12), and 84.6% (11/13) opacities, respectively. CONCLUSION: The incidence of anatomic variations was found to be similar to that reported for adults in the literature except for nasal septal deformity which was found lower. Our results showed no correlation between bony anatomic variations and sinus opacities in children.

Adolescent↗

PubMed2006

Fusion of the midplane with the left intersectional plane: a liver anatomical variation revisited with multidetector-row CT.

This article updates the description of an anatomical variation of the liver, in which the gallbladder is adjacent to the ligamentum teres, that was described until now as "right-sided ligamentum teres and right umbilical portion of the portal vein". A study of eight patients showing this anatomical variation has led to a new archetypal anatomical description of the hepatic and portal veins, using multidetector-row computed tomography (MDCT) with three-dimensional (3D) volume-rendering (VR) reconstructions. While 2D axial imaging gave the same information, MDCT imaging with VR reconstructions provided a clear 3D visualization of this anatomical variation. Typical features can be described as follows: (1) juxtaposition of the ligamentum teres and the gallbladder; (2) typical portal vein branching with a right posterior branch, a left posterior branch and a main medial branch that terminates in the ligamentum teres; (3) two main hepatic veins and a hypotrophied medial hepatic vein. We think, based on the direct comparison of anatomical findings and knowledge of chronological embryological development, that this abnormality results from the defective development of the central part of the liver and not from the persistence of the right rather than the left umbilical vein. Because of the presence of only one medial plane, containing both the gallbladder and the ligamentum teres, we propose renaming it "fusion of hepatic planes".

Adult↗

PubMed1997

Anatomical variations and sinusitis.

Paranasal sinus anatomy and variations have gained interest with the introduction of functional endoscopic sinus surgery and the concept of the ostiomeatal complex. Anatomical variations can be divided in structural abnormalities, (increased) pneumatization and supplementary openings. Most anatomical variations are equally found in control and sinusitis patients. The anatomical variations which are most commonly associated with sinus pathology are septal deviations, true conchae bullosae and supplementary maxillary ostia but the latter one only when recycling is present. The knowledge of anatomical variations is most important in the surgical management and specifically in the prevention of complications.

Adolescent↗

PubMed2004

Remarkable anatomic variations in paranasal sinus region and their clinical importance.

With the advent of functional endoscopic sinus surgery (FESS) and coronal computed tomography (CT) imaging, considerable attention has been directed toward paranasal region anatomy. Detailed knowledge of anatomic variations in paranasal sinus region is critical for surgeons performing endoscopic sinus surgery as well as for the radiologist involved in the preoperative work-up. To be in the known anatomical variants with some accompanying pathologies, directly influence the success of diagnostic and therapeutic management of paranasal sinus diseases. A review of 512 (1024 sides) paranasal sinus tomographic scans was carried out to expose remarkable anatomic variations of this region. We used only coronal sections, but for some cases to clear exact diagnosis, additional axial CT scan, magnetic resonance imaging (MRI) and nasal endoscopy were also performed. In this pictorial essay, rates of remarkable anatomic variations in paranasal region were displayed. The images of some interesting cases were illustrated, such as the Onodi cell in which isolated mucocele caused loss of visual acuity, agger nasi cell, Haller's cell, uncinate bulla, giant superior concha bullosa, inferior concha bullosa, bilateral carotid artery protrusion into sphenoid sinus, maxillary sinus agenesis, bilateral secondary middle turbinate (SMT) and sphenomaxillary plate. The clinical importance of all these variations were discussed under the light of the literature. It was suggested that remarkable anatomic variations of paranasal region and their possible pathologic consequences should be well defined in order to improve success of management strategies, and to avoid potential complications of endoscopic sinus surgery. The radiologist must pay close attention to anatomical variations in the preoperative evaluation.

Adult↗

PubMed1997

Scalene muscles and the brachial plexus: anatomical variations and their clinical significance.

Anatomical variations may be clinically significant, but many are inadequately described or quantified. Variations in neck anatomy are important to surgeons performing surgical procedures in this region. Thirty-two female and 19 male adult cadavers were studied. The commonly described anatomical relationship of the brachial plexus (BP) lying between the anterior scalene (AS) and middle scalene (MS) muscles was found in only 60% of instances. Scalenus minimus was present in 46% of instances (bilateral in 14 cadavers). The most common variation was the penetration of the AS by the C5 and/or C6 ventral rami. The C5 and C6 roots may fuse before piercing AS (15% cases, bilateral in 4 cadavers), or the C5 root alone pierce the belly of AS (13% cases, bilateral in 3 cadavers). The roots also may pierce AS independently (6% cases, bilateral in 1 cadaver). In 3%, the C5 root was found to be completely anterior to AS.

Brachial Plexus↗

PubMed2005

[Anatomic variations of the paranasal sinuses detected by computed tomography and the relationship between variations and sex].

OBJECTIVES: In this study, we evaluated anatomic variations detected by computed tomography (CT) of the paranasal sinuses and their relationship with sex. PATIENTS AND METHODS: Computed tomography scans of the paranasal sinuses of 464 patients (206 males, 258 females; mean age 37.5 years; range 4-87 years) were retrospectively analyzed. In cases requiring further investigation, axial and sagittal views were obtained using multiplanar reformatted images. Bone window images were also obtained particularly to evaluate dehiscence variations. Paranasal sinus variations were classified into eight subgroups according to their origins (nasal septum, ethmoid cells, maxillary sinus, uncinate process, frontal and sphenoid sinuses, orbit, and nasal concha). The frequency of variations was compared between male and females. RESULTS: The most common anatomic variation was agger nasi cells (80.4%) followed by pneumatization of the middle concha (37%). The least encountered variations were pneumatization of the inferior turbinate, bony dehiscence of the ethmoidal roof, and duplication of the middle and superior turbinates. The frequency of variations did not differ significantly with respect to gender (p>0.05) except for frontal hypoplasia, which was more often in females (p<0.05). CONCLUSION: Axial and sagittal views using multiplanar reformatted images can be helpful in eliminating artefacts and in identifying variations of the paranasal sinuses. Utilization of soft tissue and bone windows, when necessary, may facilitate evaluation of dehiscence abnormalities.

Adolescent↗

PubMed2002

Ruptured aneurysm on a double origin of the posterior inferior cerebellar artery: a pathological entity in an anatomical variation. Report of two cases and review of the literature.

The posterior inferior cerebellar artery (PICA) is known to be very variable, and some of its anatomical variations can explain ischemic complications that occur during endovascular treatment of aneurysms. The authors report two cases of anatomical variation of the PICA that they have called its double origin, one of which gave rise to an aneurysm. The first patient was a 36-year-old man who presented with a subarachnoid hemorrhage related to the rupture of a PICA aneurysm. The aneurysm was treated by the endovascular route. Selective and superselective studies showed that the PICA origin was low on the fourth segment of the vertebral artery (VA). The aneurysm was located on an anastomosis between the PICA and a small upper arterial branch originating from the VA. Embolization was performed through the small branch with no problem, but a lateral medullary infarct followed, probably due to occlusion of the perforating vessels. The same anatomical variation was incidentally discovered in the second patient. To the authors' knowledge, neither this anatomical variation of the PICA nor the aneurysm's topography have been previously described angiographically. This highlights the role of angiography in pretreatment evaluation of aneurysms especially when perforating vessels or small accessory branches that are poorly visualized on angiographic studies are concerned, as in the territory of the PICA. Anatomy is sometimes unpredictable, and the surgeon must be very careful when confronted with these variations because they are potentially dangerous for endovascular treatment.

Adult↗

PubMed2004

[Anatomic variations of the colon detected on abdominal CT scans].

PURPOSE: The frequency of anatomic variations of the colon detected on abdominal CT scans was examined. MATERIALS AND METHODS: 296 consequtive abdominal tomography were evaluated prospectively for the presence of retrorenal colon, retrogastric (pancreaticogastric interposition or retrosplenic) colon, high positioned colon, interposition of the colon between the psoas muscle and the kidney and hepatodiaphragmatic interposition (anterior or posterior). RESULTS: We observed 2 retrogastric colon [1 pancreaticogastric (0.3%), 1 retrosplenic (0.3%)], 7 retrorenal colon (1.2%) being bilateral in two cases, 2 interposition of colon between the psoas muscle and the kidney (0.7%), 1 posterior (0.3%) and 6 anterolateral hepatodiaphragmatic interposition (2.1%) and 12 high positioned cecum (4.2%) (in 4 of them cecum was totally subhepatic in location). Terminal ileum was lying in Morrison's pouch and anterior to renal hilus in two of the cases with subhepatic cecum. CONCLUSION: Anatomic variations of the colon probably result due to mild embryologic abnormalities of bowel rotation and fixation, short transvers mesocolon, intraperitoneal ascending or descending colon, increased intraperitoneal pressure or decreased retroperitoneal fat. Pancreaticogastric interposition occurs in approximately 0.2%, partial retrorenal colon in 9-10%, complete retrorenal colon 1%, interposition between psoas muscle and kidney in 0.7-1.7%, anterolateral hepatodiaphragmatic interposition in 1.3-3% of individuals. When located in lesser sac it simulates several pathologies of this area. On intravenous urography images it may cause mass effect. In percutaneous interventions and surgical procedures colon may be perforated. For these reasons tomography images should be evaluated for the presence of these anatomic variations.

Adult↗

PubMed1983

Extensor indicis brevis: a rare anatomical variation.

We describe a rare anatomical variant, the extensor indicis brevis--a "short" index extensor originating from the ligament over the scaphoid bone. In our patient it presented as a tender mass. The knowledge of such anatomical variations is important in diagnosing dorsal hand masses and in planning tendon transfers.

Adolescent↗

PubMed2005

Prevalence of anatomic variation demonstrated on screening sinus computed tomography and clinical correlation.

Screening sinus computed tomography (SCCT) of 133 patients performed from March 2003 to February 2004, were retrospectively reviewed, concerning anatomic variation at ostiomeatal unit (OMU) and nasal septal deviation. Six patterns of inflammatory sinus disease were designated: maxillary infundibulum, nasofrontal duct, OMU, sphenoethmoidal recess, polyposis and sporadic. The most common anatomic variation was concha bullosa (14.3%), followed by Haller cell (9.4%), large Agger nasi cell (7.9%) and paradoxical middle turbinate (5.3%). Nasal septal deviation was presented in 75 patients (56.4%). Inflammatory sinus disease was presented in 181 lateral nasal walls (68%) and maxillary infundibular pattern was the most common (33.1%). There was significant correlation between large Agger nasi cell and nasofrontal duct pattern (p < 0.05). The remaining anatomic variations and nasal septal deviation had no significant correlation to the inflammatory sinus disease. Overall, the anatomic variation which can compromise the mucociliary drainage was frequently observed, however, only the large Agger nasi cell had significant correlation to the inflammatory sinus disease.

Adolescent↗

PubMed2002

Anatomical variations and surgical strategies in right lobe living donor liver transplantation: lessons from 120 cases.

BACKGROUND: Anatomical variations in right liver lobe are common. However, clinical implications and surgical management of these variations in living donor liver transplantation have not been analyzed systematically. METHODS: Surgical anatomy of vascular and biliary structures in 120 right lobe grafts were reevaluated by reviewing the results of preoperative (computerized tomography and Doppler ultrasonography) and intraoperative (cholangiography) imaging as well as surgical findings. The data were analyzed in relation to surgical management of anatomical variations. RESULTS: The incidence of variants leading to multiple portal vein anastomoses was 7.5%. The incidence of dual right hepatic veins was 0.8%; 30% of the grafts had significant accessory hepatic veins (>5 mm) and 13.9% of these were multiple. All of them were successfully reconstructed with technical modifications including venoplasty and venous grafts, except for two cases with multiple intraparenchymal portal vein branches to the anterior segment. The incidence of dual hepatic arteries was 1.7%, but only one of them was reconstructed without negative sequelae. The incidence of variants potentially leading to multiple bile duct anastomoses was 35.0%, and eventually 39.2% of the grafts had multiple orifices. With a variety of techniques including ductoplasty, hepaticohepaticostomy, and biliary stent, total incidence of leakage and stenosis was 10.8% and 9.2%, respectively. Although ductoplasty, internal stent or no stenting, seemed to be associated with increased risk of complications, anatomical variants, multiple bile ducts, and duct-to-duct reconstruction did not bear a significant risk. CONCLUSIONS: Anatomical variations of vascular and biliary structures in right lobe grafts are common. However, most can be managed safely with technical modifications. Only cases with intraparenchymal origin of the anterior portal vein(s) may form a relative contraindication, especially when combined with similar biliary variants. Otherwise, intraoperative assessment of biliary anatomy was enough for successful management. Detailed and precise assessment of vascular and biliary anatomy is vital for appropriate surgical management.

Adult↗

PubMed1988

Anatomical variations in human carotid bodies.

The variations in anatomical structure and position of both carotid bodies were noted in 100 consecutive subjects who came to necropsy. Considerable variations in form were found. Although most carotid bodies (83% on the right and 86% on the left) were of the classic ovoid type, an appreciable minority was bilobed (9% on the right and 7% on the left) or double (7% on the right and 6% on the left); 1% were leaf shaped. All these anatomical variants have to be distinguished from the pathologically enlarged carotid body that may have a smooth or finely nodular surface. Anatomical variants (such as the bilobed) may themselves enlarge as a consequence of carotid body hyperplasia.

Aged↗

PubMed1999

Anatomic variations of the paranasal sinuses: CT examination for endoscopic sinus surgery.

Chronic rhinosinusitis endoscopic surgery requires an accurate evaluation of diseases and paranasal sinus anatomic variations. This study aims to show the main anatomical variations in the ostiomeatal complex and paranasal sinuses which are usually depicted by computed tomography (CT). CT scans obtained 2 mm thickness in axial and coronal plane from a series of 200 patients with chronic sinusitis were examined to determine the prevalence of anatomic variants. Anatomical variations determined were supraorbital recess in 6%, concha bullosa in 30%, sphenomaxillary plate in 17%, infra-orbital ethmoid cells (Haller's cells) in 6%, spheno-ethmoid cells (Onodi's cells) in 12%, pneumatization of the anterior clinoid process in 6%, carotid artery bulging into the sphenoid sinus in 8%, pneumatization of the uncinate process in 2%, paradoxical curvature of the middle turbinate in 3% and septal deviation in 36%. Level difference between the ethmoid roof and nasal vault was an average of 8 mm in right side and 9.5 mm in left side. Awareness of these different variations will help the rhinologic surgeon in his orientation during endoscopic surgical procedures.

Chronic Disease↗

PubMed2004

Frontal sinus anatomical variations with potential consequences for the orbit. Study on cadavers.

Anatomical variations of the frontal sinuses that may play a role in the correlation between frontal sinusitis and orbital complications are described. There were used 18 cadavers during routine educational cadaver dissections, one month after theirs withdrawal from the formol basin. The dissections of the cranial cavity and the orbits were performed so as to reveal the frontal sinuses. An unusual bilateral posterior extension of the frontal sinus mucosa was found in two of the cadavers. The projection of the mucosa was covering half of the orbital roof in a 60 year old male and one third of the orbital roof in a 59 year old male. Among the other cadavers that presented normal variations of the frontal sinuses, there was also a case of a 57 year old female with a complete aplasia of the frontal sinuses. Such anatomical variations with unusual extension of the frontal sinuses above orbital roof may support the correlation between frontal sinusitis and the possible complications from the orbit and these cases may be considered as 'high risk' cases for orbital complications during a frontal sinusitis.

Female↗

PubMed2006

Vascular anatomic variation in rabbits.

PURPOSE: To explore the vascular anatomic variation along the aortic arch in New Zealand White rabbits with the goal of highlighting potential anatomic configurations that might be encountered in the performance of preclinical endovascular research in rabbits. MATERIALS AND METHODS: Digital subtraction angiography images of the brachiocephalic artery (BCA) and aortic arch in New Zealand White rabbits were obtained after creation of elastase-induced aneurysms at the origin of the right common carotid artery (RCCA) in 214 animals. The patterns of origin of the RCCA and left common carotid artery (LCCA), right subclavian artery (RSCA) and left subclavian artery (LSCA), and right vertebral artery (RVA) and left vertebral artery (LVA) were analyzed. RESULTS: Five predominant variations of vessel origin were identified. In 200 of 214 cases (93%), the LCCA originated from the bifurcation of the BCA and aorta. In eight cases (4%), the LCCA directly originated from the aorta. In two cases (1%), the LCCA originated from the BCA. Aberrant RSCA anatomy in which the RSCA originated from the aortic arch instead of the BCA was found in three cases (1.5%). In a single case (0.5%), aberrant RSCA anatomy with the RVA originating from the BCA was encountered. CONCLUSIONS: Anatomic variation of the BCA in New Zealand White rabbits is similar to that seen in humans. Understanding of the normal and variant anatomy of the rabbit will aid investigators who use the rabbit model for endovascular research.

Angiography, Digital Subtraction↗

PubMed1980

Frequency of congenital abnormalities and of anatomical variations among JAX rabbits.

The frequency of congenital abnormalities and anatomical variations as observed among JAX rabbits is reported. Data were drawn from 32,082 inbred and partially inbred rabbits and 3,208 hybrids from the colony of the Jackson Laboratory over an eight-year period. Data reported here include stillbirths, rabbits dying from natural causes, and those killed for specific experimental regimens. Frequency data are based on the number of abnormalities observed in each category as a function of the total number of animals necropsied. This is approximately 95% of the animals born during the eight-year period and gives the frequency of abnormalities within each category rather than the number of individuals with one or more abnormalities. Anatomical variations have been found in almost all organ systems of JAX rabbits. Their presence adds to our knowledge of the characteristics of these strains, a knowledge that is critical to the understanding of the results of experimental manipulation or for determination of the presence of new mutations. There is considerable between-strain variation. Where frequencies are relatively high, the conditions are either known or suspected to be of genetic origin. Most of the anomalies are not deleterious, or their frequency is so low as to cause no problems within the colony. Hybrid populations have substantially fewer anomalies than do the parental strains. Where frequency is relatively high, it tends to be intermediate between the parental strains.

Animals↗