PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Anatomic Variation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2004

Anatomic variations of the hepatic arteries in 604 selective celiac and superior mesenteric angiographies.

In modern surgical and transplantation procedures the recognition of anatomic vascular abnormalities of the hepatic arteries is of greater importance than ever. The purpose of this study was to evaluate and classify these variations with respect to their impact on visceral surgery. A total of 604 selective celiac and superior mesenteric angiographies performed on patients with known or suspected liver cirrhosis or hepatic or pancreatic malignancies and on donors of partial liver grafts were analyzed retrospectively. The vascular anatomy of the liver was classified according to different established systems and with particular attention to rare variations. Hepatic arterial anatomy as considered normal in textbook descriptions was found in 79.1%, an aberrant or accessory left hepatic artery (LHA) arising from the left gastric artery in 3.0% and an aberrant or accessory right hepatic artery (RHA) branching off the superior mesenteric artery in 11.9% of the cases. In 1.4% of the cases there was a combination of anomalies of both the LHA and RHA. Variants of the celiac trunk, double hepatic arteries branching at the celiac trunk or hepatic arteries arising directly from the aorta, occurred in 4.1% of the cases. Further atypical branches of the LHA and RHA were found in 0.5% of the cases. Since the incidence and pattern of different types of hepatic arterial anatomy can require specialized preoperative diagnostic as well as intraoperative strategies, knowledge of these abnormalities and their frequency is of major importance for the surgeon as well as the radiologist.

Angiography↗
PubMedDate not supplied

Anatomical variations and relations of the bony portion of the eustachian tube.

The bony portion of the Eustachian tube was examined, using anatomical and histological methods, on 200 temporal bones of adults. This part of the tube averages 11.38 mm in length, its tympanic opening has an average diameter of 5.20 X 3.95 mm, and its lumen can be of an irregular (45%), rectangular (35%) or triangular (20%) shape. The dimensions of the bony portion of the tube diminish gradually toward the isthmus, so that in the middle the average diameter is 4.02 X 3 mm and at the level of the isthmus, 2.5 X 1.5 mm. The outer wall forms the tympanic plate of the tympanic bone, which in 65% of the cases is compact and in 35% finely pneumatized. On this wall bony trabeculae often appear, which more or less block the lumen of the tube. The medial part of the upper wall forms the bony septum toward the m. tensor tympani and the lateral represents the tegmen. The average distance from the lumen of the tube to the dura at the level of the tegmen is 3.62 mm. The tegmen above the tube may be pneumatized (45%) or compact (55%). The lower wall in 20% of the cases is represented by a shallow groove, and if formed is usually convex into the tube's lumen, but is less often concave. The jutting out of the lower wall is usually caused by its pneumatization.

Adult↗
PubMed2000

[Anatomical variations of Koch's triangle in patients with atrioventricular nodal reentrant tachycardia: usefulness of the left anterior oblique view].

OBJECTIVES: Several anatomical distances of Koch's triangle including the ablation site were measured and correlated with clinical features and slow pathway potentials in patients with atrioventricular nodal reentrant tachycardia to improve the avoidance of complete atrioventricular block. METHODS: Sixty consecutive patients (24 males and 36 females, mean age 47 +/- 12 years) with successfully eliminated atrioventricular nodal reentrat tachycardia were studied. The distances between the His-bundle area and the base of the coronary sinus ostium (Dis HBE-CS) and the distances between the successful ablation site and the base of the CS ostium (Dis SP-CS) were measured in both right anterior oblique and left anterior oblique views, and used to define the dimensions of Koch's triangle. The relationship between the slow pathway potentials at the successful ablation site and anatomical distances was estimated. RESULTS: The Dis HBE-CS in the right anterior oblique view was negatively correlated with patient age (r = -0.759, p < 0.001) and body mass index. In contrast, the Dis HBE-CS in the left anterior oblique view had only weak correlations with patient age and body mass index. The mechanism of the short Dis HBE-CS in the right anterior oblique view in elderly obese patients tended to change the shape of the tricuspid annulus from a circle to an ellipse, compressed by the ascending aorta and diaphragma. The Dis SP-CS in the right anterior oblique view associated with the low frequency potential (Haissaguerre's slow pathway potential) was longer than that associated with the high frequency potential (Jackman's slow pathway potential). CONCLUSIONS: Elderly obese patients had shorter distances between the proximal His-bundle area and the base of the coronary sinus ostium in the right anterior oblique view. In contrast, the Dis HBE-CS in the left anterior oblique view was not so narrow. Therefore, slow pathway ablation can be performed safely without complicated complete atrioventricular block, using both the slow pathway potential guided approach and the anatomical guided approach, especially in the left anterior oblique view.

Adolescent↗
PubMedDate not supplied

Anatomical variations of the right hepatic veins and their relevance to surgery.

BACKGROUND/AIMS: In a morphological study of the right hepatic veins anatomical characteristics of surgical importance were looked for. METHODOLOGY: 110 cadaveric human livers were prepared by the corrosion casts method. The confluence patterns of the superior right hepatic vein, the hepatocaval confluence, the accessory right hepatic veins and the anastomoses between hepatic veins in the right hemiliver were examined. RESULTS: Four types of the superior right hepatic vein, based on the length of its trunk and the confluence pattern of its main tributaries were determined and their frequency was calculated. Type I was found in 20%, type II in 40%, type III in 25% and type IV in 15%. Accessory right hepatic veins with a minimal caliber of 0.4 cm, which were always present in type IV, were also found in other types, all together in 27% of the casts. The tributary-free part of the superior right hepatic vein at hepatocaval confluence was longer than 1 cm in 77%. In the right hemiliver 109 anastomoses were found in 29/110 liver casts. CONCLUSIONS: Knowing the characteristics of different superior right hepatic vein types and of the accessory right hepatic veins may be useful in segment-oriented liver resections and in right side living donor resections.

Corrosion Casting↗
PubMed2006

Anatomic variations of the infraorbital fat compartment.

Resection of the infraorbital fat is performed in blepharoplasty of the lower eyelid, however, the previous anatomical reports on its compartmentalization have been in disagreement. The aim of this study was to classify the infraorbital fat based on the extent of compartmentalization, and to clarify its topographic relationship with the surrounding structures. Sixty orbits from 30 cadavers were dissected. The infraorbital fat was classified into four types based on its compartmentalization. In type I, which was the most common type (60.0%), the infraorbital fat was compartmentalised into three encapsulated medial, central, and lateral parts, which were side by side. In type II (11.7%), the medial or lateral compartment, or both compartments were under the central fat compartment. In type III (26.7%), there were two compartments, the medial and remaining part or the lateral and remaining part. In type IV (1.7%), the fat was not compartmentalised, but presented as a single pad. The average heights from the inferior orbital rim, the average widths, and the average distances from the fornix were 7.3, 17.2, and 7.1 mm in the medial compartment, 8.9, 24.2, and 8.0mm in the central compartment, and 8.1, 17.2, and 6.9 mm in the lateral compartment, respectively. The average distance from the end of the margin of the stretched lower eyelid to the most cephalic point in the compartments was 8.6 mm. These results are relevant to blepharoplasty with removal of the infraorbital fat.

Adipose Tissue↗
PubMed2004

[Anatomic variations of the spermatic vein and endovascular treatment of left varicoceles: a pediatric series].

OBJECTIVE: To report on the high incidence of anatomical variants of the origin and course of the internal spermatic vein (ISV) discovered at the time of percutaneous embolization of left varicoceles in a pediatric population. METHODS: We reviewed retrospectively the 65 cases of left varicocele treated by percutaneous embolization (grade II and III) in our institution between 1990 and 2000. The course of the left renal vein (LRV), the origin of the ISV, and the number of ISVs and their pathway were recorded in all cases, according to the Bähren classification. RESULTS: In 37/65 (57%), the ISV was single and arose from a normal LRV (type I). The following variants were encountered: type V--circumaortic LRV 9/65 (14%); type IVb--intrarenal origin of ISV 8/65 (12%); type II--multiple ISV 5/65 (8%); and pelvic collaterals 6/65 (9%). CONCLUSION: Venous anatomical variants are frequently encountered (43%) at the time of left varicocele embolization in children. Such variants often impose some adjustments to the technique of embolization and, at times, hamper the procedure.

Adolescent↗
PubMed1994

Anatomical variations of the intrinsic muscles of the thumb.

The observation of thirty dissections of intrinsic muscles of the thumb provides some information differing from earlier anatomical studies. The abductor pollicis brevis and the opponens pollicis have been divided into muscles having six or two fascicles (or bellies), respectively. The adductor pollicis muscle has been separated into nine fascicles. Many variations were observed: absence of fascicles, presence of atrophied or supplementary fascicles, or fascicles with varying insertions sites. Neither head of the flexor pollicis brevis muscle seemed to have any fascicles. The distal insertion of its superficial head observed in this work is not in accordance with the usual description found in the literature. A new classification of the thenar muscles is presented based on the present observations. Many variations were observed: some fascicles were absent, others were supplementary or atrophied, and some had variable insertions. The importance and the individual variations of the fascicles are discussed.

Humans↗
PubMed1993

Anatomic variation in the blood supply of the radial forearm flap.

The traditional radial forearm flap derives its blood supply from perforators of the radial artery. This report describes an anatomic anomaly in which the flap was supplied solely by perforators of the ulnar artery. Knowledge of this previously undescribed variation might have relevance when a radial forearm flap is raised.

Adult↗
PubMed2002

The origin of gonadal arteries in human fetuses: anatomical variations.

Testicular arterial anatomy has been well studied because of its importance in testicular physiology, as well as testicular and renal surgery. In contrast to classical anatomical descriptions, it may originate from the suprarenal or lumbar arteries or a high-positioned origin, course behind the inferior vena cava or be doubled or arise from an inferior polar renal artery. Different developmental patterns as variations in relation to origin, course and number of the renal and gonadal arteries have been reported and discussed. This study was performed on 90 spontaneously aborted fetuses obtained from two different hospitals in Konya. The study was carried out on the testicular or ovarian arteries of fetuses fixed by immersion in 10% formalin. In all, 180 gonadal arteries were studied and 16 of them were found to have variations in their origin (8.8%). The variations of the gonadal artery origins could be classified into four types. The gonadal artery variations were more commonly found in male than the female fetuses and on the right side rather than the left. In the present study, it is clear that these variations are important not only from the developmental point of view or research interest, but they also may explain some pathological conditions. Knowledge of these variations may help to avoid the clinical complications especially during radiological examinations and/or surgical approaches in this region.

Abortion, Spontaneous↗
PubMed2003

Anatomical variations of the ten triangles around the cavernous sinus.

The dimensions of the 10 triangles around the cavernous sinus were measured to define the anatomical characteristics of the triangles and to compare their consistency in shape and area. Twelve tissue blocks containing the bilateral cavernous sinuses and medial two-thirds of the middle cranial fossae were obtained from Japanese adults at autopsy, fixed to a stereotactic frame, and examined with an operative microscope. The dimensions of each triangle were measured with calipers and compared, based on the same point and border. The anteromedial triangle and the superolateral (Parkinson's) triangle were more consistent in shape than the paramedial and oculomotor triangles, but the oculomotor triangle was larger in area than these other triangles. The posteromedial (Kawase's) triangle was more consistent in shape and larger than the anterolateral, lateral, and the posterolateral (Glasscock's) triangles. The anteromedial and superolateral (Parkinson's) triangles are important for the combined epi- and subdural approach to cavernous sinus lesions. The posteromedial (Kawase's) triangle is important for gaining access to the posterior cranial fossa from the middle cranial fossa.

Adult↗
PubMed2003

Anatomical variations of the facial nerve in first branchial cleft anomalies.

OBJECTIVE: To review our experience with branchial cleft anomalies, with special attention to their subtypes and anatomical relationship to the facial nerve. STUDY DESIGN: Case series. SETTING: Tertiary care center. PATIENTS: Ten patients who underwent resection for anomalies of the first branchial cleft, with at least 1 year of follow-up, were included in the study. The data from all cases were collected in a prospective fashion, including immediate postoperative diagrams. INTERVENTION: Complete resection of the branchial cleft anomaly was performed in all cases. Wide exposure of the facial nerve was achieved using a modified Blair incision and superficial parotidectomy. Facial nerve monitoring was used in every case. MAIN OUTCOME MEASURES: The primary outcome measurements were facial nerve function and incidence of recurrence after resection of the branchial cleft anomaly. RESULTS: Ten patients, 6 females and 4 males,with a mean age of 9 years at presentation, were treated by the senior author (P.J.K.) between 1989 and 2001. The lesions were characterized as sinus tracts (n = 5), fistulous tracts (n = 3), and cysts (n = 2). Seven lesions were medial to the facial nerve, 2 were lateral to the facial nerve, and 1 was between branches of the facial nerve. There were no complications related to facial nerve paresis or paralysis, and none of the patients has had a recurrence. CONCLUSIONS: The successful treatment of branchial cleft anomalies requires a complete resection. A safe complete resection requires a full exposure of the facial nerve, as the lesions can be variably associated with the nerve.

Adolescent↗
PubMed1995

Pylorus-preserving gastrectomy with radical lymph node dissection based on anatomical variations of the infrapyloric artery.

We devised a method for performing pylorus-preserving gastrectomy (PPG) with radical lymph node dissection without compromising pyloric blood flow, based on vascular anatomical evaluation of 210 celiac angiograms. The origin of the infrapyloric artery was variable, but consistently supplied blood flow to the pylorus and the posterior wall of the antrum. When the infrapyloric artery originated from the gastroduodenal artery or from one of its pancreatic branches (type A, 88%), the right gastroepiploic artery was divided at its origin, allowing the excision of all adjacent lymph nodes. When the infrapyloric artery originated from the right gastroepiploic artery (type B, 12%), the right gastroepiploic artery was divided distal to the infrapyloric artery origin and the short right gastroepiploic artery remnant was skeletonized of lymph nodes. We have used this technique to perform PPG on 25 patients with early gastric cancer in the middle third of the stomach with minimal morbidity and no mortality.

Adult↗
PubMedDate not supplied

The impact of pelvicaliceal anatomical variation between the stone-bearing and normal contralateral kidney on stone formation in adult patients with lower caliceal stones.

OBJECTIVE: We aimed to investigate the effect of pelvicaliceal anatomical differences on the etiology of lower caliceal stones. MATERIALS AND METHODS: Records of adult patients between January 1996 and December 2005 with solitary lower caliceal stone were reviewed. After exclusion of patients with hydronephrosis, major renal anatomic anomalies, non-calcium stones, history of recurrent stone disease and previous renal surgery, 78 patients were enrolled into the study. Lower pole infundibulopelvic angle (IPA), infundibulovertebral angle (IVA), infundibular length (IL), width (IW), number of minor calices and cortical thickness of the lower pole together with other caliceal variables obtained from the whole pelvicaliceal anatomy of both stone-bearing and contralateral normal kidneys were measured from intravenous pyelogram of the patients. Total pelvicaliceal volume was also calculated by a previously described formula for both kidneys. RESULTS: There were statistically significant difference between two kidneys in terms of IW (p < 0.001) and IL (p = 0.002) of the upper calyx, IW (p = 0.001) and IVA (p < 0.001) of the lower calyx), pelvicaliceal volume (p < 0.001), IPA of middle calyx (p = 0.006) and cortical thickness over the lower pole (p < 0.001). However there was no difference between stone-bearing and contralateral normal kidneys in terms of lower pole IPA (p = 0.864) and IL (p = 0.568). CONCLUSION: Pelvicaliceal volume but not lower caliceal properties seem to be a risk factor for stone formation in lower calyx.

Adult↗
PubMedDate not supplied

Anatomical variations and relations in the medial wall of the bony portion of the eustachian tube.

The medial wall of the bony portion of the Eustachian tube was examined, by anatomical and histological methods, in 150 temporal bones of adults. This wall consists of two parts: posterolateral (labyrinthine) and anteromedial (carotid), whose shapes, sizes and relations depend upon the position of the a. carotis interna. If it is located nearer the tympanic opening of the tube, the labyrinthine part of the wall is smaller and has a triangular shape. The further the artery is removed from the tympanic opening of the tube, the greater and more rectangular the shape of this part of the wall. The part of the medial wall which corresponds to the a. carotis interna can differ in each case and in 69% of the cases this part extended more or less into the lumen of the tube. The average thickness of this part of the wall is 1.5 mm (minimum is wafer-thin and maximum is 3 mm). In 2% of the cases the bony wall above the a. carotis interna was missing, so that the artery projected into the protympanum. Through a bone defect, aneurysm of the artery can develop. In one case, during an operation, it was established that the protrusion of the a. carotis interna into the tympanic cavity was due to a defect in the medial wall of the Eustachian tube.

Adult↗
PubMed1987

Anatomical variations and relations of the medical and lateral portions of the attic and their surgical significance.

The medial and lateral attics were examined in 150 specimens of temporal bones of adults using anatomical and histological methods. The medial attic varies in shape and size, depending upon the position of the auditory ossicles, the degree of prominence of the lateral semicircular canal and the direction in which the tympanic segment of the facial canal extends. The latero-medical diameter of this attic at the level of the body of the incus averages 1.7 mm., but is somewhat smaller at the level of the head of the malleus. The medial attic always communicates with the mesotympanum through an opening between the prominence of the tympanic part of the facial canal and the superstructures of the auditory ossicles. The lateral attic is always of smaller dimensions than the medial attic and its latero-medial diameter averages less than 1 mm. This attic very seldom communicates with the mesotympanum.

Adult↗
PubMed1999

Growth hormone deficiency with ectopic neurohypophysis: anatomical variations and relationship between the visibility of the pituitary stalk asserted by magnetic resonance imaging and anterior pituitary function.

In GH-deficient children showing ectopic posterior pituitary hyperintense signal (EPP), the anatomical details of the pituitary-hypothalamic region and the relationship between the visibility of the pituitary stalk and anterior pituitary function were studied by magnetic resonance imaging (MRI). The absence or presence of the pituitary stalk was recorded by MRI before and after the injection of gadolinium in 25 children with GH deficiency and EPP at the age of 8.7+/-5.0 yr (16 males and 9 females). Patients were classified into 2 groups according to the presence (group 1; n = 14), or the absence (group 2; n = 11) of pituitary stalk visibility after gadolinium injection. Most patients in group 1 (12 of 14) demonstrated isolated GH deficiency, whereas all but 1 patient in group 2 showed multiple anterior pituitary hormone deficiency. The prevalence of a normally sized adenohypophysis was higher in group 1 than in group 2 (50% vs. 9%; P<0.05). Although the EPP was found at the median eminence in all group 2 patients, it was visualized in group 1 at different levels of the pituitary stalk in 60% of cases (8 of 14; at the proximal end of the pituitary stalk, n = 4; in the middle of the pituitary stalk, n = 2; at the distal end of the pituitary stalk, n = 2). This demonstrates that the ectopic posterior pituitary migration abnormality may be complete or partial. In conclusion, although the pathogenesis of GH deficiency with EPP remains unclear, these results suggest that in cases of GH deficiency associated with ectopic posterior pituitary hyperintense signal, patients with no visible pituitary stalk on MRI after gadolinium injection present a more severe form of the disease in childhood associated with multiple anterior pituitary hormone deficiency, whereas visibility of the pituitary stalk is related to isolated GH deficiency. Nevertheless, careful follow-up of these latter patients is necessary, as the natural history of the disease is not established until adulthood.

Adolescent↗
PubMed2001

[Thoracic pseudo-lesions induced by inadequate methodology, optical illusions, and anatomical variations].

False-positive or over-calling of findings at chest radiography may have important consequences by generating numerous and unnecessary examinations. The advances made in thoracic imaging have currently decreased the number of technical errors. However, we are frequently confronted with visual illusions or with failure to recognize anatomical variants, either congenital, age-related or physiological in nature. Other difficulties are due to functional variations. Over-calling depends on the clinical context, which may inadequately suggest an interstitial lung process, abnormalities of the vascularization or of the hila. In this article, several examples of false positives will be illustrated. An explanation for these appearances, based on the underlying etiology, will be provided.

Age Factors↗