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 973 records · Page 54Linked to original sources

PubMed1999

Hemianopsia related to dissection of the internal carotid artery.

Spontaneous dissection of the internal carotid artery is typically associated with cerebral vascular infarction along the anterior and middle cerebral distribution, whereas occipital infarction is usually related to posterior circulation abnormalities. Hemianopsia with occipital infarction related to carotid artery dissection has therefore rarely been reported. A 40-year-old woman in whom acute-onset hemianopsia developed, related to occipital infarction secondary to internal artery dissection, is described. This atypical association is explained by anatomic variations of the posterior part of the circle of Willis. Neuroimages showed occipital infarction related to internal carotid artery dissection associated with hypoplasia of the proximal portion of the cerebral posterior artery (P1). The anatomic correlation of this atypical association and a review of the literature are presented.

Adult↗

PubMed1992

Descriptive study of genital variation in healthy, nonabused premenarchal girls.

This descriptive colposcopic study of the genitals of symptom-free young girls not thought to have been sexually abused was undertaken to contribute toward our understanding of normal female genital anatomy in this age group. Girls were examined and photographed, with labial traction in a supine frog-leg position while they were under anesthesia before minor elective surgery. The final study sample consisted of 79 premenarchal girls, aged between 3 months and 11 years 7 months (mean, 5 years 4 months). The study demonstrated wide anatomic variation and a high frequency of minor irregularities that have previously been noted in studies of sexually abused girls. Specific findings included increased vascularity (44%), midline avascular areas (27%), "ragged" posterior fourchette epithelium (18%), notch configuration of the posterior fourchette (10%), delicate tethers between the hymen and perihymen (14%), hymenal bumps between the 3 and 9 o'clock positions (11%), and asymmetry of the hymenal tissue (9%). Girls who at initial examination had apparently abnormal vestibules had either large hymenal orifices (11%) or multiple irregularities (11%). The study emphasizes the danger of overinterpreting small anatomic findings when one is evaluating the possibility of sexual abuse in girls; such findings may lie within the range of normal variation.

Child↗

PubMed1992

Variations in dorsomedial hand innervation. Electrodiagnostic implications.

Sensory potentials recorded from the dorsal cutaneous branch of the ulnar nerve (DCUN) help localize ulnar nerve lesions. This conduction technique was first described by Jabre in 1980. Abnormalities detected with this technique in control populations are commonly attributed to local trauma. Anatomic variations of cutaneous innervation to the dorsum of the hand, however, have been described. We recorded DCUN responses using both the normal DCUN stimulation point and a secondary site of stimulation at the radial aspect of the forearm in 44 patients. Eleven patients demonstrated a low-amplitude DCUN response. Four of the 11 patients demonstrated sensory potentials obtained from the routine recording site of the DCUN with radial stimulation. We conclude that an abnormal DCUN response may represent anomalous innervation. To avoid some errors in localization, radial forearm stimulation should be performed whenever the DCUN response is abnormal.

Adult↗

PubMed2000

Mathematical/computational challenges in creating deformable and probabilistic atlases of the human brain.

Striking variations in brain structure, especially in the gyral patterns of the human cortex, present fundamental challenges in human brain mapping. Probabilistic brain atlases, which encode information on structural and functional variability in large human populations, are powerful research tools with broad applications. Knowledge-based imaging algorithms can also leverage atlased information on anatomic variation. Applications include automated image labeling, pathology detection in individuals or groups, and investigating how regional anatomy is altered in disease, and with age, gender, handedness and other clinical or genetic factors. In this report, we illustrate some of the mathematical challenges involved in constructing population-based brain atlases. A disease-specific atlas is constructed to represent the human brain in Alzheimer's disease (AD). Specialized strategies are developed for population-based averaging of anatomy. Sets of high-dimensional elastic mappings, based on the principles of continuum mechanics, reconfigure the anatomy of a large number of subjects in an anatomic image database. These mappings generate a local encoding of anatomic variability and are used to create a crisp anatomical image template with highly resolved structures in their mean spatial location. Specialized approaches are also developed to average cortical topography. Since cortical patterns are altered in a variety of diseases, gyral pattern matching is used to encode the magnitude and principal directions of local cortical variation. In the resulting cortical templates, subtle features emerge. Regional asymmetries appear that are not apparent in individual anatomies. Population-based maps of cortical variation reveal a mosaic of variability patterns that segregate sharply according to functional specialization and cytoarchitectonic boundaries.

Aged↗

PubMedDate not supplied

[Non-recurrent inferior laryngeal nerve].

The Authors describe a case of non recurrent inferior laryngeal nerve located on the right side observed during anatomical studies of the innervation of the larynx. The description is accompanied by photographic documentation which shows the anomalous course of the nerve and its abnormal relationship with the right subclavian artery, also anomalous. The embryological nature of such anatomical variations is discussed followed by considerations concerning possible consequences with regard to clinical aspects and thyroid surgery. Furthermore, the Authors indicate clinical signs that may suggest the presence of such anomaly so as to avoid anatomical or functional damage of the nerve which, although anomalous, plays an important role in coordinating breathing and phonation.

Humans↗

PubMed2006

An unusual variation of the omohyoid muscle and review of literature.

The omohyoid muscle is important in radical neck dissection, as it is a landmark for this operation. Because it divides the anterior and posterior cervical triangles into smaller triangles and its particular relationship to the large cervical vessels, the presence of an anatomical variation of the omohyoid muscle is important. An unfamiliar muscle was found in the left anterior cervical region of a 57-year-old male cadaver. It was attached at its caudal end to the clavicle and coursed upward to the hyoid bone and a normal omohyoid muscle with its intermediate tendon was lateral to this muscle. Both the muscles joined together near the hyoid bone and both muscles attached to the hyoid bone with the same tendon. According to its origin and insertion, the unfamiliar muscle was considered to be the cleido-hyoideus muscle. In our case report, a variant of infrahyoid muscles is presented. Such an association constitutes an exceedingly rare condition.

Functional Laterality↗

PubMed2003

MRI of the tectorial and posterior atlanto-occipital membranes in the late stage of whiplash injury.

Our aim was to characterise and classify permanent structural changes in the tectorial and posterior atlanto-occipital membranes several years after a whiplash injury, and to evaluate the reliability of our classification. We obtained sagittal proton density-weighted images of the craniovertebral junction of 92 whiplash-injured and 30 uninjured individuals. Structural abnormalities in the two membranes were classified as grades 1-3 independently by three radiologists blinded for clinical information. Grading criteria were based on reduced tectorial membrane thickness, and elongation or rupture of the posterior atlanto-occipital membrane/dura mater complex. The same images were reassessed 4 months later. Image quality was graded good in 104 cases, slightly reduced in 13 and unsatisfactory in five. Of 117 tectorial membranes 31 (26.5%) showed grade 2 or 3 lesions, in the uninjured group none were grade 3 and only three were grade 2. Pair-wise interobserver agreement (weighted kappa) was moderate (0.47-0.50), while the intraobserver agreement was moderate to good (0.51-0.70). Of 117 posterior atlanto-occipital membranes 20 (17.1%) had grade 2 or 3 lesions; there was no grade 3 and only one grade 2 lesion in the uninjured group. Inter- and intraobserver agreement was good (0.61-0.74 and 0.65-0.86, respectively). Reduced image quality was the main reason for disagreement, but partial thinning and lateral tapering, as normal tectorial membrane variations, created difficulties in some cases. This study strongly indicates that whiplash trauma can damage the tectorial and posterior atlanto-occipital membranes; this can be shown on high-resolution MRI. Better knowledge of normal anatomical variations and improved image quality should increase the reliability of lesion classification.

Adult↗

PubMed1991

The relationship of hand preference to anatomy of the corpus callosum in men.

Area of the midsagittal section of the corpus callosum, particularly in the region of the isthmus, was found previously to be greater in non-consistent-right-handed than consistent-right-handed men in a sample of 15 postmortem cases. Seven cases were obtained subsequent to this analysis. The new cases showed the same association previously observed between hand preference and area of the corpus callosum and its isthmus. In addition, a high negative correlation was found between isthmal area and a quantitative score of the direction and magnitude of hand preference. In the new cases, handedness was predicted better than chance using statistical functions of callosal anatomy derived from the previous group of 15 cases. These results support a relationship between variation in callosal anatomy and handedness in men and the hypothesis of a relationship between callosal morphology and functional asymmetry. The lack of such a relationship among women suggests that the developmental mechanisms leading to callosal anatomical variation in relation to lateralization are influenced by sex hormones. Methodological issues in the use of magnetic resonance imaging for the quantitative study of callosal anatomy are discussed.

Autopsy↗

PubMed2005

Variation in maxillary sinus anatomy among platyrrhine monkeys.

Variations in the maxillary sinus anatomy of extant and fossil catarrhine primates have been extensively examined using computed tomography (CT), and have potential utility for phylogenetic analyses. This approach has also been used to demonstrate its anatomical variation in eight of the 16 extant genera of platyrrhines and the absence of the sinus in Saimiri and Cacajao. We used this approach to evaluate the three-dimensional anatomy of the maxillary sinus in all extant platyrrhine genera, and here argue the phylogenic implications of this variation. This study confirms, for the most part, previous CT studies and augments them with the six genera not studied previously: Ateles, Lagothrix, Callithrix, Cebuella, Pithecia and Chiropotes. The entire maxilla is pneumatized by the sinus in the atelines, Cebus, and Callicebus, whereas the sinus pneumatizes only the medial part of the maxilla in the callitrichines and Aotus. Pithecia has a unique conformation in which the maxillary sinus and the expanded inferior meatus pneumatize the posteromedial and anterolateral parts of the entire maxilla, respectively. Chiropotes has no sinus, and the inferior meatus possibly expands into the area between the middle meatus and medial surface of the maxilla to disturb sinus formation, as in the case of its close relative Cacajao. Finally, we argue that the sinus that pneumatizes the entire maxilla is a primitive feature in extant platyrrhines and was probably shared by the last common ancestor of the anthropoids.

Animals↗

PubMed1999

Contamination of lymph from the major prenodal cardiac lymphatic in dogs.

Cannulation of the canine major prenodal cardiac lymphatic (MPCL) is the most common approach for the investigation of myocardial lymphatic function. However, the assumption that the MPCL drains pure cardiac lymph has been questioned. We studied variations of MPCL anatomy and investigated whether noncardiac lymph is drained by this lymphatic. After dye was injected into the lungs and left ventricular myocardium in 21 dogs, dissection of the cardiac lymphatic system yielded 3 anatomic variations. In variations 1 and 2 (81% of dogs), a mixture of cardiac and pulmonary lymph was drained via the MPCL. In variation 3 (19% of dogs) no connection was found between MPCL and pulmonary lymphatics. In variations 1 and 2, alteration of tidal volume resulted in significant changes of lymph flow rate. The pulmonary contribution to MPCL lymph flow was estimated as 34% in variation 2. We conclude that MPCL lymph may contain not only cardiac lymph but also significant pulmonary contamination. This finding should be considered in the interpretation of lymph data from cannulation of the canine MPCL.

Animals↗

PubMed1994

Autopsical observations on the blood vessels in the human lower limb.

The heterolateral femoral triangles (Scarpa's triangles, trigona femoralis) have been examined in 48 dead adult subjects of Trieste to detect relevant macroanatomical variations, performing the autopsical method. Interesting differences have been found in the topography of blood vessels, above all the arteries, from that described as normal, or better, more frequent, in the literature. The three most relevant anatomical variations for both arteries and veins are described in detail; summarizing tables and related graphics are presented for the globality of the examined cases. The percentage ratio of the observed topographic variations appears to be remarkably different when compared to their European frequency and this may be due to the exiguous number of te cases (48 subjects, that is, 96 femoral triangles) examined by us; however, the three most relevant findings have not been reported in the literature yet. Therefore, it is also reasonable to assume that the variations described in this study, either for their peculiarity or their relevant frequence, may be explained by particular functional hemodynamic needs in the examined population of Trieste, as well as by vascular developmental reasons.

Aged↗

PubMed2006

Clinical and anatomical study of retromolar foramen and canal.

PURPOSE: The retromolar canal is a rare anatomic variation of the mandible. The neurovascular content of the mandibular retromolar canal is very important for surgical procedures involving the retromolar area and there has been a lack of information on this subject. This study consists of anatomic research of the retromolar foramen and canal, planned after an impacted third molar tooth extraction operation in which we encountered a retromolar neurovascular bundle. MATERIALS AND METHODS: Eighty sides of 40 mandibles were evaluated and the presence of the retromolar foramen and its relation to the last teeth, the transverse and sagittal distances of the retromolar trigone, and the distance of the retromolar foramen to the last socket of the arch were measured. RESULTS: The neurovascular bundle includes striated muscle fibers, thin myelinated nerve fibers, numerous venules and a muscular artery. Of the 40 mandibles included in this study, retromolar foramens were found in 10 (25%). The presence of the retromolar foramen is not dependent on the last teeth of the arch. The dimensions of the retromolar trigone were measured and the presence of the retromolar foramen was found to be nonrelevant to the dimensions of the retromolar trigone. Retromolar foramen distance from the distal edge of the last socket of the arch was found to be 11.91 +/- 6.71 mm and 4.23 +/- 2.30 mm, respectively, from the second and third molars. CONCLUSIONS: This study therefore clearly establishes the incidence and importance of the retromolar canal. This study shows that the retromolar foramen and canal can be seen occasionally in routine dental surgery. Due to the neurovascular bundle passing through it, the retromolar canal and foramen must be kept in mind in all anesthetic and surgical approaches regarding the retromolar area and mandible.

Adult↗

PubMed2006

Maxillary sinus septa: prevalence, height, location, and morphology. A reformatted computed tomography scan analysis.

BACKGROUND: The sinus lift technique may be difficult to perform if an aberrant sinus anatomy is encountered during surgical exposure, such as when a septum is present on the sinus floor. The objective of this study was to determine the prevalence, size, location, and morphology of maxillary sinus septa in the atrophic/edentulous and non-atrophic/dentate maxillary segments. METHODS: The sample population consisted of 100 patients (41 women and 59 men, with a mean age of 50 years, ranging between 19 and 87 years) for whom treatment was being planned for implant-supported restorations. Reformatted computerized tomograms (CT) from 200 sinuses were analyzed using imaging software. RESULTS: The prevalence of one or more septa per sinus was found to be 26.5% (53/200), 31.76% (27/85), and 22.61% (26/115) in the overall study population and the atrophic/edentulous and the non-atrophic/dentate maxillary segments, respectively. In the analysis of the anatomic location of the septa within the sinus, it was revealed that 15 (25.4%) were located in the anterior region, 30 (50.8%) in the middle region, and 14 (23.7%) in the posterior region. The measured heights of the septa varied among the different areas. The mean heights of the septa were 1.63 +/- 2.44, 3.55 +/- 2.58, and 5.46 +/- 3.09 mm in the lateral, middle, and medial areas, respectively. CONCLUSIONS: It can be inferred that there is a wide anatomical variation in the prevalence, size, location, and morphology of maxillary sinus septa, irrespective of the degree of atrophy. Therefore, to prevent the likelihood of complications arising during sinus augmentation procedures, a thorough and extensive understanding of the anatomic structures inherent to the maxillary sinus is indispensable.

Adolescent↗

PubMed2005

[Classification of premolars as a function of root anatomy and statistics].

The frequent endodontic failures on premolar teeth can be partly attributed to their complicated root canal anatomy. Anatomical studies were initiated almost a century ago by W. Hess, resulting in the actual meticulous classification. Vertucci was the first to describe in an exhaustive way the scores of anatomical variations by assigning them to 9 types. The Wein model is just as complete but offers a more clinical approach. It will be used as reference in this article to weigh the various statistics appearing in the anatomical studies on premolars.

Bicuspid↗

PubMed1998

[Preoperative assessment of primary varicose veins].

The first step in the evaluation of a patient with primary varicose veins is a careful personal history and clinical examination. The individual advice should be based on the disturbance suffered due to the actual varicose veins, "heaviness of the legs" and the advantages and disadvantages of various therapies. The aim of an examination in any type of varicose veins is to determine their relationship to the deep and the surrounding superficial venous system. The continuous-wave Doppler method is often sufficient to examine the trunk of the long saphenous vein. Colour-coded duplex sonography is the chosen method for evaluation of the deep venous system with respect to flow feasibility and valve competence, as well as localization of deficient perforants and anatomic variations at the saphenouspopliteal junction. Phlebography is reserved for cases with inconclusive duplex-sonography results or if no duplex is available. The purpose of this exhaustive preoperative evaluation is to indicate in detail the haemodynamic and anatomic situation in the groin and in the popliteal fossa and to detect the relevant insufficient perforators. Such accurate haemodynamic assessment is the basis for an individualized operation with excellent cosmetic and functional results. Whether a reduced recurrence rate after varicose vein surgery can be shown with this extensive examination scheme has not yet been investigated in a prospective study.

Humans↗

PubMed2005

Right upper lobe venous drainage posterior to the bronchus intermedius: preoperative identification by computed tomography.

BACKGROUND: Anatomical variations of the pulmonary vessels relevant to pulmonary surgery are of concern to thoracic surgeons. Among such variations, the right upper lobe vein posterior to the bronchus intermedius (UVPBI) has received little attention thus far. METHODS: Chest computed tomographic images and medical records of 725 patients were retrospectively reviewed. The frequency, drainage pattern, diameter, and associated anatomical characteristics of the UVPBI were assessed, and our right thoracotomy cases with the UVPBI were examined. RESULTS: The UVPBI was found in 41 (5.7%) of 725 computed tomography cases, and in 9 (3.9%) of 230 right thoracotomy cases. Three UVPBI drainage sites were observed: (1) the superior pulmonary vein group, 55%; (2) the inferior pulmonary vein group, 41%; and (3) the superior segmental vein group, 4%. The diameter of the UVPBI at the level of the bronchus intermedius ranged from 1 to 7 mm (4.1 +/- 1.6 mm). The diameter of the UVPBI in the superior pulmonary vein group was significantly greater than that in the inferior pulmonary vein group (p < 0.01). The prevalence of a central vein was 43.9% for all UVPBI cases and 15.8% for large UVPBI cases (> or = 5 mm in diameter). Of the 9 right thoracotomy patients, 1 suffered UVPBI injury; this patient's UVPBI was not identified either preoperatively or intraoperatively. CONCLUSIONS: The UVPBI is not as rare as was previously believed. It can be a main drainage route of the right upper lobe. Preoperative identification of this venous variation by computed tomography is useful for safe and accurate surgical procedures.

Adult↗

PubMed1979

Variations in the canine thoracic duct system and the effects of surgical occlusion demonstrated by rapid aqueous lymphography, using an intestinal lymphatic trunk.

An alternative method for lymphography was developed in an attempt to improve the outlining of the thoracic duct system. Lymphograms obtained on 20 normal dogs demonstrated a large extent of anatomic variation. A complete obstruction of the thoracic duct was created in six dogs through transpleural resection and ligation. The lymphatic system responded by opening lymphaticovenous anastomoses proximal to the site of obstruction.

Animals↗

PubMed2006

Coupling behavior of the cervical spine: a systematic review of the literature.

OBJECTIVE: The purpose of this study was to investigate evidence of consistency of reported directional coupling patterns among selected studies and to determine its use in manual medical treatment. METHODS: The study was a systematic literature review of English-only journals using PubMed and CINAHL. The keywords included "cervical vertebrae," "biomechanics," "coupling," and "three-dimensional movement" and required coupling directional assessment of individual spine segments. RESULTS: Four 2-dimensional and 8 3-dimensional studies met inclusion criteria. This study found 100% agreement in coupling direction (side flexion and rotation to the same side) in lower cervical vertebral segments (C2-3 and lower) and variation in coupling patterns in the upper cervical segments of occiput-C1 (during side flexion initiation) and C1-2. Dissimilarities may be explained by differences in measurement devices, movement initiation, in vivo vs in vitro specimens, and anatomical variations. CONCLUSIONS: These findings suggest that use of 3-dimensional analyzed cervical coupling patterns for the lower cervical vertebral during apposition and treatment application may show clinical use for manual clinicians. The use of directional coupling based on 2-dimensional cervical coupling patterns or upper cervical spine coupling that addresses C1-2 should be questioned.

Biomechanical Phenomena↗