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 1,423 records · Page 79Linked to original sources

PubMed2006

Ulnar tendinous interconnection in type IIIA thumb hypoplasia--a pollex adductus.

We present an anatomic variation of type IIIA thumb hypoplasia in which a tendinous interconnection between the flexor pollicis longus and the extensor pollicis longus occurred on the ulnar aspect of the thumb. Interconnection between extrinsic flexor and extensor systems is well known in type IIIA thumb hypoplasia and has been reported on the radial side (pollex abductus). In our patient the ulnar location of the interconnection remained unrecognized until recurrence of the deformity in adolescence.

Adolescent↗

PubMed2005

Case of trigger finger related to an intertendinous connection between the flexor tendons.

We report a rare cause of trigger finger related to an anatomical variation of an intertendinous connection between the flexor digitorum superficialis and flexor digitorum profundus tendons in the palmar region.

Female↗

PubMed2006

Selective, reversible occlusion of the middle cerebral artery in rats by an intraluminal approach. Optimized filament design and methodology.

These studies optimized design and application of an intraluminal filament method to achieve selective middle cerebral artery (MCA) occlusion in rats. Silicone plugs of 300 microm diameter and 700-800 microm length were molded onto 6-0 suture. These were introduced into Wistar rats previously fitted with telemetric probes, using established placement procedures, with and without heparinization. Temperature and activity were monitored for 3 days, after which lesion volumes were assessed by triphenyltetrazolium chloride staining. Optimized filaments entered the MCA in 85% of Wistar rats, failures being attributable to anatomical variation at its origin from the internal carotid artery. Infarcts restricted to the MCA territory were apparent after 90 min occlusion, and maximal after 3 h occlusion. Intraischemic hyperthermia was noted in a third of occlusions performed without heparin, but never with anticoagulant treatment. Permanent occlusions were also evaluated in Fisher, Lewis, Long-Evans, Spontaneously Hypertensive and Sprague-Dawley rats, and Wistar rats from a second supplier, and compared with data for surgical MCA occlusions. Success rates varied among strains, but infarct volumes correlated with those obtained after surgical occlusions in respective populations. These studies demonstrate the feasibility and limitations of reversible and selective intraluminal filament occlusion of the MCA in rats.

Animals↗

PubMed2006

Assessment of femoral neck strength by 3-dimensional X-ray absorptiometry.

Hip fractures due to osteoporosis are accompanied with increased mortality and morbidity. Bone mineral density (BMD [g/cm(2)]) measured by dual-energy X-ray absorptiometry (DXA) is the most important risk factor. However, an overlap exists between results of fractured and nonfractured populations. Macro-architectural parameters of the femur are independent risk factors of fracture. They have been evaluated in two dimensions using X-ray films or DXA scans; therefore, they are highly dependent on patient positioning and interindividual anatomical variations. To overcome this problem, we have previously shown the possibility to reconstruct human femurs using two perpendicular DXA scans and to calculate 3-dimensional (3D) geometric parameters from these reconstructions by a method called 3-dimensional X-ray absorptiometry (3D-XA). The aim of this article is to assess whether the combination of areal BMD and 3D geometric parameters calculated from 3D-XA improves failure load prediction of human proximal femurs in stance phase configuration. Twelve femurs (11 women, 1 man; aged 88+/-9 yr; range: 72-103 yr) were included in this study. The BMD was measured using a Hologic Delphi-W device (Hologic, Waltham, MA) and 3D reconstruction of the femurs was done using two perpendicular DXA scans as previously published. The calculated 3D geometric parameters included femoral neck axis length (FNAL), mid-femoral neck cross-sectional area (mid-FN CSA), neck shaft angle (NSA), and femoral head diameter (FHD). Mechanical testing was performed using stance phase configuration, which resulted in subcapital fractures. The FHD was correlated to mid-FN CSA and FNAL (r=0.68 and 0.76, respectively; p<0.001). Failure load was correlated to age, FHD, NSA, and BMD measurements. Multiple regression analysis showed that femoral neck BMD, FHD, and mid-FN CSA gave the best statistical model for failure load prediction (r(2)=0.84; p<0.002). This is the first study suggesting that combining areal BMD to 3D geometric parameters obtained by 3D-XA improve failure load prediction in human femurs.

Absorptiometry, Photon↗

PubMed2006

Endodontic management of a maxillary first molar with a single root and a single canal diagnosed with the aid of spiral CT: a case report.

The aim of this article is to present an endodontically managed maxillary first molar with an unusual morphology of a single root and a single canal, which has not been reported in the literature so far. An accurate assessment of this unusual morphology was made with the help of a Spiral computed tomography. This report extends the range of known possible anatomical variations to include teeth with lesser number of roots and canals. This report also highlights the role of Spiral computed tomography as an objective method to confirm the three-dimensional anatomy of teeth.

Acute Disease↗

PubMed2004

Hepatic venoplasty to overcome outflow block in living related liver transplantation.

A 14-year-old boy with congenital biliary atresia underwent living related liver transplantation. Because of anatomic variation in donor hepatic vein, there were small and double orifices of hepatic veins in the harvested left hemiliver graft. To minimize the risk of outflow block after reperfusion, the recipient's native hepatic vein was used as an autologous patch for hepatic vein reconstruction. After 3 years of follow-up, the patient is alive and well with normal liver function. Follow-up duplex ultrasound scan showed adequate hepatic vein outflow without signs of late obstruction. The new technique of the autologous vascular patch grafting for successful hepatic vein reconstruction is described.

Adolescent↗

PubMed2005

[Surgical anatomy of the dorsal face of the hand and the wrist].

The anatomical knowledge of the dorsal aspect of the hand has been enriched these last years by a more surgically applied approach, especially of that of its integument and blood supply. The vascularization of the superficial nerves, the anastomoses between the dorsal and palmar arterial networks has allowed designing new flaps, ante- and retrograde, usable in the coverage of more and more distal defects. The extensor apparatus shows many anatomic variations, often asymptomatic, except the extensor digitorum brevis manus muscle, which can mimic a mass at the dorsal aspect of the hand.

Blood Vessels↗

PubMed2004

Selective brain cooling seems to be a mechanism leading to human craniofacial diversity observed in different geographical regions.

Selective brain cooling (SBC) can occur in hyperthermic humans despite the fact that humans have no carotid rete, a vascular structure that facilitates countercurrent heat exchange located at the base of the skull in some mammals. Emissary and angular veins, upper respiratory tract, tympanic cavity and cerebrospinal fluid are major components of SBC system in humans. The efficiency of SBC is increased by evaporation of sweat on the head and by ventilation through the nose, but it is surprising to find out that mammals do not display SBC during exercise hyperthermia. What is the explanation then for the SBC at high body temperatures? Our hypothesis is that selective brain cooling protects the brain from thermal damage in a long-standing manner by allowing adaptive mechanisms to change the craniofacial morphology appropriate for different environmental conditions. Since the brain can only be as big that can cool, it is not surprising to find a lower (below 1300 cm(3)) cranial volume in Australian Aborigines with respect to the one (over 1450 cm(3)) in Eskimos. In addition to lower brain volume, other craniofacial features such as thick everted lips, broader nasal cavity and bigger paranasal sinuses that provide more evaporating surfaces seem to be anatomical variations developed in time for an effective SBC in hot climates. It was reported previously that these biological adaptations result from the tissues of neural crest origin. Among the crest derivatives, leptomeninges (pia and arachnoid mater), skeletal and connective tissues of the face and much of the skull seem to be structures upon which environment operates to produce more convenient craniofacial morphology for an effective SBC. In conclusion, selective brain cooling seems to be a mechanism leading to adaptive craniofacial diversity observed in different geographical regions. Thus, SBC is necessary for long-term biological adaptation, not for protecting the brain from acute thermal damage.

Adaptation, Physiological↗

PubMed2005

Representative brain selection using a group-specific tissue probability map.

PURPOSE: To determine the anatomy of a standard brain reflecting well-defined group characteristics based on probabilistic information from group-specific anatomical variations. MATERIALS AND METHODS: We constructed a group-specific tissue probabilistic map for 20 subjects and used it to extract voxel-wise probabilistic information for each subject through regional spatial normalization using Automated Image Registration software (AIR 5.2.5). Extracted probabilistic information was then used to determine standard properties of the subjects. For comparison, we employed an empirical scoring function - a measure of entropy - in ordering the data set. A brain with minimum entropy was then selected for a group standard. The evaluation of our proposed method was performed using two different selection schemes: deformation analysis and similarity index measurements. RESULTS: This method showed highly correlated result with previous method by Kochunov et al., with fewer computational tasks. CONCLUSION: This method can thus be used to determine an appropriate standard model to compare with disease-affected brains.

Adult↗

PubMed2004

Normal MR imaging anatomy of the elbow.

The functional complexity achieved at the elbow is a reflection of the sophisticated architecture that embodies this articulation. In addition to challenging anatomic relationships to conceptualize, there are many anatomic variations that exist in the osseous, capsular, and muscular structures. This article offers a detailed description of the structural and imaging anatomy of the elbow, information that establishes the foundation of imaging interpretation of internal derangements.

Collateral Ligaments↗

PubMed2005

MR imaging of femoroacetabular impingement.

FAI is a common cause of OA of the hip. It can be caused by decreased offset of the femoral head and neck, resulting in abutment of the femoral neck against the acetabular rim (cam impingement) and abutment of this area into the well-constrained socket (pincer impingement)within normal range of motion [15]. This repetitive mechanical trauma to the hip joint causes mechanical wear of the labrum and articular cartilage; left untreated, it causes pain, labral tears, and chondral injuries leading to progressive OA of the hip. The identification of FAI as a cause of OA allows appropriate therapy early and thus delays or prevents end-stage arthritis.MR imaging and MR arthrography are accurate noninvasive imaging modalities able to demonstrate acetabular labral disease and adjacent cartilage damage as well as the subchondral cysts and synovial herniation pits associated with impingement. In addition, MR imaging is able to detect underlying subtle anatomic variations of the femoral head-neck junction and acetabulum associated with FAI.

Acetabulum↗

PubMed2005

Brain structural mapping using a novel hybrid implicit/explicit framework based on the level-set method.

This paper presents a novel approach to feature-based brain image warping, by using a hybrid implicit/explicit framework, which unifies many prior approaches in a common framework. In the first step, we develop links between image warping and the level-set method, and we formulate the fundamental mathematics required for this hybrid implicit/explicit approach. In the second step, we incorporate the large-deformation models into these formulations, leading to a complete and elegant treatment of anatomical structure matching. In this latest approach, exact matching of anatomy is achieved by comparing the target to the warped source structure under the forward mapping and the source to the warped target structure under the backward mapping. Because anatomy is represented nonparametrically, a path is constructed linking the source to the target structure without prior knowledge of their point correspondence. The final point correspondence is constructed based on the linking path with the minimal energy. Intensity-similarity measures can be naturally incorporated in the same framework as landmark constraints by combining them in the gradient descent body forces. We illustrate the approach with two applications: (1) tensor-based morphometry of the corpus callosum in autistic children; and (2) matching cortical surfaces to measure the profile of cortical anatomic variation. In summary, the new mathematical techniques introduced here contribute fundamentally to the mapping of brain structure and its variation and provide a framework that unites feature and intensity-based image registration techniques.

Algorithms↗

PubMed2005

What is the relationship between chronic sinus disease and isolated nasal septal deviation?

OBJECTIVE: The aim of this retrospective study is to examine the role of isolated nasal septal deviation (NSD) in the pathogenesis of chronic rhinosinusitis (CRS). STUDY DESIGN AND SETTING: The interaction between isolated NSD and chronic sinus disease were retrospectively evaluated in 1452 patients. Out of 1452 patients, 152 patients were included in the study. Patients with anatomical variants other than NSD were excluded from the study. Patients with NSD were enrolled in the study group and patients without NSD were enrolled in the control group. RESULTS: There was no statistically significant difference between NSD group and non-NSD group with respect to the CRS. CONCLUSIONS: The mild to moderate degree of NSD was not a risk factor for chronic sinus disease. Only gross deviation of the nasal septum itself is a risk factor for the development of CRS. SIGNIFICANCE: Excluding the subjects with ostiomeatal anatomic variations has differentiated this study from the previously reported researches (isolated NSD).

Adolescent↗

PubMed2006

Surgical consideration to optic nerve protrusion according to sinus computed tomography.

OBJECTIVES: This study aimed to investigate the prevalence of optic nerve protrusion (ONP) and its clinical indicators by using sinus computed tomography (CT) scan. STUDY DESIGN: Sinus CT scans of 260 consecutive patients with chronic inflammatory sinus disease were reviewed. RESULTS: The prevalence of ONP in our study population was 28%. Nineteen percent of the optic nerves protruded into the sphenoid sinuses including indentation of the sinus wall (12%) and coursing through the sphenoid sinus (8%). In the presence of contralateral ONP and/or ipsilateral anterior clinoid process pneumatization, the chance of ONP occurrence was significantly higher (both P < 0.01). They were reliable indicators of ONP (R(2) = 0.47, P < 0.01). CONCLUSIONS: ONP is a common anatomic variation observed in patients with chronic inflammatory sinus disease. To reduce optic nerve damage in surgeries, the presence of ONP according to sinus CT scans and the intraoperative findings should be carefully evaluated. EBM RATING: C-4.

Adolescent↗

PubMed2006

Stapedectomy in congenital stapes fixation: are hearing outcomes poorer?

OBJECTIVE: To evaluate outcomes of stapedectomy surgery for congenital stapes fixation. STUDY DESIGN: Retrospective chart review. METHODS: The charts of 463 stapedectomies performed by 1 surgeon from 1996 to 2003 were reviewed. Patients with a history of childhood hearing loss and operative findings consistent with congenital fixation of the stapes were included. Patients with a history of trauma or chronic otitis media and those with otosclerosis were excluded. Thirty-six patients underwent stapedectomy for congenital fixation. Revision cases and those with inadequate postoperative bone or air conduction data were excluded. Inclusion criteria were met for 25 patients. Operative findings and hearing outcomes were evaluated. RESULTS: The study group was comprised of 25 stapedectomies. Closure of the air-bone gap to less than 10 dB was achieved in 48% of cases, and 80% had closure within 20 dB. A gap of more than 30 dB remained in 3 cases. There were 2 cases of sensorineural hearing loss with worsening of the bone conduction thresholds by 15 dB and 30 dB. There were no instances of perilymph gusher. In addition to an excluded case that was not reconstructed because of facial nerve position, 3 of the included patients were found to have a dehiscent facial nerve at surgery. There were no facial nerve injuries, and fixation of the malleus or incus was not found in any of the included patients. When hearing outcomes were compared with our results for otosclerosis over the same time period, rates of closure to within 10 dB and 20 dB were significantly worse in the congenital group. CONCLUSION: Closure of the air-bone gap in this population differs from our results in stapedectomy done for otosclerosis. This difference likely reflects subtle anatomic variations in the congenital group that affect the effectiveness of the prosthesis. Despite the difference in results, stapedectomy for congenital fixation remains an effective method to achieve significant hearing improvement in the majority of patients. EBM RATING: B-3b.

Adolescent↗

PubMed2005

Oculomotor studies of cerebellar function in autism.

Histopathological, neuroimaging and genetic findings indicate cerebellar abnormalities in autism, but the extent of neurophysiological dysfunction associated with those findings has not been systematically examined. Suppression of intrusive saccades (square wave jerks) and the ability to sustain eccentric gaze, two phenomena requiring intact cerebellar function, were examined in 52 high-functioning individuals with autism and 52 age- and IQ-matched healthy subjects during visual fixation of static central and peripheral targets. Rates of intrusive saccades were not increased in autism during visual fixation, and foveopetal ocular drift was also not increased when subjects held an eccentric gaze. The absence of gross disturbances of visual fixation associated with cerebellar disease in individuals with autism, such as increased square wave jerk rates and foveopetal drift when holding eccentric gaze, indicates that the functional integrity of cerebellar--brainstem networks devoted to oculomotor control is preserved in autism despite reported anatomic variations. However, increased amplitude of intrusive saccades and reduced latency of target refixation after intrusive saccades were observed in individuals with autism, especially when subjects maintained fixation of remembered target locations without sensory guidance. The atypical metrics of intrusive saccades that were observed may be attributable to faulty functional connectivity in cortico-cerebellar networks.

Adolescent↗

PubMed2006

Normal MR imaging anatomy of the elbow.

Elbow Joint↗

PubMed2006

Radiological assessment of the adult chest: implications for chest compressions.

The recommended depth for chest compression during adult cardiopulmonary resuscitation (CPR) is 4-5 cm, and for children one-third the anterior-posterior (AP) chest diameter. A compression depth of one-third of the AP chest diameter has also been suggested for adult CPR. We have assessed chest CT scans to measure what proportion of the adult AP chest diameter is compressed during CPR. Measurements of AP diameter of chest CT scans were taken from the skin anteriorly at the middle of the lower half of the sternum, perpendicularly to the skin on the posterior thorax. The anatomical structure that would be compressed at this level was also noted. One hundred consecutive CT scans were examined (66 males and 34 females). The age (mean +/- S.D.) was 68+/-12 years. AP chest diameter was 253 +/- 27 mm for males and 235 +/- 30 mm for females. The proportion of total AP chest diameter compressed with current compressions is 15.8-19.8% for males and 17.0-21.3% for females. The commonest anatomical structures that would be compressed are the ascending aorta (38%) and the top of the left atrium (36%). There is also a wide anatomical variation in the shape of the adult chest. A chest compression depth of 4-5 cm in adults equates to approximately one-fifth of the AP diameter of the adult chest.

Adult↗