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At least 523 records · Page 29Linked to original sources
PubMed2006

Anatomy of neurovascular structures around the carpal tunnel during dynamic wrist motion for endoscopic carpal tunnel release.

OBJECTIVE: The purpose of this study is to investigate the anatomic relationship between neurovascular structures and the transverse carpal ligament (TCL) so as to avoid complications during an endoscopic carpal tunnel release procedure. METHODS: Fresh cadaver hands from seven men and 12 women (age range, 48-74 yr) were used. The neurovascular structures just over and under the TCL were meticulously dissected under loupe magnification. Several anatomic landmarks were calculated (average length of the TCL; average distance between the TCL distal margin and the neurovascular structures; and average lengths of the superficial palmar arch, ramus communicantes, recurrent motor branch, and palmar cutaneous branch of the median nerve). The ulnar neurovascular structure was studied with the wrist positioned in neutral, ulnar flexion, and radial flexion. RESULTS: The anatomic relationships between the TCL and vascular and neural structures were measured. The ulnar neurovascular structures usually passed just over ulnar to the superior portion of the hook of the hamate. However, in 11 hands, a looped ulnar artery coursed 1 to 4 mm radial to the hook of the hamate and continued to the superficial palmar arch. The looped ulnar artery migrates on the ulnar side of Guyon's canal (-2-2 mm radial to the hook of the hamate) with the wrist in radial flexion (of the wrist). During ulnar flexion of the wrist, the ulnar artery shifts more radially beyond the hook of the hamate (2-7 mm). CONCLUSION: It is appropriate to transect the ligament over 4 mm apart from the lateral margin of the hook of the hamate without placing the edge of the scalpel toward the ulnar side. We would also recommend not transecting the TCL in the ulnar flexed wrist position to protect the ulnar neurovascular structure. The proximal portal could be made just ulnar to the palmaris longus tendon to spare the neurovascular structures in the proximal portion of the TCL.

Aged↗
PubMed1995

Decision making in distal radius fractures.

In distal radius fractures, function follows restoration of preinjury anatomic landmarks. The allowable deviation from these measurements is relatively small if optimal results are to be achieved, particularly in younger individuals. A hierarchy of treatment options--characterized by increasing invasiveness--exists for treating these injuries. As this hierarchy is ascended, treatment-related complications increase. It appears reasonable to select the least invasive treatment option capable of achieving satisfactory anatomic alignment. Hand and extremity function must be addressed early, and a conscientious effort must be exerted to avoid residual stiffness or the development of reflex sympathetic dystrophy.

Colles' Fracture↗
PubMed2000

Isolated resection of segment 8 for liver tumors: a new approach for anatomical segmentectomy.

HYPOTHESIS: Isolated resection of segment 8 (the right anterosuperior liver segment) is one of the most difficult hepatectomies to perform because of the location of segment 8, the relation between section 8 and the main intrahepatic vessels, and the absence of any anatomical landmarks. The few reports that deal with isolated resection of section 8 generally describe the use of a deep wedge transparenchymal transection. DESIGN: Original surgical technique. PATIENTS AND METHODS: The proposed technique is based on the extraparenchymal isolation and temporary clamping of the right anterior artery and portal branches, causing ischemic demarcation on the liver surface, which corresponds to the anatomical borders of the right paramedian segments (5 and 8). The liver is widely transected along the main hepatic fissure; then the pedicles of segment 8 are selectively ligated inside the parenchyma, and the resection is accomplished. This technique was used in 10 patients: 5 with hepatocellular carcinoma on cirrhosis and 5 with liver metastases. RESULTS: The mean operation time was 253 minutes. Intraoperative blood loss was minimal in all cases, and 7 patients did not require blood transfusion. Slight complications developed in 3 patients, and there was no operative death. The mean hospital stay was 9.3 days. CONCLUSIONS: This operative procedure is safe and ensures a complete anatomical resection of segment 8. The wide opening of the liver parenchyma facilitates hemostasis and makes it possible to obtain a correct resection margin. This technique is recommended for limited metastatic lesions located in segment 8 or for hepatocellular carcinoma arising in a cirrhotic liver.

Adult↗
PubMed2005

Talairach-based parcellation of neonatal brain magnetic resonance imaging data: validation of a new approach.

BACKGROUND AND PURPOSE: Talairach-based parcellation (TP) of human brain magnetic resonance imaging (MRI) data has been used increasingly in clinical research to make regional measurements of brain structures in vivo. Recently, TP has been applied to pediatric research to elucidate the changes in regional brain volumes related to several neurological disorders. However, all freely available tools have been designed to parcellate adult brain MRI data. Parcellation of neonatal MRI data is very challenging owing to the lack of strong signal contrast, variability in signal intensity within tissues, and the small size and thus difficulty in identifying small structures used as landmarks for TP. Hence the authors designed and validated a new interactive tool to parcellate brain MRI data from newborns and young infants. METHODS: The authors' tool was developed as part of a postprocessing pipeline, which includes registration of multichannel MR images, segmentation, and parcellation of the segmented data. The tool employs user-friendly interactive software to visualize and assign the anatomic landmarks required for parcellation, after which the planes and parcels are generated automatically by the algorithm. The authors then performed 3 sets of validation experiments to test the precision and reliability of their tool. RESULTS: Validation experiments of intra-and interrater reliability on data obtained from newborn and 1-year-old children showed a very high sensitivity of >95% and specificity >99.9%. The authors also showed that rotating and reformatting the original MRI data results in a statistically significant difference in parcel volumes, demonstrating the importance of using a tool such as theirs that does not require realignment of the data prior to parcellation. CONCLUSIONS: To the authors' knowledge, the presented approach is the first TP method that has been developed and validated specifically for neonatal brain MRI data. Their approach would also be valuable for the analysis of brain MRI data from older children and adults.

Brain↗
PubMed1977

[Intramural anterior interventricular artery. Anatomical study].

In an anatomical study of 187 patients who had died from various heart disorders, the anterior descending artery (ADA) had an intra-mural course in 33 cases (17.65 p. 100). This abnormal course had had no correlation with the sex of the patients, the nature of the disease, length of the trunk of the left coronary artery, and to the relative sizes of the coronary vascular supply on the right and the left. It is associated, to a degree which may reach statistical significance, with certain abnormalities of distrubution of the ADA itself, of other pericardial arteries, and with a particularly short course which means that it does not reach the apex of the heart in more than a third of cases. The anatomical position of the intraparietal segment appears to be remarkably constant, and several anatomical landmarks (the origin of the second anterior septal artery and of the second diagonal artery, both collaterals of the anterior descending artery) may lead one to suspect the presence of an anomaly in the course of the artery when the coronary arteriogram is doubtful. The thickness of the muscular bridge is variable, but is not as a rule great. The most constant anatomical finding is that the anterior descending artery, in its intra-parietal segment, maintains a thin wall, and is never the seat of atheromatous deposits, whatever the age of the patient.

Arteries↗
PubMedDate not supplied

New anatomic repair of midline abdominal wall incisions extending to suprapubic region.

This article describes a new technique to close infraumbilical midline abdominal wall incisions extending to the suprapubic region. This repair is technically easy to perform, saves time, reduces the risk of bowel and bladder injury and takes into consideration the anatomical landmarks of the peritoneum, the rectus sheath and the arcuate line. Abdominal wall closure with this repair is especially useful in obese patients. Furthermore, with this repair the pelvic cavity is lined with smooth peritoneum, which may reduce postoperative adhesions in the pelvis. Technically easy to perform and saves time Very useful technique for obese patients Reduced risk of bowel and bladder injury Anatomical in nature Potentially minimizes postoperative adhesions.

Abdominal Wall↗
PubMed1997

Angioplasty guidewire velocity: a new simple method to calculate absolute coronary blood velocity and flow.

The Thrombolysis In Myocardial Infarction (TIMI) frame count is a relative index of coronary flow that measures time by counting the number of frames required for dye to travel from the ostium to a standardized coronary landmark in a cineangiogram filmed at a known speed (frames/s). We describe a new method to measure distance along arteries so that absolute velocity (length divided by time) and absolute flow (area x velocity) may be calculated in patients undergoing percutaneous transluminal coronary angiography (PTCA). After PTCA, the guidewire tip is placed at the coronary landmark and a Kelly clamp is placed on the guidewire where it exits the Y-adapter. The guidewire tip is then withdrawn to the catheter tip and a second Kelly clamp is placed on the wire where it exits the Y-adapter. The distance between the 2 Kelly clamps outside the body is the distance between the catheter tip and the anatomic landmark inside the body. Velocity (cm/s) may be calculated as this distance (cm) divided by TIMI frame count (frames) x film frame speed (frames/s). Flow (ml/s) may be calculated by multiplying this velocity (cm/s) and the mean cross-sectional lumen area (cm2) along the length of the artery to the TIMI landmark. In 30 patients, velocity increased from 13.9 +/- 8.5 cm/s before to 22.8 +/- 9.3 cm/s after PTCA (p <0.001). Despite TIMI grade 3 flow both before and after PTCA in 18 patients, velocity actually increased 38%, from 17.0 +/- 5.4 to 23.5 +/- 9.0 cm/s (p = 0.01). For all 30 patients, flow doubled from 0.6 +/- 0.4 ml/s before to 1.2 +/- 0.6 ml/s after PTCA (p <0.001). In the 18 patients with TIMI grade 3 flow both before and after PTCA, flow increased 86%, from 0.7 +/- 0.3 to 1.3 +/- 0.6 ml/s (p = 0.001). Distance along coronary arteries (length) can be simply measured using a PTCA guidewire. This length may be combined with the TIMI frame count to calculate measures of absolute velocity and flow that are sensitive to changes in perfusion. TIMI grade 3 flow is composed of a range of velocities and flows.

Angioplasty, Balloon, Coronary↗
PubMed1996

Validation and clinical application of computer-combined computed tomography and positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose head and neck images.

BACKGROUND: Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose (PET-FDG) improves the detection of head and neck squamous cell cancer (HNSCC), but lacks anatomical detail. The accuracy of registered computed tomography/magnetic resonance (CT/MR) and PET-FDG in delineation of HNSCC at the primary site and its clinical application was investigated. METHOD: Preoperatively 30 patients were staged clinically and each had either CT (23), MR (5), or both CT and MR (2) scans, as well as CT/MR-PET-FDG registration. Tumor margins or infiltration of specific anatomical landmarks on the different scans were compared and judged against histology. RESULTS: For primary tumors CT-PET-FDG (97%) and MR-PET-FDG (100%) delineated the tumor more accurately than CT (69%) or MR (40%) alone. Similarly, CT-PET-FDG (98%) and MR-PET-FDG (100%) were better than CT (70%) and MR alone (80%) in identifying tumor invasion of specific anatomical structures. Management was altered in 7 of 30 patients. The registered images were particularly useful in delineating tumor extension in the infratemporal fossa, maxilla and mandible, and identifying recurrences obscured by scar tissue. CONCLUSIONS: It is possible to accurately register CT, MR, and PET-FDG data sets in the head and neck. The initial results show that registered CT/ MR-PET-FDG images provide additional clinically relevant information over that obtained from clinical evaluation or conventional CT/MR imaging.

Carcinoma, Squamous Cell↗
PubMed2006

Study to outline the efficacy and illustrate techniques for steroid injection for trigger finger and thumb.

AIM: To outline the efficacy of a steroid injection in treating trigger finger. Our study defines the anatomy of the A1 pulley, and suggests methods for simple and safe flexor sheath injection for trigger finger and thumb. METHOD: Systematic review of published literature on trigger finger and thumb and its treatment, particularly steroid injection. The use of the knowledge of the superficial landmarks of the A1 pulley with the techniques described were combined to provide a comprehensive guide to injecting steroids in patients with trigger finger and thumb. RESULTS: Several studies are outlined, which provided evidence to suggest that a steroid injection into the flexor sheath of the affected digit is successful in treating most of the patients. Methods of identifying the superficial landmarks of the A1 pulley and of approaching the pulley without injury to surrounding structures are also outlined in the literature. Two different techniques used to infiltrate the flexor sheath were described. CONCLUSION: Steroid injection in the flexor sheath at the level of the A1 pulley is an effective method of treating patients with trigger finger and should be considered as the preferred treatment. Specific anatomical landmarks and methods allow the procedure to be carried out without fear of inadvertent damage to surrounding structures.

Adrenal Cortex Hormones↗
PubMed2005

The Heidelberg foot measurement method: development, description and assessment.

The aim of this study was to develop and evaluate a kinematic measurement method for the foot that could be applied clinically to measure foot function including all typical foot deformities. The ankle was modelled as two anatomically based hinge joints rotating around anatomical axes estimated by the use of projection angles. For the mid- and forefoot a descriptive approach was chosen by defining angles between anatomical landmarks or reference points derived from these landmarks. The motion of 17 markers on the lower leg and foot was measured during walking gait on 10 adult participants with no known abnormalities to determine the pattern of normal foot motion, assess reliability and provide a reference against which pathological foot behaviour could be compared. Functional angles for mid- and forefoot motions were developed to improve clinical applications of the data. The combination of anatomically and technically oriented marker placement on the foot is a reliable basis for reproducible kinematic measurements and the method was shown to be viable for clinical practice.

Adult↗
PubMed1998

A three-dimensional musculoskeletal database for the lower extremities.

A three-dimensional musculoskeletal database of the lower extremities has been developed for use in human musculoskeletal models. The locations of idealized muscle attachments on the pelvis, both femurs, both tibias and fibulas, and both feet were accurately digitized for 52 dried skeletal specimens. The mean specimen heights were 177.5 cm (male) and 166.2 cm (female) and the mean specimen age at the time of death was 48.8 yr. Statistical accumulation and scaling techniques were used to generate highly representative normative models, which were divided into groups and tested for differences based on gender and race. From the test results, the pelvis was divided into a male model (RMS = 8.6 mm), a black female model (RMS = 7.0 mm) and a white female model (RMS = 7.3 mm). The foot was separated into black (RMS = 3.7 mm) and white models (RMS = 3.6 mm). Single models were used for the femur (RMS = 6.5 mm) and the tibia/fibula (RMS = 3.7). Containing over 12000 anatomical landmarks digitized from 52 dried skeletons, this study represents an improvement over previous databases by an order of magnitude.

Black People↗
PubMed1996

Three-dimensional facial anthropometry using a laser surface scanner: validation of the technique.

Three-dimensional measurement and characterization of facial surface anatomy are fundamental to the objective analysis of facial deformity. However, existing clinical tools are inadequate. Recent innovations in laser scanning technology provide a potentially useful technique for accurate three-dimensional documentation of the face. The purpose of this study is to evaluate the reliability of interactive anthropometric landmark localization based on digitized three-dimensional facial images and to identify sources of error associated with the technique. Three-dimensional surface data were acquired using a commercially available laser scanning device (Cyberware 3030RGB digitizer), and all subsequent anthropometric analyses were performed interactively on the computer monitor. Four experimental conditions were studied, with 10 observations for each condition. A stable anthropomorphic model with prelabeled anatomic landmarks was scanned repeatedly under varying conditions of head inclination and position within the scanning gantry to determine the effect of these variables on the reliability of the technique. The scanning protocol was then repeated with the labels removed to evaluate the reliability of interactive localization of anthropometric landmarks on a digitized three-dimensional image. Optimal results were obtained with the head positioned in the center of the scanning gantry and with the Frankfort plane elevated 10 degrees from the horizontal. Under these circumstances, all 22 labeled landmarks were visualized and the variance in landmark localization was less than 0.6 mm in the x (horizontal), y (vertical), and z (depth) dimensions. Varying head position or inclination caused significant degradation of the digitized image. The variance of interactive landmark localization was analyzed in three dimensions. The reliability and the spatial orientation of variability were determined for each anthropometric point. These findings have direct implications for the clinical adaptation of this diagnostic tool for quantitative evaluation of facial surface anatomy.

Cephalometry↗
PubMed1979

Fucntional specialization and binocular interaction in the visual areas of rhesus monkey prestriate cortex.

If is is believed that neural mechanisms mediating stereoscopic vision may be localized in specific areas of the visual cortex, then it becomes necessary to be able to define these areas adequately. This is no easy matter in the rhesus monkey, an animal close to man, where the cytoarchitecturally uniform prestriate cortex is folded into deep sulci with secondary gyri. One way around this awkward problem is to use the callosal connections of the prestriate cortex as the anatomical landmarks. Callosal connections are restricted to regions at which the vertical meridian is represented. Since the visual fields, including the vertical meridian, are separately represented in each area, each has its own callosal connections. These are of great help in defining some of the boundaries of these areas, since the boundaries often coincide with the representation of the vertical meridian. With the visual areas thus defined anatomically, it becomes relatively easy to assign recordings to particular areas. Studies of binocular interactions in these areas reveal that most cells in all prestriate areas are binocularly driven. Hence, theoretically, all of the prestriate areas are candidates for stereoscopic mechanisms. The degree of binocular interaction varies from cell to cell. At the two extremes are cells which either respond to monocular stimulation only and are inhibited by binocular stimulation or ones which respond to binocular stimulation only. Changing, as opposed to fixed, disparity is signalled by two types of cells. In one category are cells activated in opposite directions for the two eyes. Such cells are always binocularly driven. In the other category are cells, some of which are monocularly activated, that are capable of responding to changing image size. In the monkey, both these categories of cells have so far been found in the motion area of the superior temporal sulcus only.

Animals↗
PubMed1995

A laboratory model for dental radiographic studies.

Though a number of laboratory models have been developed to study the effects of X-ray geometry on the appearance and relative positions of anatomical landmarks, such as the amelocemental junction and alveolar crest, many have failed to take into account the three-dimensional nature of the alveolus and its spatial relationships with the teeth. As a result, the findings of many ex vivo investigations must be questioned. The aim of this investigation was to develop and refine a new laboratory method for experimental dental radiography utilizing a series of anatomical radio-opaque acrylic models containing extracted teeth. The method allows adjustment of the beam-object relationship through the use of precision-made wedges, which are able to tilt the models through a series of angles thus simulating in vivo changes in both vertical and horizontal X-ray beam angulation. The technique is capable of being used in studies involving assessment of alveolar bone height or the depth of carious lesions. The precision of the method was tested by radiographing in nine different positions a test device consisting of four small amalgam fillings embedded in a perspex sheet. Following removal and replacement, exposures of the test device were repeated for each position. Five linear distances between pairs of fillings were selected and measured on each radiograph to give a total of 45 measurements per set of films. There was exact agreement in 39 of the measurements recorded and a discrepancy of +/- 0.1 mm in the remaining six. The estimated standard deviation for variation on repeat radiography was 0.258 and the 95% confidence interval 0.214 to 0.325. The precision of the apparatus was thus found to be adequate for the measurement of differences in small distances.

Acrylic Resins↗
PubMedDate not supplied

Model based dynamic 3D reconstruction and display of the left ventricle from 2D cross-sectional echocardiograms.

In this paper we describe a technique for dynamic three-dimensional (3D) reconstruction of the left ventricle, using boundaries from multiple two-dimensional (2D) echocardiographic views. We use a geometric model of the left ventricle and anatomical landmarks to relate the recorded views to positions within the model. The reconstruction is step-wise refined by replacing model data with recorded contour data.

Algorithms↗
PubMed2007

MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications.

INTRODUCTION: Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve. METHODS: A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm. Anatomical landmarks were palpated and marked with MRI markers. After MR scanning, the sciatic nerve was identified by two readers independently in the resulting 3D dataset. RESULTS: In every volunteer, the sciatic nerve could be identified bilaterally over the whole length of the thigh, even in areas of close contact to isointense muscles. The landmark of the greater trochanter was falsely palpated by 2.2 cm, and the knee joint by 1 cm. The mean distance between the bifurcation of the sciatic nerve and the knee-joint gap was 6 cm (+/-1.8 cm). The mean results of the two readers differed by 1-6%. CONCLUSION: With the described method of MR neurography, the sciatic nerve was depicted reliably and objectively in great anatomical detail over the whole length of the thigh. Important anatomical information can be obtained. The clinical applications of MR neurography for the brachial plexus and lumbosacral plexus/sciatic nerve are discussed.

Adolescent↗
PubMed2005

MRI-based surface-assisted parcellation of human cerebellar cortex: an anatomically specified method with estimate of reliability.

We revisit here a surface assisted parcellation (SAP) system of the human cerebellar cortex originally described in Makris, N., Hodge, S.M., Haselgrove, C., Kennedy, D.N., Dale, A., Fischl, B., Rosen, B.R., Harris, G., Caviness, V.S., Jr., Schmahmann, J.D., 2003. Human cerebellum: surface-assisted cortical parcellation and volumetry with magnetic resonance imaging. J Cogn Neurosci 15, 584-599. This system preserves the topographic and morphologic uniqueness of the individual cerebellum and allows for volumetric analysis and representation of multimodal structural and functional data on the cerebellar cortex. This methodology integrates features of automated routines of the program FreeSurfer as well as semi-automated and manual procedures of the program Cardviews to create 64 cerebellar parcellation units based on fissure information and anatomical landmarks of the cerebellar surface. Using this technique, we undertook the parcellation of ten cerebella by two independent raters. The reliability of the resulting parcellation units (64 total) was high, with an average Intraclass Correlation Coefficient (ICC) of 0.724 in the vermis and 0.853 in the hemispheres. Clusters of parcellation units were then created, based on lobar and connectivity data and functional hypotheses. These 36 clusters, when treated as anatomical units, had an average ICC of 0.933. Whereas the individual units provide a high level of detail and anatomical specificity, the clusters add flexibility to the analysis by providing higher reliability.

Algorithms↗
PubMed2001

Epidural motor cortex stimulation with functional imaging guidance.

Chronic epidural motor cortex stimulation (MCS) has been shown to have promise in the treatment of patients with refractory deafferentation pain. Precise placement of the electrode over the motor cortex region corresponding to the area of pain is essential for the success of this procedure. Whereas standard anatomical landmarks have been used in the past in conjunction with image guidance, the use of functional brain imaging can be beneficial in the precise surgical planning. The authors report the use of functional imaging-guided frameless stereotactic surgery for epidural MCS. Five patients underwent MCS in which functional imaging guidance was used. Prior to surgery, patients underwent magnetic resonance (MR) imaging with skin fiducial markers placed on standard anatomical reference prints, followed by magnetoencephalography (MEG) mapping of the sensory and motor cortices. In two patients, functional MR imaging was also performed using a motor task paradigm. The functional imaging data were integrated into a frameless stereotactic database by using a three-dimensional coregistration algorithm. Subsequently, a frameless stereotactic craniotomy was performed using the integrated anatomical and functional imaging data for surgical planning. Intraoperative somatosensory evoked potentials (SSEPs) and direct stimulation were used to confirm the target and final placement of the electrode. Direct stimulation and SSEPs performed intraoperatively confirmed the accuracy of the functional imaging data. Trial periods of stimulation successfully reduced pain in three of the five patients who then underwent permanent internal placement of the system. At a mean 6-month follow up, these patients reported an average reduction in pain of 55% on a visual analog scale. The integration of functional and anatomical imaging data allows for precise and efficient surgical planning and may reduce the time necessary for intraoperative physiological verification.

Humans↗