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Results for “Anatomic Landmarks”

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At least 73 records · Page 4Linked to original sources

PubMed2005

Important anatomical landmarks in the lateral nasal wall.

OBJECTIVE: The study aimed to investigate the anatomy of the lateral nasal wall to provide a set of measurements among some important anatomical landmarks and to reveal the relationship between them. METHODS: Fifty half heads were dissected to determine the distances between important landmarks in the lateral nasal wall for endoscopic sinus surgery. Landmarks were measured with an electronic caliper. This study was carried out between December 2002 and February 2003 at the Anatomy Research Laboratory, Faculty of Medicine, Akdeniz University, Antalya, Turkey. RESULTS: Results were provided as mean +/- standard deviation. In our study, some of the critical distances as in the lateral nasal wall were measured and results showed consistency to the data found in the literature. CONCLUSION: Our results are useful to achieve safe endoscopic sinus surgery.

Cadaver↗

PubMed1999

Pelvis and lower limb anatomical landmark calibration precision and its propagation to bone geometry and joint angles.

Human movement analysis using stereophotogrammetry is based on the reconstruction of the instantaneous laboratory position of selected bony anatomical landmarks (AL). For this purpose, knowledge of an AL's position in relevant bone-embedded frames is required. Because ALs are not points but relatively large and curved areas, their identification by palpation or other means is subject to both intra- and inter-examiner variability. In addition, the local position of ALs, as reconstructed using an ad hoc experimental procedure (AL calibration), is affected by photogrammetric errors. The intra- and inter-examiner precision with which local positions of pelvis and lower limb palpable bony ALs can be identified and reconstructed were experimentally assessed. Six examiners and two subjects participated in the study. Intra- and inter-examiner precision (RMS distance from the mean position) resulted in the range 6-21 mm and 13-25 mm, respectively. Propagation of the imprecision of ALs to the orientation of bone-embedded anatomical frames and to hip, knee and ankle joint angles was assessed. Results showed that this imprecision may cause distortion in joint angle against time functions to the extent that information relative to angular movements in the range of 10 degrees or lower may be concealed. Bone geometry parameters estimated using the same data showed that the relevant precision does not allow for reliable bone geometry description. These findings, together with those relative to skin movement artefacts reported elsewhere, assist the human movement analyst's consciousness of the possible limitations involved in 3D movement analysis using stereophotogrammetry and call for improvements of the relevant experimental protocols.

Biomedical Engineering↗

PubMed1998

Teaching successful central venous cannulation in infants and children: audio Doppler versus anatomic landmarks.

OBJECTIVE: To determine if vein localization with an audio Doppler increases successful central venous cannulation and decreases complications in infants and children when performed by inexperienced operators, compared with vein localization by anatomic landmarks (ALs). DESIGN: A prospective cohort of infants and children undergoing central venous cannulation for cardiac surgery. SETTING: A university-affiliated children's hospital with a pediatric anesthesia fellowship program. PARTICIPANTS: All infants and children undergoing cardiac surgery between July 1, 1996, and January 1, 1997. INTERVENTIONS: Subjects had central venous catheters (CVCs) placed by an anesthesia fellow by either ALs or audio-Doppler localization of the veins. MEASUREMENTS AND MAIN RESULTS: Eighty-four children were studied. Internal jugular vein (IJV) cannulation was attempted in 71 (85%) children and femoral vein cannulation in 13 (15%) children. Time to catheter insertion, number of needle passes, and artery puncture were noted. Sixty-one of 63 (97%) children had successful central venous cannulation by an anesthesia fellow using audio-Doppler vein localization. This was significantly greater than the 13 of 21 (62%) successful cannulations among children who had veins localized by ALs. Time to insertion did not differ by method of vein localization; however, the number of needle passes was significantly greater in the AL group. Artery puncture did not differ significantly by method of vein localization. CONCLUSION: Vein localization by audio Doppler significantly increases the rate of successful central venous cannulation and decreases the number of needle passes in pediatric patients when used by inexperienced operators.

Adolescent↗

PubMed2003

Anatomic landmarks for the cervical portion of the thoracic duct.

OBJECTIVE: Avoidance of injury to the thoracic duct during neurosurgical procedures involving the cervical region depends on a working knowledge of its location. This study evaluates superficial anatomic landmarks for the cervical portion of the thoracic duct that may be encountered in neurosurgery of the neck. METHODS: Fifteen dissections of human cadavers were performed to study the relationship between the proximal thoracic duct and superficial landmarks (e.g., the cricoid cartilage and sternal notch of the manubrium). RESULTS: The cervical portion of the thoracic duct was found to be approximated by a roughly 4.4-cm(2) region in the left supraclavicular area beginning approximately 2.0 cm lateral to the midline and 3.5 cm superior to the sternal notch, extending superiorly to a point roughly 3.5 cm from the midline and 2.5 cm inferior to the cricoid cartilage, and terminating within the venous system at a point approximately 4.5 cm lateral to the midline and 3.0 cm superior to the sternal notch. CONCLUSION: Through an increased appreciation for its location, injury to the thoracic duct may be minimized.

Aged↗

PubMed2002

Anatomical landmarks for image registration in frameless stereotactic neuronavigation.

OBJECTIVE: Frameless stereotactic navigation devices require preoperative application of skin markers (SM) and planning radiography, which limits their even wider use. Therefore, we prospectively studied the applicability and accuracy of anatomic "natural" markers (NM) for image registration. METHODS: The accuracy of NM was evaluated in 26 patients operated on in the supine (n=24) or sitting (n=2) position, either by comparison to our standard navigation protocol using SM and planning radiography or by the deviation of anatomic landmarks using a routine diagnostic radiograph. In 21 cases, NM were compared to SM with planning radiography (computed tomography, or CT, in nine cases and magnetic resonance imaging, or MRI, in 12). The root mean square error (RMSE) of the registered volume was calculated by the Philips EasyGuide Neuro frameless stereotactic navigation system and compared between the two registration modalities. RESULTS: The mean RMSE was 3.2 mm+/-1.0 mm standard deviation using NM vs 2.9+/-1.0 mm using self-adhesive SM (P=0.13, Student's t-test). Computed tomography was slightly more accurate than MRI planning (mean RMSE 3.2 mm vs 3.3 mm). In three cases, diagnostic radiography (MRI) was used with a mean RMSE of 5.3 mm but acceptable intraoperative landmark correlation. CONCLUSION: Our pilot study demonstrates insignificant loss of registration accuracy using NM compared to SM. Additionally, the radiologic planning investigation and accuracy loss due to SM movement may be avoided.

Adolescent↗

PubMed2001

The parasagittal line: an anatomic landmark for axial imaging.

BACKGROUND AND PURPOSE: No validated imaging landmark exists for characterizing the medial-lateral position of abnormalities at the high convexity-parasagittal region. Our understanding of the courses and deflections of the upper cerebral sulci is limited. Our purpose, therefore, was to define a frontooccipital line with reproducible anatomic relations to the upper cerebral gyri and sulci and to validate that line for use as an anatomic landmark by specific analysis of the gyral-sulcal relationships along it. METHODS: In 100 subjects of all ages, the gyri and sulci visualized on serial axial CT sections of the upper brain were traced onto a single flat surface to delineate the anatomic relationships among the midline interhemispheric fissure, the paramedian superior frontal sulci (SFS) and intraoccipital sulci (IOS), the medial surface sulci, the high convexity sulci, and the inner table of the skull. These tracings provided a template for drawing a straight, best-fit parasagittal line from the SFS to the IOS and for assessing how reproducibly key anatomic structures align along the parasagittal line. To assure the applicability of the line to MR imaging, selected relationships were retested on serial axial MR sections in the same subjects. RESULTS: The parasagittal line could be drawn in each case and showed reproducible alignment with the SFS, hand-motor area, partes marginales, pars deflections, postcentral "parentheses," distal intraparietal sulci, and IOS. In supraventricular sections, the parasagittal line separated the sulci arising along the medial surface from those arising along the convexity. CONCLUSION: Because the anatomic relationships of the parasagittal line are reproducible, it may serve as a reference line or landmark. The tendency of this line to demarcate medial sulci from convexity sulci suggests immediate application to the definition of vascular territories and vascular watersheds, a topic under active investigation.

Adolescent↗

PubMed1983

Spatial relationship between anatomic landmarks in edentulous patients: a radiographic study.

In 67 edentulous patients the crests of the residual ridges, the incisive papillae, the maxillary tuberosities, and the mandibular retromolar pads were located and identified with metallic wires inside the acrylic resin denture bases. Occlusal cephalometric radiographs were used to record the spatial relationship between the described anatomic landmarks in the dentures with the mandible in centric relation.

Adult↗

PubMed1995

Transvaginal sacrospinous colpopexy: anatomic landmarks to be aware of to minimize complications.

Transvaginal sacrospinous colpopexy is currently used to repair varying degrees of vaginal vault prolapse. It involves placing a stitch from the vaginal cuff to the sacrospinous ligament approximately 2 cm medial to the ischial spine to correct the defect. This may be associated with pudendal artery and nerve (pudendal complex) along with sciatic nerve injury if the procedure is not carefully performed. This study was designed to emphasize the anatomic landmarks that make the sacrospinous ligament a potentially dangerous zone that surgeons must be aware of to minimize complications. Twenty-four female cadavers were obtained from the Louisiana State University Medical School anatomy laboratory. They were carefully dissected to expose the anatomic structures of interest. The following measurements were then obtained: the distance from the ischial spine to the medial border of the sacrum, the medial and lateral aspects of the pudendal complex, and the sciatic nerve. The obstetric conjugate of the pelves was also obtained. The pudendal complex and sciatic nerve were found to be 0.90 to 3.30 cm medial to the ischial spine. After the six smallest and largest pelves were compared, it was noted that the larger the obstetric conjugate the longer the sacrospinous ligament and vice versa. Also, the distance from the ischial spine to the sciatic nerve correlated with the size of the obstetric conjugate. The pudendal complex and sciatic nerve travel underneath the lateral third of the sacrospinous ligament. Therefore we recommend that the placement of the stitch be made medial to that portion of the ligament. More importantly, the stitch must be placed as superficial as possible and never across the entire thickness of the sacropinous ligament. This should decrease the rate of complications associated with this type of colpopexy.

Cadaver↗

PubMed2006

The anatomic landmarks of ethmoidal arteries for the surgical approaches.

Knowledge of variations in the possible patterns of origins, courses, and distributions of the ethmoidal arteries are necessary for the diagnosis and important for the treatment of orbital disorders. Ethmoidal arteries are damaged in endonasal surgical interventions and in operations performed on the inner wall of the orbita.A description of the anatomic landmarks of the ethmoidal arteries and ethmoidal canals is presented, based on data from microdissection in 19 adult cadavers studied after injection of red-dyed latex into the arterial bed. In all subjects, each of ethmoidal arteries originated from ophthalmic artery. The anterior ethmoidal artery was observed in all specimens except for one case. The diameter of the artery thicker than the posterior ethmoidal artery was 0.92 +/- 0.2 mm on the right and 0.88 +/- 0.15 mm on the left. The branching of the anterior ethmoidal artery from the ophthalmic artery was determined in four different types. The diameter of the posterior ethmoidal artery was measured as 0.66 +/- 0.21 mm on the right and 0.63 +/- 0.19 mm on the left. The anterior ethmoidal canal was located between the second and third lamella in 29 of 38 cases. The mean distance between the limen nasi and anterior ethmoidal canal was 48.1 +/- 3.2 mm.The article confirms the well-known variability of the ethmoidal arteries and their topographic relation to the ethmoidal canals. Advances in surgical techniques, instrumentation, and regional arterial anatomy have resulted in functional operations of endoscopic sinus and orbital surgery with fewer complications.

Adult↗

PubMed1998

Stereotactic pallidotomy and thalamotomy using individual variations of anatomic landmarks for localization.

OBJECTIVE: The optimal choice of imaging and localization for stereotactic surgery for movement disorders remains uncertain, with controversy surrounding the use of microelectrode recording and the role of distortion of magnetic resonance imaging (MRI) scans in reducing the accuracy of lesion placement. We review our experience with 67 pallidotomies and 35 thalamotomies performed without microelectrode recording, using instead individual variations in anatomic landmarks. METHODS: Computed tomography is used as the primary modality, with comparison with carefully angled MRI scans and the use of neural structures, such as the mamillary bodies and the vascular anatomy. Pallidal target sites are chosen immediately lateral and superior to the optic tract on a line bisecting the axis of the peduncle, with macrostimulation guiding the final adjustment of target position. Forty-seven patients undergoing unilateral pallidotomies were studied in the "off" state and the "on" state using a modified Unified Rating Scale for Parkinson's disease (URSP) score and a dyskinesia scale, preoperatively and postoperatively at 2 weeks, 2 months, 6 months, and 12 months. In the 31 patients undergoing thalamotomy, tremor was rated preoperatively and postoperatively as near-complete resolution, partial resolution, and failure. RESULTS: The "off" state Unified Rating Scale for Parkinson's disease motor score declined from 42.0 to 32.2 at 2 weeks after surgery (P < 0.0001, n = 42). The Unified Rating Scale for Parkinson's disease motor score was 34.2 at 2 months (P < 0.0001, n = 35), 29.4 at 6 months (P < 0.0001, n = 27), and 24.9 at 12 months (P = 0.005, n = 12), representing an overall improvement in "off" state motor function of approximately 25 to 40%. The "on" state dyskinesia score fell from 5.5 to 2.0 at 2 weeks (P < 0.0001) and persisted in the later visits. The dyskinesia score for the contralateral side fell from 2.5 preoperatively to 0.26 at 2 weeks, 0.28 at 2 months, 0.22 at 6 months, and 0.0 at 12 months. Of the patients undergoing thalamotomies, 65% experienced near-complete or complete tremor resolution, 23% experienced partial tremor relief, and 13% were considered treatment failures. CONCLUSION: Stereotactic procedures for movement disorders requiring high precision can be safely and successfully performed without the use of microelectrode recording techniques. Meticulous alignment of MRI and computed tomographic scans based on visualized anatomy allows precise lesion placement and avoids the distortion inherent in MRI scans.

Globus Pallidus↗

PubMed2007

Posterior approach technique for accessory-suprascapular nerve transfer: a cadaveric study of the anatomical landmarks and number of myelinated axons.

Accessory-suprascapular nerve transfer by the anterior supraclavicular approach technique was suggested to ensure transferrance of the spinal accessory nerve to healthy recipients. However, a double crush lesion of the suprascapular nerve might not be sufficiently demonstrated. In that case, accessory-suprascapular nerve transfer by the posterior approach would probably solve the problem. The aim of this study was to evaluate the anatomical landmarks and histomorphometry of the spinal accessory and suprascapular nerve in the posterior approach. Dissection of fresh cadaveric shoulder in a prone position identified the spinal accessory and suprascapular nerve by the trapezius muscle splitting technique. After that, nerves were taken for histomorphometric evaluation. The spinal accessory nerve was located approximately halfway between the spinous process and conoid tubercle. The average distance from the conoid tubercle to the suprascapular nerve (medial edge of the suprascapular notch) is 3.3 cm. The mean number of myelinated axons of the spinal accessory and suprascapular nerve was 1,603 and 6,004 axons, respectively. The results of this study supported the brachial plexus reconstructive surgeons, who carry out accessory-suprascapular nerve transfer by using the posterior approach technique. This technique is an alternative for patients who have severe crushed injury of the shoulder or suspected double crush lesion of the suprascapular nerve.

Accessory Nerve↗

PubMed1990

Transcranial Doppler sonography: anatomical landmarks and normal velocity values.

Until recently, both the diagnosis of intracranial occlusive disease of the large brain arteries, as well as intracranial flow abnormalities due to extracranial arterial lesions, have been a "blind spot" for ultrasound techniques. With the advent of transcranial Doppler sonography (TCD), however, a broad spectrum of potential clinical and scientific applications of TCD to the intracranial vasculature has been advocated. In order to achieve an informative insonation of vessels and a correct interpretation of findings, knowledge of both anatomical landmarks within the skull and flow characteristics of distinct vessel segments are necessary. This paper presents such data elaborated from 64 carotid and 42 vertebral angiograms, 40 contrast-medium enhanced CT scans demonstrating the circle of Willis, 122 normal sagittal MRI scans of the brainstem, 40 cadaver skulls, 38 fresh cadavers, 106 normal volunteers and 59 patients with subclavian steal mechanisms. The main findings were as follows: The inner internal carotid artery bifurcation, the M1-segment of the middle cerebral artery, the C3-segment of the carotid siphon, the vertebral artery junction and the top of the basilar artery were found at insonation depths of 60.4 +/- 7, 40 +/- 8 to 60.4 +/- 7, 62 +/- 4, 84 +/- 8 and 108 +/- 8 mm, respectively. Normal mean flow velocities within the M1-segment, the posterior cerebral artery, the carotid siphon and the basilar trunk were 58 +/- 15.6, 39 +/- 9.9, 47 +/- 13.8 and 41 +/- 10 cm/s, respectively, and revealed a marked decrease with age. Intraindividual side-to-side differences were low. Vertebrobasilar data from measurements of neuroradiological material closely met in vivo findings in normals and patients. Criteria for the identification of various vessel segments are provided. On the basis of these findings, a topographical orientation within the skull should be possible in order that beginners commence TCD accurately. Normative velocity data are helpful for differentiating normal and pathological flow conditions at different ages.

Adolescent↗

PubMed2003

The safe face lift with bony anatomic landmarks to elevate the SMAS.

The risk for facial nerve injury has been reported to be increased with the inclusion of superficial musculoaponeurotic system (SMAS) elevation as compared with a skin-only face lift. The facial nerve courses through the parotid gland. The SMAS is elevated superficial to the parotid gland. However, in elevating the SMAS anterior to the parotid gland, the facial nerve is at risk of injury where its branches emerge from the anterior edge of the parotid gland. The purpose of this study was to identify bony anatomic landmarks to predict the location of the anterior edge of the parotid gland to avoid injury to the facial nerve branches as they exit the parotid gland. The authors dissected 20 cadaver face halves to determine bony landmarks-the masseteric tuberosity and the inferior lateral orbital rim-to predict the location of the anterior parotid edge. Then they measured the anterior edge of the parotid gland in relation to the vector formed between these two bony landmarks. They identified and measured the most anterior portion of the parotid gland in relation to this vector. Then the most posterior aspect of the parotid gland in relation to this vector was measured. In the 20 dissections, the authors found the most anterior portion of the parotid gland to be 2.7 +/- 1.0 mm anterior to the vector from the inferior lateral orbital rim to the masseteric tuberosity. The most posterior part of the anterior edge of the parotid gland in relation to this vector was found to be 1.0 +/- 1.5 mm posterior to this vector. The parotid gland measured an average of 38.8 +/- 3.5 mm in width from the tragus to the anterior parotid edge. In elevating the SMAS with a face lift, the facial nerve branches can be predicted to exit the anterior edge of the parotid gland, which can be located 38.8 mm anterior to the tragus and near the vector from the inferior lateral orbital wall to the masseteric tuberosity.

Cephalometry↗

PubMed2005

Translevator posterior intravaginal slingplasty: anatomical landmarks and safety margins.

The posterior intravaginal sling is a new tension-free needle suspension technique. It is used for the treatment of middle compartment (vaginal vault or uterine) prolapse. The Prolene sling suspends the vagina at the upper border of level II support as described by DeLancey (Am J Obstet Gynecol 166:1717, 1992). Human cadaveric dissections were undertaken to explore the pertinent anatomy that is involved when using this blind needle technique. Pre-dissected cadaveric material was used to obtain didactic illustrations of the anatomy of the procedure. Description of the surgical technique using anatomical landmarks and relative distances of the needle to these landmarks will improve the surgeon's visual understanding of the procedure. The measurements obtained demonstrate that the needle stays at a minimal distance of 4 cm away from the major (pudendal) vessels that could potentially cause life-threatening haemorrhage.

Cadaver↗

PubMedDate not supplied

Verification of selected anatomic landmarks used as reference points for universal goniometer positioning during knee joint mobility range measurements.

The study was concerned with verification of the selection of reference points used for knee joint mobility range goniometry. The verification was based on photometric and electrogoniometric methods of femorotibial angle measurements. The material for measurements were three knee joint preparations. The obtained data were subjected to descriptive analysis; photographic documentation of geometric relations between the reference points was also prepared. Considerable divergence of measurement results was observed with respect to the actual knee joint flexion angle, amounting even to 16 degrees. The differences are due to the selection of anatomic landmarks, and depend in particular on the distance of the point to which the goniometer axis is applied from the approximate location of the mechanical joint axis. The corrections of knee joint flexion angle measurements were also estimated on the basis of data obtained from the photographs and the derived mathematical formula.

Humans↗

PubMed2002

Lower blepharoplasty using bony anatomical landmarks to identify and avoid injury to the inferior oblique muscle.

In the resection of redundant orbital fat during lower blepharoplasty, selective excision is performed from the medial, central, and lateral compartments. During transcutaneous blepharoplasty, the inferior oblique muscle is susceptible to injury because of its intimate association between the medial and central compartments. When performing a transconjunctival approach, the inferior oblique muscle is even more susceptible to injury because it lies in the direct path of dissection for fat pad exposure. Injury to the inferior oblique muscle can result in symptoms ranging from transient diplopia to a more debilitating permanent strabismus. Fresh cadaver heads were used to identify bony anatomical landmarks that would help to more accurately define the origin and body of the inferior oblique muscle. The orbital rim, infraorbital foramen, and supraorbital notch were chosen as guideline landmarks. The origin of the inferior oblique muscle was designated with respect to the above structures, and the muscle course was delineated. The inferior oblique muscle originates on the orbital floor, 5.14 +/- 1.21 mm posterior to the inferior orbital rim, on a line extending from the infraorbital foramen to 10 +/- 0.9 mm inferior to the supraorbital notch along the supramedial orbital rim. The muscle belly extends from this origin to its insertion into the posterolateral globe in an oblique direction toward the lateral canthal area. Identification of the orbital rim, infraorbital foramen, and supraorbital notch more accurately localizes the origin and course of the inferior oblique muscle, which may facilitate fat resection during lower blepharoplasty by preventing morbidity associated with inferior oblique muscle injury.

Adipose Tissue↗

PubMed2006

Anatomic landmarks: their usefulness in safe laparoscopic cholecystectomy.

The incidence of bile duct injury in laparoscopic cholecystectomy is 0.3% to 1.0%. This is higher than the incidence reported for open cholecystectomy (i.e., 0.1-0.2%), and the surgeons all over the world are relentlessly trying to find the ways and means to lower this incidence. Various operating strategies, techniques, and instrumentations such as the 0 degrees telescope, intraoperative cholangiogram, hydrodissection, and peanut gauze dissection have been claimed by various authors to minimize the risk of bile duct injury during cholecystectomy. However, the surgical fraternity agrees that there has been no substitute for meticulous dissection and display of various vital structures near the common bile duct. The authors describe seven anatomic landmarks encountered during laparoscopic cholecystectomy that assist in safe dissection to prevent bile duct and vascular injury. On the basis of their experience, they believe that if surgeons adhere to these landmarks, excellent results can be achieved.

Adult↗

PubMed2005

Soft tissue artifact compensation in knee kinematics by double anatomical landmark calibration: performance of a novel method during selected motor tasks.

The purpose of the present work was to describe and assess the performance on two selected subjects of a new method for the compensation of soft tissue artifact on knee rotations and translations during the execution of step up/down, sit-to-stand/stand-to-sit, and flexion against gravity. Soft tissue artifact has been recognized as the most critical source of error in gait analysis data. Its propagation strongly affects joint angles, in particular those characterized by a small range of motion, such as knee ab/adduction and internal/external rotation. This may be critical in the exploitation of gait analysis data for clinical decisions. The proposed method is based on the flexion/extension angle interpolation of two anatomical landmark calibrations taken at the extremes of motion. Its performance on knee rotation and translations was tested on a kinematics data-set obtained by the synchronous combination of traditional stereophotogrammetry and 3-D fluoroscopy. The newly proposed method was extremely effective on the compensation of soft tissue artifact propagation to knee rotations, in particular mean values of the root mean square error on ab/adduction and internal/external rotation angles decreased from 3.7 degrees and 3.7 degrees to 1.4 degrees and 1.6 degrees, respectively, with respect to single calibration. Mainly, knee translations calculated from stereophotogrammetric data using the proposed compensation method were found to be reliable with respect to the fluoroscopy-based gold standard. The residual mean values of the root mean square error were 2.0, 2.8, and 2.1 mm for anterior/posterior, vertical, and medio/lateral translations, respectively.

Aged↗