Consistent Anatomic Landmarks Research Articles

A novel osteotomy in shoulder joint replacement based on analysis of the cartilage/metaphyseal interface

BackgroundThe accuracy of reconstruction is thought to impact on functional outcome following glenohumeral joint arthroplasty. The objective of this study was to define an area of minimal anatomic variation at the cartilage/metaphyseal interface of the proximal humerus to optimize the osteotomy of the humeral head, enabling accurate reconstruction with a prosthetic component. MethodsHand held digitization and 3D surface laser scanning techniques were used to digitize 24 cadaveric arms and determine the normal geometry. Each humeral head was then examined to identify the most consistent anatomical landmarks for the ideal osteotomy plane to optimize humeral component positioning. FindingsThe novel, posterior referencing, osteotomy resulted in a mean increase in retroversion of only 0.4° when compared to the original geometry. A traditional anterior referencing osteotomy, by comparison, produced a mean increase in retroversion of 11°. In addition, the novel osteotomy only increased axial diameter by 0.71mm and head height by 0.02mm compared to an anterior referencing osteotomy (3.0mm and 2.7mm respectively). InterpretationThe traditional osteotomy, referencing the anterior border of the cartilage/metaphyseal interface potentially resulted in an increase in prosthetic head size and retroversion. The novel osteotomy, referencing from the posterior cartilage/metaphyseal interface enabled a more accurate recovery of head geometry. Importantly, the increase in retroversion created by the traditional osteotomy was not replicated with the novel technique. Referencing from the posterior cartilage/metaphyseal interface produced a more reliable osteotomy, more closely matching the original humeral geometry. Level of EvidenceBasic Science, Anatomic study, Computer model.

New Findings In Hip Capsular Anatomy: A Cadaveric Study of the Ligamentous and Muscular Contributions to the Hip Capsule

Interest in capsulotomy techniques for access to advanced arthroscopic procedures of the hip continues to grow. Extra-articular capsulotomy has been proposed as an expedient means of obtaining access to the periarticular structures of the hip. The purpose of this study was to establish consistent anatomical landmarks based on observed capsular attachments for safe and reproducible extra articular capsulotomy. Detailed dissections of twelve nonpaired, fresh-frozen cadaveric adult hips were performed. Using a modified hemi-quadrant system, capsular thickness at 40 locations across its length and circumference was recorded. The insertions and attachments of the surrounding pericapsular structures including the minimus, rectus femoris, and iliocapsularis muscles were also recorded according to footprint size and distance from reproducible osseous landmarks. The intra-articular distance of the capsular origin from the bony acetabular rim and the intra-articular distance of the capsular insertion from the femoral head-neck junction was measured. All measurements were made to the nearest 0.1 mm with a digital caliper (Neiko Tools; Ontario, CA) with measurement accuracy of ± 0.02 mm. The intraclass correlation coefficient (ICC) for all measurements taken was > 0.90. Along the acetabular origin, the capsule was thickest along its posterosuperior and superior hemi-quadrants. The midcapsular quadrants were thickest superolaterally. At its femoral insertion, the capsule was thickest anteriorly.Tabled 1QuadrantAcetabular OriginCenter of CapsuleFemoral InsertionPosterior2.1 ± 1.92.4 ± 0.80.5 ± 0.2Postero-Inferior1.9 ± 1.31.5 ± 0.30.8 ± 0.3Inferior1.3 ± 0.31.2 ± 0.41.7 ± 0.8Antero-Inferior1.3 ± 0.71.4 ± 0.53.3 ± 1.5Anterior1.2 ± 0.61.5 ± 0.93.4 ± 1.4Antero-Superior1.6 ± 0.92.3 ± 1.82.0 ± 0.6Superior5.1 ± 3.13.4 ± 2.11.3 ± 0.9Postero-Superior4.2 ± 3.45.3 ± 1.51.0 ± 0.3Capsular Thickness Open table in a new tab The iliocapsularis, indirect head of the rectus and gluteus minimus tendons all demonstrated consistent capsular contributions. Using extra-articular landmarks as a reference, the capsular origin was located approximately 13 mm distal to the AIIS and 11 mm lateral to the pectineal eminence. The mean distance of the capsular insertion along the proximal femur measured from the chondral head-neck junction was 26.2 mm. Safe Zone for Anterior Capsulotomy Our data demonstrates that the hip capsule is thickest along its anterior and superior quadrants. In addition, there are consistent and large muscular contributions from the iliocapsularis, gluteus minimus, and reflected head of the rectus. A precise understanding of the consistent relationships that exist between the pericapsular musculature and capsular thickness may facilitate the identification of a consistent "safe zone" for anterior capsulotomy during hip arthroscopy. Further research is needed to establish whether anterior capsulotomy can be reliably performed in a manner that minimizes damage to this anterior capsular anatomy.

The Subzygomatic Triangle

The masseteric nerve is a valuable donor nerve in the management of facial paralysis; however, its location is less familiar to surgeons because this motor nerve is not commonly exposed in other head and neck procedures. Current techniques for masseteric nerve identification rely on physical measurements from surface or bony landmarks that may be unpredictable across patient age, ethnicity, and size. The authors sought to identify a rapid and minimally invasive technique based on surgical anatomy independent of intraoperative physical measurements. A two-phase, fresh-frozen cadaver study was performed followed by a clinical application that included 11 consecutive patients undergoing facial reanimation procedures between May of 2012 and October of 2012. Ten cadavers were dissected and 11 clinical applications are reported. In all dissections, the masseteric nerve was identified through the newly described "subzygomatic triangle." This triangle is formed by the zygomatic arch superiorly, the temporomandibular joint posteriorly, and the frontal branch of the facial nerve inferiorly and anteriorly. This finding was consistent across patient ages (8 to 49 years) and ethnicities. By using the short-scar, minimal dissection approach described in the study, average time to nerve identification was 10.2 minutes during the clinical application. The subzygomatic triangle is a consistent anatomic landmark for rapid, reliable, and minimally invasive identification of the masseteric nerve. Use of the subzygomatic triangle obviates the need for extensive dissection and surgeon reliance on soft-tissue measurements that may vary among patients of different size, sex, or ethnicity. Therapeutic, IV.

St George's Vascular Institute Protocol: An Accurate and Reproducible Methodology to Enable Comprehensive Characterization of Infrarenal Abdominal Aortic Aneurysm Morphology in Clinical and Research Applications

To define the reproducibility of a protocol for the analysis of infrarenal abdominal aortic aneurysm (AAA) morphology for clinical and research purposes. A protocol for the comprehensive assessment of preoperative AAA morphology based on formal systematic review and expert opinion featured 114 morphological parameters (maximum and minimum diameters, cross-sectional areas, vessel lengths, volumes, angulation, and calcification and tortuosity indices) in each of 3 regions: the neck, sac, and access vessels. To validate the protocol, 4 observers measured these variables on the preoperative computed tomographic angiograms from 50 patients (45 men; mean age 75 years, range 52-89) scheduled for endovascular aneurysm repair using software for 3-dimensional image reconstruction. One observer performed repeated measurements. The intra- and interobserver variabilities were calculated for all parameters; measurement time for all 114 features was recorded. Aortoiliac diameter, length, volume, area, and tortuosity index measurements showed good inter/intraobserver agreement. Aortic neck and aortoiliac angle measurements displayed high intra/interobserver repeatability coefficients (28%-43% and 29%-61%, respectively). Calcification measurements had the highest variability within and between observers: 39%-65% and 44%-96%, respectively. The measurement protocol was completed in a mean 105 minutes (range 55-420). Accurate 3-dimensional analysis of AAA morphology can be performed reliably within a reasonable time. Measurements that relied on consistent anatomical landmarks were most reproducible. Assessment of angulation and calcification required a number of subjective judgments, increasing the potential for variation. Automated methods are likely to be more suitable for certain measurements.

A surgical view of the superior nasal turbinate: anatomical study

Differences of the superior nasal turbinate (SNT), presence of the supreme nasal turbinate (SpNT) and measurements of opening sphenoid sinus (OSS) are consistent anatomical landmarks that allow for safe entrances, such as posterior ethmoidectomy and sphenoid sinusotomy. The purpose of study was to investigate the anatomical details of the SNT for approaching the OSS on 20 specimens of adult cadavers under an operating microscope. The SNT and SpNT were localized more perpendicular than parallel to their axes. The SpNT structure was observed in 12 specimens (60%) and it was classified into three types. Type A SpNT was shortest of all turbinates (58.3%). In types B and C, SpNT was equal or larger than the SNT. These types were seen in 41.7% of specimens. In 11 specimens, posterior ethmoidal cells opened to supreme nasal meatus. In 7 specimens, there was one opening to supreme nasal meatus, while 2 openings were detected in 12 specimens, and 3 openings were seen in 1 specimen. All these openings belonged to posterior ethmoidal cells. To determine the position of the OSS, distances between some anatomical points were measured. In cases where the SpNT is present or the SpNT is bigger than the SNT, it is certain that a different method will be applied during the procedure in the nasal cavity. The SNT and the SpNT may easily be injured by unrecognized dissection in types B and C, leading to the disruption of its olfactory neuroepithelium and possibly to postoperative hyposmia.

The Lateral Intercondylar Ridge—A Key to Anatomic Anterior Cruciate Ligament Reconstruction

As our techniques for anterior cruciate ligament reconstruction have evolved, our focus has drifted from anatomy. We believe that it is important to hearken back to anatomy and to fully understand normal anatomy so that we can try to restore it with anterior cruciate ligament reconstruction surgery. The results associated with current anterior cruciate ligament reconstruction techniques are adequate but not exceptional. A recent meta-analysis of the outcomes of anterior cruciate ligament reconstruction indicated that only 33% of patients who had reconstruction with hamstring tendon graft and 41% of those who had reconstruction with bone-patellar tendon-bone graft had normal outcomes according to the final International Knee Documentation Committee score1. There is clearly room for improvement, and we think that the keys to improvement will be based on anatomical anterior cruciate ligament reconstruction. In their paper entitled “Morphology of the Femoral Intercondylar Notch,” Farrow et al. evaluate the anatomy of the lateral intercondylar notch in 200 cadaveric specimens. The authors' goal—namely, to perform a detailed study of the area where the anterior cruciate ligament attaches in order to provide more reliable guidance for femoral tunnel placement—is admirable. The authors note that the osseous ridge that Dr. Clancy termed the “resident's ridge” was present in 194 of …

The Lateral Intercondylar Ridge-A Key to Anatomic Anterior Cruciate Ligament Reconstruction

The Lateral Intercondylar Ridge-A Key to Anatomic Anterior Cruciate Ligament Reconstruction

Is the Bare Spot a Consistent Landmark for Shoulder Arthroscopy? A Study of 20 Embalmed Glenoids With 3-Dimensional Computed Tomographic Reconstruction

Our aim was to test a published methodology for arthroscopically quantifying glenoid bone loss for its dependability in a cadaver-based anatomic study with 3-dimensional (3-D) computed tomographic (CT) reconstructions of 20 embalmed glenoids. Manual macroscopic measurements were made in a standardized fashion. In addition, we marked the center of the visible bare spot in 20 embalmed glenoids with a titanium pin. The shoulder joints were carefully selected for intact rotator cuff, missing capsule-labral deficiency, and absence of severe cartilage degeneration. 3-D reconstructed CT scans were evaluated for consistency of the bare spot. The mean distance from the bare spot to the anterior margin measured manually was 10.9 mm (CT-based, 13.9 mm), to the posterior margin 13.7 mm (CT-based, 16.4 mm), and to the inferior margin 9.7 mm (CT-based, 15.1 mm). Distances were significantly different. The bare spot did not prove its consistency in 20 carefully selected specimens. Therefore, we conclude that this methodology is not a reliable way to intraoperatively determine bony glenoid deficiency. We recommend preoperative bilateral CT scans for evaluation of bony glenoid deficiency for exact quantification of the bone loss.

The sizes of internal jugular veins in Turkish children aged between 7 and 12 years

Objective: In this study, we aimed at searching for internal jugular vein (IJV) diameters in Turkish children in order to learn about anatomic details of IJV diameters and to supplement the diagnostic criteria in vascular pathologies such as phlebectasia. Methods: A total of 92 children within the age range of 7–12 years were included in this study. In order to provide a consistent anatomical landmark in all subjects, all of the children were imaged by ultrasonography (USG) at the level of the cricoid cartilage. The measurements consisted the maximal antero-posterior (AP) and transverse (T) cross-sectional internal diameters of the internal jugular veins during both regular breathing and Valsalva maneuver. For the statistical purposes, the following analyses were performed: the relationship between the IJV diameters obtained at rest and those obtained during Valsalva maneuver, with the paired t-test; the relationship between the age groups and the IJV diameters, with the unpaired test. The significance was set at P<0.05. Results: During regular breathing, the mean transvers diameters of the right and left IJVs were 11.26 and 10.01 mm, respectively, while they were 16.28 and 13.61 mm during straining phase of the Valsalva maneuver. The mean antero-posterior diameters of the right and left IJVs before and during Valsalva maneuver were 7.64 and 6.8 mm versus 11.53 and 9.84 mm. The IJV diameters were larger on the right side than those on the left and also there were significant increases in the diameters by Valsalva maneuver. Conclusion: As a result, in this study performed among Turkish children aged between 7–12 years, it was shown that there was no correlation between the IJV diameters and the age groups ( P>0.05), while there was a significant increase in the IJV diameters on Valsalva maneuver ( P<0.05). We think that the results we obtained in this study may be useful and important for comparison in the patients with phlebectasia and also for the required knowledge of the anatomic details in medical interventions performed through IJV. However, since children aged between 0 and 6 years were not included in this study and the lack of relation found in our study may not be the same among 0–6 years, a further study is needed to show any interrelationship between former age group and size.

Endoscopic transethmoidal sphenoidotomy

The posterior ethmoid and sphenoid sinuses often have significant anatomic variation resulting in operative challenges for the endoscopic surgeon. The hazards of surgery in this region are serious. Complications such as optic nerve and/or orbital trauma, and cerebrospinal fluid leak still occur despite increasing training and experience. Factors that lead to surgical complications include the lack of orientation within the dissection field and/or impaired visualization. Because minimally invasive sinus surgery is now being performed more frequently, surgical techniques designed to reduce the risk of complications are more important than ever. Anatomic landmarks that reliably orient the dissection within the posterior ethmoids and guide the surgeon to the sphenoid sinus could reduce such adverse outcomes. As with any surgical approach, it is better to rely on consistent anatomic landmarks within the operative field to perform the surgery safely, rather than rely on a range of measurements or adjunctive radiographic techniques, as described in many prior reports. The superior meatus and superior turbinate, skull base, and medial orbital wall are relatively reliable landmarks within the dissection field that can orient the surgeon. These anatomic landmarks allow safe dissection within the posterior ethmoid and a reliable approach to the sphenoid sinus, especially in patients undergoing revision surgery or in those with anatomic variations. The authors present their technique for the transethmoidal approach to the sphenoid sinus and discuss its advantages.

Quantifying glenoid bone loss arthroscopically in shoulder instability

Purpose: Our goal was to establish a consistent methodology for quantifying glenoid bone loss by arthroscopic means. Type of Study: This study was an anatomic investigation of glenoid structure and its consistent anatomic landmarks as determined by arthroscopic means in live subjects and by direct measurement in fresh-frozen cadaver specimens. Methods: We arthroscopically evaluated and measured the location of the bare spot of the glenoid in 56 subjects that had no evidence of instability (average age, 40 years). We also measured the exact location of the glenoid bare spot in 10 cadaver shoulders (average age, 76 years). Results: The bare spot of the glenoid was a consistent reference point from which to determine glenoid bone loss because it was located almost exactly at the center of the circle that was defined by the articular margin of the inferior glenoid below the level of the midglenoid notch. The tightly clustered standard deviations of the bare spot measurements in both the live subjects and the cadaver specimens confirmed its consistent location. Conclusions: The glenoid bare spot can be used as a central reference point to quantify the percentage bone loss of the inferior glenoid. Such objective measurement of glenoid bone loss can be clinically useful to the surgeon in deciding whether bone grafting is necessary to restore stability to the shoulder with a bone-deficient glenoid.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 5 (May-June), 2002: pp 488–491

Ultrasonography of the normal feline pancreas and associated anatomic landmarks: a prospective study of 20 cats.

The sonographic appearance of the feline pancreas and associated anatomic landmarks including the pancreatic duct, duodenum, duodenal papilla, portal vein, and gastric lymph node were evaluated in 20 healthy, awake cats. The pancreas appeared nearly isoechoic to surrounding mesenteric tissues, isoechoic to slightly hyperechoic to adjacent liver lobes, and hypoechoic to the spleen. The mean thickness measurements for the right pancreatic lobe, body, and left pancreatic lobe were 4.5 mm (range 2.8-5.9), 6.6 mm (range 4.7-9.5), and 5.4 mm (range 3.4-9.0), respectively. The pancreatic duct was consistently visualized in the left pancreatic lobe and had a mean thickness of 0.8 mm (range 0.5-1.3). It could be differentiated from the pancreatic vessel, by its central location, and the duct's lack of Doppler flow signal. The duodenum was used as a landmark to identify the right lobe of the pancreas. The mean duodenal wall thickness measurement was 2.8 mm (range 2.1-3.8) in sagittal section, and 3.0 mm (range 2.2-4.4) in transverse section. The duodenal papilla was identified in 4 of 20 cats. It ranged in size from 2.9 to 5.5 mm in width, and had a maximum height of 4.0 mm in transverse section. The portal vein was used as a consistent anatomic landmark for identification of the left lobe and body of the pancreas. The mean diameter of the portal vein at the level where the pancreatic body joins the left pancreatic lobe was 4.3 mm (range 2.7-5.9) when viewed in sagittal section, and 4.5 mm (range 3.6-6.1) in transverse section. The gastric lymph node was identified cranial and ventromedial to the pyloroduodenal angle in 6 of 20 cats. It had an asymmetrical shape with a larger caudal pole in five of the six cats. The largest dimensions of the gastric lymph node were 10 mm in length, and 6 mm in width for the larger caudal pole, and 5.1 mm in width for the smaller cranial pole.

A stepwise surgical technique using the medial orbital floor as the key landmark in performing endoscopic sinus surgery.

The medial orbital floor (MOF) and adjacent bony ridge of the antrostomy, when combined with columellar measurements, are easily identifiable and consistent anatomic reference points from which critical orbital and skull base structures can be found during endoscopic sinus surgery. Two examiners, with varying endoscopic sinus surgery experience, performed endoscopic and direct measurements from the columnella and medial orbital floor to critical orbital and skull base structures on 11 human cadaver heads (18 sides). The distances to four critical skull base or orbital structures and to the anterior and posterior wall of the sphenoid sinus were measured. The mean, ranges, and standard deviations for all measurements (endoscopic and direct) were calculated and simple regression analysis was performed. The mean and range of values for each of the variables correlated well between examiners, and between endoscopic and direct measurements. There was slightly more variability in measurements when the MOF was used. However, the differences were no more than a few millimeters and did not appear to affect the overall clinical use of these values. The MOF and adjacent bony ridge of the antrostomy, when combined with columellar measurements, are easily identifiable and consistent anatomic landmarks that are not affected by the presence of significant inflammatory disease or previous surgery. These reference points provide even the most inexperienced surgeon with precise anatomic localization within the paranasal sinuses. They also determine the correct anteroposterior trajectory into the sphenoid sinus, whereby inadvertent intracranial or intraorbital complications may be avoided.

Functional anatomy of pointing and grasping in humans.

The functional anatomy of reaching and grasping simple objects was determined in nine healthy subjects with positron emission tomography imaging of regional cerebral blood flow (rCBF). In a prehension (grasping) task, subjects reached and grasped illuminated cylindrical objects with their right hand. In a pointing task, subjects reached and pointed over the same targets. In a control condition subjects looked at the targets. Both movement tasks increased activity in a distributed set of cortical and subcortical sites: contralateral motor, premotor, ventral supplementary motor area (SMA), cingulate, superior parietal, and dorsal occipital cortex. Cortical areas including cuneate and dorsal occipital cortex were more extensively activated than ventral occipital or temporal pathways. The left parietal operculum (putative SII) was recruited during grasping but not pointing. Blood flow changes were individually localized with respect to local cortical anatomy using sulcal landmarks. Consistent anatomic landmarks from MRI scans could be identified to locate sensorimotor, ventral SMA, and SII blood flow increases. The time required to complete individual movements and the amount of movement made during imaging correlated positively with the magnitude of rCBF increases during grasping in the contralateral inferior sensorimotor, cingulate, and ipsilateral inferior temporal cortex, and bilateral anterior cerebellum. This functional-anatomic study defines a cortical system for "pragmatic' manipulation of simple neutral objects.

A surgical guide for identifying the lateral femoral circumflex vessels during free vascularized fibular transfer for avascular necrosis of the femoral head.

Free vascularized fibular transfer for avascular necrosis of the femoral head was developed in an attempt to preserve, rather than replace, the femoral head. In this procedure, the peroneal vessels of the autogenous fibular graft are anastomosed to recipient branches of the lateral femoral circumflex vessels. A problem with this procedure has been the difficulty in locating the lateral femoral circumflex vessels. An anatomic and surgical study was conducted to seek a consistent anatomic landmark for use in isolating these vessels. Ten cadaveric and 29 surgical hip dissections were performed. A falx, or fascial band, was consistently found approximately 10 cm distal to the anterior superior iliac spine; it is attached to the anterior intertrochanteric line of the proximal femur, with additional attachments to the investing fascia of the tensor fascia lata and rectus femoris muscles. Cautious release of this falx from superficial to deep leads to the fat layer surrounding the lateral femoral circumflex vessels. This study has shown that an anatomic landmark exists, which consistently leads to location of the lateral femoral circumflex vessels during a free vascularized fibular transfer. By incorporating the use of this landmark ito the authors' surgical technique, they have significantly reduced surgical dissection time and have provided a safe method for isolating the recipient vessels during this challenging operation.

Tibial tunnel placement in ACL reconstruction

In reconstructing the ACL, ideal tibial tunnel placement requires an understanding of the unique anatomy of the ACL tibial footprint and its relationship to the PCL, lateral meniscus, and medial tibial part of the spine. In addition to precise placement of the tibial tunnel, its length and angulation are factors to consider. Using consistent anatomic landmarks with attention to detail, the tibial tunnel can be reproducibly placed in a manner that is not detrimental to the graft.

Identification and Transfer of Free Cutaneous Flaps by Microvascular Anastomosis in the Dog

An axial pattern cutaneous free flap in the dog based on superficial cervical vessels was identified. Consistent anatomic landmarks were proposed. The vessels consistently emerged from the angle formed by the omotransversarius and trapezius muscles, and coursed in a craniodorsal direction. Eight orthotopic transfers were performed to evaluate the flap's potential as a free tissue transfer. Six of eight (75%) flaps survived. Arterial insufficiency was the likely cause of one failure. The cause of the other failure was considered to be venous occlusion. We conclude that the superficial cervical flap can be used successfully as a microvascular free tissue transfer in the dog.

Surgery of the Parotid Gland and the Viscerovertebral Angle

The use of consistent anatomic landmarks and the mobilization of the viscerovertebral angle facilitate localization of the facial nerve. This straightforward approach to surgery of the parotid gland provides a reproducible methodology for the preservation of the seventh cranial nerve.

Surgeon's view of the skull base from the lateral approach.

This paper presents the surgical anatomy of the skull base and infratemporal fossa. The information has been derived from the author's own experience in surgical and cadaver dissection, standard anatomical references, and selected experience of other skull base surgeons. Because the lateral approach has become the utilitarian method of exposure, the intricate detailed anatomy is demonstrated from this view at five levels of dissection, so the surgeon may gain a practical understanding of the surgical relationship of critical structures. Consistent anatomical landmarks can be used by the surgeon in the location of these critical structures. The styloid process, sphenoidal spine, and middle meningeal artery identify the internal carotid artery as it enters the carotid canal. The bony or fibrous septum that divides the jugular foramen into neural and vascular compartments may be used to better identify nerves IX, X, and XI. The zygomatic root is useful for location of the middle fossa dura. The lateral pterygoid plate leads directly to the foramen ovale. The increased precision of dissection permitted by use of the microscope requires an increased level of knowledge of anatomical structures in this area. It is hoped that the information presented in this paper will assist surgeons in the meticulous and thorough removal of skull base tumors and in the preservation of neural and vascular structures that are presently being sacrificed.