Publications by authors named "Michael Pretterklieber"

37 Publications

Micro-CT evaluation of historical human skulls presenting signs of syphilitic infection.

Wien Klin Wochenschr 2021 Jun 31;133(11-12):602-609. Epub 2021 Mar 31.

Institute of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University Vienna (MUV), Vienna, Austria.

Background: In tertiary syphilis, Treponema pallidum triggers the formation of granulomatous nodules in various organs of the human body. Within the skeleton, predominantly in the skull and long bones, these characteristic syphilitic lesions cause typical patterns of bone damage. In this study, micro-computed tomography (µ-CT) was used to assess the microarchitecture of these osseous defects in untreated syphilitic skull bones.

Material And Methods: Bone structure of 30 macerated human skulls was noninvasively examined by means of µ-CT images (Viscom X8060 NDT). A total of 20 specimens showing typical morphological signs of syphilis were provided by the Collection of Anatomical Pathology of the Museum of Natural History in Vienna. They were compared to 10 macerated control skulls provided by the Division of Anatomy of the Medical University of Vienna.

Results: All samples affected by syphilis showed perforating defects and increased porosity. Furthermore, we observed sclerotic reorganization and complete loss of the cortical bone in 80% of infected cases. Cortical thinning occurred in 75%.

Conclusion: Our findings revealed extensive micromorphological bone destruction and a broad variability of osseous manifestations of (tertiary) syphilis.
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http://dx.doi.org/10.1007/s00508-021-01832-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8195897PMC
June 2021

A ratio to approximate the proximodistal extent of the flexor retinaculum in relation to the hand length.

Ann Anat 2021 Mar 17;234:151659. Epub 2020 Dec 17.

Medical University of Vienna, Center for Anatomy and Cell Biology, Division of Anatomy, Währinger Str. 13, 1090 Vienna, Austria. Electronic address:

The flexor retinaculum of the hand is a fibrous structure forming the carpal tunnel in conjunction with the carpal bones. To prevent incomplete release of the carpal tunnel it is of benefit to know about the expected longitudinal expansion of the flexor retinaculum. The objective of the present study was to identify a possible correlation between the proximodistal expansion of the flexor retinaculum and the length of the hand. We conducted an anatomical study on 124 hands of 62 body donors. The hand length and the length of the flexor retinaculum were measured in millimeters. By dividing the length of the flexor retinaculum by the hand length an individual ratio was calculated. The mean length of the observed hands was 187.8 mm. The mean proximodistal length of the flexor retinaculum was 27.2 mm (range, 14-39 mm). A positive correlation was noted between the proximodistal length of the flexor retinaculum and length of the hand (p = 0.01). On average, the length of the flexor retinaculum corresponded to 14% (range, 8-20%) of the hand length in right hands versus 15% (range, 11-20%) in left hands. A greater proximodistal length of the flexor retinaculum in longer hands compared to shorter hands can be expected. The length of the flexor retinaculum corresponds to 14-15% of the length of the hand. However, one should be aware that the length of the flexor retinaculum extends as far as 20 % of the length of the hand.
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http://dx.doi.org/10.1016/j.aanat.2020.151659DOI Listing
March 2021

Innervation of the distal part of the vastus medialis muscle is endangered by splitting its muscle fibers during total knee replacement: an anatomical study using modified Sihler's technique.

Acta Orthop 2021 04 24;92(2):194-198. Epub 2020 Nov 24.

Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna.

Background and purpose - The distal part of the vastus medialis muscle is an important stabilizer for the patella. Thus, knowledge of the intramuscular nerve course and branching pattern is important to estimate whether the muscle's innervation is at risk if splitting the muscle. We determined the intramuscular course of the nerve branches supplying the distal part of the vastus medialis muscle to identify the surgical approach that best preserves its innervation.Material and methods - 8 vastus medialis muscles from embalmed anatomic specimens underwent Sihler's procedure to make soft tissue translucent while staining the nerves to study their intramuscular course. After dissection under transillumination using magnification glasses all nerve branches were evaluated.Results - The terminal nerve branches were located in different layers of the muscle and ran mostly parallel but also transverse to the muscle fibers. In half of the cases, the latter formed 1 to 3 anastomoses and coursed close to the myotendinous junction. Additionally, most of the branches extended into the ventromedial part of the knee joint capsule.Interpretation - To preserve the innervation of the distal part of the vastus medialis muscle, any split of the muscle during surgical approaches to the knee joint should be avoided.
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http://dx.doi.org/10.1080/17453674.2020.1851459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8158273PMC
April 2021

A Phylogenetic and Ontogenetic Perspective of the Unique Accumulation of Arterial Variations in One Human Anatomic Specimen.

Medicina (Kaunas) 2020 Sep 4;56(9). Epub 2020 Sep 4.

Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna, Austria.

Anatomical dissection is an indispensable means of acquiring knowledge about the variability of the human body. We detected the co-existence of several arterial variations within one female anatomic specimen during routine anatomical dissection. The aim of this study was to evaluate if this status is a regular pattern in any of other vertebrates. : Besides of a meticulous anatomic dissection, we performed a literature review concerning the frequency, the phylogenesis, and ontogenesis of all of these variations. : Exceptionally, the middle colic artery arose from an extraordinarily divided celiac trunk. The kidneys received three polar arteries. On the left side, a corona mortis replaced the obturator artery. The aortic arch gave rise to a bicarotid trunk, and the right subclavian artery originated and coursed as a typical lusorial artery leading to a non-recurrent laryngeal nerve on the right side. Furthermore, variations of the branches of the thyrocervical trunk were found to be present. Extraordinarily, in their cervical portion both internal carotid arteries gave rise to two arteries each. All of these variations developed within two to three weeks, around the sixth week of gestation. It was not possible to ascribe all or even one of the variations to a singular species of vertebrates. : Apparently, arterial variations are frequently a result of random development. Medical professionals must always be aware of anatomical variations; the absence of such awareness would create major difficulties during surgery. The present case confirms the relevance of anatomical dissection, particularly for medical students.
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http://dx.doi.org/10.3390/medicina56090449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557825PMC
September 2020

Relationship between the Thickness of the Coracoid Process and Latarjet Graft Positioning-An Anatomical Study on 70 Embalmed Scapulae.

J Clin Med 2020 Jan 12;9(1). Epub 2020 Jan 12.

Center for Anatomy and Cell Biology, Division of Anatomy, Medical University of Vienna, Währinger Straße 13, 1090 Vienna, Austria.

Background: The Latarjet procedure is a popular technique with the aim of the reconstruction of glenoid cavity bone defects in patients with chronic anterior shoulder instability. Studies have shown that the Congruent arc Latarjet procedure is better able to reconstruct larger defects than the Classic Latarjet, but there is a lack of information on the limitations of both methods.

Methods: The dimensions of the glenoid width and the native coracoid process of two groups with 35 Formol-Carbol embalmed scapulae each were measured using a digital caliper. The relationship between the coracoid graft and the anterior-posterior diameter of the glenoid cavity was calculated to determine the maximum defect size of the glenoid cavity width, which can be treated by both Latarjet techniques.

Results: The average restorable defect size of the anterior segment of the glenoid cavity was 28.4% ± 4.6% (range 19.2%-38.8%) in the Classic Latarjet group, and 45.6% ± 5.2% (range 35.7%-57.1%) in the Congruent arc Latarjet group. Based on our results, the feasibility of the Classic Latarjet procedure to reconstitute the anatomical width of the glenoid cavity was 86% in a 25% bone loss scenario, and only 40% in a 30% bone loss scenario.

Conclusion: Based on our results we are unable to define a clear threshold for the optimal Latarjet graft position. In glenoid cavity defects <20%, the Classic Latarjet technique usually provides enough bone stock for anatomical reconstruction. Defects ≥35% of the glenoid cavity width should only be treated with a coracoid graft in the Congruent arc position. In the critical area between 20% and 35% of bone loss, we suggest the preoperative assessment of coracoid dimensions, based on which the graft position can be planned to restore the anatomical anterior-posterior diameter of the glenoid cavity.
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http://dx.doi.org/10.3390/jcm9010207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019441PMC
January 2020

When and why was the phrenicoabdominal branch of the left phrenic nerve placed into the esophageal hiatus in German textbooks of anatomy? An anatomical study on 400 specimens reevaluating its course through the diaphragm.

Ann Anat 2020 Jan 9;227:151415. Epub 2019 Sep 9.

Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria.

Background: The phrenicoabdominal branch of the left phrenic nerve passes between muscle fiber bundles within the costal part of the diaphragm near the pericardium. In most German textbooks of anatomy, however, its passage is described to be found in the esophageal hiatus. The aim of this study was to reevaluate its topography relative to the diaphragm in a multicentric study and to identify the initiation of this description.

Methods: In this multicentric study, the most dorsomedial branch of the left phrenic nerve was identified as the phrenicoabdominal branch in 400 embalmed anatomic specimens of Caucasian origin. The distance between its passage and the apex of the pericardium, the left border of the esophageal hiatus, and the inner aspect of the left sixth rib was measured on the cranial aspect of the diaphragm. Textbooks on human anatomy published in German language between 1700 and 2018 were reviewed for their description of the passage of the left phrenicoabdominal branch through the diaphragm.

Results: The first statement on the passage of the left phrenicoabdominal branch through the esophageal hiatus was given in 1791 by Sömmering. Since then, in German textbooks of anatomy, a duality in the description of the passage of the left phrenicoabdominal branch persists. In none of the individuals examined in this study, the left phrenicoabdominal branch passed through the esophageal hiatus. In 99.5% of all cases, it pierced the costal part of the diaphragm dorsal to or at the same level as the apex of the pericardium. The mean distances (standard deviations) were 3.4 (±1.5) cm to the apex of the pericardium, 5.8 (±2.2) cm to the esophageal hiatus, and 5.5 (±1.6) cm to the inner aspect of the left sixth rib.

Conclusion: The findings on the position of the left phrenicoabdominal branch relative to the diaphragm help to improve topographical knowledge and prevent inadvertent nerve injury during surgical interventions on or near the diaphragm. Further to this, these results may form a substantial basis to adopt the correct description of the passage of the left phrenicoabdominal branch to anatomical textbook knowledge.
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http://dx.doi.org/10.1016/j.aanat.2019.151415DOI Listing
January 2020

The anterolateral ligament of the knee and the lateral meniscotibial ligament - Anatomical phantom versus constant structure within the anterolateral complex.

Ann Anat 2019 Nov 19;226:64-72. Epub 2019 Jul 19.

Medical University of Vienna, Center for Anatomy and Cell Biology, Division of Anatomy, Waehringer Strasse 13, Vienna 1090, Austria. Electronic address:

Background: Concerning the ongoing controversy about the existence and nature of the anterolateral ligament (ALL) of the knee joint, we reinvestigated the formation of the anterolateral part of its fibrous capsule in anatomic specimens. Furthermore, we wanted to clarify if the lateral meniscus has established a constant anchoring to the lateral tibial condyle via a lateral meniscotibial ligament (lmtl).

Methods: Forty paired embalmed lower extremities taken from 20 human body donors (15 men and five women) underwent exact macroscopic dissection. For the detailed evaluation of the lmtl, additionally 12 specially dissected joint specimens were used. In two of these specimens, the lmtl underwent further histological examination.

Results: In all specimens, the anterolateral part of the knee joint fibrous capsule was established by the iliotibial tract and the anterior arm of the aponeurosis of the biceps femoris muscle. According to their close connection and the fact that the anterolateral part of the fibrous capsule is exclusively assembled by these two aponeuroses, they do not leave any space for a distinct ALL connecting the lateral femoral epicondyle and the lateral tibial condyle. The constantly present lmtl was identified as a flat, rectangular bundle of collagen and also elastic fibers reinforcing the inner aspect of the fibrous capsule. Following an oblique direction, it connected the lateral face of the lateral meniscus with the superolateral margin of the lateral tibial condyle. The lmtl measured, on average, 17.1mm in longitudinal and 13mm in anteroposterior direction.

Conclusion: Our results show that there is no evidence for the existence of an ALL in human knee joints. It is represented either by the iliotibial tract or - most likely - by the anterior arm of the short head of the biceps femoris muscle. On the other hand, the lmtl was found to be a constantly present structure.
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http://dx.doi.org/10.1016/j.aanat.2019.06.005DOI Listing
November 2019

There are no safe areas for avoiding the perforating arteries along the proximal part of the femur: A word of caution.

Clin Anat 2020 May 13;33(4):507-515. Epub 2019 May 13.

Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Wien, Austria.

Knowledge about the variable course of the perforating arteries near the body of the femur is essential during surgical procedures (e.g., percutaneous cerclage wiring, plate osteosynthesis, Ilizarov technique). Our aims were to determine the number of perforating arteries, and to identify safe zones along the body of the femur within which perforating arteries are unlikely to pass toward the back of the thigh. The number of perforating arteries was determined in both legs of 100 formalin-fixed anatomic specimens of both sexes. The level of passage of perforating arteries near the body of the femur was measured in reference to a line from the anterior superior iliac spine to the medial femoral condyle. In each leg, two to seven perforating arteries were present. In 64% of legs, at least one artery divided into two to four branches before entering the back of the thigh. Thus, the total number of branches passing near the body of the femur varied between two to nine. Perforating arteries passed to the back of the thigh at every level between 14.0 and 36.5 cm from the anterior superior iliac spine (16-39% of the leg length). Within this distance, no safe zones along the body of the femur could be identified. The present study shows the high variability regarding number and course of the perforating arteries. Surgeons can be faced with an artery at every level on the posteromedial aspect of the body of the femur between 14.0 and 36.5 cm distally to the anterior superior iliac spine. Clin. Anat. 33:507-515, 2020. © 2019 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ca.23398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7186815PMC
May 2020

Sexual dimorphism in the anatomy of the ulnar collateral thumb ligament.

Wien Klin Wochenschr 2019 May 1;131(9-10):216-220. Epub 2019 Apr 1.

, Laudongasse 25, 1080, Vienna, Austria.

Background: Treatment of ruptured ulnar collateral thumb metacarpophalangeal (MCP) joint ligaments (UCL) necessitate a profound anatomic knowledge for optimal surgical repair in order to preserve range of motion and ensure postoperative joint stability. Therefore, knowledge of the angle between the UCL and the longitudinal axis of the first metacarpal bone could be useful.

Methods: In this study 46 ulnar collateral thumb MCP joint ligaments in 15 male and 15 female embalmed anatomic specimens were dissected and the angles between the longitudinal axis of the first metacarpal bone and the proper (PUCL) as well as the accessory ulnar collateral thumb MCP ligament (AUCL) were measured.

Results: In male specimens the angle for the PUCL measured on average 133.5° (±2.35°) and 122.75° (±3.8°) for the AUCL. A significantly different angle was measured for female specimens which showed on average 137.88° (±3.51°) for the PUCL and 128.65° (±4.14°) for the AUCL.

Conclusions: Optimal surgical repair or reconstruction of torn ulnar collateral thumb MCP joint ligaments should aim for an angle of approximately 135° in PUCL and 126° in AUCL in relation to the longitudinal axis of the metacarpal bone. Differences in men and women should be considered if possible.

Level Of Evidence: IV (anatomic study).
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http://dx.doi.org/10.1007/s00508-019-1483-8DOI Listing
May 2019

Paget's Disease of Long Bones: Microstructural Analyses of Historical Bone Samples.

Calcif Tissue Int 2019 07 8;105(1):15-25. Epub 2019 Mar 8.

Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090, Vienna, Austria.

Although Paget's disease of bone (PDB) is the second most common metabolic bone disease, there is only limited information about the microarchitecture of affected bones. Therefore, the aim of this study was to determine cortical and trabecular bone properties in clinically relevant locations by microcomputed tomography (µCT). Ten femora and ten tibiae affected by Paget's disease taken from the Natural History Museum Vienna were compared to 13 femora and 10 tibiae of non-affected body donors. Digitization of the cortical and trabecular bone microarchitecture was performed with an X-ray-based µCT scanner. Additionally, semi-quantitative gradings of trabecular and cortical architectural parameters of the femora and the tibiae were generated. Microcomputed tomography images showed changes in the thickness of cortices, cortical porosity, and trabecularization of cortical structures. Moreover, severe disorganization of trabecular structures, trabecular defects, and thickening of (remaining) trabeculae were detected. Numerical cortical analyses showed lower total bone volume (BV) and lower BV in the outer region (66-100%) (- 36%, p = 0.004, and - 50%, p < 0.001, respectively), lower total volume (TV) in the outer region (66-100%) (- 42%, p < 0.001), lower total bone volume fraction (BV/TV) and BV/TV in the outer region (66-100%) (- 23%, and - 12%, p < 0.001, respectively), higher BV and TV in the middle region (33-66%) and higher BV/TV in the inner region (0-33%) (123%, p = 0.011, 147%, p = 0.010, and 33%, p = 0.025, respectively) in Pagetic compared to non-affected bones. Trabecular analyses showed higher BV/TV (96%, p = 0.008) and Tb.Th (43%, p = 0.004) in Pagetic compared to non-affected bones. There is a major and consistent structural alteration of PDB at cortical and trabecular sites in weight-bearing long bones. Our findings are relevant for the differential diagnosis of PDB and for the pathogenesis of associated complications, since the disorder produces abnormalities in the structure that might lead to bone fragility.
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http://dx.doi.org/10.1007/s00223-019-00539-8DOI Listing
July 2019

Recommendations of the working group of the Anatomische Gesellschaft on reduction of formaldehyde exposure in anatomical curricula and institutes.

Ann Anat 2019 Jan 25;221:179-185. Epub 2018 Oct 25.

Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Saarland, Homburg, Saar, Germany.

The practice of human and veterinary medicine is based on the science of anatomy and dissection courses are still irreplaceable in the teaching of anatomy. Embalming is required to preserve body donors, for which process formaldehyde (FA) is the most frequently used and well characterized biocidal substance. Since January 2016, a new occupational exposure limit (OEL) for FA of 0.37mg/m issued by the European Committee on Hazardous Substances is obligatory since FA has been classified as a human 1B carcinogen. The anatomical institutes in the German-speaking region are called upon to consolidate efforts to reduce use of FA in anatomical curricula and body donations. As a result, the Anatomische Gesellschaft (AG) has formed a "Working Group for Reduction of Formaldehyde Exposure in Dissection Courses" tasked with discussion and recommendation of measures to reduce FA. Based on the assessment of the Working Group, the AG has issued an official opinion to the effect that, at this point in time, embalming of body donors without FA completely is not feasible. Therefore, a combination of approaches are to be used to reduce FA exposure, including technical and structural (architectural) adaptations, modification of protocols for fixation and preservation as well as organizational measures. One structural measure considered unavoidable is the integration of air supply and exhaust of individual dissecting tables into the ventilation system of the anatomy building. To embalm human body donors, intra-arterial perfusion fixation with up to 4% FA and a total fluid volume of 150mL/kg body weight will suffice. For animals where body weights and biology of bodies vary widely (i.e. special needs of fixation for ruminants, large animals as horses) perfusion fixation with up to 4% FA and a quantity of fixative solution of 10-15% of the body weight may be required. Preservation of body donors in storage (immersion) can be done with 40% ethanol or in a full bath preservation containing up to 2% FA. Corpse humidification in the dissecting room is possible with 2% phenoxyethanol, in each case without FA. In veterinary anatomy, microbiological burden is often higher and therefore might lead to a need of FA in long-time storage. Compliance with the current OEL in all institutes would appear to be feasible in combination with various organizational measures.
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http://dx.doi.org/10.1016/j.aanat.2018.10.007DOI Listing
January 2019

Comparison of mesh fixation devices for laparoscopic ventral hernia repair: an experimental study on human anatomic specimens.

Surg Endosc 2018 07 16;32(7):3158-3163. Epub 2018 Jan 16.

Department of Surgery, SMZ Floridsdorf Hospital Vienna, Vienna, Austria.

Background: As there is a lack of clarity in terms of the tensile strength of mesh fixation for laparoscopic ventral hernia repair (LVHR), our aim was to investigate the immediate tensile strength of currently available mesh fixation devices on human anatomic specimens.

Methods: Sixteen recently deceased body donators (mean body mass index of 24.4 kg/m) were used to test the immediate tensile strength (Newton) of 11 different LVHR mesh fixation devices.

Results: Each of the 11 different laparoscopic fixation devices was tested 44 times. Non-articulating tackers provided higher fixation resistance to tensile stress in comparison to articulating tackers (5.1-mm ReliaTack™: 16.9 ± 8.7 N vs. 12.2 ± 5.6 N, p = 0.013; 7-mm ReliaTack™: 19.8 ± 9.4 N vs. 15.0 ± 7.0 N, p = 0.007). Absorbable tacks with a greater length, i.e. ≥6 mm (7-mm ReliaTack™, 6-mm SorbaFix™ and 7.2-mm SecureStrap™) had significantly higher fixation tensile strength than tacks with a shorter length, i.e. < 6 mm (5.1-mm ReliaTack™ and 5.1-mm AbsorbaTack™) (p < 0.001). Furthermore, transfascial sutures (PDS 2-0 sutures 26.3 ± 5.6 N) provided superior fixation tensile strength than 5.1-mm AbsorbaTack™ (13.6 ± 7.3 N) and cyanoacrylate glues such as LiquiBand FIX8™ (3.5 ± 2.4 N) (p < 0.001, respectively). There was a significant deterioration in fixation capacity in obese body donators with a body mass index > 30 kg/m (13.8 ± 8.0 vs. 17.9 ± 9.7 N, p = 0.044).

Conclusions: Although articulating laparoscopic tackers improve accessibility and facilitate the utilization of tacks within the fixation weak spot adjacent to the trocar placement, an articulating shaft that is not ergonomic to use may limit mechanisms of force transmission. For mesh fixation in LVHR, transfascial sutures and tacks with a longer length provide better immediate fixation tensile strength results.
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http://dx.doi.org/10.1007/s00464-018-6031-5DOI Listing
July 2018

Accessory Spleen in the Greater Omentum: Embryology and Revisited Prevalence Rates.

Cells Tissues Organs 2017 19;203(6):374-378. Epub 2017 Apr 19.

Department of Anatomy, Ross University School of Medicine, Roseau, Commonwealth of Dominica.

Purpose: To investigate in a large sample the prevalence rates of accessory spleens located in the greater omentum and to explain the embryological background and the vascular supply of this rare congenital disorder.

Methods: Evaluation of the presence of accessory spleens located in the greater omentum was performed in 5 different international anatomical centers investigating a total of 1,045 body donors. Arterial and venous blood supply and the precise location of the respective vasculature within the splenic ligaments are described based on dissection of this rare condition in a male specimen.

Results: The reported prevalence rates from 5 different centers were: 0.5% (out of 380 body donors), 0% (out of 230 donors), 0% (out of 200 donors), 2% (out of 200 donors), and 0% (out of 35 donors). The cumulative prevalence rate obtained from 1,045 anatomical dissections was 0.6%. The identified accessory spleen measured 3 × 3 × 2.5 cm and was located in the left upper abdominal quadrant. A vascular stag 7.5 cm in length was identified within the gastro-splenic ligament, containing an artery and a vein piercing the greater omentum from posterior.

Conclusion: An accessory spleen located in the greater omentum is a rare congenital disorder. Physicians should be aware of the fact that in patients without any representative symptom history a nodular mass located within the greater omentum could be an accessory spleen.
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http://dx.doi.org/10.1159/000458754DOI Listing
March 2018

Distribution Pattern of the Superior and Inferior Labial Arteries: Impact for Safe Upper and Lower Lip Augmentation Procedures.

Plast Reconstr Surg 2017 May;139(5):1075-1082

Roseau, Commonwealth of Dominica; Salzburg and Vienna, Austria; and Kiel, Munich, Tuebingen, and Luebeck, Germany.

Background: Understanding the precise position and course of the superior and inferior labial arteries within the upper lip and the lower lip is crucial for safe and complication-free applications of volumizing materials.

Methods: One hundred ninety-three anatomical head specimens (56.5 percent female cadavers) of Caucasian ethnicity were investigated in this large multicenter anatomical study. In total, six 3-cm-long vertical incisions were performed on each lip (midline and 1 cm medial to the angles of the mouth) to identify the position of the superior and inferior labial arteries in relation to the orbicularis oris muscle.

Results: Three different positions of the superior and inferior labial arteries were identified: submucosal (i.e., between the oral mucosa and the orbicularis oris muscle in 78.1 percent of the cases), intramuscular (i.e., between the superficial and deep layers of the orbicularis oris muscle in 17.5 percent of the cases), and subcutaneous (i.e., between the skin and the orbicularis oris muscle in 2.1 percent of the cases). The variability in changing the respective position along the labial course was 29 percent for the total upper and 32 percent for the total lower lip. The midline location was identified in both the upper and lower lips to be the most variable.

Conclusions: Based on the results of this investigation, a safer location for the application of volumizing material is the subcutaneous plane in the paramedian location of both the upper lip and the lower lip. Care has to be taken when aiming to inject in the midline, as the artery can be identified more frequently in superficial positions.
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http://dx.doi.org/10.1097/PRS.0000000000003244DOI Listing
May 2017

Fast estimation of Colles' fracture load of the distal section of the radius by homogenized finite element analysis based on HR-pQCT.

Bone 2017 04 7;97:65-75. Epub 2017 Jan 7.

Institute for Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland. Electronic address:

Fractures of the distal section of the radius (Colles' fractures) occur earlier in life than other osteoporotic fractures. Therefore, they can be interpreted as a warning signal for later, more deleterious fractures of vertebral bodies or the femoral neck. In the past decade, the advent of HR-pQCT allowed a detailed architectural analysis of the distal radius and an automated but time-consuming estimation of its strength with linear micro-finite element (μFE) analysis. Recently, a second generation of HR-pQCT scanner (XtremeCT II, SCANCO Medical, Switzerland) with a resolution beyond 61 μm became available for even more refined biomechanical investigations in vivo. This raises the question how biomechanical outcome variables compare between the original (LR) and the new (HR) scanner resolution. Accordingly, the aim of this work was to validate experimentally a patient-specific homogenized finite element (hFE) analysis of the distal section of the human radius for the fast prediction of Colles' fracture load based on the last generation HR-pQCT. Fourteen pairs of fresh frozen forearms (mean age = 77.5±9) were scanned intact using the high (61 μm) and the low (82 μm) resolution protocols that correspond to the new and original HR-pQCT systems. From each forearm, the 20mm most distal section of the radius were dissected out, scanned with μCT at 16.4 μm and tested experimentally under compression up to failure for assessment of stiffness and ultimate load. Linear and nonlinear hFE models together with linear micro finite element (μFE) models were then generated based on the μCT and HR-pQCT reconstructions to predict the aforementioned mechanical properties of 24 sections. Precision errors of the short term reproducibility of the FE analyses were measured based on the repeated scans of 12 sections. The calculated failure loads correlated strongly with those measured in the experiments: accounting for donor as a random factor, the nonlinear hFE provided a marginal coefficient of determination (R) of 0.957 for the high resolution (HR) and 0.948 for the low resolution (LR) protocols, the linear hFE with R of 0.957 for the HR and 0.947 for the LR protocols. Linear μFE predictions of the ultimate load were similar with an R of 0.950 for the HR and 0.954 for the LR protocols, respectively. Nonlinear hFE strength computation led to precision errors of 2.2 and 2.3% which were higher than the ones calculated based on the linear hFE (1.6 and 1.9%) and linear μFE (1.2 and 1.6%) for the HR and LR protocols respectively. Computation of the fracture load with nonlinear hFE demanded in average 6h of CPU time which was 3 times faster than with linear μFE, while computation with linear hFE took only a few minutes. This study delivers an extensive experimental and numerical validation for the application of an accurate and fast hFE diagnostic tool to help in identifying individuals who may be at risk of an osteoporotic wrist fracture and to follow up pharmacological and other treatments in such patients.
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http://dx.doi.org/10.1016/j.bone.2017.01.003DOI Listing
April 2017

Congenital Bilateral Absence of the Radial Artery: A Very Rare Variation in Humans - Phylogenetic and Ontogenetic Aspects.

Cells Tissues Organs 2017 12;203(3):194-202. Epub 2016 Nov 12.

Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria.

In an 80-year-old Caucasian woman, both radial arteries were found to be replaced by an enlarged anterior interosseous artery. Additionally, the right forearm revealed a persistent median artery which formed the superficial palmar arch together with the ulnar artery. In both hands, the replaced radial artery was connected only to the deep but not the superficial palmar arch. In clinical practice, lack of an arterial pulse on the radial aspect of the wrist joint may indicate the presence of this anatomic variation. In this case, arterial blood sample collections, application of contrast media, invasive measurements of blood pressure, and several angiographic interventions cannot be performed via the radial artery. As this is the fourth reported case since 1830, bilateral aplasia of the radial artery appears to be an exceptional variation in humans. Thus, the phylo- and ontogenetic aspects of this anomaly are discussed.
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http://dx.doi.org/10.1159/000450575DOI Listing
May 2017

The arterial supply of the tendon of the long head of the biceps brachii in the human: a combined anatomical and radiological study.

Ann Anat 2014 Dec 22;196(6):449-55. Epub 2014 Sep 22.

Medical University of Vienna, Center of Anatomy and Cell Biology, Department of Applied Anatomy, Waehringer Straße 13, A-1090 Vienna, Austria.

Purpose: Arthroscopic repair of superior labral anterior to posterior (SLAP) lesions is often associated with a prolonged period of pain during the rehabilitation process. This might possibly be due to hypoxia in the biceps tendon anchor caused by sutures. The purpose of the study was to investigate the arterial supply of the long head of the biceps brachii tendon (LHBT) that may be impaired by surgery in the region of the biceps tendon anchor.

Methods: On 20 human formalin-fixed bodies, the anterior circumflex humeral artery (ACHA) was located and followed into the intertubercular groove until it reached the LHBT. On 10 fresh-frozen anatomic specimens of the upper extremities, contrast medium was injected into the axillary artery, a 3D scan was performed, and multiplanar reconstructed (MPR) slices were generated. A set of maximum intensity projection (MIP) reconstructions from 10 computed tomography angiographies (CTA) of the upper extremities was used to confirm the findings of the 3D scan.

Results: All anatomical dissections and radiological investigations revealed that the proximal portion of the LHBT was consistently supplied by an ascending branch of the ACHA. No artery was found to supply the biceps tendon anchor from the proximal aspect.

Conclusions: As the arterial supply of the LHBT is mainly provided by the ACHA, which enters the glenohumeral joint from the distal aspect, surgery at the bony origin of the LHBT may not interfere with this specific vessel.
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http://dx.doi.org/10.1016/j.aanat.2014.08.006DOI Listing
December 2014

Reliability of radiographic landmarks in medial patello-femoral ligament reconstruction in relation to the anatomical femoral torsion.

Int Orthop 2015 Mar 24;39(3):423-8. Epub 2014 Sep 24.

Department of Traumatology, Barmherzige Brüder Hospital, Johannes von Gott Platz 1, 7000, Eisenstadt, Austria,

Purpose: Anatomically correct graft positioning at the femoral insertion site is a key factor in surgical reconstruction of the medial patello-femoral ligament (MPFL). Basically there are two techniques to define this point in fluoroscopy during surgery. The role of the anatomical femoral torsion on the accuracy and reproducibility of both procedures has not been clarified.

Methods: Twenty human anatomical leg specimens were dissected. The femoral insertion of the MPFL was marked by two K-wires. The position of the ligament insertion was determined fluoroscopically in the true lateral view as used in routine clinical practice. The anatomical MPFL insertion was compared to the radiographic landmarks which were recommended by two previous studies. The anatomical femoral torsion of the specimens was assessed by computed tomography scans.

Results: In true lateral view fluoroscopy, the mean distance of the femoral MPFL insertion was -0.2 mm distal to the vertical reference line intersecting the posterior point of Blumensaat's line. In the anteroposterior direction, the mean distance was -2.0 mm posterior to the femoral cortex reference line. There was no correlation between anatomical femoral torsion and the distance of the femoral MPFL insertion to the posterior cortex.

Conclusions: The results of this study strongly recommend use of a vertical line intersecting the most posterior point of Blumensaat's line as a reference to identify the MPFL insertion in the craniocaudal direction. In the anteroposterior direction, the femoral MPFL insertion showed distinctive variation and was found -2.0 mm posterior to the femoral cortex reference line without being influenced by the anatomical femoral torsion.
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http://dx.doi.org/10.1007/s00264-014-2523-7DOI Listing
March 2015

Finite element based nonlinear normalization of human lumbar intervertebral disc stiffness to account for its morphology.

J Biomech Eng 2014 Jun;136(6):061003

Disc degeneration, usually associated with low back pain and changes of intervertebral stiffness, represents a major health issue. As the intervertebral disc (IVD) morphology influences its stiffness, the link between mechanical properties and degenerative grade is partially lost without an efficient normalization of the stiffness with respect to the morphology. Moreover, although the behavior of soft tissues is highly nonlinear, only linear normalization protocols have been defined so far for the disc stiffness. Thus, the aim of this work is to propose a nonlinear normalization based on finite elements (FE) simulations and evaluate its impact on the stiffness of human anatomical specimens of lumbar IVD. First, a parameter study involving simulations of biomechanical tests (compression, flexion/extension, bilateral torsion and bending) on 20 FE models of IVDs with various dimensions was carried out to evaluate the effect of the disc's geometry on its compliance and establish stiffness/morphology relations necessary to the nonlinear normalization. The computed stiffness was then normalized by height (H), cross-sectional area (CSA), polar moment of inertia (J) or moments of inertia (Ixx, Iyy) to quantify the effect of both linear and nonlinear normalizations. In the second part of the study, T1-weighted MRI images were acquired to determine H, CSA, J, Ixx and Iyy of 14 human lumbar IVDs. Based on the measured morphology and pre-established relation with stiffness, linear and nonlinear normalization routines were then applied to the compliance of the specimens for each quasi-static biomechanical test. The variability of the stiffness prior to and after normalization was assessed via coefficient of variation (CV). The FE study confirmed that larger and thinner IVDs were stiffer while the normalization strongly attenuated the effect of the disc geometry on its stiffness. Yet, notwithstanding the results of the FE study, the experimental stiffness showed consistently higher CV after normalization. Assuming that geometry and material properties affect the mechanical response, they can also compensate for one another. Therefore, the larger CV after normalization can be interpreted as a strong variability of the material properties, previously hidden by the geometry's own influence. In conclusion, a new normalization protocol for the intervertebral disc stiffness in compression, flexion, extension, bilateral torsion and bending was proposed, with the possible use of MRI and FE to acquire the discs' anatomy and determine the nonlinear relations between stiffness and morphology. Such protocol may be useful to relate the disc's mechanical properties to its degree of degeneration.
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http://dx.doi.org/10.1115/1.4027300DOI Listing
June 2014

High-resolution ultrasound visualization of the subcutaneous nerves of the forearm: a feasibility study in anatomic specimens.

Muscle Nerve 2014 May;49(5):676-9

Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, 1090, Austria.

Introduction: The aim of this ultrasound-anatomical study was to evaluate the ability of high-resolution ultrasound (HRUS) to visualize and infiltrate small subcutaneous nerves of the forearm in anatomic specimens.

Methods: Seven nonembalmed human bodies (4 men, 3 women; mean age at death, 60 years) were included in the study. Two investigators scanned the anatomic specimens using 15-MHz and 18-MHz HRUS transducers. The lateral, medial, and posterior antebrachial cutaneous nerves were scanned and interventionally marked with ink using HRUS-guidance. Subsequently, dissections were performed to assess the anatomical correlation of HRUS findings.

Results: All 3 nerves were identified consistently using HRUS. The precision of the ink-markings was excellent, with good correlation with the small peripheral branches of all 3 nerves.

Conclusions: HRUS can identify precisely the small subcutaneous nerves of the forearm and may aid in both diagnosis and therapy in cases of neuropathy.
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http://dx.doi.org/10.1002/mus.24064DOI Listing
May 2014

Injury of the gluteal aponeurotic fascia and proximal iliotibial band: anatomy, pathologic conditions, and MR imaging.

Radiographics 2013 Sep-Oct;33(5):1437-52

UCSD Teleradiology and Education Center, 8899 University Center Lane, Suite 370, San Diego, CA 92122-1041.

The fascia lata, or deep fascia of the thigh, is a complex anatomic structure that has not been emphasized as a potential source of pelvic and hip pain. This structure represents a broad continuum of fibrous tissue about the buttock, hip, and thigh that receives contributions from the posteriorly located aponeurotic fascia covering the gluteus medius muscle and from the more laterally located iliotibial band (ITB). At the pelvis and hip, the ITB consists of three layers that merge at the lower portion of the tensor fasciae latae muscle. The gluteal aponeurotic fascia and ITB merge at the buttock and hip before extending inferiorly to the Gerdy tubercle at the anterolateral tibia. Injuries to these anatomic structures are an underdiagnosed cause of pain and disability and may clinically mimic more common processes affecting the hip and proximal thigh. Categories of disease include overuse injuries, traumatic injuries, degenerative lesions, and inflammatory lesions. Familiarity with the anatomy and pathologic conditions of the fascia lata and its components is important in their recognition as a potential source of symptoms. This article illustrates the anatomy of this complex fascia through anatomic-pathologic correlation and describes the magnetic resonance imaging appearances of the pathologic conditions involving it.
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http://dx.doi.org/10.1148/rg.335125171DOI Listing
April 2014

The Patellar Arterial Supply via the Infrapatellar Fat Pad (of Hoffa): A Combined Anatomical and Angiographical Analysis.

Anat Res Int 2012 6;2012:713838. Epub 2012 Jun 6.

Center of Anatomy and Cell Biology, Department of Applied Anatomy, Medical University of Vienna, Waehringerstrasse 13, 1090 Vienna, Austria.

Even though the vascular supply of the human patella has been object of numerous studies until now, none of them has described in detail the rich arterial supply provided via the infrapatellar fat pad (of Hoffa). Therefore, we aimed to complete the knowledge about this interesting and clinically relevant topic. Five human patellae taken from voluntary body donators were studied at the Department of Applied Anatomy of the Medical University of Vienna. One was dissected under the operation microscope, a second was made translucent by Sihlers-solution, and three underwent angiography using a 3D X-ray unit. The results revealed that the patella to a considerable amount is supplied by arteries coursing through the surrounding parts of the infrapatellar fat pad. The latter were found to branch off from the medial and lateral superior and inferior genicular arteries. Within the infrapatellar fat pad, these arteries formed a dense network of anastomoses which are all contributing to the viability of the patellar bone. Due to the rich arterial supply reaching the patella via the infrapatellar fat pad, it seems advisable to preserve the fat pad during surgery of the knee in order to reduce the risk of vascular impairment of the patella.
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http://dx.doi.org/10.1155/2012/713838DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3375036PMC
August 2012

Anatomy and variants of the triangular fibrocartilage complex and its MR appearance at 3 and 7T.

Semin Musculoskelet Radiol 2012 Apr 30;16(2):93-103. Epub 2012 May 30.

Department of Radiology, MR Centre-Highfield MR, Medical University of Vienna, Vienna, Austria.

Due to the small size and complexity of its constituents, the triangular fibrocartilage complex (TFCC) has been a challenging structure for magnetic resonance (MR) imaging. Higher-field MR units, at 3T and 7T, with increased spatial resolution and the development of novel MR sequences, are promising tools for an improved visualization of the ulnocarpal complex. Anatomically, the TFCC consists of the TFC proper, the ulnomeniscal homolog, the ulnar collateral ligament, the ulnotriquetral and ulnolunate ligament, and radioulnar ligaments at the volar (palmar) and the dorsal side, as well as the sheath of the extensor carpi ulnaris tendon and the capsule of the distal radioulnar joint. This article describes the normal anatomy of the TFCC and its appearance on high-field MRI. Anatomical variants, such as the positive ulnar variance, and changes during pronation and supination are addressed.
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http://dx.doi.org/10.1055/s-0032-1311761DOI Listing
April 2012

The influence of comorbidities and etiologies on the success of extracorporeal shock wave therapy for chronic soft tissue wounds: midterm results.

Ultrasound Med Biol 2011 Jul 2;37(7):1111-9. Epub 2011 Jun 2.

Department of Surgery, Austrian Armed Forces Hospital-Vienna, Vienna, Austria.

Possible effects of comorbidities and of different wound etiologies on the success of extracorporeal shock wave therapy (ESWT) of chronic soft tissue wounds were investigated. From September 2003 until February 2007, 282 patients, being previously treated unsuccessfully were enrolled. Treatment consisted of ESWT occurring at defined intervals. At each treatment session a wound bed score was recorded, also at initial presentation a detailed patient history and wound etiology. Observed comorbidities were pooled according to the chapters of the ICD-10 system. Two hunderd fifty-eight patients were analyzed (91.49%) and underwent follow-up for a median of 31.8 months. Wound closure occurred in 191 patients (74.03%) by a median of two treatment sessions. No wound reappeared at the same location. A multivariate logistic regression model showed that pooled comorbidities and wound etiologies did not have a significant influence on success. Comorbidities and wound etiologies have surprisingly no significant influence on the success of ESWT.
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http://dx.doi.org/10.1016/j.ultrasmedbio.2011.04.007DOI Listing
July 2011

The role of fabric in the large strain compressive behavior of human trabecular bone.

J Biomech Eng 2010 Dec;132(12):121006

Department of Mechanics, Faculty of Civil Engineering, Czech Technical University, Prague Thakurova 7, Prague 166 29, Czech Republic.

Osteoporosis-related vertebral body fractures involve large compressive strains of trabecular bone. The small strain mechanical properties of the trabecular bone such as the elastic modulus or ultimate strength can be estimated using the volume fraction and a second order fabric tensor, but it remains unclear if similar estimations may be extended to large strain properties. Accordingly, the aim of this work is to identify the role of volume fraction and especially fabric in the large strain compressive behavior of human trabecular bone from various anatomical locations. Trabecular bone biopsies were extracted from human T12 vertebrae (n=31), distal radii (n=43), femoral head (n=44), and calcanei (n=30), scanned using microcomputed tomography to quantify bone volume fraction (BV/TV) and the fabric tensor (M), and tested either in unconfined or confined compression up to very large strains (∼70%). The mechanical parameters of the resulting stress-strain curves were analyzed using regression models to examine the respective influence of BV/TV and fabric eigenvalues. The compressive stress-strain curves demonstrated linear elasticity, yielding with hardening up to an ultimate stress, softening toward a minimum stress, and a steady rehardening followed by a rapid densification. For the pooled experiments, the average minimum stress was 1.89 ± 1.77 MPa, while the corresponding mean strain was 7.15 ± 1.84%. The minimum stress showed a weaker dependence with fabric as the elastic modulus or ultimate strength. For the confined experiments, the stress at a logarithmic strain of 1.2 was 8.08 ± 7.91 MPa, and the dissipated energy density was 5.67 ± 4.42 MPa. The latter variable was strongly related to the volume fraction (R(2)=0.83) but the correlation improved only marginally with the inclusion of fabric (R(2)=0.84). The influence of fabric on the mechanical properties of human trabecular bone decreases with increasing strain, while the role of volume fraction remains important. In particular, the ratio of the minimum versus the maximum stress, i.e., the relative amount of softening, decreases strongly with fabric, while the dissipated energy density is dominated by the volume fraction. The collected results will prove to be useful for modeling the softening and densification of the trabecular bone using the finite element method.
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http://dx.doi.org/10.1115/1.4001361DOI Listing
December 2010

Validation of an HR-pQCT-based homogenized finite element approach using mechanical testing of ultra-distal radius sections.

Biomech Model Mechanobiol 2011 Jul 5;10(4):431-44. Epub 2010 Aug 5.

Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Gusshausstrasse 27-29, Vienna, Austria.

Osteoporotic (Colles' type) fractures of the distal radius occur relatively early in lifetime and could estimate risk of fracture of other, more endangered anatomical sites. High-resolution peripheral quantitative computed tomography (HR-pQCT) based micro finite element (μFE) analysis was shown to better predict fracture load of the distal radius than densitometry or histomorphometric measures. As an alternative to μFE, homogenization-based FE (hFE) approach may provide at least equivalent predictive power with reduced computational needs. The aim of this study was to validate the hFE approach with compression tests of 25 distal radius sections extracted at the location which is relevant in Colles' fractures. HR-pQCT-based input parameters of the hFE models were calibrated with respect to μCT. HR-pQCT-based hFE models were then built and their ability to predict experimental stiffness and ultimate load was compared to those of the density-based parameters, histomorphometric indices and μFE models assessed from the same input images. Bone mineral content was the best non-FE-based predictor (R (2) = 0.86) of ultimate force. Both FE methods were not only the strongest predictors, but provided quantitatively correct fracture loads. The calibrated hFE approach provided closely as strong prediction (R (2) = 0.94) as μFE (R (2) = 0.95), but the former was computationally cheaper. The results of this validation study suggest that FE simulation could be used as an efficient and precise tool to predict Colles' fracture load.
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http://dx.doi.org/10.1007/s10237-010-0245-3DOI Listing
July 2011

Breathing with the pelvic floor? Correlation of pelvic floor muscle function and expiratory flows in healthy young nulliparous women.

Int Urogynecol J 2010 Apr 8;21(4):475-81. Epub 2009 Dec 8.

Department of Internal Medicine, Hochzirl Hospital, Hochzirl 1, 6170, Zirl, Austria.

Introduction And Hypothesis: The aim of this cross-sectional study was to determine correlations between pelvic floor muscle (PFM) function and expiratory function in healthy young nulliparous women.

Methods: In 40 volunteers, PFM function was assessed by vaginal palpation. Forced expiration patterns were evaluated visually and by palpation of the suprapubic insertion region of the anterolateral abdominal muscles. Forced vital capacity (FVC) and forced expiratory flows (FEF) were determined by spirometry.

Results: Incremental positive correlation was found between voluntary PFM contraction strength and forced expiratory flow at 25%, 50% and 75% (FEF(25%), FEF(50%), FEF(75%)) of the FVC, respectively. Positive correlation was also found between PFM contraction strength and forced expired volume in 1 s (FEV(1)). No correlation was found between PFM contraction strength and FVC or peak expiratory flow (PEF).

Conclusions: Despite some limitations of this study, the observed correlation between PFM contraction strength and forced expiratory flows may serve as theoretical background for a potential role of coordinated abdominal and PFM training in diseases with expiratory flow limitations.
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http://dx.doi.org/10.1007/s00192-009-1060-1DOI Listing
April 2010

Prepatellar quadriceps continuation: MRI of cadavers with gross anatomic and histologic correlation.

AJR Am J Roentgenol 2009 Mar;192(3):W111-6

Department of Radiology, University of California, San Diego and VA San Diego Healthcare System, 3350 La Jolla Village Dr., San Diego, CA 92161, USA.

Objective: The "prepatellar quadriceps continuation" is the appropriate designation for the deepest soft-tissue layer that lies anterior to the patella, related to the deep rectus femoris tendinous fibers. The purpose of this study was to define and investigate the prepatellar quadriceps continuation and its relationship with the patella in cadavers using MRI and gross anatomic and histologic analyses.

Materials And Methods: MRI of 12 fresh-frozen knee specimens was performed using T1-weighted sequences in the axial and sagittal planes. Specimens were then sectioned in 3-mm-thick slices to correspond precisely with the MR images. Histologic analysis was performed in two specimens. The MR images were compared with findings seen on anatomic sectioning and histology. In addition, the layered organization of the patellar tendon was analyzed in 29 embalmed knee specimens obtained from human cadavers of both sexes.

Results: The normal prepatellar quadriceps continuation was seen as a band of low signal intensity in the MR images. This structure could not be differentiated easily from the low signal intensity of the patellar cortical bone. The sagittal plane was the most optimal plane for visualization of the attachment site of this continuation to the patella. Gross anatomic dissections revealed that at the proximal pole of the patella, the quadriceps tendon was formed by the rectus femoris and vastus intermedius muscles. The entire quadriceps tendon had an average thickness of 8.54 mm in this region. The thickness of the quadriceps tendon fibers extending over the anterior patellar surface measured, on average, 0.68 mm, and the average thickness of those fibers inserting into the proximal patellar pole was 7.87 mm. Histologic analysis showed that the attachment site of the prepatellar quadriceps continuation was formed by the distal extension of the deep longitudinal fibers of the rectus femoris tendon. At the border zone between the tendons and the patella, the tendinous fibers gradually were transformed into fibrocartilage. This so-called chondroapophyseal type of attachment was found to cover the entire anterior surface of the patella. The average thickness of the fibrocartilage at the insertion of the quadriceps tendon, patellar tendon, and prepatellar quadriceps continuation measured 0.136, 0.023, and 0.004 mm, respectively.

Conclusion: The prepatellar quadriceps continuation is formed by fibers of the rectus femoris tendon and connects the quadriceps and patellar tendons. All tendons are attached through formation of a chondroapophyseal zone and are therefore transformed into a seam of fibrocartilage. Based on these anatomic features, separation of the prepatellar quadriceps continuation from the patella in the absence of more extensive abnormalities of the quadriceps mechanism is plausible.
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http://dx.doi.org/10.2214/AJR.07.3107DOI Listing
March 2009

Terminal bifurcation of the biceps brachii muscle and tendon: anatomic considerations and clinical implications.

AJR Am J Roentgenol 2008 Dec;191(6):W248-55

Department of Radiology, University of California, San Diego, San Diego, CA, USA.

Objective: The objective of our study was to describe the anatomic variation of a bifurcated distal biceps tendon with MRI, histology, and dissection in cadavers and to report the MR appearance of superimposed lesions in a patient population with this anatomic variant.

Materials And Methods: Visual and histologic examinations of the distal biceps brachii tendon in eight sectioned fresh-frozen elbow specimens were performed. Dissection of 17 elbow specimens was performed to describe the distal biceps brachii tendon. In addition, all elbow MRI reports over a 3-year period (n = 411) were retrospectively reviewed to determine the presence of bifurcation of the distal biceps brachii tendon.

Results: The distal biceps brachii tendon appeared bifurcated in 25% of the sectioned specimens, and these findings were confirmed histologically. The distal biceps brachii tendon was completely separable into two components-that is, a short head and long head- throughout their proximal to distal extent in 41.2% of the dissected specimens. The distal biceps brachii tendon appeared bifurcated in 11.8% of 68 clinical cases that showed distal biceps brachii tendon abnormalities or injuries. The following patterns of injury were noted: complete rupture of both tendons (n = 1), complete rupture of the short head and normal insertion of the long head (n = 2), complete rupture of the short head and partial tear of the long head (n = 2), partial tear of both tendons (n = 2), and complete rupture of the short head and tendinosis in the long head (n = 1).

Conclusion: A bifurcated distal biceps brachii tendon is an anatomic variant that arises from persistent division between the short head and long head of the distal biceps brachii tendon and can be characterized with MRI. Knowledge of a bifurcated distal biceps brachii tendon is important to characterize injury to the components and to avoid pitfalls in imaging diagnosis.
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http://dx.doi.org/10.2214/AJR.08.1048DOI Listing
December 2008

Reference data for in vivo magnetic resonance imaging properties of meniscoids in the cervical zygapophyseal joints.

Spine (Phila Pa 1976) 2008 Oct;33(21):E778-83

Department of Radiology, MR Center of Excellence, Medical University Vienna, Vienna, Austria.

Study Design: Prospective in vivo study of meniscoids in the cervical zygapophyseal joints.

Objective: To generate reference data for in vivo magnetic resonance (MR) imaging properties of meniscoids in the cervical zygapophyseal joints.

Summary Of Background Data: Meniscoids, also called synovial folds, are tiny anatomic structures within the zygapophyseal joints. It has been suggested that pathologic conditions of meniscoids may be a potential source of cervical pain. Prior studies were limited to in vitro observations. To identify pathologic conditions of the meniscoids, it is necessary to obtain reference data of basic in vivo MR imaging properties of meniscoids in a healthy population.

Methods: Fifty-six healthy volunteers (33 women, 23 men; mean age 42.0 +/- 17.1 years) were investigated in a 3.0 Tesla MR scanner using high resolution isotropic 3-dimensional sequences. Presence, size, location, and signal intensity of the meniscoids were assessed, and their dependence on sex, age, body mass index, and degenerative changes were analyzed by t test and correlation analysis.

Results: There was no significant difference in presence (20.3 +/- 4.8 vs. 19.7 +/- 4.8) and size (3.8 +/- 0.7 mm vs. 4.1 +/- 0.5 mm) of meniscoids between women and men. Presence of meniscoids decreased with increasing age (r = -0.38, P = 0.004). Size of meniscoids did not significantly depend on age (r = 0.02, P = 0.91). Meniscoid entrapment (location) was a rare condition (0.4%). Tissue composition (signal intensities) of the meniscoids was 61.6% mainly fatty, 15.8% mainly fibrous, and 22.6% mixed.

Conclusion: Basic data about in vivo MR imaging properties of cervical meniscoids in a healthy population have been successfully generated. Subsequent studies may use these data as reference for the identification of meniscoid pathologies.
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http://dx.doi.org/10.1097/BRS.0b013e318182c399DOI Listing
October 2008
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