scholarly journals Estimation of the Anterior Extent of the Meyer Loop Using MR Tractography

2008 ◽  
Vol 29 (3) ◽  
pp. e4-e4
Author(s):  
K. Abdel-Aziz ◽  
P. Goulding
Keyword(s):  
Anterior Extent

Acetabular Labral Tear Dimensions and Number of Suture Anchors Used to Repair in Patients with Femoroacetabular Impingement Syndrome

2021 ◽  
Author(s):  
Guillaume D. Dumont ◽  
Matthew J. Pacana ◽  
Adam J. Money ◽  
Thomas J. Ergen ◽  
Allen J. Barnes ◽  
...  
Keyword(s):  
Femoroacetabular Impingement ◽  
Impingement Syndrome ◽  
Labral Tear ◽  
Labral Repair ◽  
Suture Anchors ◽  
Labral Tears ◽  
Femoroacetabular Impingement Syndrome ◽  
The Mean ◽  
Tear Size ◽  
Anterior Extent

AbstractFemoroacetabular impingement syndrome (FAIS) is commonly associated with acetabular labral tears. Correction of impingement morphology and suture anchor repair of labral tears have demonstrated successful early and midterm patient-reported outcomes. The purpose of this study was to evaluate the posterior and anterior extent and size of labral tears in patients with FAIS undergoing arthroscopic labral repair, and to evaluate the number of suture anchors required to repair these tears. The design of this study was retrospective case series (Level 4). A single surgeon's operative database was retrospectively reviewed to identify patients undergoing primary arthroscopic hip labral repair between November 2014 and September 2019. Patient-specific factors and radiographic measurements were recorded. Arthroscopic findings including labral tear posterior and anterior extents, and the number of suture anchors utilized for the repair were recorded. Linear regression was performed to identify factors associated with labral tear size. The number of suture anchors used relative to labral tear size was calculated. Three-hundred and thirteen patients were included in the study. The mean posterior and anterior extent for labral tears were 11:22 ± 52 and 2:20 ± 34 minutes, respectively. Mean tear size was 2 hours, 58 minutes ± 45 minutes. The mean number of suture anchors utilized for labral repair was 3.1 ± 0.7. The mean number of anchors per hour of labral tear was 1.1 ± 0.3. Increased age, lateral center edge angle, and α angle were associated with larger labral tears. Our study found that acetabular labral tears associated with FAIS are, on average, 3 hours in size and centered in the anterosuperior quadrant of the acetabulum. Arthroscopic labral repair required 1.1 anchors per hour of tear size, resulting in a mean of 3.1 anchors per repair. Level of Evidence IV

Mechanics of Embryonic Head Fold Morphogenesis

2008 ◽  
Author(s):  
Victor D. Varner ◽  
Dmitry A. Voronov ◽  
Larry A. Taber
Keyword(s):  
Embryonic Development ◽  
Incubation Period ◽  
Neural Plate ◽  
Vitelline Membrane ◽  
Heart Tube ◽  
Germ Layers ◽  
Embryonic Tissues ◽  
Anterior Extent ◽  
Insight Into ◽  
Embryonic Head

Head fold morphogenesis constitutes the first discernible epithelial folding event in the embryonic development of the chick. It arises at Hamburger and Hamilton (HH) stage 6 (approximately 24 hours into a 21-day incubation period) and establishes the anterior extent of the embryo [1]. At this stage, the embryonic blastoderm is composed of three germ layers (endoderm, mesoderm, and ectoderm), which are organized into a flat layered sheet that overlies the fibrous vitelline membrane (VM). Within this blastodermal sheet, a crescent-shaped head fold develops just anterior to the elongating notochord, spanning across the embryonic midline at the rostral end of neural plate. At the crest of this fold, the bilateral precardiac plates fuse in a cranial to caudal direction and give rise to the primitive heart tube and foregut [2, 3]. An understanding of head fold morphogenesis may thus offer insight into how embryonic tissues are arranged to make ready for proper cardiac formation.

The anterior extent of dorsal development of the Xenopus embryonic axis depends on the quantity of organizer in the late blastula

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 363-372 ◽  
Author(s):  
R.M. Stewart ◽  
J.C. Gerhart
Keyword(s):  
Xenopus Laevis ◽  
Cell Population ◽  
Marginal Zone ◽  
Organizer Region ◽  
Blastula Stage ◽  
Dorsal Midline ◽  
Anterior Dorsal ◽  
Lateral Width ◽  
Anterior Extent ◽  
Anterior Posterior

In amphibian gastrulae, the cell population of the organizer region of the marginal zone (MZ) establishes morphogenesis and patterning within itself and within surrounding regions of the MZ, presumptive neurectoderm, and archenteron roof. We have tested the effects on pattern of reducing the amount of organizer region by recombining halves of Xenopus laevis late blastulae cut at different angles from the bilateral plane. When regions within 30 degrees of the dorsal midline are excluded from recombinants, ventralized embryos develop lacking the entire anterior-posterior sequence of dorsal structures, suggesting that the organizer is only 60 degrees wide (centered on the dorsal midline) at the late blastula stage. As more and more dorsal MZ (organizer) is included in the recombinant, progressively more anterior dorsal structures are formed. In all cases, when any dorsal structures are missing they are deleted serially from the anterior end. Thus, we suggest that the amount (lateral width) of the organizer in the MZ determines the anterior extent of dorsal development.

Radiographic Location of the Lateral Intercondylar Ridge

2008 ◽  
Vol 36 (10) ◽  
pp. 2002-2006 ◽  
Author(s):  
Lutul D. Farrow ◽  
Robert J. Gillespie ◽  
Brian N. Victoroff ◽  
Daniel R. Cooperman
Keyword(s):  
Confidence Interval ◽  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Radiographic Images ◽  
Cruciate Ligament Reconstruction ◽  
Blumensaat’S Line ◽  
The Mean ◽  
Anterior Cruciate ◽  
Lateral Intercondylar Ridge ◽  
Anterior Extent

Background The lateral intercondylar ridge (resident's ridge) is considered to be an important landmark during anterior cruciate ligament reconstruction. Presently, no study exists describing the location of this vital landmark on plain radiographic images. Hypothesis Lateral intercondylar ridge location can be estimated on lateral plain film images. Study Design Descriptive laboratory study. Methods Lateral radiographic images were taken of 20 distal femora with metallic markers overlying the lateral intercondylar ridge. The length of Blumensaat's line and the distance from the anterior extent of Blumensaat's line to the point where the lateral intercondylar ridge intersects Blumensaat's line were measured. The ratio of these measurements was then determined (Blumensaat's-ridge ratio). The angle of the lateral intercondylar ridge with respect to Blumensaat's line (Blumensaat's-ridge angle) was also determined. Results The mean length of Blumensaat's line was 32.1 mm (95% confidence interval, 31.0–33.2 mm). The mean distance from the anterior extent of Blumensaat's line to the point where the lateral intercondylar ridge intersects Blumensaat's line was 25.3 mm (95% confidence interval, 24.3–26.3 mm). The mean Blumensaat's-ridge ratio was 0.79 (95% confidence interval, 0.77–0.81). The mean Blumensaat's-ridge angle was 75.5° (95% confidence interval, 72.0°–79.1°). Conclusion The lateral intercondylar ridge intersects Blumensaat's line at a point defined by multiplying the Blumensaat's line length by 0.79. From this point, the ridge runs at a 75.5° angle with respect to Blumensaat's line. Clinical Relevance Awareness of the radiographic location of the lateral intercondylar ridge may help confirm accurate tunnel placement when arthroscopic positioning is in doubt. Furthermore, femoral tunnel position can be quickly and accurately assessed in the outpatient setting in patients with unsatisfactory outcomes after anterior cruciate ligament reconstruction.

Champsosaurus (Diapsida: Choristodera) from the Paleocene of west Texas: paleoclimatic implications

2010 ◽  
Vol 84 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Thomas M. Lehman ◽  
Ken Barnes
Keyword(s):  
Mean Annual Temperature ◽  
West Texas ◽  
Early Paleocene ◽  
Southward Extension ◽  
Latitudinal Range ◽  
Anterior Extent ◽  
Temperate Climates

A specimen of the aquatic reptile Champsosaurus sp. from the Paleocene Black Peaks Formation in southwestern Texas is the southernmost yet known. the fragmentary specimen exhibits some unusual features, such as a great anterior extent of the quadratojugal on the lower temporal arch, and cannot be attributed with confidence to any of the named species. Champsosaurus appears to have been tolerant of temperate climates and had a northern latitudinal range exceeding that of crocodylians. It seems likely that the brief southward extension in range of Champsosaurus during early Paleocene time resulted from a decrease in mean annual temperature, comparable to over 10° of paleolatitude.

scholarly journals SOME THOUGHTS ON INTERSPECIFIC MANDIBULAR MORPHOLOGY IN FOSSIL AND MODERN ALLIGATOR

2021 ◽  
Author(s):  
Jeremy Stout
Keyword(s):  
Fossil Record ◽  
Small Sample Size ◽  
Morphological Characters ◽  
Small Sample ◽  
Alligator Mississippiensis ◽  
Early Pleistocene ◽  
Species Determination ◽  
Fossil Species ◽  
Wide Variability ◽  
Anterior Extent

Alligator is diagnosed in the fossil record using discrete morphological characters.  These characters are used with systematic analyses to determine hypothetical phylogenetic relationships.  Examined here are two such characters for applicability in fossil species determination and relationship. One is the curvature of the dentary between the fourth and tenth alveoli (observed in several taxa), while the other is a further investigation into the anterior extent of the splenial (in modern Alligator mississippiensis and the early Pleistocene A. hailensis).  In a small sample size, the curvature of the dentary exhibits wide variability in character states both intraspecifically and interspecifically, bringing into question its utility in fossil crocodylian systematic applications.  The anatomy of the anterior extent of the splenial is phylogenetically informative, and a new method for inferring its presence as a basal or derived state (as a scar on the dentary) is described.

Intersubject variability in the anterior extent of the optic radiation assessed by tractography

2007 ◽  
Vol 77 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Daniel Nilsson ◽  
Göran Starck ◽  
Maria Ljungberg ◽  
Susanne Ribbelin ◽  
Lars Jönsson ◽  
...  
Keyword(s):  
Optic Radiation ◽  
Intersubject Variability ◽  
Anterior Extent

Host-induced variations in Haematoloechus buttensis (Trematoda: Haematoloechidae)

1980 ◽  
Vol 58 (3) ◽  
pp. 427-442 ◽  
Author(s):  
Murray J. Kennedy
Keyword(s):  
Life Cycle ◽  
Egg Size ◽  
Morphological Variations ◽  
As Species ◽  
Prior Use ◽  
Natural Hosts ◽  
Rana Pretiosa ◽  
Species Specific ◽  
Anterior Extent ◽  
Uninfected Host

The life cycle of Haematoloechus buttensis was maintained in the laboratory by using the usual natural hosts: Rana pretiosa, Physa nuttalli, and Ischnura perparva. Morphological variations in important taxonomic characters were studied and compared with those found when one of the usual hosts was replaced by a sympatric, but usually uninfected, host. In all, six species of Amphibia, three of Insecta, and three Mollusca were used.The effect of host size, sex, and ambient temperature was also studied using R. pretiosa as definitive host.The most reliable taxonomic characters were determined to be the sucker ratio, egg size of 21-day-old and older worms, position of the testes, and the anterior extent of the extracaecal uterine loops.The unreliability of other characters and their prior use as species-specific features suggests that many of the currently recognized species of Haematoloechus are not valid.

Phylogenetic position of Sphincterodiplostomum Dubois, 1936 (Digenea: Diplostomoidea) with description of a second species from Pantanal, Brazil

2021 ◽  
Vol 95 ◽  
Author(s):  
T.J. Achatz ◽  
J.A. Bell ◽  
F.T.V. Melo ◽  
A. Fecchio ◽  
V.V. Tkach
Keyword(s):  
Morphological Study ◽  
Type Species ◽  
Sequence Data ◽  
First Record ◽  
Phylogenetic Position ◽  
Neotropical Fish ◽  
Mature Adult ◽  
Dna Sequence Data ◽  
Interspecific Divergence ◽  
Anterior Extent

Abstract Sphincterodiplostomum is a monotypic genus of diplostomid digeneans that parasitize fish-eating birds in the neotropics. The type species Sphincterodiplostomum musculosum has a unique, dorsal, tubular invagination in the opisthosoma with a muscular sphincter. Whereas larvae of S. musculosum are relatively commonly reported in Neotropical fish helminth surveys, adult specimens from birds are rarely collected. Prior to our study, no DNA sequence data for S. musculosum were available. Our molecular and morphological study of mature and immature adult Sphincterodiplostomum specimens from three species of birds and one species of crocodilian revealed the presence of at least two species of Sphincterodiplostomum in the neotropics. We provide the first molecular phylogeny of the Diplostomoidea that includes Sphincterodiplostomum. In addition, this is the first record of S. musculosum from caimans, along with the first record of fully mature adult S. musculosum from green kingfisher Chloroceryle americana. The new species of Sphincterodiplostomum (Sphincterodiplostomum joaopinhoi n. sp.) can be morphologically distinguished from S. musculosum based on the anterior extent of vitelline follicles, narrower prosoma, substantially smaller holdfast organ and structure of tegumental spines. Our data revealed 0.7% interspecific divergence in 28S and 10.6–11.7% divergence in cox1 sequences between the two Sphincterodiplostomum species.

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