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Results for “Notch shape”

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9 recordsLinked to original sources

PubMed2026

Sex-stratified analyses of femoral intercondylar notch morphology and ACL injury risk: a systematic review and meta-analysis.

BACKGROUND: Anterior cruciate ligament (ACL) injury is more common in females. Although ACL injury risk is multifactorial, involving neuromuscular, hormonal, and biomechanical factors, femoral intercondylar notch morphology is a proposed non-modifiable anatomical contributor that may help explain this disparity. This review synthesizes evidence on its association with ACL injury risk, analyses stratified by male and female sex. METHODS: A literature search of PubMed, Web of Science, and Scopus was conducted through January 2026. After duplicate removal, 527 unique records were screened and 134 full texts assessed for eligibility. Twenty-four studies met inclusion criteria, with 22 providing quantitative data. Data were extracted on ACL-injured (ACLi) and control (ACLc) knees, stratified by sex. RESULTS: ACLi knees had narrower notch widths than ACLc knees in both females (MD -1.74 mm, 95% CI -2.54 to -0.95) and males (MD -1.31 mm, 95% CI -1.94 to -0.68), with substantial heterogeneity (I2 81-95%). NWI differences were significant in males (MD -0.01, 95% CI -0.02 to 0.00) but not females. Limited notch shape data suggested higher ACL injury odds with A-shaped notches in females (OR 2.85, 95% CI 0.07-110.66) and males (OR 1.67, 95% CI 0.00-3.98 × 105). CONCLUSION: Narrower femoral intercondylar notch width was consistently associated with ACL injury in both sexes, whereas findings for NWI and notch shape were limited by heterogeneity and sparse data. These results provide a structured synthesis of sex-specific anatomical risk factors and support femoral notch narrowing as a shared contributor, while highlighting the need for prospective, standardized studies in the future.

Humans↗

PubMed1978

[Modification of the vacuum extraction device (author's transl)].

The article describes a bell-shaped vacuum extractor with a rigid tube neck connected via a ball and socket joint. The advantages of this device over the "classical" device described by Malmström (2), are as follows: Easier insertion of the bell adjusted at an angle of 90 degrees, improved pushing-up of the bell for fastening to the head when this is still in elevated position, better placing of the bell at the desired location, better manipulation into the desired direction of pull, possibility of pushing up the anterior part in case of late cesarean section, and better sealing of the suction tube at the point of transition from the tube to the flexible hose. Another improvement concerns the adhesion, achieved by means of ring-shaped notches on the inside of the bell.

Cesarean Section↗

PubMedDate not supplied

Impedance and admittance tympanometry. I. Experimental approach.

In this experimental study a procedure is developed which enables the conversion of susceptance and conductane tympanograms to reactance and resistance tympanograms. Special attention was given to the subtraction of the ear canal admittance. The procedure was applied to bell-shaped and W-notched susceptance and conductance tympanograms. Computed reactance curves showed always an inverted-V shape, computed resistance curves were always flat.

Acoustic Impedance Tests↗

PubMedDate not supplied

[Vectorcardiographic findings in atrial enlargement].

Rational interpretation of changes of the P loop, due to atrial enlargements, must be based on the magnitude and spatial orientation of the main resulting vectors of the atrial activation phenomenon. Under normal conditions, these ones give origin to a mean vector oriented to the left, downward and slightly forward. Right atrial enlargement can be recognized by P loops of more than 100 mcv. The main axis of the elongated PF is comprised between + 60 degrees and + 90 degrees; that of the open PH between + 70 degrees and + 80 degrees and that of PS is located around + 135 degrees. Left atrial enlargement can be diagnosed by a characteristic box glove configuration of the PF loop as well as by an eight-shaped PH. In some cases, the PS loop also becomes eight-shaped. Biatrial enlargement gives rise to slurrings and notchings of the distal portion of the PF loop, a diphasic aspect and frequently an eight-shaped configuration of the PH loop and a triangular morphology of PS, whose base lasts 30 msec. or more.

Cardiomegaly↗

PubMed1978

A contribution to the functional morphology of articular surfaces.

The variations of the joint shape are first analyzed in the acetabulum and the ulnar trochlear notch of man. Then an attempt is made to explain the basic shape of the lunate surface and the types of articular surface diverging from it with regard to causal histogenesis and the general theory of joint stress (Pauwels), as well as the theoretical distribution of stress in the perfect ball and socket joint (Kummer). Certain statements are made about the position, size, changes in direction and course of the resultant forces at the joint, statements which seem very likely to be accurate when compared to facts already known about the hip joint in man. Under these preconditions, the various forms of the observed articulating surfaces may be theoretically reconstructed in every case. In this connection, it is first shown that the preservation of the joint cartilage is also dependent on the period of time during which the resultant force is effective in the various areas of the articular surface. The term "relative constancy" is used to express this time factor. Two functional explanations are given for the presence of incisions and divisions in the lunate surface and in the trochlear notch: 1. It is assumed that the "relative constancy" of the resultant forces is of varying magnitude in the different areas of the articular surface. The incisions and divisions in the joint cartilage are thus seen as areas in which the resultant joint stress does not rise above the minimum value for preservation of the articular cartilage. 2. The radius of the convex articular surface can be slightly larger than the radius of the concave articular surface. Because of this incongruity no pressure will be transmitted in an area of the lunate surface or of the trochlear notch because of the defective contact. It follows that the cartilage-preserving stimulating pressure is also absent from this area. According to Pauwels, the magnitude and distribution of the stresses arising in the articulating surfaces may be determined from the varying density distribution of the subchondral bony tissue, as seen in x-rays. The density distribution of the subchondral bone at the ulnar socket shows clear basic parallels to the extent of the surface covered by joint cartilage. The relatively low density in the area of the notch is seen as being the result of lower stress, in accordance with the functional explanation of division of the cartilage surfaces. In photoelastic model experiments, the dependence of the degree of relative stress on the form of the articular surface is illustrated by means of the number of isochromes. Here, the distribution of density of the subchondral bony tissue corresponds to the local magnitude of stress in the corresponding model joint. Functional analysis of the tangential fiber layer of the joint cartilage at the femoral head and the elbow joint, shows basic agreement between the split line patterns and the trajectoral pattern, as described in articulating surfaces examined by Pauwels, Konermann and Molzberger...

Acetabulum↗

PubMedDate not supplied

Impedance and admittance tympanometry. II. Mathematical approach.

The W-notching of susceptance, conductance and admittance tympanograms, as well as inverted-V shapes, found at high probe tone frequencies are explained, starting from realistic assumptions on the shape of resistance and reactance tympanograms. Necessary conditions for obtaining the different types of tympanograms are given. The theory shows that no pathology is necessary to explain W-notching or inverted-V shapes at higher-frequency probe tones.

Acoustic Impedance Tests↗

PubMed1977

Otoadmittance measurements in patients with rheumatoid arthritis.

Analysis of middle ear function has for many years been accomplished by acoustic impedance measurements and this has proved of great clinical value. The vectors which contribute to impedance are functions of mass, stiffness and resistance of the system and information about these components may be obtained by use of the otoadmittance meter. The shape of the tympanogram may be altered both by pathologies which change the relative magnitude of the vectors and by variation in the probe tone frequency. Patients with rheumatoid arthritis (55 ears) were compared with a series of controls (50 ears); 38% of 'rheumatoid ears' demonstrated a marked notch on the 660 Hz susceptance curve whilst only 8% of the control group showed this abnormality. The pattern suggests a decrease in the stiffness of the transducer mechanism in rheumatoid arthritis.

Acoustic Impedance Tests↗

PubMed1979

Pressure-dependent changes in nuclei and the process origins of the endothelial cells lining Schlemm's canal.

Monkeys eyes were fixed with glutaraldehyde in vivo at positive intraocular pressure of 35 or 25 mm Hg and compared with eyes fixed without a positive pressure gradient, with the use of light microscopy and transmission and scanning electron microscopy. The entire endothelial lining of the inner wall of Schlemm's canal ballooned or distended toward the external wall of the canal at positive intraocular pressure. Characteristic nuclear shapes were identified and appeared to result from the increased pressure forcing the lining away from the meshwork opposed by a restraining or anchoring effect of cytoplasmic processes attached to the subendothelial cells and trabecular meshwork. Without positive intraocular pressure endothelial cell nuclei were rounded, with many folds and notches in the nuclear membrane and were not deformed by their cytoplasmic processes. These findings suggest that the cells may be capable of elastic recoil or contraction.

Animals↗

PubMed1979

The influence of the surface electrogram on the rising phase of the mammalian cardiac action potential.

1. When guinea pig cardiac tissue is stimulated, the rising phase of the action potential is influenced by the shape of the concomitant local surface electrogram. This, in turn, depends on the direction of the wave of excitation passing the recording microelectrode. 2. A symmetrical biphasic surface electrogram yields sigmoid upstrokes with masimum upstroke velocity (Vmax) lower than when it is either zero or uniphasic and negative. 3. When the main direction of the depolarization wave in guinea pig ventricular myocardium is receding from the recording microelectrode, giving rise to negative uniphasic extracellular potentials, a notch might distort the registration of the rising phase of the action potential. 4. When the main direction of the depolarization wave is approaching the recording microelectrode, giving rise to positive uniphasic extracellular potentials, Vmax is transferred to less negative membrane potentials. 5. The extracellular surface electrogram influences the overshoot of the action potentials of the normal atrial and depressed (D-600) ventricular myocardium and is changed, depending on how the wave of excitation passes the recording microelectrode.

Action Potentials↗