Notch Morphology Research Articles

Morphological changes to the intercondylar space in different stages of osteoarthritis - a retrospective cross-sectional study.

The intercondylar space is defined as the topographic area walled by the intercondylar notch (IN) and encasing the central ligaments of the knee joint. As the anterior cruciate ligament (ACL) is not only impinged against the roof but also against the lateral wall of the IN, information concerning changes to the IN during the progression of osteoarthritis could be potentially relevant in predicting the future risk for ACL-rupture and -degeneration and ensure preventive measures as early as possible. Therefore, the purpose of this study was to evaluate the influence of osteoarthritis on osseous notch morphology. Image data was retrieved from the Osteoarthritis Initiative. Patients were subdivided into five groups according to the severity of osteoarthritis following the Kellgren and Lawrence classification. 415 patients were selected randomly to ensure equally large groups. Osseous structures were measured in coronal and axial planes in MRI. At the level of the popliteal groove and on the level of the joint line, the width of the lateral and medial femoral condyle, the notch width (NW) as well as the total width of the distal femur were measured. The notch width index (NWI) as ratio between the NW and the total width of the distal femur was calculated. Three shapes (A-shape, Inverse-U-shape and Ω-shape) of the IN were differentiated. The morphology of the IN is directly influenced by the development of osteoarthritis. Especially the Ω-shape is characteristic for more severe cases of osteoarthritis (p<0.001). Measurements were also significantly influenced by the imaging plane and the level of measurements (both p<0.001). The results of this study reflect significant changes to the intercondylar space in increasing grades of osteoarthritis. Additionally, the recommendation on the location of measurements of the IN should be revised, as especially the measurements on the level of the joint line in coronal plane MRI are a more reliable and objective indicator for the diagnosis of IN stenosis and therefore of changes to the intercondylar space, which always influences the health of the ligaments housed. At the level of the popliteal groove a NWI<0.25 and NW<19mm and at the level of the joint line a NWI<0.17 and a NW<14mm should be interpreted as severe notch stenosis and a definitive risk factor for ACL rupture.

The Transverse Sigmoid Notch Morphology Unravelled.

Background: Several studies have described pathology in relation to transverse sigmoid notch morphology, using the Tolat transverse sigmoid notch classification. It is believed that the entire shape of a sigmoid notch can be described using Tolat sigmoid types. We hypothesised that the determination of the sigmoid notch shape (SNS) depends on the level of the transverse CT plane on the axial axis of the distal radius. The aim of this study was to determine and compare the transverse SNS on different axial CT levels in the same wrist. Methods: The transverse SNS of 53 participants were independently qualitatively classified by two researchers in accordance with the four morphologies described by Tolat et al. The SNS was determined at two levels on the axial axis of the distal radius; at the level of the most prominent part of Lister tubercle, determined on the sagittal plane and at the level of the 'smallest distance between the ulnar head and sigmoid notch' (SDUS). Results: Forty-seven percent of the wrists demonstrated different SNS types according to Tolat classification, depending on the axial level of the CT scan. Interobserver agreement on the transverse sigmoid shape was 87% at Lister tubercle and 85% at SDUS, which can both be interpreted as 'excellent'. Conclusions: Despite an excellent interobserver agreement, 47% of the study population had different transverse sigmoid notch types within the same wrist. We, therefore, conclude that Tolat transverse sigmoid classification may not be useful for the description of potential pathology in relation to the sigmoid notch morphology.

Coronary microvascular dysfunction and autoregulatory capacity interfere with resting Dicrotic notch morphology

Coronary microvascular vasodilator capacity is substantially associated with coronary pressure waveform and dicrotic notch morphology, with or without concomitant epicardial disease. A prominent dicrotic notch is associated with preserved microvascular vasodilatory capacity and adequate resting microvascular tonus without relative hyperaemic state, cumulatively indicating a better microcirculatory health.

Medial sigmoid depression prevalence and association with a sigmoid notch: cone beam computed tomography and panoramic image study

This study aims to determine whether and how the data of the medial sigmoid depression (MSD) area via cone beam computed tomography (CBCT) differs from panoramic radiography. This study also aims to evaluate various sigmoid notch types and assess the relationship between sigmoid depression and notch morphology. A total of 129 individuals consisting of 258 sides were evaluated. Chi-Square/Fisher Exact tests were used to assess parameters on a categorical scale between two or more groups. McNemar’s test compared the findings detected on panoramic and CBCT images. MSD was more prevalent in females than males in both techniques, but this difference was not statistically significant. There was no association between the prevalence of MSD and the morphology of the sigmoid notch. The incidence of MSD shape was not significantly different between both imaging modalities. In both panoramic and CBCT, we found a high and similar prevalence of MSD. While the MSD prevalence was 66.7% for CBCT, it was 58.1% for panoramic. The shape or prevalence of MSDs in either approach did not correlate with sigmoid notch morphology. The two approaches' identical prevalence indicates that the panoramic image has adequately defines MSD. The high prevalence of MSD demonstrated how important it is for clinicians to characterize this anatomical variation accurately for the surgical treatment.

The relationship of medial sigmoid depression and sigmoid notch morphology with vertical and sagittal growth patterns in Turkish population

Medial sigmoid depression (MSD) is an anatomical variation located just below the deepest point of the sigmoid notch (SN). The etiology of MSD is unknown. It has been reported that increased maximum bite force affects the occurrence of MSD, and vertical growth pattern affects SN morphology. The aim of this study was to investigate the effects of these malocclusions on the presence and morphology of MSD and SN, since bite force can change with vertical and sagittal growth patterns. This is the first study to investigate the effects of vertical growth pattern on the presence and morphology of MSD, and the effects of sagittal growth pattern on SN morphology. Panoramic and lateral cephalometric radiographs of a total of 634 (427 female, 207 male) patients aged from 18 to 35 years (mean 19.58) were included in this retrospective study. MSD and SN shapes, SN depth and width were evaluated on panoramic radiographs. Mann Whitney-U, Kruskal-Wallis and Chi-square tests were used for data analysis. Sagittal and vertical growth patterns were not significantly associated with the presence and shape of MSD (p&gt;0.05). SN depth was greater in individuals with class III malocclusion, and both SN depth and width were lower in hyperdivergent individuals. There was no significant relationship between SN shapes and vertical and sagittal growth patterns (p&gt;0.05). SN depth is affected by both vertical and sagittal growth pattern, and SN width is affected only by vertical growth pattern. The presence of MSD was not associated with growth pattern.

Magnetic Resonance Imaging-Based Morphometric Analyses of the Bicruciate Injury of the Knee: Is There a Clue in the Distal Femur?

The morphology of the distal femur's intercondylar notch has been implicated in the susceptibility to and severity of cruciate ligament injuries. While previous research has primarily focused on isolated anteriorcruciate ligament (ACL) or posterior cruciate ligament (PCL) injuries, the relationship between notch morphology and combined cruciate injuries remains less understood. This study aimed to explore the association between femoral notch morphology and the severity of combined cruciate ligament injuries in adult males. In this retrospective cohort study, MRI scans from 118 adult male participants with and without knee dislocations (60 cases with Schenk classification Type II or higher knee dislocations and 58 controls) were analyzed. The study period ranged from 2015 to 2023. Femoral notch width, notch width index (NWI), and notch shape (U shape, A shape) were assessed using a Philips Multiva 1.5 Tesla system (Philips, Amsterdam, Netherlands). The statistical significance of differences in measurements between cases and controls was evaluated using independent sample t-tests performed with IBM SPSS Statistics, version 26 (IBM Corp., Armonk, NY). The case group exhibited a significantly smaller mean femoral notch width (15.88 mm ± 2.7 mm) and NWI (0.238 ± 0.58) compared to the control group (notch width 18.29 mm ± 3.4 mm, NWI 0.25 ± 0.31), with p-values of 0.004 for both measurements. The notch shape was predominantly A-shaped in the case group (n = 49) as opposed to U-shaped in the control group (n = 41). The study identifies a significant association between reduced femoral notch dimensions and the severity of complex cruciate ligament injuries. These findings support the notion that specific femoral notch morphologies may predispose individuals to more severe ligamentous injuries.

Decoding the Interplay Between Tidal Notch Geometry and Sea‐Level Variability During the Last Interglacial (Marine Isotope Stage 5e) High Stand

AbstractRelic coastal landforms (fossil corals, cemented intertidal deposits, or erosive features carved onto rock coasts) serve as sea‐level index points (SLIPs), that are widely used to reconstruct past sea‐level changes. Traditional SLIP‐based sea‐level reconstructions face challenges in capturing continuous sea‐level variability and dating erosional SLIPs, such as tidal notches. Here, we propose a novel approach to such challenges. We use a numerical model of cliff erosion embedded within a Monte Carlo simulation to investigate the most likely sea‐level scenarios responsible for shaping one of the best‐preserved tidal notches of Last Interglacial age in Sardinia, Italy. Results align with Glacial Isostatic Adjustment model predictions, indicating that synchronized or out‐of‐sync ice‐volume shifts in Antarctic and Greenland ice sheets can reproduce the notch morphology, with sea level confidently peaking at 6 m and only under a higher than present erosion regime. This new approach yields insight into sea‐level trends during the Last Interglacial.

The influence of age on greater sciatic notch morphology: testing the Walker method in an Australian population.

Sex estimation is an integral aspect of a forensic biological profile. The pelvis, being the most dimorphic part of the skeleton, has been studied in considerable detail relative to morphological and metric variation. However, empirical data on the effect of age on pelvic morphology relative to sex-specific morphological variation is limited, especially in regard to the estimation of skeletal sex. This study assesses whether there are age-related differences in the distribution of the Walker (2005) morphological scores for the greater sciatic notch (GSN) in an Australian population. Three-dimensional volumetric reconstructions derived from multi-detector computed tomography (MDCT) scans of 567 pelves of 258 females and 309 males aged 18 to 96years were scored following Walker (2005). Differences in score distributions and means by sex and age group were tested using Pearson's chi-squared test and ANOVA, respectively. The accuracy of sex estimates derived from logistic regression equations was explored using leave-one-out cross-validation. Significant differences were found in score distribution and means among age groups in females, but not in males. There was a tendency toward higher scores in older females. The overall sex estimation accuracy was 87.5%. When comparing age groups 18-49 and 70 + years, estimation accuracy decreased in females (99% vs. 91%), while the opposite was found for males (79% vs. 87%). These findings suggest that age affects GSN morphology. Higher mean scores in older females imply that, on average, the GSN becomes narrower with increasing age. It is thus recommended due consideration of estimated age when assessing sex based on the GSN in unidentified human remains.

Correlation of suprascapular notch morphology with suprascapular nerve palsy: a 3D-computed tomography study

The morphology of the suprascapular (SS) notch is a very important factor in treatment of suprascapular nerve (SSN) palsy. Several studies have reported SS notch morphology in cadavers or using a three-dimensional computed tomography (3D-CT); however, none has reported the distribution of SS notch morphology according to the age group. In addition, the correlation between SS notch morphology and SSN palsy remains unclear. The purposes of this study were to investigate the morphological distribution of the SS notch by age group in a large population and to assess the relationship between SS notch morphology and SSN palsy. We studied the 3D-CT images of 1063 shoulders in 1009 patients (mean age, 60.8 years; age range, 14-96 years). There were 53 shoulders with SSN palsy and 1010 shoulders without SSN palsy. Morphology of the SS notch was classified by Rengachary's classification (types I-VI). Shoulders with types I-IV were classified into the nonossified superior transverse scapular ligament (STSL) group (group N) and those with types V and VI into the ossified STSL group (group O). The Rengachary's classifications of the 1063 shoulders were as follows: type I: n=113, 10.6%; type II: n=313, 29.4%; type III: n=383, 36.0%; type IV: n=109, 10.3%; type V: n=107, 10.0%; and type VI: n=38, 3.6%. Mean age was significantly older in the ossified STSL group, and the age was <40 years for only two shoulders in this group. The Rengachary's classifications of the SSN palsy cases were as follows: type I: 7.5%, II: 24.5%, III: 34.0%, IV: 15.1%, V: 13.2%, and VI: 5.7%. There was no statistical difference in age and sex, Rengachary type, or ossification between SSN palsy and non-SSN palsy cases. Ossification of the STSL was significantly more common in older patients, which suggests age-related change. In addition, no relation was identified between narrow notch or ossification of the STSL with the onset of SSN palsy.

Assessment of femoral notch morphology in male patients with anterior cruciate ligament injury: an MRI study

Aim: The objective of the present study was to evaluate the femoral notch type, notch width index (NWI), notch angle (NA) and α angle in patients with ACL injury and compare with nonathletic male population, using magnetic resonance imaging (MRI).Methods: 79 patients with complete ACL tear and 80 patients as control group (aged 19-43 years) who had knee MRI were evaluated. NWI, NA measurements and notch shape were evaluated on axial fat-saturated proton-weighted sequences. Femoral notch shape was classified as A, U and W types.Results: A statistically significant association was found between notch type, NWI, NA and ACL injury (p&amp;lt;0,001). Type A notch in the ACL-injured group (79.75 %) was significantly higher than the control group (24%). NWI was lower in patients with ACL-injured group than in control group (0.249 ± 0.020 vs 0.281 ± 0.022) Notch angle was lower in patients with ACL-injured group than in control group (47.15 º ± 5.63 º vs 50.73 º ± 5.44º). A significant association between stenotic notch type A and NWI (p &amp;lt;0,001). The α angle was lower in patients with ACL-injured group than in control group but it was not statistically different (41.9 º ±2.79 ºvs 42.06 º ±2.53 º; p= 0.978).Conclusion: This study showed that however low NWI, NA values are a risk factor for ACL injury, the strongest predictive factor was stenotic femoral notch type A. α angle had no significant correlation in ACL injury.

Morphological variations of mandibular sigmoid notch in children aged 4-14 years

Aim: The sigmoid notch additionally known as the mandibular notch is a deep notch setting apart the coronoid process and the condyle. Different morphological variations of sigmoid notch (wide, round and sloping) have been documented in literature as indispensable aids in anthropological and forensic research. The study aimed to assess the morphological appearance of sigmoid notch during primary dentition, mixed dentition and permanent dentition. Methods: 400 panoramic images of 194 boys and 296 girls were collected and divided into three groups bases on the stage of dentition. Shape of the sigmoid notch was determined by tracing the print out of the panoramic image on an x-ray viewer. Results: It was observed that during primary and mixed dentition stage shape of the sigmoid notch was wide and as growth and development occured during permanent dentition stage the sigmoid notch shape changed to round. Conclusions: This study describes the normal morphology of mandibular sigmoid notch in children during primary, mixed and permanent dentition and also states that growth of craniofacial region has a significant role in determining sigmoid notch morphology.

Magnetic resonance based morphometric analysis of the tentorial notch.

The study of the tentorial notch can improve the understanding of brain injury mechanisms. Tentorial morphology has been analysed primarily in cadaveric studies. However, the postmortem effect can cause variability in the measurements. The objective was to evaluate the morphometry of the tentorial notch and the third cranial nerve on living subjects using magnetic resonance imaging (MRI). A retrospective cross-sectional study was performed. Using consecutive cases, 60 MRI scans were analysed for tentorial notch morphology. Maximum notch width (MNW), notch length (NL), interpedunculoclival (IC) distance, apicotectal (AT) distance, third cranial nerve (CN-III) distance, and inter- CN-III angle, were obtained. For the classification of the tentorial notch quartile distribution technique for MNW, NL, AT distance, and IC distance were used. According to the quartile of the MNW, patients were stratified into narrow, midrange, and wide groups. Using the NL quartile groups, they were also classified as short, midrange, and long. With these, the tentorial notch could be classified into eight types. Statistical differences between genders in the MNW and inter-CN-III angle were found, as well as a strong positive correlation between NL and AT distance, and between right and left CN-III distances. There were differences between the cadaveric samples and living subjects in the CN-III distances. This difference could be explained by the dehydration of brain volume in the postmortem process which may cause nerve elongation. Morphometry of the tentorial notch and its neurovascular relations allows a better understanding of the mechanisms of brain herniation.

Prediction on aeroengine blade foreign object damage validated by air gun tests

Aeroengine in service was prone to ingest foreign objects, leading to foreign object damage (FOD) and failure accidents of the blades. In this paper, laboratory FOD tests were firstly conducted on TC4 and AM355 steel simulated airfoil specimens impacted by 3 mm diameter projectile at a speed of 350 m/s, and numerically reproduced using Johnson-Cook (J-C) model with failure criterion. A penetrating-type notch (P-notch) with severe material loss was observed, and a good agreement between experiments and finite element (FE) predictions could be found for both notch morphology and size. The influence of impact velocity on FOD and the FOD-induced residual stress were investigated by the proposed FE model. High tensile stress was observed along the notch edge, while the bottom of notch was mainly dominated by compressive stress. Finally, a FE model of aeroengine blade considering the initial centrifugal force was developed, and the influences of FOD to compressor blade on its modal properties were discussed. Compared to the normal blade, the damage induced a deviation in frequency within 1 %.

Anatomical Variations of the Suprascapular Notch and Its Importance in Nerve Entrapment

Background and Aim: Entrapped neuropathy syndrome could be effectively managed with detailed anatomical knowledge of suprascapular notch. Suprascapular nerve injuries are now widely acknowledged as a cause of shoulder pain and dysfunction. The present study aimed to determine the anatomical variation of the suprascapular notch and its importance in nerve entrapment. Methodology: A total of 128 human scapulae of either gender were taken from the department of Anatomy, Saidu Group of Teaching Hospitals, Swat and Women Medical and Dental College Hospital Abbottabad during the period from January to June, 2021. Four parameters of Suprascapular notch (SSN) i) Superior transverse depth (STD), ii) Maximum depth (MD), iii) middle transverse diameter (MTD), and total circumferential diameter (TCD) were defined based on incisura inferior border shape and vertical diameters. Suprascapular notch presence or absence was grossly examined for all the scapulae. Vernier caliper was used for the measurement of the four suprascapular notch parameters. SPSS version 23 was used for data analysis. Results: Out of 128, 61 (47.7%) were right-sided and 67 (52.3%) were left-sided human scapulae. The prevalence of U-shaped, V-shaped, and J-shaped notch were 62 (48.4%), 27 (21.1%), and 13 (10.2%) respectively. The incidence of the large double foramen, complete, and incomplete suprascapular notch were 2 (1.6%), 7 (5.5%), and 8 (6.3%) respectively. W-notched was present in 3 (2.3%) scapulae whereas 6 (4.7%) scapulae had no notch. The vertical and transverse diameters for right and left-sided type-II scapulae were 4.9±2.1 mm and 8.9±3.1 mm and 4.8±1.7 mm and 9.1±2.3 mm respectively. Conclusion: The prevalence of U-shaped and V-shaped notch was 48.4% and 21.1% respectively. Suprascapular notch morphology could be determined with anatomical knowledge and play a critical role for neurosurgeons, clinicians, orthopedic surgeons, and radiologists for proper diagnosis and management of shoulder region surgical procedure and protocol. Keywords: Suprascapular notch, Anatomical knowledge, Nerve entrapment

Stress distribution pattern in the distal radioulnar joint before and after ulnar shortening osteotomy in patients with ulnar impaction syndrome

Ulnar shortening osteotomy (USO) for ulnar impaction syndrome potentially leads to degenerative changes of the distal radioulnar joint (DRUJ). This study was performed to evaluate the effect of the sigmoid notch morphology on the stress distribution pattern of the DRUJ using computed tomography (CT) osteoabsorptiometry (CT-OAM). We reviewed the pre- and postoperative transverse CT images of 15 wrists that had undergone USO. The examined wrists were classified into two groups based on the sigmoid notch morphology: the linear-type notch (type L) and the curved-type notch (type C). We calculated and statistically compared the percentage of the high-density area (%HDA) in each divided region of the sigmoid notch. In type L, %HDA was significantly larger in the distal-dorsal region of the sigmoid notch before USO. Postoperatively, in type L, no specific regions showed a significantly different %HDA. In type C, %HDA was significantly larger in the distal-volar region of the sigmoid notch before USO. Postoperatively, %HDA of type C was significantly larger in the proximal-volar region. Our results suggest that in patients with ulnar impaction syndrome, morphological evaluation of the sigmoid notch can serve as a predictor of osteoarthritis in the DRUJ with or without USO.

Sex estimation of the subadult ilium prior to acetabular fusion

Previous studies evaluating sexual dimorphism in subadult pelvic features present variable, and at times conflicting, conclusions. As a result, there is yet to be a consensus on whether the subadult pelvis can be used in sex estimation methods. This study aims to assess the forensic utility of ilium shape and greater sciatic notch morphology in sexing subadult pelves prior to acetabular fusion. A sample of 397modern U.S. individuals with unfused acetabula (i.e., tri-radiate cartilages) aged birth to 14years was queried from a larger sample of postmortem computed tomography scans. Elliptical Fourier analyses were performed on ilium and greater sciatic notch outlines and resultant PCs were evaluated for significant effects of sex and age. Greater sciatic notch metrics were also collected. Stepwise linear discriminant function analyses with leave-one-out cross-validation were performed on the PCs and metric variables. Analyses were performed on pooled samples, on age-specific cohort samples, and on samples that iteratively removed the youngest one-year cohort. Cross-validated correct classification rates ranged from 57% to 65% and no patterns were observed to support an appearance and/or consistent expression of sexually diagnostic traits. Based on the results, sex estimation using these features is not recommended in pelvic remains prior to acetabular fusion, although the sample sizes of individuals over 5years of age were limited in this study. Future studies should focus on the sexually diagnostic ability of pelvic traits in subadult samples post-fusion of the acetabulum.

Femoral notch and proximal tibial morphology and their relationship with an anterior cruciate ligament injury in the Indian population: A magnetic resonance imaging-based study

Objectives: We aim to study the incidence of anterior cruciate ligament (ACL) injury to proximal tibia bone morphology in Indian patients. Materials and Methods: Forty male subjects who sustained non-contact ACL injury who presented to our center between October 2015 and December 2016 studied and compared to 40 non-ACL injury knee magnetic resonance imaging scans. Notch morphology and both medial and lateral posterior tibial slope measurements were performed and studied. Results: We noted that the difference in notch depth and notch angle between the two groups was not significant. There was a statistically significant higher incidence of ACL injury in patients with smaller notch widths. Both an increased medial and lateral posterior tibial slope did not demonstrate a statistically significant incidence in ACL injury. Conclusion: Notch width is a major contributing risk factor for ACL injury in Indian patients. This is in agreement with previously published literature.

Mid to Late-Holocene relative sea-level fluctuations and palaeoenvironment: Evidences from the southern Saurashtra coast, western India

Around 2 m thick relict mudflat, stabilized coastal dune and marine notches are used to estimate the relative sea level (RSL) changes during the mid-Holocene along the part of southern Saurashtra coast. The study identifies two events of high RSL which are dated to 7.3 cal yr BP to 5.1 cal yr BP (Mid-Holocene) and ~1 ka BP (Late-Holocene). Based on the geochemical proxies, the Mid-Holocene high RSL is ascribed to the combined contribution of global ice melt and the strengthened Indian Summer Monsoon (ISM), whereas, the Late-Holocene high RSL is attributed to the Medieval Climate Anomaly. A decline in the ISM is observed at ~4.2 ka which also corresponds with the declining trend in the RSL. However, after 4 ka, a sustained ISM is inferred which continued till 1 ka. The uplift estimated based on the tectonic overprinting of the raised intertidal platforms and marine notches shows ~1.5–2 m uplift after the Mid-Holocene. This implies that the net RSL component during the Mid to Late-Holocene was marginally high (above the present high-tide mark). Further, the notch morphology and empirically driven erosion rate estimates indicate that the coastal uplifts occurred at ≤ 4 ka and was probably responsible for the present-day coastal configuration.

A Novel Method for In Vitro 3D Imaging of Dissecting Pressurized Arterial Segments Using X-Ray Microtomography

Background:It is commonly admitted that a dissection initiates with an intimal tear or at least a defect inside the arterial wall. Nevertheless, few studies investigated the initiation sequence due to the difficulty to monitor this process.Objective:The objective of this work was to observe and investigate the mechanisms leading an intimal tear to propagate into a dissection.Methods:A custom-made tension-inflation device fitting inside an X-ray microtomography setup was designed. A notch was created inside a porcine carotid artery before performing the tension-inflation test. The X-ray tomography setup allowed observing the wall-structure and the notch behavior during the inflation of the carotid artery.Results:A quantitative description of the notch morphology was performed, suggesting the prevalence of high shear stress in the region of the crack tip as a possible trigger for propagation of a dissection.Conclusions:The present experimental approach allowed understanding better the mechanisms leading to dissection and constitutes a first step toward the improvement of failure modeling and risk assessment of this disease.

Low cycle fatigue damage model and sensitivity analysis of fatigue crack initiation by finite element approach

To meet the design requirements, different types of defects are often machined on the surface of fatigue components. Local stress concentration formed at the notch accelerate the initiation of fatigue crack, therefore greatly shorten the service lives of such components. Based on the theory of continuous damage mechanics and the principle of irreversible thermodynamics, the damage evolution model of low cycle fatigue is investigated. By programming the damage evolution model as UMAT subroutine and coupling it to ABAQUS, the fatigue damage and crack initiation life of notched P92 steel samples under specific loads are simulated, and the crack initiation location is determined. Furthermore, the damage evolution and crack initiation sensitivity of notch morphology are considered. The results show that the crack initiation occurs easily in the notch root where the damage is greatest and the plastic strain accumulates fastest under cyclic loading. The fatigue damage accumulates slowly at the initial stage, but the damage accumulates rapidly after the cumulative damage reaches a critical value. The fatigue damage evolution and fatigue initiation life are very sensitive to the notch morphology parameters. The notch morphology need to be carefully analyzed, to improve the fatigue life of the notched samples.