Purpose: The accessory parotid gland is a collection of salivary tissue separate from the main parotid gland. When present, it may complicate parotidectomies, promote parotitis, and serve as a potential site for benign and malignant lesions to arise. The aim of this study was to provide a comprehensive and current overview of the anatomy of the accessory parotid gland, as there is a wide discrepancy in the literature regarding its prevalence. Materials and Methods: The authors conducted a search in PubMed, Embase, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect, Korean Journal Database, and Russian Citation Index to identify all studies which reported relevant data on the accessory, with no date or language restrictions applied. Data on prevalence, side of occurrence, and sex dimorphism of the accessory parotid gland were extracted and pooled into a meta-analysis. Results: A total of 13 articles (n = 3115 subjects) were included in the study. The results revealed that the overall pooled prevalence of an accessory parotid gland was 32.1% (95% confidence interval: 21.2–44.0). It was more prevalent in cadaveric studies (35.8%) than in computed tomography studies (21.5%), had a higher prevalence in Asia (33.8%) as compared to North America (23.5%), and when present, it was most often found as an unilateral structure (77.8%). Conclusions: With respect to the findings presented, the accessory parotid gland may be considered an anatomical variation likely to encounter in the population. More anatomical studies on the structure and its prevalence are needed, in all regions of the world, to provide a representative global overview.

Background: The posterior meniscofemoral ligament (pMFL) of Wrisberg attaches to the posterior horn of the lateral meniscus and the lateral intercondylar aspect of the medial femoral condyle and passes posteriorly to the posterior cruciate ligament (PCL). The pMFL plays a role in recovery after PCL injuries and offers stability to the lateral meniscus, promoting normal knee function. Purpose/Hypothesis: The aim of the magnetic resonance imaging (MRI) arm of this study was to evaluate the prevalence of the pMFL in Polish patients. The purpose of the systematic review and meta-analysis was to evaluate the clinical relevance of the pMFL in knee surgery. It was hypothesized that extensive variability exists in reports on the prevalence, function, and clinical significance of the pMFL. Study Design: Cross-sectional study and systematic review; Level of evidence, 3. Methods: A retrospective MRI investigation was conducted on 100 randomly selected lower limbs of Polish patients (56 male, 44 female) performed in 2019 to determine the prevalence of the pMFL. Additionally, an extensive literature search of major online databases was performed to evaluate all reported data on the pMFL. Assessments of article eligibility and data extraction were completed independently by 2 reviewers, and all disagreements were resolved via a consensus. A quality assessment of the included articles was performed using the Anatomical Quality Assessment tool. Results: In the MRI arm of this study, the pMFL was observed in 73 of the 100 limbs. In the meta-analysis, 47 studies were included, totaling 4940 lower limbs. The pooled prevalence of the pMFL was found to be 70.4% (95% CI, 63.4%-76.9%); the mean length was 27.7 mm (95% CI, 24.8-30.5 mm) and the mean widths were 4.5, 6.1, and 4.1 mm for the meniscal and femoral attachments and midportion, respectively. The mean pMFL thickness was 2.3 mm (95% CI, 1.8-2.7 mm). Conclusion: Despite the variability in the literature, the pMFL was found to be a prevalent and large anatomic structure in the knee joint. The shared features of this ligament with the PCL necessitate the consideration of its value in planning and performing arthroscopic procedures of the knee.

Background: The anterior meniscofemoral ligament (aMFL) of Humphrey is an anatomically variable fibrous band of connective tissue that attaches between the lateral aspect of the medial femoral condyle and posterior horn of the lateral meniscus, running posterior to the anterior cruciate ligament and anterior to the posterior cruciate ligament (PCL). The presence of an intact aMFL may contribute to stabilization of the lateral compartment of the knee joint. Purpose: The original magnetic resonance imaging (MRI) arm of this study aimed to assess the aMFL incidence among Polish patients. The goal of the systematic review and meta-analysis was to review the literature discussing the clinical anatomy of the aMFL and provide data on its prevalence. It was hypothesized that significant heterogeneity exists within the published literature. Study Design: Cross-sectional study and systematic review; Level of evidence, 3. Methods: A retrospective investigation was performed on the MRI scans of 100 knees (52 right, 48 left) of Polish patients. Scans were randomly selected from a database of MRI examinations performed in 2019. For the meta-analysis, major online databases were queried for data on the aMFL, and 2 authors independently assessed and extracted data from all included studies. A quality assessment of the included articles was performed using the Anatomical Quality Assessment tool. Results: In the MRI arm of this study, the aMFL was found in 62 of the 100 lower limbs. The meta-analysis included 41 studies with a total of 4220 limbs. The aMFL was present in 55.5% (95% CI, 45.5%-65.3%) of cases. Arthroscopic studies yielded the highest prevalence (82.3% [95% CI, 36.6%-100.0%]); of MRI studies, the highest prevalence was at 3.0-T strength (51.0% [95% CI, 13.3%-88.2%]). Conclusion: Significant variability in the prevalence of the aMFL was found in the literature. More emphasis should be placed on the clinical relevance of injuries to the aMFL because of its significant role in the function of the knee. It is important to be aware that, because of the anatomy of the aMFL, the ligament can also function to support a torn PCL.