Exploring consistent ratios in morphometry of the proximal tibia: insights for knee arthroplasty.

INTRODUCTION: The current study, which delves into proximal tibia morphometric parameters in a Greek sample, not only analyzes whether specific linear distance ratios are consistent but also paves the way for a potential novel metric system for knee arthroplasty imaging studies using constant ratios. These findings could have significant implications for future enlarged research and clinical practice. METHODS: A total of 38 dried tibiae were evaluated by two independent investigators. The following distances were measured with a digital Vernier sliding caliper: (1) the mediolateral distance of the proximal surface (A), (2) the anteroposterior distance of the proximal surface (B), (3) The longitudinal length of the bone (C), (4) the line connecting the anterior margin of the proximal surface with the highest peak of the tibia tuberosity (D), (5) the depth of the proximal margin of the medial articular facet (AF) (medial plateau) (E) and (6) the depth of the proximal margin of the lateral AF (lateral plateau) (F). RESULTS: The A, B, C, D, E, and F mean distances were 71.3 mm, 47.4 mm, 340.2 mm, 37.1 mm, 42 mm, and 35.9 mm. Reliability analysis for each observer on all measurements revealed an interclass correlation (ICC) score of 0.975 (observer 1) and 0.971 (observer 2). The ratio A/B was 1.5, A/C was a constant 0.2, and D/C was 0.1. The ratio E/F was 1.2. The six measurements (A-F) showed excellent inter-observer reliability (all ICC values > 0.990). CONCLUSIONS: The study established constant ratios of the studied linear distances around the proximal tibia. Considering these ratios, asymmetrical tibial components in knee arthroplasty seem to replicate the native anatomy more closely. Furthermore, the distance from the anterior margin of the proximal surface to the tibial tuberosity peak, constituting one-tenth of the longitudinal length of the tibia, shows promise as a metric system for imaging studies, especially in assessing lesions around tibial components.

A scarce combination of arterial variants: an occipital artery originating from the internal carotid artery associated with a linguofacial trunk.

The occipital artery (OA) typically originates from the external carotid artery (ECA). Variations of the ECA has been well described in the current literature, while the OA is a relatively stable vessel, and its variations are uncommon. In the current case report, an aberrant OA has been found coexisting with a linguofacial trunk (LFT) on the right hemineck of a 51-year-old male patient. The OA was identified originating from the cervical internal carotid artery (ICA) at the level of the second cervical vertebra (C2). On the ECA, the lingual and facial arteries were emanating in common, as LFT. The left hemineck of the patient was free of variations. The current coexistence of arterial variants has been reported only once previously; therefore, the current case corresponds to the second case in the English literature. The aberrant OA origin from the ICA has been estimated with a pooled prevalence of 0.37%, while the origin at the C2 level and from the anterior surface of the ICA corresponds to a very rare variation. Additionally, the LFT is one of the most common trunk that can be found on the ECA. Interventional radiologists and surgeons must be aware of common and uncommon variation to avoid iatrogenic lesion.

Accessory thoracic muscles in human fetuses.

BACKGROUND: Typically, the anterior thoracic wall musculature is composed of the pectoralis major and pectoralis minor. Embryologically, these two muscles are originated from a common pectoral muscle mass; therefore, disruption of the normal development and differentiation could give rise to an aberrant or accessory muscle. The main aim of this study is to demonstrate and classify the accessory muscles of the pectoralis region in human fetuses. MATERIAL AND METHODS: Fifty spontaneously aborted human fetuses (25 male and 25 female, 100 sides) aged 18-38 weeks of gestation at death, and fixed in 10% formalin solution were examined. Following parental approval, the fetuses were donated to the Medical University anatomy program. The pectoralis major and minor muscle's morphology, the possible occurrence of accessory muscles of pectoral region and its morphology, their origins, and insertions, as well as the morphometric details, were assessed. RESULTS: The pectoralis major and minor were bilaterally found in all fetuses (100 cases). The accessory muscles of pectoral region were found in 16 cases (16%), and four types were differentiated. The Pectoralis Quartus muscle was the most common type of accessory muscles found in this study and occurred in 8 cases. The axillary arch muscle was observed in 3 cases. The chondrocoracoideus muscle was observed in 3 cases. The sternalis muscle occurred in 2 cases, and one of them was bifurcated. CONCLUSIONS: The thoracic region is characterized by a large amount of morphological variations, which are observed not only in adult population, but also among human fetuses. The pectoralis quartus was the most frequent variation in this study. Accessory structures like sternalis muscle, chondrocoracoideus muscle, pectoralis quartus muscle, or axillary arch muscle may have clinical implications, and knowledge about them is very useful for clinicians, especially plastic surgeons, thoracic surgeons, and orthopedics.

The brachioradialis longus: an unreported accessory form of the brachioradialis muscle.

The brachioradialis muscle (BR) belongs to the lateral forearm muscle. Typically, the radial nerve innervates it. BR morphological variability, such as split muscular belly, split tendon, or accessory BR (ABR), has been described in the current literature. A 68-year-old female donated cadaver was routinely dissected for research and educational purposes. A variant muscle was identified extending at the right arm's lateral and forearm compartments. It originated from the humerus lateral surface between the deltoid and the triceps brachii lateral head, joined the second muscular head from the brachialis muscle, and inserted into the radius styloid process. According to its origin, course, and insertion, the variant muscle probably corresponded to the BR accessory form. However, in the current literature, the ABR morphology corresponds to an accessory muscle originating adjacent to the typical BR and inserted into the radial tuberosity. At the same time, it was defined as "brachioradialis brevis." In the current case, the variant muscle differed significantly from the current literature due to the origin, insertion, length, and relationship with the typical BR; therefore, the term "brachioradialis longus" seemed adequate to describe this variant muscle.

Variability in the projection level of the vertebra prominens: a cadaveric study.

The 7th cervical vertebra (C7) is described as having the most prominent spinous process (SP) and is characterized as the "vertebra prominens" (VP) of the cervical spine in anatomy textbooks. The VP is an important anatomical landmark of the neck for clinical examination and therapeutic intervention. The present study identifies the level of the most prominent SP of the cervical and uppermost thoracic vertebrae in a cadaveric cohort. Thirty-nine (23 female and 16 male) cadavers of a mean age of 77.5 years were investigated in a prone position and a certain cervical kyphotic bending. The most prominent SP, at the base of the neck, was palpated and marked with a wedging nail into the SP of the vertebra. The cervical region was dissected, and a blind investigator examined whether the nail was placed into the SP of C7 or the SP of another upper or lower vertebra. In 19 out of 39 cadavers (48.7%), the C7 was identified as the VP (typical anatomy), followed by the C6 (in 14 cadavers, 35.9%), C5 (in 4 cadavers, 10.3%). In 2 cadavers (5.1%) the first thoracic vertebra was identified as having the most prominent SP. Although C7 is described as the VP, in the present study the SP of C7 was the most prominent in less than 50%. The high variable projection level of the most prominent SP of the cervical vertebra holds great clinical significance for spine examination, neck surgery, and spinal anesthesia.

Right-Sided Aortic Arch: A Computed Tomography Angiography Investigation, A Systematic Review with Meta-Analysis.

Background/Objectives: The right-sided aortic arch (RAA) is an uncommon variation of the aortic arch (AA), characterized by the aorta crossing over the right main bronchus. In the RAA, the descending aorta can be found on either the right or left side of the spine. The current study comprises a comprehensive retrospective computed tomography angiography (CTA) investigation into the prevalence of the RAA within the Greek population. Additionally, we will conduct a systematic review and meta-analysis to elucidate both common and rare morphological variants of the RAA. This research is significant as it sheds light on the prevalence and characteristics of the RAA in a specific population, providing valuable insights for clinical practice. Methods: Two hundred CTAs were meticulously investigated for the presence of a RAA. In addition, the PubMed, Google Scholar, and Scopus online databases were thoroughly searched for studies referring to the AA morphology. The R programming language and RStudio were used for the pooled prevalence meta-analysis, while several subgroup analyses were conducted. Results: Original study: A unique case of 200 CTAs (0.5%) was identified with an uncommon morphology. The following branches emanated from the RAA under the sequence: the right subclavian artery (RSA), the right common carotid artery (RCCA), the left common carotid artery (LCCA), and the left vertebral artery (LVA) in common origin with the aberrant left subclavian artery (ALSA). The ALSA originated from a diverticulum (of Kommerell) and followed a retroesophageal course. Systematic Review and Meta-Analysis: Sixty-two studies (72,187 total cases) met the inclusion criteria. The pooled prevalence of the RAA with a mirror-image morphology was estimated at 0.07%, and the RAA with an ALSA was estimated at <0.01%. Conclusions: AA anomalies, specifically the RAA, raise clinical interest due to their coexistence with developmental heart anomalies and possible interventional complications. Congenital heart anomalies, such as the Tetralogy of Fallot and patent foramen ovale, coexisted with RAA mirror-image morphology.

The quadratus femoris muscle anatomy: Do we know everything?

INTRODUCTION: The purpose of this study was to characterize the morphological variations in the quadratus femoris muscle (QF) and to create an anatomical classification that could be used in the planning of surgical procedures in this area, radiological imaging, and rehabilitation. MATERIALS AND METHODS: Ninety-two lower limbs from 46 cadavers, fixed in 10 % formalin solution, were examined. RESULTS: The QF muscle was present in all specimens. According to morphology, the QF muscle was classified into three types. The most common type was Type I, characterized by one muscular belly (78.3 %), while the second most common type was Type II, characterized by two bellies, was observed in 17.4 % of cases. The rarest type was Type III. It was characterized by three bellies and was found in 4.3 % of the cases. CONCLUSIONS: The current classification system on quadratus femoris morphological variability is novel. Morphological variants may contribute to clinical issues, such as the ischiofemoral impingement syndrome, that could arise from type I quadratus femoris. Hence, the current study may be applicated to planning surgical procedures, imaging, and rehabilitation.

Jugular bulb anatomical variations and pneumatization patterns: a comprehensive CBCT analysis.

PURPOSE: This study aims to assess the anatomical possibilities of the jugular bulb (JB). METHODS: Fifty archived CBCT scans were analyzed. RESULTS: The average distance between the internal acoustic canal (IAC) and the JB was 7.97 mm on both sides (Right: SD = 2.56 mm, range 3.16-13.3 mm; Left: SD = 2.5 mm, range 2.9-13.6 mm). JB walls' pneumatization was classified into eight patterns. Deep petrosal cells (DPCs) prevailed in the lateral wall of the JB. The absence of pneumatization (NP) was commonly found on the left side. The presence of infralabyrinthine and hypotympanic cells varied. Less common types included accessory occipital cells (AOCs), posteromedial tracts (PMTs), and basi-occipital cells (BOCs), which determined a consistent variation of the lateral wall pneumatization patterns. Pneumatization of the medial wall was not observed in 50 right sides and 49 left sides. The inferior wall analysis revealed symmetry in AOC distribution and a predominant occurrence of NP. Cases with hypotympanum (HT) in the lateral wall showed a statistically significant IAC-JB distance increase by an average of 4.67 mm compared to NPs. Specific pneumatizations, particularly HT on the lateral side, have a significant effect on the IAC-JB distance, showing a clear pattern of increasing distance from DPC to NP and then to HT. A significant distance increase in HT pneumatization was noted. There were also recorded instances of JB hypoplasia and hyperplasia, JB diverticula, dehiscent JBs, and high JBs. CONCLUSION: This study establishes a novel classification of JB pneumatizations to aid in the understanding of the temporal bone anatomy.

Fenestration of the anterior and posterior cerebral arteries in coexistence with a contralateral posterior cerebral artery of fetal origin.

PURPOSE: The present case report aims to describe the rare coexistence of three variants of the cerebral arterial system diagnosed by computed tomography angiography (CTA). METHODS: A retrospective study on head and neck CTAs was performed on a Greek adult population from the Department of Radiology, University Hospital of Larissa. An interesting case of an 80-year-old male was further investigated. RESULTS: The cerebral arterial circle presented with a combination of three variations. The left anterior cerebral artery (ACA) was fenestrated 1.4 mm proximally to the anterior communicating artery formation. The left posterior cerebral artery (PCA) was also fenestrated, 5.5 mm distally to its origin from the basilar artery. Lastly, the right PCA originated from the ICA supraclinoid segment. CONCLUSIONS: This case report highlights an unusual coexistence of A1 and P1 segments fenestration with a fetal PCA, resulting in a unique cerebral circle. A1 segment fenestration has been previously reported as rare, while the PCA fenestration as extremely rare variant. Awareness of these rare variations could aid interventionists in their preoperative assessments.

An ectopic thyrolingual trunk arising from the common carotid artery: a rare variant.

The common carotid artery (CCA) typically bifurcates into the external and internal carotid arteries (ECA and ICA). In the head and neck area, the ECA gives off a few anterior branches from proximal to distal: the superior thyroid artery (STA), the lingual artery (LA), and the facial artery (FA). Occasionally, these branches can fuse into trunks, with the linguofacial trunk being the most common. During a computed tomography angiography (CTA) of a 67-year-old patient, a common arterial trunk, 11.3 mm proximal (prior) to the CCA bifurcation was recorded. The trunk was formed by the STA and the LA fusion and was characterized as a thyrolingual trunk (TLT). These trunks have been reported with a prevalence ranging between 0.3 and 1% and correspond to one of the rarest variants of the ECA anterior branches. Knowledge of the typical and variant anatomy of the carotid arteries and their branches is of paramount importance to surgeons and interventional radiologists.

A bicaudatus sartorius muscle: a rare variant with potential clinical implications.

BACKGROUND: Sartorius muscle (SM) belongs to the thigh anterior compartment musculature. It corresponds to the longest muscle of the human body, while its variations are described rarely. The current case reports aims to describe a distal bifurcation of the SM, forming the bicaudatus SM variant. MATERIALS AND: M: ETHODS: An 84-year-old male cadaver was dissected for educational and research purposes at the Department of Anatomy, National and Kapodistrian University of Athens. RESULTS: On the left lower limb, the SM was typically originated from the anterior superior iliac spine. After 351.22 mm length, it was bifurcated into an anterior and posterior part. Both muscular parts were contributing to the pes anserinus morphology. Femoral nerve branches were providing innervation to the variant muscle, while the saphenous nerve and vein were coursed posteriorly to the variant muscle. CONCLUSIONS: SM morphological variability is described quite rarely. The current case report corresponds to the bicaudatus SM variant. Accessory parts of SM could lead to compression symptoms to the femoral nerve anterior branches, as well as to the saphenous nerve.

Renal Artery Triplication: An Unusual Morphological Variant.

Renal vasculature depicts great morphological variability and clinical significance due to the great number of procedures performed on kidneys. The current imaging report presents a right-sided renal artery (RA) triplication and origin from the abdominal aorta (AA), which was incidentally identified during computed tomography angiography (CTA). The typical RA corresponded to the main hilar artery (MHA), the second RA corresponded to the superior polar artery (SPA), and the third RA corresponded to the inferior polar artery (IPA). RA triplication occurs in 0.9%-4.5% and depicts wide morphological variability. The current report corresponds to one superior polar, one inferior polar, and a main hilar renal artery, which represents a rare morphological type of RA triplication. Kidney transplantation surgery, endoscopic surgery, and renal angiography require adequate knowledge of RAs and their variants to avoid pitfalls and iatrogenic lesions from clinicians.

Considerations for the value of three-dimensional printed (3DP) versus cadaveric specimens for anatomy education.

We enjoyed reading the Brumpt et al. paper, which showed that a three-dimensional printed model (3DPM) of the ear was more effective than conventional cadaveric models for teaching anatomy. We would like to comment on the findings of this exciting study. In this case, the 3DPM of the ear was compared with dried bone models but not with a cadaveric specimen (with all adjacent soft tissues). The better results after the first test of students who used the 3DPMs were probably attributed to the optimized 3D representation of the ear anatomy. Also, the educational outcomes will likely be better if a more complex 3DPM is used, as it permits better visualization of the structures compared to the dried bone specimens. We certainly agree that 3DPMs have a remarkable ability to represent anatomy. Still, their effectiveness has not been proven superior to cadaveric specimens teaching complex anatomy. In conclusion, although we agree that 3DPMs have a high educational potential and can contribute to complex anatomy teaching, those models were not proven significantly more effective than cadaveric specimens in the Brumpt et al. study. The better effectiveness of 3DPMs compared to dried bone specimens (at the first test) does not mean those models are superior to specimens with retained soft tissues. Such cadaveric specimens permit visualization of complex structures and have proven valuable for teaching complex anatomy. Currently, the literature does not support the educational superiority of 3DPMs to those cadaveric specimens.

A bilateral gastrocnemius tertius coexisting with a unilateral two-headed plantaris muscle.

The current cadaveric report aims to present a coexistence of two uncommon variants of the posterior leg compartment. The variations were detected, during classical dissection in an 84-year-old donated male cadaver. On the left lower limb, the gastrocnemius muscle was identified as having a third head that was attached to the lateral head. This variant is known as gastrocnemius tertius muscle and was bilaterally identified. The left-sided plantaris muscle had two distinct heads that fused into a common tendon that was inserted into the calcaneal tuberosity. Knowledge of these variants is important, due to their close relationship with the popliteal neurovascular bundle. Clinicians should be aware, to avoid pitfalls and take them into account in their differential diagnosis.

Morphological variability of the pectoralis minor muscle. Study in human fetuses.

BACKGROUND: The pectoralis minor muscle is located in the anterior thoracic wall. Typically, is constituted by a single belly originating from the 3rd to the 5th rib and inserted into the coracoid process near the origins of the biceps brachii shorth head and of the coracobrachialis muscle. The current study, on human fetuses, aims to detect all morphological muscle variants and to create a new classification system. MATERIAL AND METHODS: Classical dissection of the thoracic wall and the upper limb was bilaterally performed on 25 (13 male and 12 female) human formalin-fixed fetuses aged 18-38 weeks of gestation. The spontaneously aborted fetuses were donated after parental consent to the Medical University anatomy program. The pectoralis minor muscle's morphology, the number of the muscle's bellies, their origins, and insertions, as well as the morphometric details of each belly of the pectoralis minor, were assessed. RESULTS: The pectoralis minor was bilaterally found in all fetuses (50 cases). Three types of muscle were identified based on the number of muscle bellies. In type, I (typical anatomy), were classified the cases with a single belly (in 66%). This type was divided into two subtypes (Ia and Ib). In the subtype Ia, the single belly had a typical course, and in Ib, a proximal attachment was characterized by two small bellies connecting together and creating one muscular mass. In type II, two bellies (24%), and in type III, three bellies (10%) were identified. CONCLUSIONS: Pectoralis minor is morphologically variable in the number of its bellies, its course, its origins, its insertions, and the location of its proximal attachments. The most common type (typical anatomy) was the type I represented by one belly. Other identified variants in the number of bellies by the present study may be hypothetically a result of prematurely terminated embryogenesis.

Systematic Review and Meta-analysis of Suprascapular Notch Morphological Variability: Do We Know Everything?

The suprascapular notch represents a depression on the lateral part of the superior border of the scapula, medially to the coracoid process. The current paper presents a systematic review with a meta-analysis of the suprascapular notch morphological variability. Related clinical implications were further discussed as well to emphasize the value of the topic. A total of 31 articles were included in the meta-analysis, which depicted great heterogeneity. Thus, due to the different classification systems, difficulties were faced in creating a complete and united classification. All the problems and pitfalls that arise from each classification system were discussed, and we concluded with the most complete one. The knowledge of the suprascapular notch morphological anatomy is of great importance, especially for orthopedic surgeons, due to its relationship with the suprascapular nerve. Thus, further research in this area is adequate.

A Bilateral Symmetrical Variant Formation of the Sural Nerve.

Typically, the sural nerve is formatted by the connection of the lateral sural cutaneous nerve (branch of the common fibular nerve) and the medial sural cutaneous nerve (branch of the tibial nerve). The current cadaveric report aims to describe a quite unusual symmetrical variant of the sural nerve. Classical dissection was performed on an 84-year-old donated male cadaver. On both sides, the sural nerve was formatted directly by the sciatic nerve. After its emanation, it continued its typical course between the gastrocnemius muscle heads. Sural nerve formation has been extensively studied due to its great clinical significance. The identified variant corresponds to one of the rarest types of sural nerve formation. Knowledge of sural nerve variants may play a crucial role in lower limb surgery and nerve harvest for reconstruction.

The Anatomical Variation of the Distal Anterior Cerebral Artery: An Angiographic Study in a Greek Population Sample.

Objective The current retrospective angiographic study establishes the rates of variants in the distal anterior cerebral artery (DACA) in a sample of the Greek population. Methods Data were collected from 456 patients who underwent two-dimensional (2D) or three-dimensional (3D) digital subtraction angiography (DSA) of the carotid and vertebral arteries bilaterally. The study focused on patients with good visualization of the anterior and posterior circulations and employed magnetic resonance (MR) or computed tomography (CT) angiography for 3D reconstruction. The anterior cerebral artery (ACA) was classified into one of its two basic configurations, that is, with or without the callosomarginal artery (CMA). The bihemispheric, median, and azygos ACA patterns were also identified. Results The majority (373/456, 81.8%) exhibited a typical DACA pattern. The bihemispheric, median, and azygos patterns were identified in 66/456 (14.5%), 10/456 (2.2%), and 7/456 (1.5%), respectively. The CMA was present in 824/912 (90.4%) of the hemispheres, with a trend toward male predominance for bilateral presence (males: 167/192, 86.98%; females: 210/264, 79.55%; p = 0.05). In particular, the CMA was present significantly more frequently (p = 0.002) in the left hemispheres of male patients. Gender differences in CMA presence persisted in the analysis of the patients with a typical DACA pattern. Conclusion This study provides insights into the variations of the DACA in the Greek population. The observed gender differences in CMA rates suggest potential morphological variations in cerebral vasculature between males and females and contribute to a better understanding of vascular anatomy for clinical and surgical applications.

A bilateral four-headed brachialis muscle with a variant innervation: a cadaveric report with possible clinical implications.

PURPOSE: Anterior compartment muscles of the arm present high morphological variability, with possible clinical significance. The current cadaveric report aims to describe a bilateral four-headed brachialis muscle (BM) with aberrant innervation. Emphasis on the embryological background and possible clinical significance are also provided. METHODS: Classical upper limb dissection was performed on an 84-year-old donated male cadaver. The cadaver was donated to the Anatomy Department of the National and Kapodistrian University of Athens. RESULTS: On the left upper limb, the four-headed BM was supplied by the musculocutaneous and the median nerves after their interconnection. On the right upper limb, the four-headed BM received its innervation from the median nerve due to the musculocutaneous nerve absence. A bilateral muscular tunnel for the radial nerve passage was identified, between the BM accessory heads and the brachioradialis muscle. CONCLUSION: BM has clinical significance, due to its proximity to important neurovascular structures and frequent surgeries at the humerus. Hence, knowledge of these variants should keep orthopedic surgeons alert when intervening in this area. Further dissection studies with a standardized protocol are needed to elucidate the prevalence of BM aberrations and concomitant variants.

The anterior communicating artery variants: a meta-analysis with a proposed classification system.

Morphological and morphometric variants of the anterior communicating artery (AComA) have been described by multiple studies; however, a complete classification system of all possible morphological variants with their prevalence is lacking. The current systematic review with meta-analysis combines data from different databases, concerning the AComA morphological and morphometric variants (length and diameter). Emphasis was given to the related clinical implications to highlight the clinical value of their knowledge. The typical AComA morphology occurs with a pooled prevalence (PP) of 67.3%, while the PP of atypical AComA is 32.7%. The identified AComA morphological variants (artery's hypoplasia, absence, duplication, triplication, differed shape, fenestration, and the persistence of a median artery of the corpus callosum- MACC) were classified in order of frequency. The commonest presented variants were the AComA hypoplasia (8%) and the anterior cerebral artery (ACA) fusion (5.9%), and the rarest ones were the MACC persistence (2.3%), and the AComA triplication (0.7%). The knowledge of those variants is essential, especially for neurosurgeons operating in the area. Given the high prevalence of AComA aneurysms, an adequate and complete classification of those variants is of utmost importance.