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Despite the significance of anatomical variability in various specialties, there is currently limited research dedicated to this topic. Most studies focus on the brain, with only a small number examining the human skull, primarily in relation to anatomical variability in childhood. AIM: Therefore, the aim of our work is to determine the individual anatomical variability of the lateral dimensions of the facial section of the adult human skull. MATERIALS AND METHODS: The study included 115 skulls of mature individuals, comprising 35 dry bone specimens from the anatomy museum collection and 80 results from human head CT scans without bone tissue pathologies. To detail the craniometric characteristics of the lateral surface of the facial section of the skull, polygons (polygons) were constructed with dividing of the facial section of the skull is into the orbital-frontal, nasal, and maxillary. The facial profilegram of the skull was formed as a set of predetermined dimensions between facial profile points, presenting a continuous line passing through points gl-n-rhi-ns-pr-id-pg, reflecting the shape, dimensions, and position of the cranial profile of mature adults regardless of sex or cranial type. RESULTS: It was established that the longitudinal anteroposterior dimensions of the facial skull exhibit a certain range of variability in mature individuals depending on gender. For instance, the distance between the points gl-po (glabella-porion) reaches its maximum values in individuals with a brachycranial skull shape, ranging from 107 mm to 130 mm in men and from 104 mm to 128 mm in women. In individuals with a mesocranial skull shape, this parameter gradually decreases to 109-126 mm in men and 107-124 mm in women. A similar decrease is observed in those with a dolichocranial skull shape, where the range is 109-121 mm in men and 109-120 mm in women. The distance between n-po (nasion-porion) in brachycranial and mesocranial individuals remains within 96-123 mm and 102-123 mm, regardless of gender, indicating that this parameter is relatively stable. However, in dolichocranial individuals, this distance decreases to 104-115 mm. CONCLUSIONS: Individual anatomical variability of the anteroposterior lateral dimensions of the facial skeleton in mature individuals has been determined. A more in-depth analysis of the existing range of individual variability in the profile configuration of the facial skull was conducted using sagittal polygons. It was found that the polygons gl-po-n, n-po-rhi, and rhi-po-ns relate to the structure of the bony profile of the orbital-temporal and nasal regions of the facial skull, reflecting the upper, combined orbital-nasal section of the head.

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The internal iliac artery arises as a terminal extension of the common iliac artery and supplies blood to the pelvic region. This study aims to identify the anatomic variations of the internal iliac artery (IIA) in a Mexican population sample. This is a retrospective cross-sectional observational study. A total of 81 angiographies via the femoral artery approach performed on patients undergoing various medical procedures were included. Variations in the IIA branching patterns were identified by evaluating the angiographic images and grouped according to Adachi's classification into five types (I-V). A total of 139 hemipelvises were analyzed (78 right and 61 left). The frequencies of each type of variation were as follows: Type I (71.2%), Type II (10.79%), Type III (0 cases), Type IV (0.7%), Type V (12.94%), and unclassified (4.31%). The most frequent anatomical variants of the IIA in the western Mexican population sample were Type I, followed by Types V and II. Even though Type V is rare in most populations, it was the second most frequent variant in this study. Understanding the variants of the IIA branching pattern is necessary for performing invasive procedures in the pelvic region with precision and minimizing complications.

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Previous studies have reported various anatomical differences in the cerebral artery between healthy subjects and patients with posterior circulation cerebral infarction. In particular, basilar artery angulation has been associated with posterior circulation cerebral infarction. We compared anatomical variations and the degree of anterior and lateral vertebrobasilar artery angulation and deviation to compare the incidence of cerebral infarction of healthy subjects and patients with posterior circulation cerebral infarction. We compared basilar artery anatomy using brain magnetic resonance angiography in 97 patients who underwent brain magnetic resonance angiography during health checkups at our hospital and in 92 patients diagnosed with posterior circulation cerebral infarction between 2012 and 2022. Anatomical variations, including fetal-type posterior cerebral artery, hypoplastic P1 segment, vertebrobasilar dolichoectasia, and dominant vertebral artery, as well as the degree of anterior and lateral deviation and angulation, were evaluated. Correlations between these variations and the occurrence of cerebral infarction were analyzed. The prevalence of hypoplastic P1 was significantly differences in patients with posterior circulation cerebral infarction (odds ratio: 5.655). Furthermore, patients with posterior circulation cerebral infarction exhibited more acute anterior and lateral angulation, as well as lateral deviation. Hypoplastic P1 and more acute anterior or lateral angulation of the vertebrobasilar artery are associated with increased frequency of cerebral infarction.

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The chordae tendineae, described as fibro-collagenous structures, support the leaflets of the atrioventricular valves of the heart in various ways. The chordae tendineae are composed of collagen and elastic fibers. They connect to the ventricular side of the valve leaflets' free border and hinder the leaflets from swinging back into the atrial cavity during systole. Mitral valve chordae tendineae have been classified using a variety of classification systems. To our knowledge, we report a variant chordae tendinea that has yet to be described in the literature. The variant, present only on the mitral anterior papillary muscle, did not show the characteristic appearance of the chorda tendineae. Muscular fibers were observed extending from a larger than usual mitral anterior papillary muscle, inserting into the rough zone of the anterior leaflet. Several tendinous primary and secondary true leaflet chordae emerge from the apical portion of the anterior papillary muscle, inserting into the anterior leaflet's free edge and rough zone. Contraction of this muscular chorda during systole could disrupt the mechanics of valvular closure and result in possible regurgitation across the mitral valve. Additionally, this structure may be subject to rupture during myocardial infarction, leading to valvular dysfunction. The developmental connection between the chordae and papillary muscles could explain the anomalous muscularization of the chordae tendineae observed in this case.

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Variant anatomy in the axillary region is of great clinical significance. It is one of the most frequently accessed regions for radical dissection surgery. During routine dissection of embalmed cadavers, we found a rare case of two accessory muscular slips emerging from the lateral border of latissimus dorsi (LD) and the inferolateral border of pectoralis major (PM), crossing the neurovascular structures in the axilla and merging distally together to the brachial fascia at the upper end of humerus below the bicipital groove. The accessory slip from LD is commonly referred to as the "axillary arch" in literature. We identified the accessory slip from the PM crossing over the axilla as pectoralis quartus. These aberrant slips can cause neurovascular compression in the axilla and can have clinical implications. Prior knowledge of the variant anatomy is the key to successful surgery in the axilla, thereby avoiding inadvertent injuries and post-operative complications.

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PURPOSE: To systematically review published studies on the prevalence of the thyroid foramen (TF), perform a meta-analysis to generate pooled prevalence estimates, and identify factors associated with its presence. METHODS: A systematic literature search was conducted in Google Scholar, PubMed, and Journal Storage databases. Studies reporting the prevalence of the thyroid foramen were included without language or date restrictions. Quality assessment was performed using AQUA tool. A random-effects meta-analysis was performed with subgroup analyses. Heterogeneity was assessed using Higgins' I2 statistics, and publication bias was evaluated using funnel plots and Egger's test. RESULTS: Out of 271 entries, 38 studies met the inclusion criteria, comprising 3,030 subjects from various continents. The overall TF prevalence was 24.5% (95% CI: 19.2-29.8%, I2 = 93.44%), with unilateral TF present in 16.9% and bilateral TF in 6.2%. Prevalence was highest in North America (31.4%,) and lowest in Africa (12.3%). No significant prevalence difference was found between adults and younger populations (p = 0.15). Publication bias, or the small-study effect, was detected (p < 0.01). CONCLUSION: This meta-analysis reveals a 24.5% overall prevalence of TF, with significant heterogeneity primarily explained by geographical differences. The TF's clinical relevance necessitates awareness among surgeons and radiologists to avoid complications during laryngeal surgeries and prevent misdiagnosis in imaging studies.

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PURPOSE: The saphenous nerve is a predominantly sensory nerve. It is the longest nerve of the body which supplies the skin of the medial side of the leg and foot as far as the ball of the great toe. We present here an unusual motor branch of the saphenous nerve to the sartorius muscle. METHOD: Institutional guidelines for use of human cadaver were followed. Routine dissection of the lower limbs for undergraduate medical teaching was performed in a 67 years old female cadaver employing standard methods. Relevant gross features of the variations were photographed. H&E staining of relevant structure was done and photomicrographed. RESULTS: The unusual motor branch to Sartorius was observed in the right thigh. The branch was given off in the lower third of the thigh after the saphenous nerve exited the adductor canal. The branch was distinctly seen entering the substance of the sartorius. The structure was confirmed to be a peripheral nerve by histological examination. The saphenous nerve then descended between the sartorius and gracilis tendons, pierced the fascia lata and became cutaneous. CONCLUSION: The motor branch to the sartorius muscle is a very rare branch whose knowledge is important for clinicians as it can get damaged during arthroscopy and other knee surgery or during adductor canal block.

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PURPOSE: Our aim in the study is to measure the area and volume of the tarsal bones and examine the typing of the talus and calcaneus joint surfaces according to sex. METHODS: In our study, the area and volume measurements of 630 tarsal bones and the morphology of the talus/calcaneus were analyzed by transferring thin-section Computed Tomography (CT) images to the 3D Slicer program. RESULTS: The volume and area sizes of the foot bones are calcaneus, talus, cuboid, navicular, medial cuneiform, lateral cuneiform, and intermediate cuneiform, respectively. All area and volume values of males were statistically higher than females (p < 0.05). The right side calcaneus area, intermediate cuneiform area, and lateral cuneiform area values were statistically higher than the left side (p < 0.045, p < 0.044, p < 0.030, respectively). There was no statistical relationship between age and area/volume values (p > 0.05). Three different types were seen in the calcaneus and seven in the talus. The most common type in the calcaneus was B1 (40%), and the least common type was A (27.8%). Regardless of the subgroups, the most common type in the talus was type B (37.8%), while the least common type was E2 (1.1%). CONCLUSION: Although morphometric measurements of tarsal bones differed according to sex, they did not differ according to age. The frequency of occurrence of the types of articular surfaces of the talus and calcaneus varies according to populations. We think that the morphometry and morphology of tarsal bones will contribute to invasive procedures regarding tarsal bones and surrounding structures, and that three-dimensional bone modeling can be used to create educational materials.

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PURPOSE: A translation of the initial observation of vertebral arteria lusoria reported by Hyrtl in 1859 is followed by a review of all cases published until May 2023 to identify the anatomical and clinical features characterizing the typical form of this rare variant. METHODS: PubMed, Google Scholar, and Google queries were performed with "vertebral arteria lusoria", "retroesophageal vertebral artery", and "aberrant vertebral artery" as keywords (in English, German, and French). A feature was considered typical when present in at least 75% of analyzed cases. A case of incidentally discovered vertebral arteria lusoria illustrates the typical form of the variant. RESULTS: The analysis of 56 publications yielded 66 observations of right-sided vertebral arteria lusoria published between 1859 and May 2023. A small caliber, a retro-esophageal location, and passage through the foramen transversarium of C7 were typical. There was no evidence of association with clinical symptoms or other cardiovascular anomalies. CONCLUSION: A typical vertebral arteria lusoria is an incidentally discovered nondominant aberrant right VA originating from the proximal descending aorta and following a retro-esophageal course to enter the C7 foramen transversarium, without associated aortic arch branching anomalies or congenital cardiovascular pathologies.

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PURPOSE: The variations of Cerebral arterial circle (Circle of Willis) are not rare. The study is done to assess the pattern of the component vessels of its anterior part with regard to Right- Left variations and compare with other studies. MATERIAL AND METHOD: 56 formalin fixed cadavers were analyzed. The diameter, length and variations of the following vessels were observed: Anterior Cerebral Artery (proximal A1 segment to distal A2 segment) and anterior communicating artery. Statistical analysis was done by Statistica 14.0.1 software. RESULT: 53.57% had normal anterior cerebral artery- anterior communicating artery complex. Length and diameter were slightly more on left side. Unilateral hypoplasia, Azygos and Tripple Anterior Cerebral Artery was present in 21.43%, 3.57 and 1.78% respectively. Aplastic, double and fenestration type anterior communicating artery were present in 5.3%, 8.92% and 1.78% respectively. CONCLUSION: Anatomical knowledge of variations should be updated regularly for neurosurgeons, radiologists and clinicians to avoid unexpected consequences.

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Autologous breast reconstruction using abdominally based perforator flaps has become increasingly popular following mastectomy for breast cancer. Of these, the deep inferior epigastric artery perforator (DIEP) flap represents one of the most popular techniques. However, surgeons must remain cognizant of anatomic variations in the abdominal wall vasculature that could complicate or preclude planned DIEP flaps. In this case, a 64-year-old female with a history of prior tubal ligations and caesarean sections underwent preoperative computed tomographic angiography (CTA) for planned autologous breast reconstruction with a DIEP flap. CTA revealed complete absence of the left deep inferior epigastric artery, with a sizeable left abdominal wall perforator visualized receiving retrograde flow from a crossing midline branch originating from the contralateral right deep inferior epigastric system. This vessel traversed the midline in a superficial plane in the subcutaneous tissue. Despite this aberrant anatomy, the surgical team successfully raised a unilateral DIEP flap based on the right pedicle. This case represents a unique anatomical variation of the abdominal wall and emphasises the importance of preoperative imaging when planning abdominally based free flaps.

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During standard cadaveric dissection we encountered multiple vascular variations in the retroperitoneum: duplicated and dilated left ovarian vein with the coexistence of a persistent right mesonephric artery.

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PURPOSE: Various anatomical variations of the inferior alveolar canal increase the incidence of surgical complications; Therefore, this study aimed to evaluate the frequency and configuration of bifid and trifid mandibular canals using cone beam computed tomography (CBCT) in the Turkish subpopulation. METHODS: The inferior alveolar canal was evaluated on 1014 hemi-mandibles in the CBCT (I-CAT 3D Imaging System) images of 513 patients. The frequency and configuration of the bifid and trifid mandibular canal (MC) were examined. The relationship between bifid MC configuration and dental status and age groups was analyzed. The distance of the accessory canal to the buccal and lingual walls and the alveolar crest was measured. The diameter of the main canal and accessory canal was measured and its relationship with dental status and age groups was evaluated. RESULTS: Bifid MC was found in 266 hemi-mandibles (24.7%) and 212 (41.3%) of 513 patients. The most common type of bifid MC was the retromolar canal (87 sides), followed by the forward canal without confluence (41; 4%) and the dental canal (34; 3.4%). 10 of the dental canals were opening to the 1st molar, 14 of the 2nd molars, and 10 of the 3rd molars. The number of retromolar foramina was 1 on 56 sides, 2 on 15 sides, and 3 on 4 sides. Forward canal without confluence was more common in edentulous patients than in dentulous patients, while the dental canal was more common in dentulous patients. The main canal diameter was 3.53 ± 0.97 mm and the bifid MC diameter was 1.82 ± 0.70 mm. Distance of the bifid MC to the lingual wall was higher in the > 64 years group than in the 18-39 years group (p = 0.022). Distance of the bifid MC to the alveolar crest was lower in the > 64 years group compared to the 18-39 years group and 40-64 years group (p = 0.015). The main canal diameter was higher in the 40-64 years group than in the 18-39 years group (p = 0.012). CONCLUSION: Bifid MC has a high prevalence, occurring in almost one in two patients. Dental and retromolar types, which are close to the teeth, are more common, and this increases the possibility of complications. CBCT is the most accurate imaging technique used to detect and define these variations.

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BACKGROUND: The xiphoid process (XP) in animals such as sheep and rats are well known to have cartilage called xiphoidal cartilage (XC). In humans, the cartilage in the xiphoid process is considered an anatomical variant and is not well understood. The aim of this study was to investigate the morphology of the XP. METHODS: A total of twenty embalmed European descendant cadaveric sterna (aged 52 to 98 years) were used. Transilluminated XPs and midsagittal sections of XPs were used to examine the bone and cartilage. Subsequently, a sagittally-sectioned XP was harvested for histology and stained with Masson's trichrome. The results of the transillumination and histological examinations were compared qualitatively. RESULTS: The dark area visible in transilluminated XPs was consistent with the bony part in the midsagittal XP sections, which contained bone marrow; the bright area was consistent with the cartilage part in the midsagittal XP sections. This was all demonstrated histologically. Most of the XPs (85%) had some portion of cartilage. The XP was classified into four types based on its proportions of bone and cartilage: Type I, no ossification (< 1/3 ossification) 45%; Type II, minor ossification (1/3 - 1/2 ossification) 20%; Type III, major ossification (1/2-2/3 ossification) 20%; Type IV, complete ossification (> 2/3 ossification) 15%. Most of the XPs (85%) had bone and cartilage, which could have been overlooked in studies using skeletons or CT. CONCLUSION: Previous studies probably underestimated or overestimated the size of the XP. The XC needs to be considered as normal anatomy.

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PURPOSE: To describe a case of multiple extremely rare cervical arterial variations. METHODS: A 55-year-old man with a tentative diagnosis of right internal carotid artery (ICA) stenosis was examined using computed tomography (CT) angiography for the evaluation of vascular lesions in the neck and head region. A 64-slice CT machine was used. RESULTS: On CT angiography, there was laterally located and narrowed petrous segment of the right ICA, indicative of aberrant course of the petrous ICA. Right vertebral artery (VA) was small in caliber and a relatively large anomalous artery arose from the proximal right ICA. This anomalous artery entered the posterior fossa via the foramen magnum, indicative of a type 1 proatlantal artery. Right occipital artery (OA) arose from the proximal ICA. The left OA also arose from the proximal ICA. CONCLUSION: An aberrant course of the petrous ICA is an extremely rare arterial variation which is formed by segmental agenesis of the cervical ICA, and the collateral channel passes through the middle ear cavity. It can be dangerous during middle ear surgery. The type 1 proatlantal artery is also an extremely rare arterial variation formed by the persistence of the proatlantal intersegmental artery. It is clinically significant because of its unique blood flow from the carotid system to the vertebrobasilar system. The OA rarely arises from the proximal ICA. Identification of these cervical arterial variations before surgery and vascular intervention are important to avoid complications during the procedure.

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PURPOSE: There have been over 40 descriptions of the common developmental variants of the accessory ossicles of the feet. Although predominantly asymptomatic, they sometimes may be linked to painful conditions. One of the most common accessory ossicles in the foot is the accessory navicular bone (AN), located on the medial side of the foot. Our research provides a first meta-analysis on this topic that establishes its frequency by contrasting 39 studies from across the globe. METHODS: Up to February 2024, PubMed and Embase databases were thoroughly searched for research on the AN. Eligible data regarding AN prevalence was extracted. This study strictly adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: A total of 39 studies, 11,015 patients, and 36,837 feet were analyzed in our study. The pooled prevalence estimate (PPE) of AN was found to be 17.5% (95%CI: 11.5-25.7) and 12.6% (95%CI: 10.1-15.5) in patients and feet analyses, respectively. Accessory navicular occurred bilaterally in 50.0% of patients, with similar distribution in gender-based groups (21.1% of males and 22.0% of females were confirmed with AN). Accessory navicular was most prevalent in the East Asian population (38.4%) and least prevalent in North Americans (8.0%). No significant differences in AN prevalence were found when comparing different imaging modalities (X-ray and cadaver dissection). CONCLUSION: Accessory navicular is a common finding in imaging studies. Its prevalence depends on the population covered by the study but is not affected by the patient's gender or the imaging modality utilized for AN assessment.

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PURPOSE: The brachioradialis muscle (BRM) belongs to the lateral group of forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABRM) or "brachioradialis accessorius" represents an uncommon BRM variant, not been enough studied. The present study investigates the prevalence of the ABRM, along with its origin, insertion, and innervation. MATERIALS: Eighty-three upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABRM presence. When the variant muscle was identified, morphometric measurements were obtained. RESULTS: The ABRM was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BRM, and its insertion was identified into the anterior surface of the radius (proximal third). The ABRM was innervated by the radial nerve, coursing posteriorly (deeply). CONCLUSIONS: In the current study, the variant muscle was observed in 2.4%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABRM could precipitate radial neuropathy.

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PURPOSE: To highlight the clinical and diagnostic importance of correctly identifying cervical internal carotid artery fenestration (fcICA), an extremely rare vascular anomaly, and to present a case where fcICA was initially misdiagnosed as a dissection in a patient with fibromuscular dysplasia (FMD). METHODS: A 47-year-old woman with pulsatile tinnitus underwent computed tomography angiography (CTA) and digital subtraction angiography (DSA) to differentiate between fenestration and dissection of the internal carotid artery. RESULTS: CTA revealed a fusiform dilatation of the distal C1 segment of the right internal carotid artery (ICA) with a linear filling defect, suggesting either fenestration or dissection. DSA confirmed the presence of a fenestrated right ICA segment composed of two symmetrical, smooth-walled limbs without a dissection flap, along with signs of FMD in the proximal vessel. The patient's symptoms were attributed to local flow perturbations induced by fcICA and FMD. CONCLUSION: This case illustrates that fcICA can be a true anatomical variant rather than a result of dissection, emphasizing the need for accurate imaging and diagnosis to avoid unnecessary treatments. The coexistence of fcICA with FMD increases the risk of dissection, necessitating careful monitoring. The distinction between fenestration and pseudofenestration remains challenging, requiring comprehensive imaging and close collaboration between radiologists and vascular neurologists.

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