Anatomical Variations Research Articles

Nanoceria-induced variations in leaf anatomy and cell wall composition drive the increase in mesophyll conductance of salt-stressed cotton leaves

Nanomaterials as an emerging tool are being used to improve plant′s net photosynthetic rate (AN) when suffering salt stress, but the underlying mechanisms remain unclear. To clarify this, a hydroponic experiment was conducted to study the effects of polyacrylic acid coated nanoceria (PNC) on the AN of salt-stressed cotton and related intrinsic mechanisms. Results showed that the PNC-induced AN enhancement of salt-stressed leaves was strongly facilitated by the mesophyll conductance to CO2 (gm). Further analysis showed that the PNC-induced improvement of gm was related to the increased chloroplast surface area exposed to intercellular airspaces, which was attribute to the increased mesophyll surface area exposed to intercellular airspaces and chloroplast number due to the increased K+ content and decreased reactive oxygen species level in salt-stressed leaves. Interestingly, our results also showed that PNC-induced variations in cell wall composition of salt-stressed cotton leaves strongly influenced gm, especially, hemicellulose and pectin. Moreover, the proportion of pectin in cell wall composition played a more important role in determining gm. Our study demonstrated for the first time that nanoceria, through alterations to anatomical traits and cell wall composition, drove gm enhancement, which ultimately increased AN of salt-stressed leaves.

Population-based in silico modeling of anatomical shape variation of the knee and its impact on joint loading in knee osteoarthritis.

Anatomical knee joint features and osteoarthritis (OA) severity are associated, however confirming causals link to altered knee loading is challenging. This study leverages statistical shape models (SSM) to investigate the relationship between joint shape/alignment and knee loading during gait in knee OA(KOA) patients to understand their contribution to elevated medial knee loading in OA. Musculoskeletal (MSK) models were created for the mean as well as the first eightSSM principal modes of variation (-3,-2,-1, +1, +2, +3 standard deviations for each mode) and used as input to a MSK modeling framework. Using an identical KOA gait pattern (i.e., joint kinematics and ground reaction forces), we ran simulations for each MSK model and evaluated medial compartment loading magnitude and contact distribution at the instant of first and second peak of knee joint loading. An increase in external rotation, posterior tibia translation and a decrease in medial joint space and medial femoral condylar size predisposed the medial compartment knee joint to overloading during gait. This was coupled with an anterior and medial shift in contact location with increasing external rotated tibial position and increasing posterior tibial translation with respect to the femur. Next, results also highlighted a posterior shift of the medial compartment loading location with decreasing medial joint space. This study provides important population-based insights on how knee shape and alignment predispose individuals with KOA to elevated medial compartmental knee loading. This information can be crucial in assessing the risk for medial KOA development and progression.

Finding MeVO: Identifying Intracranial Medium-Vessel Occlusions at CT Angiography.

The development of methods to detect and treat intracranial large-vessel occlusions (LVOs) has revolutionized the management of acute ischemic stroke. CT angiography (CTA) of the head and neck is effective in depicting LVOs and widely used in the evaluation of patients who have had a stroke. Ongoing efforts are now focused on the potential to detect and treat intracranial medium-vessel occlusions (MeVOs), which by definition are smaller than LVOs and thus more difficult to detect with CTA. The authors review common and variant anatomies of medium-sized cerebral arteries and the appearance of a variety of MeVOs on CT angiograms. Possible pitfalls in MeVO detection include rare anatomic variants, calcified thrombi, and stump occlusions. Current recommendations for performing CTA and ancillary methods that might aid in MeVO detection are discussed. Understanding the relevant anatomy and the variety of appearances of MeVOs aids radiologists in identifying these occlusions, particularly in the setting of urgent stroke. ©RSNA, 2024 See the invited commentary by Ospel and Nguyen in this issue.

Imaging of the Inferior Mesenteric Vasculature.

The inferior mesenteric artery (IMA) and inferior mesenteric vein (IMV) supply and drain blood from the distal colon and rectum, respectively. Routinely imaged at cross-sectional imaging of the abdomen and pelvis, these vessels play a vital role in gastrointestinal tract health but may be neglected due to their diminutive caliber relative to other mesenteric vessels and potential lack of inclusion in routine search patterns. The authors describe and illustrate normal and abnormal appearances of the IMA and IMV and findings that are diagnostic of primary vascular abnormalities or can offer diagnostic clues. After the embryologic features, normal anatomy, and anatomic variants of the IMA and IMV are reviewed, various manifestations of IMA and IMV abnormalities, such as aneurysm and pseudoaneurysm, stenosis, occlusion, dissection, hemorrhage, arteriovenous malformations and fistulas, tumoral invasion, vasculitis, and perivascular lymphatic dilatation, are explored with use of case examples. The role of the IMA and IMV as collateral vasculature, including the clinical scenarios of superior mesenteric arterial occlusion, aortic endoleak, and portosystemic venous shunt, are discussed. Finally, diagnostic clues that the inferior mesenteric vessels and adjacent soft tissues can provide, including mesenteric venous gas, compression or displacement from bowel volvulus or internal hernias, lymphadenopathy, and venous flow artifacts, are highlighted. The authors provide a comprehensive reference for radiologists who evaluate the IMA and IMV on cross-sectional images and shine a spotlight on these neglected but important vessels. ©RSNA, 2024 Supplemental material is available for this article.

Circle of Willis and Its Anatomical Relevance

The Circle of Willis is an arterial network located at the base of the brain, formed by the interconnection of the anterior, middle, and posterior cerebral arteries, along with the anterior and posterior communicating arteries. It connects the internal carotid arteries to the vertebral arteries, allowing the distribution of cerebral blood flow. Its significance lies in its ability to offer an alternative pathway in cases of arterial obstruction, helping to prevent cerebral ischemia. However, anatomical variations of this structure are common, and only 20% to 25% of the population has a "complete" or symmetrical configuration. Such variations can influence the risk of cerebrovascular diseases, such as stroke, as they may compromise the efficiency of the compensatory mechanism. These anatomical variations have a direct impact on the diagnosis and treatment of neurological conditions. The integrity of the Circle of Willis can influence the severity of symptoms in cases of ischemic strokes, as well as affect aneurysm formation and its clinical implications. Advances in imaging techniques, such as CT angiography and magnetic resonance imaging, have enabled more accurate diagnoses and the development of more effective treatments for conditions associated with the Circle of Willis, making its anatomical understanding essential for the prevention and management of cerebrovascular diseases.

The Significance of Biliary Anatomical Variation as a Key Indicator in Laparoscopic Bile Duct Injuries

Introduction: The science of Gastrointestinal (GI) endoscopy is the science and art of millimeters that has marvelously evolved over the past 30 years. Cholecystectomy, most of which is done laparoscopically, is one of the most common procedures performed today (approximately 750,000 cases are performed annually in the USA) and is considered relatively safe. However, laparoscopic cholecystectomy is associated with bile duct injuries. Several studies examining bile duct injuries have found significant rates of complication (0.39%---1.5%, that comes roughly to over 3,000 patient per year). Therefore, bile duct injuries are commonly encountered, and a clear understanding of the extensive variation in biliary anatomy is imperative to appropriately and successfully manage this common clinical problem to ultimately provide the highest level of patient care.

Radiographic Variants Associated With Allergic Fungal Rhinosinusitis: Key Differences for Pre-Operative Planning.

Allergic fungal rhinosinusitis (AFRS) often results in expansion of disease beyond the paranasal sinuses, which may put important structures, such as the anterior ethmoid artery (AEA) or lateral lamella of the cribiform, at risk of injury during endoscopic sinus surgery (ESS). This study aims to compare the AEA to skull base (AEA-SB) length in patients with AFRS versus chronic rhinosinusitis with nasal polyps (CRSwNP), as well as additional anatomic variants. A single institutional retrospective chart review of patients undergoing ESS for AFRS and CRSwNP was performed. AEA-SB length were compared between the 2 groups. Other anatomic variants, including Keros measurement and presence of supraorbital ethmoid air cells (SOEC), concha bullosa (CB), sphenoethmoidal, and infraorbital ethmoid cells were measured and compared between the 2 groups. Twenty-one patients were included in each cohort. The AFRS group was younger in age (P = .015) and had a significantly longer AEA-SB length (P = .014) compared to the CRSwNP group. No significant differences were observed between the 2 groups regarding Keros measurement, presence of concha bullosa, infraorbital ethmoid, sphenoethmoidal, or SOEC. No association was seen between AEA-SB length and Keros class in either group. AFRS harbors anatomical differences when compared to CRSwNP, with the former associated with a longer AEA-SB length. This key difference should be considered in preoperative planning to prevent injury to the AEA in patients undergoing ESS for AFRS.

The natural history of cerebral infundibula: A retrospective cohort study.

Debate exists regarding the true pathogenicity of cerebral infundibula (CI). Pre-aneurysmal lesions and benign anatomical variants have both been proposed. In this study, we present the largest single cohort series on the natural history of CI. Retrospective review of prospective surveillance of 420 CI was undertaken in a single tertiary cerebrovascular centre. All CI diagnosed by a neuroradiologist, diagnosed on either a Magnetic resonance angiography (MRA), Computed tomography angiography (CTA) or Digital subtraction angiography (DSA) were eligible for inclusion. Imaging and demographic characteristics were recorded at baseline. CI growth and aneurysm transformation were the outcomes of interest. Groupwise comparison was conducted via Fischer exact testing. Kaplan Meir curves and Cox proportional hazard ratios were used to assess variables of interest with respect to time on surveillance. 402 patients with 420 CI were surveyed over 2418 infundibula-years. Eleven CI (2.62%) grew on surveillance, and three (0.7%) transformed into aneurysms. Median time to growth was 85 months (36-263) and median time to aneurysm transformation was 112 months (96-142). Of the CI that grew, male sex and CI >2 mm at diagnosis were significant predictors of growth (all p<0.05). Of the CI that grew in surveillance, 2/11 (18.2%) transformed into aneurysms (p=0.001). Aneurysm transformation occurred at a rate of 1.27 per 1000 infundibula years. CI growth on surveillance (p= 0.00016) and size at diagnosis (p=0.038) remained significant predictors of aneurysm transformation on Kaplan Meir curves. The transformation of a CI to an aneurysm occurs at a low rate. A history of growth on surveillance imaging represents significant risk for aneurysm transformation.

Non-contrast-enhanced MR-angiography of the abdominal arteries: intraindividual comparison between relaxation-enhanced angiography without contrast and triggering (REACT) and 4D contrast-enhanced MR-angiography.

To evaluate Relaxation-Enhanced Angiography without Contrast and Triggering (REACT), a novel 3D isotropic flow-independent non-contrast-enhanced magnetic resonance angiography (non-CE-MRA) for imaging of the abdominal arteries, by comparing image quality and assessment of vessel stenosis intraindidually with 4D CE-MRA. Thirty patients (mean age 35.7 ± 16.8years; 20 females) referred for the assessment of the arterial abdominal vasculature at 3T were included in this retrospective, single-centre study. The protocol comprised both 4D CE-MRA and REACT (navigator-triggering, Compressed SENSE factor 10, nominal scan time 02:54min, and reconstructed voxel size 0.78 × 0.78 × 0.85 mm3). Two radiologists independently evaluated 14 abdominal artery segments for stenoses, anatomical variants, and vascular findings (aortic dissection, abdominal aorta aneurysms and its branches). Subjective image quality was assessed using a 4-point Likert scale (1 = non-diagnostic, 4 = excellent). REACT had a total acquisition time of 5:36 ± 00:40min, while 4D CE-MRA showed a total acquisition time (including the native scan and bolus tracking sequence) of 3:45 ± 00:59min (p = 0.001). Considering 4D CE-MRA as the reference standard, REACT achieved a sensitivity of 87.5% and specificity of 100.0% for relevant (≥ 50%) stenosis while detecting 89.5% of all vascular findings other than stenosis. For all vessels combined, subjective vessel quality was slightly higher in 4D CE-MRA (3.0 [IQR: 2.0; 4.0.]; P = 0.040), although comparable to REACT (3.0 [IQR: 2.0; 3.5]). In a short scan time of about 5min, REACT provides good diagnostic performance for detection of relevant stenoses, variants, and vascular findings of the abdominal arteries, while yielding to 4D CE-MRA comparable image quality.

Incidence and predictors of radial artery occlusion following transradial coronary procedures

Abstract Background Transradial access for percutaneous coronary procedures has grown in popularity because of its advantages over the femoral approach. However, the benefit is overshadowed by an increased rate of radial artery occlusion (RAO). We aim to assess incidence and predictors of RAO after transradial catheterization. The anatomic variations of the radial artery (RA) were also studied. Methods This prospective study enrolled 427 patients who underwent coronary angiography or angioplasty via transradial access. An ultrasound evaluation of forearm arteries was performed. In case of RAO, another ultrasound check-up was performed after 1 month and 3 months of the procedure. Results Our study population includes 288 patients (32.6% female). The mean age was 61.9 ± 11.1 years. RAO occured in 48 patients (11.24%), among whom spontaneous recanalization was observed within 3 months in 15 patients (32.6%). On multivariate analysis, a younger age (OR 0.642 [CI 95%: 0.480 – 0.858], P = 0.031), low periprocedural systolic blood pressure, (OR 0.598 [CI 95%: 0.415 – 0.862], P = 0.007), a small radial diameter (OR 0.371 [CI 95%: 0.323 – 0.618], P = 0.031), insufficient anticoagulation (OR 0.287 [CI 95%: 0.163 – 0.505], P &amp;lt; 0.001), occlusive hemostasis (OR 0.128 [CI 95%: 0.047 – 0.353], P &amp;lt; 0.001), and a long duration of hemostasis emerged as independent predictors of radial occlusion. The overall incidence of radial artery anatomic variations was 14,8% (n=63). Among these patients, 40 (63.5%) had a high radial origin, 18 (28.6%) had extreme radial artery tortuosity, and 5 (7.9%) had a full radioulnar loop. Conclusion The incidence and prevalence of radial artery occlusion is expected to increase. Insufficient heparinization and occlusive hemostasis are the main modifiable predictors. The preventive strategy should focus primarily on these 2 predictive factors.

Prognostic value of the right coronary venous anatomy in patients undergoing cardiac resynchronization therapy

Abstract Background The size and distribution of the coronary veins (CV) reflect both intracavitary pressure and myocardial blood flow, and therefore, in patients with cardiomyopathy, CV anatomy could potentially become a biomarker of disease severity. While the left coronary veins have been well described, there are few descriptions of the right CV system. Purpose Given these considerations, the aim of the study was to evaluate the anatomy of the right CV system and its potential prognostic significance in patients with advanced cardiomyopathy. Methods We analyzed CV angiograms from 121 patients (age 67±14 years) undergoing cardiac resynchronization therapy (CRT). The right ventricular (RV) veins were seen to fill during the injection of contrast through multiple connections with the left sided venous system. Patients were followed for a median of 43 [IQR 3-73] months, during which 12 patients expired. Results Anterior cardiac veins (ACV), which overlay the RV wall were observed in 85 (70%) patients and had a maximum ostial diameter of 2.04±0.8 mm. Multiple ACVs were seen in 62 patients. These veins were observed to empty directly into the venous sinus of right atrium (VSRA), into the RV, the right atrium (RA), or into the small cardiac vein (SCV) in 68, 9, 5, and 3 patients respectively. The right marginal vein (RMV) was visualized in 21 (17%) patients, had a diameter of 2.3±1.2 mm, and ran a course along the right border of the RV, emptying directly into RV, RA or into VSRA in 9, 4 and 8 patients respectively. The VSRA present in 91 (75%) patients, coursed parallel to the right coronary sulcus, collecting blood from the ACV’s and RMV’s and drained into the RA (Figure A); in 7 patients, 2 VSRA ostia were noted. VSRA lengths and diameters varied (11-119 mm, mean 41±25 mm) and (1.2-6.9mm, mean 2.7±1.2mm) respectively. The VSRA lengths correlated significantly with RV fractional area change, RV systolic pressure, tricuspid regurgitation severity evaluated by echocardiography, and P wave amplitude in ECG lead II (r=-0.65; p=0.041, r=0.88; p=0.019, r=0.52; p=0.030, and r=0.79; p=0.031 respectively). The VSRA diameters, which were significantly larger in patients with obstructive sleep apnea (3.6±1.5 vs. 2.3±1.2mm; p=0.021) correlated significantly with RV systolic pressure, and tricuspid regurgitation severity by echocardiography (r=0.77; p=0.009, and r=0.63; p=0.006 respectively). Patients who expired during follow-up had a significantly longer VSRA than patients who remained alive (Figure B). The VSRA length, RV fractional area change, and baseline QRS duration independently predicted survival in a Cox multivariate model that also included age and left ventricular ejection fraction. Conclusions RV venous system demonstrates a highly variable anatomy that has not been previously well described. The size of the VSRA correlated with parameters of RV function and predicted survival in patients undergoing CRT.Figure

A Practical Guide to Loco-Regional Nerve Blocks for Oromaxillofacial Surgery in Dogs and Cats.

This article provides an overview of the neuroanatomy of the head with a detailed explanation and visual images to enable accurate placement of loco-regional nerve blocks to achieve pre-emptive blockade of the nociceptive input which occurs when performing oral surgery. Variations in anatomy and between species are addressed to assist in accurate placement.

Understanding perioperative risk determinants in carotid endarterectomy: the impact of compromised circle of Willis morphology on inter-hemispheric blood flow indices based on intraoperative internal carotid artery stump pulse pressure and backflow patterns.

Carotid artery stenosis (CAS) often requires surgical intervention through carotid endarterectomy (CEA) to prevent stroke. Accurate cerebrovascular risk assessments are crucial in CEA, as poor collateral circulation can lead to insufficient interhemispheric blood flow compensation, resulting in ischemic complications. Therefore, understanding perioperative risk determinants is vital. This study aims to determine the impact of compromised circle of Willis (CoW) morphology on inter-hemispheric blood flow, focusing on indices based on intraoperative internal carotid artery stump pulse pressure and backflow patterns. In 80 CAS patients who underwent CEA, preoperative CT angiography for CoW was conducted. Patients were categorized into five subgroups based on their CoW anatomy and three additional groups based on intraoperative internal carotid artery (ICA) stump backflow patterns evaluated by the surgeon. Continuous blood pressure signals, including systolic, diastolic, mean, and pulse pressure values, were recorded during the procedure. The relationship between CoW anatomical variants and the systolic and diastolic segments of the averaged pressure waveforms, particularly diastolic pressure decay, was analyzed. The correlation between CoW anatomy and stump backflow intensity was also examined. Significant variability in ICA stump backflow and pressure values was evident across CoW variants. Patients with compromised CoW morphology exhibited weaker backflow patterns and lower ICA stump pulse pressure values, consistent with impaired interhemispheric blood flow. Notably, ICA stump diastolic pressure decay was consistent across most CoW variant groups, indicating developed collateral circulation in cases with CoW anomalies. Thus, impaired CoW integrity is associated with compromised interhemispheric blood flow indices based on intraoperative ICA stump pulse pressure and backflow patterns during CEA. Integrating intraoperative pulse waveform analysis with preoperative CT angiography provides a more detailed assessment of cerebrovascular risk, guiding the selective use of shunts. This combined approach may improve surgical outcomes and patient safety by identifying patients at increased risk of perioperative neurological events due to CoW anomalies.

PO0249: Assessment of Anatomical Variation for Patient-Tailored Cervical Cancer Brachytherapy Applicator Development

PO0249: Assessment of Anatomical Variation for Patient-Tailored Cervical Cancer Brachytherapy Applicator Development

Anatomical Variations in Nasal Cavities and Paranasal Sinuses on Computed Tomography in Chronic Rhinosinusitis: Implications for Diagnosis and Treatment

Anatomical Variations in Nasal Cavities and Paranasal Sinuses on Computed Tomography in Chronic Rhinosinusitis: Implications for Diagnosis and Treatment

Main Anatomical Variations Found in Patients with Carpal Tunnel Syndrome: Literature Review

Main Anatomical Variations Found in Patients with Carpal Tunnel Syndrome: Literature Review

Variations of Anterior Skull Base Seen on Computed Tomography Scans of the Paranasal Sinuses

Abstract Context: The anterior skull base (ASB) and the paranasal sinuses are known for anatomical variations. Therefore, a preoperative assessment for the assessment of these variations is a necessity. This study aims to determine the profile of variations of the ASB using computed tomography of the paranasal sinuses (CT-PNS) scans. Settings and Design: Observational Study. Materials and Methods: Forty CT-PNS scans were studied with measurement of different parameters. Statistical Analysis: Observational study analysis – Descriptive stats, t-tests, Chi-square, nonparametric tests, analysis of variance, regression, P &lt; 0.05 significance level. A significance level of P &lt; 0.05 was used for all tests. Results: Seventeen male and 23 female CT-PNS scans were studied. Different measurements on the right and left sides, as well as between genders, were examined and compared. The supraorbital ethmoidal cell is the most often seen anatomical variation. Variations in the ASB are equally visible on both sides in men and on the right in females (Type-II &gt; Type-1). Type I was more common among female, whereas Type II was more common. The existence of the anterior ethmoidal foramen is a dependable marker for the anterior ethmoidal artery. In the group under investigation, there was no lamina papyracea abnormality. Conclusion: This study aims to assess anatomical variations in the Indian population undergoing ASB surgeries, contributing to the current understanding of Indian paranasal sinuses and skull base dynamics.

Safety and efficacy of using stapler device for wide cystic duct ligation in acute setting of laparoscopic cholecystectomy

This research explores the challenges posed by variations in cystic duct anatomy during laparoscopic cholecystectomy and the potential use of stapler devices to address such complexities. It aims to assess the safety and efficacy of stapler devices, particularly in cases involving short, and wide cystic duct. The study, conducted at King Abdulaziz Medical City in Riyadh, Saudi Arabia, between 2021 and 2023. The study design involved a retrospective cohort approach, and the sample size encompassed all cases meeting the inclusion criteria during the study period. Data was analyzed using SPSS program. The study involving 568 patients, with the predominant technique for ligation being clipping (89.3%). The primary indication for using the Endo GIA stapler was a wide cystic duct (6.2%). Analysis revealed a significant association between stapler device use and hypertension (p = 0.042), diabetes (p = 0.001), CKD (p = 0.011), and obstructive jaundice (p = 0.006). Multivariate regression demonstrated that older patients were 2.1 times more likely to use stapler devices (AOR = 2.125; p = 0.039), while those with obstructive jaundice had a 2.2 times higher likelihood (AOR = 2.168; p = 0.049). Throughout the years, metal clips have shown the best prognosis compared to any other method for securing the cystic duct during closure in laparoscopic cholecystectomy. However, to avoid incomplete sealing of wide, short, or inflamed ducts, other instruments have emerged as possible alternatives for such conditions. Use of Endo-GIA is a safe and effective method for patients with wide, short cystic duct. Selective usage of endo-GIA is considered cost effective and may add a positive impact in decreasing post operative biliary leak.

Metopism and Its Clinical Relevance: A Persistent Suture.

Metopic suture is a dense fibrous joint extending from nasion to bregma. Normally, closure of this suture takes place between 1-8 years of age. Failure of this closure beyond 8 years leads to persistent metopic suture. Persistent metopic suture may mimic skull fracture. To differentiate metopism from frontal bone fracture. 54 dry skull of adult humans in were studied. These skulls were observed for the presence (complete or incomplete suture) or absence of metopic suture. Metopic suture was found in 3.7% skulls. Both complete and incomplete metopic suture were found in 1.85% of the dry skulls. Neurosurgeons, radiologists, otorhinolaryngologists, physicians, anatomists, forensic specialists, anthropologists and evolutionary biologists should have knowledge of this anatomical variation. This case series focusses on the importance of metopism. Metopism is a topic, which has not been much studied.

Supernumerary Head of the Biceps Brachii Muscle Influences the Topography of the Coracobrachialis and Biceps Brachii Muscles

Background/Objectives: Anatomical variations in the biceps brachii muscle (BBM) are extremely frequent, leading to developmental and clinical implications. We studied the topography of the BBM and analyzed its correlations with other structures in the brachial region. Methods: A total of 103 cadaveric upper extremities were dissected. The length of the upper extremities was utilized as a reference line. The origin and insertion of the BBM, the coracobrachialis muscle (CBM), and the related neurovascular system were evaluated. Results: Each variable was calculated as a percentile and compared according to the presence of the considered variation; in particular, a supernumerary head of the BBM was found in 12/103 (11.65%) of upper extremities and was associated with a longer upper limb (506.25 ± 32.55 mm vs. 484.27 ± 30.41 mm, p = 0.022). When the variables were standardized by the length of the upper limb, the accessory head of the BBM was associated with the distal insertion point of the CBM (28.18 ± 3.54% vs. 30.59 ± 2.94%, p = 0.011) and BBM length (55.11 ± 2.17% vs. 58.18 ± 3.72%, p = 0.006). Other variables did not present significant differences with respect to the presence of the supernumerary head of the BBM. Conclusions: BBM variations may affect the topography of other structures, such as the length of the upper extremities, insertion of the CBM, and length of the BBM. Further studies are required to elucidate its clinical implications.