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An 89-year-old Caucasian male cadaver with prostate cancer demonstrated bilateral persistence of the median artery and bifid median nerve (BMN) during upper limb dissection. The persistent median artery (PMA) originated from the common interosseous artery and coursed alongside the median nerve. Proximal to the carpal tunnel, the median nerve bifurcated into medial and lateral branches. To our knowledge, this is the first documented case of a bilateral PMA and BMN. While the majority of existing literature focuses on a unilateral PMA or unilateral BMN, bilateral occurrences of either variation are rare. This report presents a novel finding by documenting the simultaneous presence of a bilateral PMA and BMN.

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Objective This pilot project aimed to assess the prevalence and variations of the median artery (MA) on a small scale in preparation for a large-scale study investigating MA in Lithuanian cadavers. Methods Eight formalin-fixed adult female cadavers were used in this study. Dissection was performed to allow for the observation of MA presence, type, origin, termination, and relations with other structures. The gathered data was analyzed, and a literature search was performed to compare the findings. Results MA was found in 10 of the 16 upper limbs examined; therefore, the incidence of MA in the present study was 62.5%. Of the 10 MAs found, six (60%) were of the antebrachial type (a-MA), and four (40%) were palmar (p-MA). Thus, the prevalence of a-MA and p-MA in the upper limbs examined was 37.5% (N = 6/16) and 25% (N = 4/16), respectively. Among the six cadavers that were found to possess MA, it was identified bilaterally in four (66.7%) and unilaterally in two (33.3%). The associations between the antimere and the presence of MA or MA-type were not statistically significant. MA most commonly originated from the common interosseous artery (50%, N = 5/10), followed by the ulnar artery (UA) (40%, N = 4/10), and the anterior interosseous artery (10%, N = 1/10). Two (33.3%) of the six a-MAs terminated in the mid-forearm, while four (66.7%) a-MAs ended in the distal forearm. Meanwhile, three (75%) of the four p-MAs terminated by joining the UA, while one (25%) terminated as the first common palmar digital artery. In the forearm, nine (90%) of the 10 MAs traveled anteriorly to the anterior interosseous nerve (AIN), and only one (10%) traveled posteriorly to the AIN. Additionally, one (10%) of the 10 MAs was found to pierce the median nerve. Conclusions Our findings confirm the variability in MA characteristics reported by previous studies. The high incidence of MA discovered in our sample calls attention to the importance of being aware of MA in a clinical setting, as this would allow for a timely and accurate response to a potential pathology associated with this structure.

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Here, we present a 37-year-old right-handed female patient who presented with increasing paresthesia, tingling, and numbness in the radial palm and lateral three fingers of her right hand for six months. Because of the intense wrist discomfort and unilateral involvement, ultrasonography was used to evaluate the patient in addition to a nerve conduction study to exclude secondary causes of carpal tunnel syndrome.

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During a routine cadaveric dissection of a 93-year-old male donor, unique arterial variations were observed in the right upper extremity. This rare arterial branching pattern began at the third part of the axillary artery (AA), where it gave off a large superficial brachial artery (SBA) before bifurcating into the subscapular artery and a common stem. The common stem then gave off a division for the anterior and posterior circumflex humeral arteries, before continuing as a small brachial artery (BA). The BA terminated as a muscular branch to the brachialis muscle. The SBA bifurcated into a large radial artery (RA) and small ulnar artery (UA) in the cubital fossa. The UA branching pattern was atypical, giving off only muscular branches in the forearm and a deep UA before contributing to the superficial palmar arch (SPA). The RA provided the radial recurrent artery and a common trunk (CT) proximally before continuing its course to the hand. The CT from the RA gave off a branch that divided into anterior and posterior ulnar recurrent arteries, as well as muscular branches, before it bifurcated into the persistent median artery (PMA) and the common interosseous artery. The PMA anastomosed with the UA before entering the carpal tunnel and contributed to the SPA. This case presents a unique combination of arterial variations in the upper extremity and is clinically and pathologically relevant.

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The median artery is a transient embryological structure that normally disappears with the development of the radial and ulnar arteries. In rare instances, though, it persists as the persistent median artery (PMA). The superficial and deep palmar arches are formed through the anastomoses of the radial and ulnar arteries, giving hand and digits their main blood supply. This complex network of vessels and their anastomoses are prone to anatomical variations based on how the anastomosis occurs and which arteries contribute to this anastomosis. While it normally forms through the anastomosis of the radial and ulnar arteries, the superficial palmar arch (SPA) may also form differently, as in our case here, where the median artery persisted and branched off the radial artery, anastomosing with the ulnar artery to give rise to the SPA. This may also interfere with the normal compartmental architecture within the hand, possibly contributing to various clinical pathologies like carpal tunnel syndrome (CTS). Notably, in addition to the persistent median artery, our findings revealed a reversed palmaris longus and a bifid median nerve. These two additional variations can potentially exacerbate the risk of CTS. Alone, the coexistence of the PMA and the reversed palmaris longus is deemed a rare anomaly, only reported once in the literature. The addition of a third variation to the existing ones, like the bifid median nerve, is first reported by us and calls for more investigation for a possible genetic mutation. In this case, we report a persistent median artery, reversed palmaris longus muscle, and bifid median nerve in the forearm of a male cadaver found during a routine anatomy teaching session.

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PURPOSE: This report describes a bilateral persistent median artery (PMA) originating from the ulnar artery and terminating at different levels of the upper limb. The PMA coexisted with a bilateral bifid median nerve (MN) and two bilateral interconnections (ICs characterized with the symbol -) of the MN with the ulnar nerve (UN) (MN-UN) and a unilateral reverse IC (UN-MN). Emphasis was given to the artery's developmental background. METHODS: The PMA was identified in an 80-year-old formalin-embalmed donated male cadaver. RESULTS: The right-sided PMA terminated at the wrist, posterior to the palmar aponeurosis. Two neural ICs were identified: the UN joined the MN deep branch (UN-MN), at the forearm's upper third, and the MN deep stem joined the UN palmar branch (MN-UN), at the lower third (9.7 cm distally to the 1st IC). The left-sided PMA ended in the palm giving off the 3rd and 4th proper palmar digital arteries. An incomplete superficial palmar arch was identified by the contribution of the PMA, radial, and ulnar arteries. After the MN bifurcation into superficial and deep branches, the deep branches formed a loop, that was penetrated by the PMA. The MN deep branch communicated with the UN palmar branch (MN-UN). CONCLUSIONS: The PMA should be evaluated as a causative factor of carpal tunnel syndrome. The modified Allen's test and the Doppler ultrasound may detect the arterial flow and the angiography may depict the vessel thrombosis in complex cases. PMA could also be a "salvage" vessel for the hand supply, in radial and ulnar artery trauma.

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INTRODUCTION: Cadaveric studies suggest an increasing prevalence of the persistent median artery (PMA) over a prolonged timeframe. The aim of this retrospective cross-sectional study was to evaluate the PMA prevalence in haemodialysis patients who had computed tomographic fistulograms (CTFs), and if present, their calibres and origins. METHODS: All consecutive adult patients referred for an upper limb CTFs for assessment of arteriovenous fistula (AVF) dysfunction from 2006 to 2021 were included. Patients whose CTF did not include the forearm were excluded. PMA was identified as an artery running alongside the median nerve between flexor digitorum superficialis and flexor digitorum profundus. Patient demographics, presence of PMA including size and origin were recorded. RESULTS: A PMA was found in 91/170 (53.5%) CTFs (7:3 male-to-female ratio, mean age 71-years). When stratified by age, prevalence increased with decreasing age; 51% in >70-year-olds, 54% in 50-70-year-olds and 67% in <50-year-olds. The average PMA diameter was 2.2 mm proximally and 1.8 mm distally. No stenosis was observed in the PMAs. CONCLUSION: The PMA prevalence appears to increase with decreasing age and is a frequently encountered anatomical variant. Radiologists assessing forearm vasculature need to be aware of this anatomical variant and potentially include it in their future reports. Further research into the PMA may make its potential use as arterial conduits for AVF, potential donor grafts for coronary artery bypass surgery or additional vascular access options possible. Whether the reducing prevalence with age reflects an overall increasing prevalence is yet to be determined.

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OBJECTIVES: Thrombosis of the persistent median artery (PMA) is a rare cause of acute carpal tunnel syndrome (ACTS). Existence of a congenitally absent radial artery in this setting has not been described in the literature. METHODS: Computed Tomography Angiography (CTA) and doppler screening were used in pre surgical planning. Open surgical decompression was achieved through the release of the flexor retinaculum in the left hand. A regimen of 100 mg of Aspirin for 3 months time was initiated to encourage clot resolution and recanalization of the thrombosed artery. RESULTS: The PMA was found to be abnormally large measuring approximately 4 mm in diameter. Visible clotting off of the PMA in keeping with the doppler scans with maintenance of distal flow and was left intact with the hopes that it would recanalize over time. At the 3-month post-op review the antiplatelet therapy was ceased and the patient was symptom free, demonstrated no signs of ischaemia in the hand, and had returned to full functionality and physical activity. CONCLUSIONS: Although infrequently encountered, the knowledge of the anatomical variations of the forearm and hand together with doppler screening and CTA is essential to the surgical management of ACTS.

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Carpal tunnel syndrome (CTS) is an upper extremity median nerve entrapment disorder that is rare in children and adolescents. Anatomical variations of the wrist, such as anomalous muscles, persistent median artery (PMA), and bifid median nerves (BMN), are rare etiology of CTS. Coexistence of all three variants combined with CTS in adolescents has been rarely reported. Case description: A 16-year-old right-hand dominant male presented to our clinic with several years of bilateral thenar muscle atrophy and weakness but no paresthesia or pain in his both hands. Ultrasonography showed that the right median nerve become significantly thinner, and the left median nerve was split into two branches by PMA. Magnetic resonance imaging (MRI) revealed that anomalous muscles in the bilateral wrist extending to the carpal tunnel, causing compression of the median nerve. Considering the possibility of CTS clinically, the patient underwent bilateral open carpal tunnel release without resection of anomalous muscles and PMA. The patient has no discomfort after 2 years. This suggests that anatomical variations of the carpal tunnel may contribute to CTS, which can be confirmed by preoperative ultrasonography and MRI, and the possibility of carpal tunnel anatomical variations should be considered when CTS occurs in adolescents. Open carpal tunnel release is an effective treatment for juvenile CTS without the need to resect abnormal muscle and PMA during the operation.

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The presence of both a superficial ulnar artery (SUA) and persistent median artery (PMA) of antebrachial type is of both clinical and surgical significance. In an 84-year-old female cadaver received through the Gift Body Program at Saint Louis University School of Medicine, the right brachial artery was seen divided into an SUA and radial artery (RA) slightly below the interepicondylar line of the humerus. At the level of the radial neck, the RA sent out the common interosseous artery that then gave off the radial recurrent artery before bifurcating into anterior interosseous artery (AIA) and posterior interosseous artery. The AIA continued to appear to branch into the anterior ulnar recurrent artery and posterior ulnar recurrent artery, as well as a PMA of the antebrachial type. In the hand, the SUA and RA contributed to the complete superficial palmar arch seemingly equally, and the RA was the dominant contribution to the deep palmar arch. Ninety-one other arms were assessed for this variation, and none were observed. Knowledge of an anatomical variation such as this may lead to decreased complications in the planning of surgical bypass grafting.

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Background: The median artery is an embryonic structure that typically regresses during gestation. Occasionally, the artery remains and is then termed a persistent median artery (PMA). A PMA can be associated with other anatomic anomalies, and has been known to contribute to carpal tunnel syndrome (CTS). Recent literature has observed an increase in PMA prevalence, speculated to indicate microevolutionary change. We performed a prospective observational study to investigate the current prevalence rate of PMA in patients undergoing carpal tunnel release (CTR). Methods: Institutional review board approval was obtained. From October 2020 to January 2021, patients ≥18 years old undergoing open CTR by 9 orthopaedic hand surgeons were included in analysis. Patients undergoing endoscopic CTR were excluded. Intraoperatively, the carpal tunnel was evaluated for the presence of a PMA, median nerve anomalies, or any other anatomic anomalies. If a patient underwent bilateral CTR during the study, only one side was included in analysis as determined randomly. Results: Three hundred and sixty open CTRs in 327 patients were performed during the study. Twenty-seven PMAs were identified, for an overall prevalence rate of 8.3%. The average age of patients with a PMA was 63.6 years (SD 13.3 years), consisting of 15 men and 12 women. There were no statistical differences in age, gender, or laterality between patients that did and did not have a PMA. Thirty-three patients underwent bilateral CTR during the study, with 3 being found to have a PMA unilaterally, and zero having a PMA bilaterally. Two bifid median nerves (0.6%) were also identified. Conclusion: This study represents the highest prevalence rate of PMA directly observed in CTR patients reported to date (8.3%). A PMA is not a rare finding, and it should be recognized and protected during CTR. Occasionally, a PMA can be the cause of an acute presentation of CTS.

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PURPOSE: The purpose of this study is to characterize the division of the median nerve by the persistent median artery (PMA) and highlight the associated clinical implications. Penetration of the median nerve by the PMA is believed to cause compression of the median nerve and affect nerve conduction velocity. This paper explored whether the origin and the pattern of PMA dictate its ability to divide the median nerve. METHODS: Origin, and relationship of the PMA to the median nerve were documented in 60 cadavers donated to the Human Anatomy Program at UT Health San Antonio. Entire path of this artery was followed in the forearm and the hand. RESULTS: Twenty-five cases of a persistent median artery (PMA) were found in the upper limbs (20.83%; 25/120) of these donated cadavers. Most of the persistent median arteries originated from the ulnar artery (48%; 12/25) and the others originated either from the anterior interosseous artery (36%; 9/25) or from the common interosseous artery (16%; 4/25). Sixty percent (15/25) of the persistent median arteries penetrated and divided the median nerve in the forearm. Interestingly, all the persistent median arteries that originated from the ulnar artery (100%; 12/12) divided the median nerve in the forearm and a palmar type of PMA was found to be more likely to divide the median nerve. CONCLUSION: Clinicians performing surgeries in the forearm and hand need to be aware of this anomaly and should screen patients for the presence of this artery prior to surgical intervention.

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Being aware of the variants of upper extremity anatomy is of utmost importance to a surgeon. This case report describes a patient who presented with two separate wrist masses. Operative exploration was planned, and both the structures were investigated. The distal mass was identified as a volar wrist ganglion, and the more proximal mass was identified as the muscle belly of a reversed palmaris longus muscle. Incidentally, it was noted that the patient had a patent, persistent median artery. Although many variants of the palmaris longus have been described, as have been cases of a persistent median artery, both have not been previously documented in a single patient. Although this is rare, having knowledge of possible anatomic variations is valuable for any surgeon operating on the upper extremity.

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BACKGROUND: It is vital to know the anatomical variations of the wrist to avoid iatrogenic injuries during carpal tunnel (CT) surgery. PURPOSE: To determine the anatomical variations of the median nerve (MN) and the prevalence of persistent median artery (PMA) on wrist magnetic resonance imaging (MRI). MATERIAL AND METHODS: A total of 300 wrists evaluated by MRI during 2013-2015 were retrospectively identified. While branching of the MN distal to the CT is accepted as the normal anatomy, proximal to the tunnel and within the tunnel were considered as variations. The prevalence of PMA was also evaluated. The patients were assigned to groups according to age, gender, and wrist side and compared to determine whether there was any significant difference in terms of these variations. All evaluations were assessed with the shared decision of a musculoskeletal radiologist and a radiology resident. RESULTS: Of the 300 wrists, 38 (12.7%) and 34 (11.3%) had a bifid MN proximal to the CT and within the CT, respectively. Only one nerve trifurcation was seen within the CT. The MN exhibited branching distal to the CT in 227 (76%) patients. PMA was observed in 44 (14.7%) patients. Of the 44 PMA cases, 28 (63.6%) also had a coexisting MN variation. There was no significant difference in the prevalence of MN variations and PMA in the subgroups (P > 0.05). CONCLUSION: Nearly one in four patients (24.4%) have MN variations and 14.8% had PMA. Preoperative evaluation of these common anatomical variations with MRI will be protective against postoperative complications of CT surgery.

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BACKGROUND: The acute presentation of carpal tunnel syndrome (CTS) is rare. When symptoms start acutely with no obvious causes, ultrasound (US) imaging may provide clues to the etiology. OBJECTIVE: This study describes the clinical, electromyographic, and US findings in 25 patients presenting with acute CTS (ACTS). METHODS: In this analysis, of the patients referred for electrodiagnostic confirmation of CTS over the past decade, 25 had an acute onset of symptoms. All patients underwent EMG/NCV and US of the median nerve at the carpal tunnel and forearm. RESULTS: Of the 25 cases with ACTS, 5 (20%) had bilateral involvement leading to the total hands studied to 30. In 14 (56%) patients, an inciting event was identified as a possible cause of ACTS. In 11 (44%) patients without an antecedent event, 7 (64%) had a persistent median artery (PMA) detected by US. Electrodiagnostic studies showed prolonged distal motor latency with normal motor conduction velocity proximal to the carpal tunnel in 24 (80%) of 30 hands, 6 (20%) hands showed absent compound muscle action potentials over the abductor pollicis brevis (APB), and 22 (73%) hands had absent sensory potentials. Denervation changes were seen in the APB in 13 (43%) hands, and motor unit potentials were absent in 6 (20%) hands. Sixteen (64%) patients underwent a carpal tunnel release for severe symptoms. CONCLUSION: CTS may present acutely without a clinically identifiable cause. US complements electrodiagnostic studies and is particularly useful when electrodiagnostic tests are non-diagnostic (due to absent compound muscle and sensory action potentials). US may also provide clues to the underlying cause.

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INTRODUCTION & IMPORTANCE: Carpal tunnel syndrome (CTS) is the most common neuropathy in the world and is caused by compression of the median nerve. It has many known risk factors, including hemodialysis and a persistent median artery (PMA), which can be an incidental finding during carpal tunnel release (CTR). CASE PRESENTATION: A 65-year-old woman with end-stage renal disease (ESRD) on dialysis for seven months presented with typical signs and symptoms of carpal tunnel syndrome. Nerve conduction studies (NCS) displayed severe neuropathy. Upon carpal tunnel release (CTR) a rare superficial non-calcified persistent median artery critical to the circulation of the hand was found. The patient's symptoms resolved completely within four weeks of the operation. CLINICAL DISCUSSION: The PMA is a relatively common anomaly and could cause carpal tunnel syndrome by: directly pressing the median nerve, thrombosing, or in the setting of an aneurysm. Although usually found deep to the flexor retinaculum, the PMA could also be found superficially. It can be critical to the blood supply of the hand and should therefore be dealt with carefully. CONCLUSION: Surgeons should be aware of the possibility of finding a PMA when performing CTR. The PMA could be deep or superficial to the transverse carpal ligament. Where possible, the PMA should be preserved. Especially if its contributions to the blood supply of the hand are undetermined.

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The discovery of modern evolutionary anatomy shows that the persistent median artery in the upper arm is a common variant with an increasing trend. This phenomenon can explain well the transition from the eleven meridians described in the Han silk and bamboo slips to the twelve meridians finalized in Neijing and the addition of the hand- jueyin meridian in Han dynasty. After systematic analysis and comparison, the author proposes the hypothesis that "yin meridians are arteries, and yang meridians are nerve-like structures" to explain the meridian theory prior to acupuncture and acupoints in the Qin and Han dynasties. It is clear that over two thousand years ago, Chinese physicians already described the distribution, physiology, and pathology of the six main arteries and six important nerves in the human extremities. The finding suggests that it was the addition of acupuncture and acupoints that had changed the direction of TCM development in Neijing or later and promoted the maturation of qi and blood, meridians, and zangfu theories.

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The presence of a persistent median artery (PMA) has been implicated in the development of compression neuropathies and surgical complications. Due to the large variability in the prevalence of the PMA and its subtypes in the literature, more awareness of its anatomy is needed. The aim of our meta-analysis was to find the pooled prevalence of the antebrachial and palmar persistent median arteries. An extensive search through the major databases was performed to identify all articles and references matching our inclusion criteria. The extracted data included methods of investigation, prevalence of the PMA, anatomical subtype (antebrachial, palmar), side, sex, laterality, and ethnicity. A total of 64 studies (n = 10,394 hands) were included in this meta-analysis. An antebrachial pattern was revealed to be more prevalent than a palmar pattern (34.0% vs. 8.6%). A palmar PMA was reported in 2.6% of patients undergoing surgery for carpal tunnel syndrome when compared to cadaveric studies of adult patients in which the prevalence was 8.6%. Both patterns of PMA are prevalent in a considerable portion of the general population. As the estimated prevalence of the PMA was found to be significantly lower in patients undergoing surgery for carpal tunnel syndrome than those reported in cadaveric studies, its etiological contribution to carpal tunnel syndrome is questionable. Surgeons operating on the forearm and carpal tunnel should understand the anatomy and surgical implications of the PMA and its anatomical patterns.

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The discovery of modern evolutionary anatomy shows that the persistent median artery in the upper arm is a common variant with an increasing trend. This phenomenon can explain well the transition from the eleven meridians described in the Han silk and bamboo slips to the twelve meridians finalized in

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BACKGROUND: A rare case of carpal tunnel syndrome caused by a thrombosed persistent median artery is presented here. CASE: The diagnosis was delayed due to the overlapping cervical radiculopathy. Acute severe pain and nocturnal paresthesia were chief complaints. Ultrasonography, magnetic resonance imaging, and computed tomography angiography revealed that the median nerve was compressed by the occluded median artery. Instead of surgery, conservative therapy was tried. It worked well for six months. CONCLUSIONS: The importance of using modalities for decision making of diagnosis and treatment is emphasized in this report.