Additional head of the biceps brachii (AHBB) has been reported in different po (Folia Morphol 2014; 73, 2: 193-198)

ObjectiveTo determine the frequency and features of communication between the musculocutaneous nerve (MCN) and median nerve (MN) in a sample of the Colombian population, and assess its clinical implication.MethodsThe arms of 53 cadaver specimens that had been subjected to necropsy at the National Institute of Forensic Medicine, in Bucaramanga, Colombia, were studied. The structures of the anterior compartment of the arm were dissected and characterized regarding the presence of communication between the MCN and MN.ResultsA communicating branch was found in 21/106 upper limbs (19.8%), occurring bilaterally in 10 (47.6%) and unilaterally in 11 (52.4%), without significant difference regarding the side of occurrence (p = 0.30). In 17% of the cases, there was MCN-MN communication in which the communicating branch was seen leaving the MCN after piercing the coracobrachialis muscle (Type I). In 2.8%, the connection was from the MN to the MCN (Type II). The length of the communicating branch was 57.8 ± 33.4 mm. The distances from the proximal and distal points of this branch to the coracoid process were 138 ± 39.4 mm and 188 ± 48.3 mm, respectively. The communicating branch was located mostly in the middle third of the arm.ConclusionsThe frequency of MCN-MN communication observed in the present study is in the middle of the range of what was reported in previous studies. MCN-MN connections need to be taken into account in diagnosing and managing peripheral nerve lesions of the upper limbs.

Background: The accessory head of the flexor pollicis longus (AHFPL) has an oblique trajectory from medial to lateral aspect of the forearm below the flexor digitorum superficialis muscle and then joins the flexor pollicis longus muscle. When the anterior interosseous nerve (AIN) courses underneath the muscle belly of the AHFPL an entrapment neuropathy may occur, known as anterior interosseous nerve syndrome (AINS). Materials and methods: This descriptive cross-sectional study evaluated 106 fresh upper extremities. When the AHFPL was present, its fascicle was traced up to evaluate the origin site. The morphometric variables were measured using a digital micrometre (Mitutoyo, Japan). The relationship between the AHFLP and the AIN was evaluated. Results: The AHFPL was found in 34 (32.1%) of the 106 forearms. The AHFPL arose from the flexor digitorum superficialis muscle in 16 (47.1%) forearms, the medial epicondyle of the humerus in 10 (29.4%) forearms and the coronoid process of ulna in 8 (23.5%) forearms. The average total length of the AHFPL was 94.11 ± ± 10.33 mm. The AIN was located lateral to the AHFPL in 3 (8.8%) forearms, posterolateral in 7 (20.6%) forearms and posterior in 24 (70.6%) forearms. Conclusions: This study performed in a South American population sample revealed a prevalence of the AHFPL in a lower range compared to previous studies in North Americans and Asians. The AIN coursed more frequently underneath the muscle belly of AHFPL. This finding has clinical significance in the onset of the AINS and the subsequent surgical procedure for the AIN decompression.

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RESUMEN:Se presenta un raro caso de múltiples variaciones en los miembros superiores de un espécimen cadavérico de 45 años de género masculino, del laboratorio de morfología de la Universidad Industrial de Santander (Bucaramanga-Colombia). Se observó variaciones musculares (presencia bilateral de cabezas adicionales del bíceps braquial y del musculo flexor largo del pulgar, agenesia del palmar largo derecho), nerviosas (anastomosis entre mediano y nervio musculocutáneo, y entre ulnar y mediano al nivel palmar superficial). Adicionalmente, presentó el origen de la arteria radial izquierda desde el segmento superior de la braquial. Estas diversas expresiones morfológicas determinan relevantes implicaciones clínicas y deben tenerse en cuenta en los diferentes abordajes quirúrgicos de los miembros superiores.

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Most histopathological studies have reported that the segment of the coronary artery below the myocardial bridge does not present atheromatous plaque, while the segment proximal to the myocardial bridge may have it. The aim of this study was to evaluate the microscopic environment of myocardial bridges. This descriptive study was carried out with 60 hearts of individuals who underwent autopsy at the National Institute of Legal Medicine and Forensic Sciences in Bucaramanga-Colombia. For each specimen, the coronary arteries and their branches were dissected, removing the subepicardial adipose tissue to identify the myocardial bridges and obtain histological sections of the compromised arterial branches. The presence of myocardial bridges was observed in 22 hearts (36.7 %) with a length of 17.31 + 4.41 mm and a thickness of 904.57 + 312.27 mm. The coronary vessel caliber at the prepontine level was 246.57 + 49.33 mm and was significantly higher than in the pontine (188.92 + 60.55 mm) and postpontin (190.40 + 47 mm) segments (p=0.001 for both values). Atheromatous plaque was observed in the prepontine segment in 12 cases (46.15 %) and in 8 samples (30.76 %) at the pontine level, but in this segment, there was slight damage to the vascular endothelium, or phase I level. The thickness of the tunica intima in the cases with atheromatous plaque was 15.68 + 13.39 mm and that of the plaque-free segments was 5.10 + 4.40 mm (p=0.005), and in the pontine segment the overlying periarterial adipose tissue had a thickness of 72.01 + 69.44 mm, which was higher than the other three locations (p=0.005). The morphometry of the perivascular fat pad and the presence of phase I atheromatous plaque are the main contributions of this study to the histology of myocardial bridges.