Partial agenesis of the pectoralis major and minor muscle: A cadaveric case report.

RATIONALE: The pectoralis major and minor muscles, located in the anterior chest wall, are crucial for upper limb movements. PATIENT CONCERNS: Their nonsyndromic absence is rare but significant for surgical procedures involving the axillary and pectoral regions. DIAGNOSES: Ultrasound can confirm the diagnosis and delimit the extent of the muscular abnormality, detect abnormalities of the costal cartilages, among others. INTERVENTIONS: This descriptive, cadaveric case report involves a formalin-fixed 57-year-old North American male, with no clinical or family history of similar conditions. The study was conducted at the Human Anatomy Laboratory of the School of Medicine of the Universidad Finis Terrae in Santiago, Chile, in August 2022. OUTCOMES: We present a cadaveric case of bilateral partial agenesis of the pectoralis muscles discovered during routine dissection. The pectoralis major muscle exhibited only the clavicular portion, with the sternocostal and abdominal portions absent and replaced by a thin layer of connective tissue bilaterally. The pectoralis minor muscle showed partial muscle fibers only in the most distal and inferior portions bilaterally. LESSONS: This case report is significant due to the rarity of this condition without accompanying anatomical variations. Understanding this variant is valuable for clinical situations involving the shoulder and thorax region, such as trauma to the proximal third of the humerus, clavicular region, suprascapular region, and anterior chest wall. It may complicate conservative and/or surgical treatments due to different functional and irrigation patterns in the area and is also important for educating future professionals.

Músculo Esternal Bilateral, Descripción de un Caso e Implicancias Clínicas / Bilateral Sternal Muscle, Description of a Case and Clinical Implications

El músculo esternal corresponde a una variante muscular supernumeraria de la musculatura torácica, cuya descripción más antigua se remonta al año 1604. A lo largo de la historia ha sido denominado músculo "epiesternal", "preesternal", "recto torácico" o "recto esternal". Se ubica entre la fascia superficial y el músculo pectoral mayor, tiene una prevalencia de entre 3 % y 8 % en la población general, se presenta de forma unilateral o bilateral exhibiendo una alta variabilidad interracial y puede ser motivo de dilemas diagnósticos durante cirugías y exámenes de imagen. Disección en un cadáver adulto de sexo masculino. Se encontraron dos músculos esternales conectados superiormente por un tendón central. El músculo esternal derecho se extendía desde el manubrio esternal hasta el séptimo cartílago costal derecho. El músculo esternal izquierdo se extendía desde el manubrio esternal hasta el sexto cartílago costal izquierdo. Su inervación estaba dada por ramos cutáneos anteriores de los nervios intercostales y su vascularización por ramas perforantes provenientes de los vasos torácicos internos. El músculo esternal presenta una alta variabilidad morfológica y su prevalencia se ve influenciada por factores raciales. Conocer esta variación muscular enriquece la capacidad diagnóstica y quirúrgica reduciendo la posibilidad de iatrogenia.

SUMMARY: The sternal muscle corresponds to a supernumerary muscle variant of the thoracic musculature, whose oldest description dates to 1604. Throughout history it has been called the "episternal", "presternal", "rectus thoracis" or "rectus sternalis" muscle. It is located between the superficial fascia and the pectoralis major muscle, has a prevalence of between 3 % and 8 % in the general population, presents unilaterally or bilaterally, exhibits a high interracial variability and can be the cause of diagnostic dilemmas during surgery and imaging examinations. Dissection in an adult male cadaver. Two sternal muscles were found connected superiorly by a central tendon. The right sternal muscle extended from the sternal manubrium to the right seventh costal cartilage. The left sternal muscle extended from the sternal manubrium to the left sixth costal cartilage. The innervation was given by anterior cutaneous branches of the intercostal nerves and the vascularization by perforating branches coming from the internal thoracic vessels. The sternal muscle presents a high morphological variability and the prevalence is influenced by racial factors. Knowing this muscle variation enriches the diagnostic and surgical capacity, reducing the possibility of iatrogenesis.

Serie de Casos: Síndrome de Poland Completo vs. Incompleto. Resolución Quirúrgica / Case Series: Poland Syndrome Complete vs Incomplete. Surgical Resolution

INTRODUCCIÓN: El síndrome de Poland es una enfermedad congénita polimalformativa extremadamente rara, su etiología es aún desconocida, afectando principalmente el desarrollo del músculo pectoral mayor; se acompañan frecuentemente de malformaciones de la mano, mama, complejo areola-pezón, pectoral menor ipsilateral y otras malformaciones asociadas. Su diagnóstico se basa en un correcto examen clínico junto con una tomografía axial computarizada con reconstrucción en 3D. El tratamiento quirúrgico final es individualizado y dependerá de la existencia de una o más malformaciones. CASOS CLÍNICOS: Se trató de cuatro pacientes con cuadro clínico compatible con síndrome de Poland, siendo común el subdesarrollo o ausencia del músculo pectoral mayor. EVOLUCIÓN: Se realizó a cada paciente una tomografía axial computarizada con reconstrucción en 3D para confirmar su diagnóstico y realizar un tratamiento quirúrgico según la necesidad de cada paciente, después del procedimiento se dio seguimiento a los pacientes con una respuesta favorable y sin complicaciones. CONCLUSIONES: El síndrome de Poland se caracteriza por un cuadro clínico variable, con la ausencia o subdesarrollo del músculo pectoral mayor, el tratamiento quirurgico fue personalizado para cada paciente. Las técnicas quirúrgicas incluyeron reconstrucción de la pared torácica mediante osteosíntesis en los casos graves independientemente del sexo del paciente; rotación de colgajos del músculo dorsal ancho, colocación de expansores tisulares y prótesis mamarias en el caso de las pacientes femeninas y colocación de prótesis preformadas mediante estereolitografía en el caso de los pacientes masculinos.

BACKGROUND: The Poland syndrome is an extremely rare polymalformative congenital disease, the etiology is still unknown, mainly affecting the development of the pectoralis major muscle; they are frequently accompanied by malformations of the hand, breast, nipple-areola complex, ipsilateral minor pectoral and other associated malformations. The diagnosis is based on a correct clinical examination together with a computerized axial tomography with 3D reconstruction. The final surgical treatment is individualized and will depend on the existence of one or more malformations. CASE REPORTS: Four patients with a clinical picture compatible with the Poland syndrome were treated, with underdevelopment or absence of the pectoralis major muscle being common. EVOLUTION: Each patient underwent a computerized axial tomography with 3D reconstruction to confirm their diagnosis and perform a surgical treatment according to the needs of each patient; after the procedure, patients were followed up with a favorable response and without complications. CONCLUSIONS: The Poland syndrome is characterized by a variable clinical picture, with the absence or underdevelopment of the pectoralis major muscle, the surgical treatment was customized for each patient. Surgical techniques included reconstruction of the chest wall by osteosynthesis in severe cases regardless of the sex of the patient; rotation of flaps of the latissimus dorsi muscle, placement of tissue expanders and mammary prosthesis in the case of female patients and placement of preformed prostheses by stereolithography in the case male patients.

Abordagem vertical do peitoral maior nas inclusões mamárias / Vertical approach to the pectoralis major in breast implant insertion

INTRODUÇÃO: O trabalho demonstra uma abordagem alternativa para ampliarmos a escolha do espaço retromuscular e evitarmos os efeitos indesejáveis nas inclusões de próteses mamárias neste plano. MÉTODOS: Foram avaliados 328 pacientes do sexo feminino, com idade entre 17 e 62 anos, com queixa de hipomastia e certo grau de ptose mamária bilateral. Todas as pacientes foram submetidas à inclusão de próteses bilaterais e incisão vertical no músculo peitoral maior. A avaliação foi realizada com um período mínimo de 6 meses. RESULTADOS: A tática cirúrgica de incisão vertical no músculo peitoral maior nos permitiu ampliar a indicação do espaço retromuscular nas cirurgias de inclusão de próteses de mamas, conseguindo alcançar com êxito o posicionamento adequado da prótese e do tecido mamário, evitando cicatrizes adicionais. CONCLUSÕES: A técnica mostrou-se eficaz na sua propositura, evitando cicatrizes e o efeito de dupla-bolha e ampliando a indicação do espaço retromuscular.

INTRODUCTION: This study demonstrates an alternative method to access the retromuscular space and avoid undesirable effects caused by breast implant insertion in this space. METHODS: We evaluated 328 female patients, aged 17 to 62 years, with complaints of micromastia and bilateral ptosis. All patients underwent insertion of bilateral implants using a vertical incision in the pectoralis major. Follow-up was performed for at least 6 months. RESULTS: The technique of vertical incision in the pectoralis major increases the options for access to the retromuscular space in breast implant insertion. This method successfully achieves appropriate positioning of the implant and avoids additional scars. CONCLUSIONS: The technique proved to be effective, avoiding scars and the double-bubble effect, and increases the options for access to the retromuscular space.

[Supernumerary muscular masses of the anterior thoracic wall. Case report and review].

INTRODUCTION: On the anterior thoracic wall, some supernumerary muscular masses can be present, like the sternalis muscle, which is situated over the pectoralis major muscle fascia, deep to the subcutaneous tissue. Its fibers can be parallel or oblique to the sternum, and are clinically important due to the possibility that during certain radiologic procedures they can be confused with some types of breast pathologies. MATERIAL AND METHODS: Bibliographic review of supernumerary muscular masses of the anterior thoracic wall and case report in a colombian male cadaver of mixed ethnia, dissected by medical students at the Department of Morphology at the Universidad del Valle, in Cali, Colombia. RESULTS: In the right side of the anterior thoracic wall of the cadaver an anatomical variation of low occurrence in the general population, the sternalis muscle, was found. The muscle fibers had a vertical direction, parallel to the right sternal margin. Considering all the muscular fascicles, its dimensions were approximately 7,0 cms in length and 2,9cms in width. CONCLUSION: Having in mind the characteristics of the present anatomical variation, and that there can be some radiologic, surgical and clinical implications, it is important for the health professional to know the anatomy and epidemiology of the sternalis muscle.

Sternalis muscle: an anatomic variation of the anterior chest wall

The sternalis muscle’s presence is an uncommon anatomic variation of the anterior chest wall’s musculature. It is insufficiently mentioned by the most of anatomical textbooks, although it has been well described by the literature. The study of this anatomic variation is extremely relevant, principally for the interpretation of image’s exams that approach this region. For this study’s achievement, 102 cadavers were dissected (97 of the male sex and 5 of the female sex). The study of the sternalis muscle avoids the expenses with exams and the indication of aggressive treatments in a wrong way.

Aesthetic improvements in Poland's syndrome treatment with omentum flap.

BACKGROUND: There are many techniques that can be used to reconstruct anomalous breast volume in Poland's syndrome, but repair of the stigmatizing deformities such as the transverse skin fold in the anterior axillary pillar, infraclavicular depression, and anomalous breast contours continues to be a challenge. This study aimed to demonstrate the superior results of laparoscopically harvested omentum flap to achieve these aesthetic improvements. METHODS: Patients with Poland's syndrome from a clinical database were identified and their outcomes were studied. RESULTS: In 15 consecutive patients with Poland's syndrome, the breast contour, the anterior axillary pillar, and the infraclavicular depression were treated with omentum flap and evaluated. Silicone implants were used beneath the flap in 80% of cases to improve symmetry. Flap consistency was similar to that of the natural breast and only a small incision in the breast fold was needed. The flap is extremely malleable, adapts to irregular surfaces, and has a long vascular pedicle. It does not leave a scar at the donor site as muscular flaps do. The omentum can repair small irregularities in breast contour, achieving a natural result different from all other flaps. Due to its malleability, it is possible to reconstruct even the extension to the axillary pillar, which is impossible with all other techniques. CONCLUSIONS: The omentum flap technique is a means of repairing the deformities caused by Poland's syndrome and improves the aesthetic result with outcomes that seem superior to any other reconstructive option.

Bilateral presence of axillary arch muscle passing through the posterior cord of the brachial plexus / Presencia bilateral del arco muscular axilar pasando por el fascículo posterior del plexo braquial

The axillary arch can be described as an anomalous muscular slip of latissimus dorsi muscle. In this paper, a rare case of bilateral axillary arch is reported during routine dissection of the axillary region of a 57-year old male cadaver. On both sides, the axillary arch muscle took origin from latissimus dorsi and teres major, and passed upwards through the posterior cord of the brachial plexus, but posterior to the bulk of axillary neurovascular bundle. It then split into two slips: the medial slip was inserted into the root of the coracoid process, while the lateral slip which was intracapsular, was attached to the lesser tubercle, above the attachment of subscapularis. The presence of the muscle has important clinical implications, and the position, bilateral presence, penetration of the posterior cord, and multiple connective tissue attachments makes the case most unique. The anatomy, surgical implications, and embryology of the anomalous muscle are discussed in this paper.

El arco axilar puede ser descrito como un fascículo muscular anómalo del músculo latísimo del dorso. En este trabajo, un raro caso de arco axilar bilateral se encontró durante la disección de rutina de la región axilar de un cadáver de 57 años de sexo masculino. En ambos lados, el músculo arco axilar se originó desde los músculos latísimo del dorso y redondo mayor y pasó hacia arriba a través del fascículo posterior del plexo braquial, pero posterior a la mayor parte del paquete neurovascular axilar. A continuación, se dividió en fascículos: el fascículo medial se insertó en la raíz del proceso coracoides, mientras que el fascículo lateral, era intracapsular y se insertaba en el tubérculo menor del húmero, por encima de la inserción del músculo subescapular. La presencia de este músculo axilar tiene importantes implicaciones clínicas, y la posición, la presencia bilateral, la penetración del fascículo posterior, y múltiples uniones de tejido conectivo hacen al caso más especial. La anatomía, las implicaciones quirúrgicas y embriología del músculo anómalo son discutidos en este trabajo.

Arco axilar de langer (músculo axilopectoral): variante supernumeraria inusual del músculo latísimo del dorso: reporte de tres casos / Langers's axillary arch (axillopectoral muscle): inusual supernumerary variant's latissimus dorsi: three cases report

El arco axilar de Langer o músculo axilopectoral es una variación relativamente rara de la inserción del músculo latísimo del dorso. Se identifica en aproximadamente el 1.7 a 7 por ciento de las disecciones axilares y corresponde a un complejo músculofascial, la parte muscular junto con el tendón del músculo pectoral mayor se inserta dentro del labio lateral del surco intertubercular del húmero, mientras que, la parte fascial está formada por bandas fibrosas que se extienden en la parte profunda del músculo pectoral mayor para insertarse en el proceso coracoide entre la unión de los músculos coracobraquial y pectoral menor. El reconocimiento de esta anomalía es importante para los médicos clínicos, cirujanos y fisioterapeutas, ya que obliga a plantearse el diagnóstico diferencial de masas axilares, historia de obstrucción venosa axilar intermitente, o su aparición inesperada en el transcurso de la disección axilar del linfonodo centinela o linfadenectomías. Se presentan tres casos de arco axilar de Langer diagnosticados en la Unidad de Patología Mamaria del Instituto Autónomo Hospital Universitario de los Andes, Mérida, Venezuela, en el periodo 1999-2006, en el transcurso de 210 disecciones axilares practicadas en pacientes con cáncer de mama para identificación del linfonodo centinela o en linfadenectomías.

The Langer's axillary arch or axillopectoral muscle is a is a relatively rare anatomical variation of latissimus dorsi muscle insertion. Langer's arch is identified in up to 1.7 a 7 percent of axillary explorations, and is a musclefascial complex continuous with the iliacal fibers of the latissimus dorsi. The muscular part, together with the tendon of pectoralis major muscle, inserted into the lateral lip of the intertubercular sulcus of the humerus, whereas the fascial part was formed by a fibrous band that extended deep to the pectoralis major muscle to insert into the coracoid process between the attachments of the coracobrachialis and pectoralis minor muscles. The recognition of this anomalies is important to clinicians, surgeons and physical therapist because It should be considered in the differential diagnosis of axillary masses an unexpected finding during axillary dissection by sentinel lymoh nodes or lymphadenectomy. We report three cases of Langer's axillary arch encountered during sentinel lymph node biopsy or lymphadenectomy en 210 patients with breast cancer, at the patology mammary Unit of the University Los Andes Hospital, in 1999-2006 period.

Unilateral quadripartite composition of pectoral major muscle: anatomical description and clinical implications / Composición unilateral cuadripartita del músculo pectoral mayor: descripción anatómica e implicancias clínicas

A unilateral anomalous disposition of the muscular slips of pectoralis major was observed in an adult male cadaver during routine gross anatomy teaching session. The pectoralis major muscle displayed unusual configuration and comprised of four parts delineated by three intramuscular clefts. Further, the sternocostal part was found to divide into two fasciculi. The origin and insertion of pectoralis major muscle was as usual and unremarkable. Interestingly, the innervation of the muscle was observed to bear an important variation. The clavicular and sternocostal slips of pectoralis major muscle received a direct branch from the lateral cord of brachial plexus in addition to its usual innervation from the lateral and medial pectoral nerves. The multiplicity of innervation of pectoralis major as encountered in the present study would presumably augment its suitability for its use in reconstructive procedures. An additional anomalous attachment of the pectoralis minor muscle was also observed emanating from the second rib, apart from the usual third, fourth and fifth ribs. These variants of the pectoral muscles may also have implications in biomechanical studies, as they may alter the kinematics.

Una disposición anómala unilateral de los vientres musculares del músculo pectoral mayor se observó en un cadáver adulto de sexo masculino durante una clase de rutina de anatomía. El músculo pectoral mayor mostró una configuración inusual y presentaba cuatro partes delimitadas por tres depresiones intramusculares. Además, la parte esternocostal se encontraba dividdida en dos fascículos. El origen y la inserción del músculo pectoral mayor era normal. Curiosamente, la inervación de los músculos, presentaba una importante variación anatómica. Los fascículos clavicular y esternocostal del músculo pectoral mayor recibieron una rama directa del fascículo lateral del plexo braquial, además de su inervación normal de los nervios pectoral lateral y medial. La múltiple inervación del músculo pectoral mayor como se encuentró en el presente estudio, probablemente, haga aumentar su idoneidad para el uso en procedimientos reconstructivos. También se observó un fascículo adjunto anómalo adicional del músculo pectoral menor, que se originaba de la segunda costilla, además de su origen en la tercera, cuarta y quinta costillas. Estas variaciones de los músculos pectorales también puede tener implicancias en estudios biomecánicos, ya que probablemente alteran la cinemática.

Breast mass or sternalis muscle?

This is the first description of the sternalis muscle being found among the cadavers used during the last two decades in the dissection laboratories of the San Juan Bautista School of Medicine.

Breast mass or sternalis muscle?

This is the first description of the sternalis muscle being found among the cadavers used during the last two decades in the dissection laboratories of the San Juan Bautista School of Medicine.

Unilateral pectoralis minimus muscle: a case report / Músculo pectoralis minimus unilateral: reporte de caso

Presence of additional muscles in the pectoral region has often been reported. We report about the presence of Pectoralis Minimus muscle, in a male cadaver. It was present deep to the pectoralis major muscle and superomedial to the pectoralis minor muscle. The variant was closely related to the branches of thoracoacromial vessels where one of the branches was passing between the pectoralis minor muscle and the variant muscle. Hyperabduction of the arm may compress these vessels giving rise to certain vascular symptoms. Also these variations should be borne in mind during certain surgical procedures in the pectoral region

Presencia de músculos supernumerarios en la región pectoral han sido reportados. En un cadáver de un hombre se describe la presencia de un músculo Pectoralis Minimus. El músculo se localizaba profundo al músculo pectoral mayor y superomedial al músculo pectoral menor. La variación se relacionaba con las ramas de los vasos toracoacromiales donde una de las ramas pasaba entre el músculo pectoral menor y la variación muscular. La hiperabducción del brazo puede comprimir estos vasos provocando síntomas vasculares. Estas variaciones se deben tener en cuenta durante los procedimientos quirúrgicos en la región pectoral

Unilateral absence of the thoracic part of the trapezius muscle.

The absence of some muscles, such as pectoralis major, serratus anterior and quadratus femoris have been described, however the absence of trapezius, either in isolation or in association with other structures, is not often observed. In this case study, we present a case of partial absence of the left trapezius muscle in an adult black male cadaver, which had a large aponeurosis replacing the ascending fibres and some of the transverse fibres of the muscle. Histological analysis showed the presence of a few muscle fibres in the aponeurosis. From a functional viewpoint, it is possible that this individual would have had difficulty in moving his shoulder, especially during flexion, abduction and circumduction of the arm.

Agenesia del músculo pectoral mayor / Agenesic major pectoral muscle

Se describe un caso de agenesia de músculo pectoral mayor y otras anomalías concomitantes. Presenta una frecuencia de 0,4 por ciento en nuestro estudio estadístico en cadáveres disecados para docencia. Se relaciona con su origen embriológico y el mecanismo de inducción y los procesos involucrados en el desarrollo de las masas musculares. Se descarta la existencia de una secuencia de Poland

Síndrome de Poland y autoinmunidad / Poland's syndrome and autoimmunity

Se presentan dos pacientes, un varón y una mujer con diagnóstico de síndrome de Poland que desarrollaron lupus eritomatoso generalizado y enfermedad de Graves Baselow. Ambos casos, aunados a una publicación procedente de nuestro medio y en la cual se informó una paciente con síndrome de Poland que desarrolló miastenia gravis sugieren que el desarrollo de enfermedades autoimmunes en el síndrome de Poland puede ser más frecuente de lo sospechado previamente

Malformaciones o anomalías en el desarrollo de la mama / Malformations or abnormalities in breast development

Las malformaciones mamarias se clasifican en congénitas o adquiridas; por defecto o por exceso y en anomalías de número, forma, tamaño y situación. En el capítulo se anlizan los diversos tipos de malformaciones tales como atelia y politelia; amastia, polimastia, macro y micromastia. Se mencionan también algunas alteraciones funcionales como la hipertrofia juvenil y la del embarazo. Se hace hincapié en el pezón invertido o umbilicado por sus repercusiones en la lactancia materna