The axillary arch inserted to the coracoid process compressing the brachial plexus / El arco axilar insertado en el proceso coracoideo comprimiendo el plexo braquial

The axillary arch is a variant slip extending between the latissimus dorsi muscle and the pectoralis major. During educational dissection, a variant muscle was found in left arm of 70-year-old female cadaver. A slip muscle originated from the lateral margin of the latissimus dorsi and crossed the axilla obliquely. Therefore, we defined this muscular variation as axillary arch. It ran anterior (superficial) to the medial and lateral cords of the brachial plexus, and then it inserted to coracoid process. We reported this variant muscle and discussed its clinical significances.

El arco axilar es una variante que se extiende entre el músculo dorsal ancho y el pectoral mayor. Durante la disección educativa, se encontró una variante muscular en el brazo izquierdo de un cadáver de una mujer de 70 años. El músculo deslizante se originó en el borde lateral del dorsal ancho y cruzó la axila oblicuamente. Por lo tanto, definimos esta variación muscular como el arco axilar. Se extendió anterior (superficial) a los cordones medial y lateral del plexo braquial, y luego se insertó en el proceso coracoideo. Reportamos esta variante muscular y discutimos sus significados clínicas.

Variation of the Axillary Arch in Korean Cadaver / 체질인류학회지

Axillary arch is relatively common variation of muscle in the axilla. There were several attentions on axillary arch due to its anatomical and surgical importance. During educational dissection, a variant muscle was found in right arm of 68-year-old female cadaver. The variation of muscle originated from the lateral edge of the latissimus dorsi muscle as muscular form. And then, it crossed the axillary artery and median nerve as tendinous form. Finally it became wide as muscular form and inserted into the pectoralis major. We reported this variant muscle and discussed its clinical significances.

Muscular axillary arch accompanying variation of the musculocutaneous nerve: axillary arch / 대한해부학회지

Continuous attention has been developed on the anatomical variations of the axilla in anatomist and surgeon due to their clinical importance. The axillary region is an anatomical space between the lateral part of the chest wall and the medial aspect of the upper limb. During the routine dissection of embalmed cadavers, we found variant muscular slip originating from the lateral border of tendinous part of the latissimus dorsi and continuing 9 cm more crossing the axilla. And then, it inserted into the superior margin of the insertion of the pectoralis major. We considered this muscular variation as axillary arch muscle. Correct identification of the relevant anatomy and subsequent simple surgical division is curative, paying special attention to anatomical variations in this region and its clinical importance due to its close relationship to the neurovascular elements of the axilla.

Langer’s Axillary Arch and Its Clinical Implications.

Introduction: The axillary arch muscle of Langer is the most common anatomical variant of axillary musculature which is of clinical and surgical importance. It may lead to neurovascular compression syndrome in the cervicoaxillary region and can be misinterpreted while examining axilla and also impairs movements of shoulder joint. Observation: During routine dissection of axilla for undergraduate teaching, an unusual muscular slip in the left axilla was observed .The muscular slip was extending from lattisimus dorsi muscle to undersurface of pectoralis major muscle, arching over axillary vessels and cords of brachial plexus. Conclusion: The axillary arch may cause obstruction to axillary vessels and nerves and may be involved in thoracic outlet syndrome and shoulder instability. The knowledge of this muscular variant could help to minimize intraoperative complications related to surgeries in or nearby axilla such as mastectomy, breast reconstruction and axillary lymphadenectomy or lymph node biopsy.

Clinical Significance of the Axillary Arch in Sentinel Lymph Node Biopsy / 한국유방암학회지

PURPOSE: The axillary arch is an anomalous muscle that is not infrequently encountered during axillary sentinel lymph node biopsy (SLNB) of breast cancer patients. In this study, we aimed to investigate how often the axillary arch is found during SLNB and whether it affects the intraoperative sentinel lymph node (SLN) identification rate. METHODS: We retrospectively analyzed the correlation between the presence of the axillary arch and the SLN sampling failure rate during SLNB in 1,069 patients who underwent axillary SLNB for invasive breast cancer. RESULTS: Of 1,069 patients who underwent SLNB, 79 patients (7.4%) had the axillary arch present. The SLNB failure rate was high when the patient's body mass index was > or =25 (p=0.026), when a single SLN mapping technique was used (p=0.012), and when the axillary arch was present (p<0.001). These three factors were also found to be statistically significant by multivariate analysis, and of these three factors, presence of the axillary arch most significantly increased the SLNB failure rate (hazard ratio, 10.96; 95% confidence interval, 4.42-27.21; p<0.001). Additionally, if the axillary arch was present, the mean operative time of SLNB was 20.8 minutes, compared to 12.5 minutes when the axillary arch was not present (p<0.001). If the axillary arch was present, the SLN was often located in a high axillary region (67%) rather than in a general low axillary location. CONCLUSION: The axillary arch was found to be a significant factor affecting intraoperative SLN failure rate. It is necessary to keep in mind that carefully checking the high axillar region during SLNB in breast cancer patients with the axillary arch is important for reducing SLN sampling failure.

Rare multiple variations in brachial plexus and related structures in the left upper limb of a Dravidian male cadaver / 대한해부학회지

Anatomical variations of the nerves, muscles, and vessels in the upper limb have been described in many anatomical studies; however, the occurrence of 6 variations in an ipsilateral limb is very rare. These variations occur in the following structures: the pectoralis minimus muscle, the communication between the external jugular vein and cephalic vein, axillary arch, the Struthers ligament, the medial, lateral, and posterior cords of the brachial plexus, and the common arterial trunk from the third part of the axillary artery. The relationship of these variations to each other and their probable clinical presentation is discussed.

Duplicated axillary arch muscles arising from the latissimus dorsi / 대한해부학회지

Many origins and insertions of an axillary muscular slip (also known as Langer's or axillary arch muscles) have been documented previously. In this report, we found duplicated axillary arch muscles (two variant muscular slips) originating from the inferolateral border of the right side latissimus dorsi muscle. Obviously, these axillary arch muscles can be distinguished as short and long muscular strips. While the origin was the same, the short muscular slip inserts into the fascia covering on the pectoralis minor, whereas the longer one inserts on/into the aponeurosis of pectoralis major. For the surgery in the axillary region, this rare variation should be considered a cause of surgical interventions.

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.

The Axillary Arch of Langer (Axillopectoral Muscle): A Case Report / 한국유방암학회지

The axillary arch of Langer (Axillopectoral muscle) is the most common anatomical variant of the axillary musculature. The incidence of the variant is about 7% or less in the population and despite the reported frequency, its presence has been rarely reported. A 33-yr-old woman visited our institution due to the presence of a right breast mass and was diagnosed with right breast cancer by an ultrasound guided core biopsy. Previously, the patient had had no complaints of sensory and motor dysfunction of the right arm. The patient underwent a modified radical mastectomy and we identified an abnormal muscle that originated from the latissimus dorsi, and was inserted in the trilaminar tendon of the pectoralis major during axillary lymph node dissection. The muscle interfered the level I area due to its longitudinally oblique direction. We separated this muscle, and carefully dissected the medial axillary group and lateral axillary group. After follow-up for two years, there was no evidence of axillary recurrence, lymphedema or any limitation of motion of the right arm. We discuss the definition, clinical complications and clinical importance of the axillary arch of Langer. We report here the first case of axillary arch of Langer that was identified during surgery in Korea.

Innervation of Muscular Axillary Arch by a Branch from Pectoral Loop / Inervación del Arco Muscular de la Axila por un Ramo Pectoral

The latissimus dorsi muscle is a flat and triangular muscle that covers the lumbar region and the inferior part of thorax. This muscle supplied by thoracodorsal nerve(C6, C7,C8), a branch of posterior cord of brachial plexus. Many reports showed that a muscular axillary arch , flat muscle arising from lateral border of latissimus dorsi , may be seen in 7% of the population, but there is little information about the innervation of this part. This report deals with dissecting the axillary region of a 41 year-old male cadaver in which we observed a muscular axillary arch was innervated by a single nerve branch of pectoral loop.

El músculo latísimo del dorso es un músculo triangular aplanado que cubre la región lumbar y la parte inferior del tórax. Este músculo está inervado por el nervio toracodorsal (C6, C7,C8), un ramo del fascículo posterior del plexo braquial. Algunos reportes han mostrado que el arco muscular de la axila, es un músculo aplanado que se origina desde el borde lateral del músculo latísimo del dorso y que ha sido encontrado en el 7% de la población, pero es poca la información existente acerca, de la inervación del mismo. Se relata un caso de arco muscular de la axila encontrado en una disección de un cadáver de sexo masculino de 41 años, en el cual se observó la inervación del músculo por un simple nervio ramo del arco pectoral.