Morphological and morphometric analysis of Psoas Minor Muscle in cadavers

The Psoas Minor Muscle is considered inconstant and it’s often absent. This muscle consists of a short proximal fixation tendon originated from the sides of the twelfth thoracic vertebra, first lumbar vertebra and corresponding intervertebral disc, continuous with a short spindle-shaped morphology muscular venter, ending with a long distal fixation tendon inserted in the pectineal line of the pubis and iliopectineal eminence. Due to the lack of information in liteature regarding Psoas Minor muscle’s morphology and morphometry, this study aimed to obtain more detailed information about the muscle in order to expand knowledge of its morphology and morphometry. In order to perform this study, it was used as work material 30 cadaver parts of lower limbs belonging to the anatomical specimens’ collection of Federal Rural University of Pernambuco and Federal University of Pernmabuco. It was found in this study, an absence percentage of Psoas Minor Muscle around 73%. The muscles analyzed did not show any anatomical variation and presented as morphometric characteristics a proximal tendon with average length of 18.11 mm, a muscular venter with average of 71.25 mm for your lenght and a lenght for a distal tendon with average of 150.97 mm. This study confirms the literature’s descriptions, demonstrating the inconstancy of Psoas Minor Muscle and, in our results, it did not show any morphological changes related to its proximal or distal fixation, and to its muscular venter. However, our results showed unpublished data related to width and thickness of the muscle venter of the Psoas Minor.

Anatomical study on the psoas minor muscle in human fetuses / Estudio anatómico del músculo psoas menor en fetos humanos

The anatomy of the psoas minor muscle in human beings has frequently been correlated with ethnic and racial characteristics. The present study had the aim of investigating the anatomy of the psoas minor, by observing its occurrence, distal insertion points, relationship with the psoas major muscle and the relationship between its tendon and muscle portions. Twenty-two human fetuses were used (eleven of each gender), fixed in 10 percent formol solution that had been perfused through the umbilical artery. The psoas minor muscle was found in eight male fetuses: seven bilaterally and one unilaterally, in the right hemicorpus. Five female fetuses presented the psoas minor muscle: three bilaterally and two unilaterally, one in the right and one in the left hemicorpus. The muscle was independent, inconstant, with unilateral or bilateral presence, with distal insertions at different anatomical points, and its tendon portion was always longer than the belly of the muscle.

La anatomía del músculo psoas menor, en los seres humanos ha sido a menudo vinculada con cuestiones de orden étnico-raciales. Este estudio tuvo como objetivo evaluar la anatomía del músculo psoas menor en relación a su presencia, puntos de origen e inserción, relación con el músculo psoas mayor y sus porciones tendinosa y muscular. Se utilizaron 22 fetos humanos (11 de cada sexo) que fueron fijados en solución de formalina al 10 por ciento por perfusión a través de la arteria umbilical. El músculo psoas menor se encontró en 8 fetos de sexo masculino, siete bilateralmente y apenas uno unilateralmente en el hemicuerpo derecho. En los fetos de sexo femenino, cinco tenían el músculo psoas menor, tres bilateralmente y dos unilateralmente, siendo uno encontrado en el hemicuerpo derecho y otro en el izquierdo. El músculo es independiente, inconstante, de presencia unilateral o bilateral, con la inserción en diferentes sitios anatómicos y su porción tendinosa siempre mayor que el vientre muscular.

Anatomia seccional da origem do músculo psoas maior: estudo através do método de plastinaçäo / Sectional anatomy of the origin of psoas major: study made by plastination method

Através de dissecçao macro e microscópica das colunas de cinco cadaveres, previamente fixados por infusao intra-arterial de soluçao de aldeido fórmico, com exposiçao do psoas maior, esquerdo e direito, e da plastinaçao de secçoes, com 2 mm de espessura, paralelas e transversais ao eixo do segmento das colunas vertebrais, de T4 ao nível S3-S4, de outros sete cadaveres conservados sob congelamento a-20 graus Celsius, estudou-se a origem do psoas maior, a disposiçao de seus feixes musculares e sua possível relaçao com o forame intervertebral. Confirmou-se a origem das duas cabeças do músculo, a anterior ou principal, na face ântero-lateral dos corpos vertebrais e discos intervertebrais, e a posterior ou acessória, nos processos costais de L3 e L4. Observou-se comunicaçao entre as fibras musculares das duas cabeças e o envolvimentos dos forames intervertebrais. Os autores concluíram pela utilidade da técnica de plastinaçao para o estudo da anatomia seccional e possível correlaçao com os métodos de imagem.