Gross anatomical study of the subcutaneous structures that create the three-dimensional shape of the buttocks.

The purpose of this study was to clarify the subcutaneous structures involved in the morphology of the gluteal region for clinical application. Thirty-seven formalin-fixed cadavers and one soft-fixed cadaver were used in this study. Gluteal tissue was removed from five formalin-fixed cadavers. A horizontal section and sections parallel to the long axis of the body were made from the excised tissue, and the subcutaneous fat was removed to observe the fibrous structure within the subcutaneous fat. Two formalin-fixed cadavers and one soft-fixed cadaver were used to perform conventional gross anatomical dissection and histological examination. On 30 formalin-fixed cadavers, the thickness of the subcutaneous fat was measured in various areas of the buttocks. The thickness of subcutaneous fat was thicker in the center of the buttocks and thinner on the lateral buttocks. Superficial fascia (SF) was found only in the upper buttock, being indistinct in the lower buttock. In the sacral and coccygeal areas, the dermis was tightly adhered to the bone as a single mass. Fibers arose from around the iliac crest to the SF. On the medial side of the gluteal fold, a strong fiber arose from the sciatic tubercle and inserted into the gluteus maximus and dermis. By identifying the characteristic subcutaneous structures of the gluteal region, we were able to identify the anatomical structures that shape the three-dimensional morphology of the buttocks. These findings may be useful in surgical treatments such as improving the buttock shape.

Anatomic Variation of the Sciatic Nerve: A Study on the Prevalence, and Bifurcation Loci in Relation to the Piriformis and Popliteal Fossa.

OBJECTIVE: To examine and identify sciatic nerve variations in relation to the piriformis muscle, its prevalence, pattern and the course of its bifurcation loci. MATERIALS AND METHODS: Twenty-eight formalin fixed male cadavers comprising 56 lower limbs were used for this study. Dissection of the gluteal region and posterior compartment of the thigh was conducted to expose the sciatic nerve. Variations in the sciatic nerve anatomy, their relationship to the piriformis muscle and points of bifurcation, and other observable features were noted and recorded. RESULTS: Fifty-two lower limbs (93%) showed normal anatomy of the sciatic nerve. Four regions (7.1%) showed variations in the morphology of the sciatic nerve. Of these, one (1.8%) showed a variation of the sciatic nerve with the piriformis muscle. This single case showed a common peroneal nerve emerging on the left between the heads of a double piriformis muscle - a variant not described in the original Beaton and Anson classification, with the tibial nerve deep to the muscle. In two other limbs, the sciatic nerves showed a normal relationship with the piriformis, but had variations in the bifurcation loci (bilateral). The divisions were in upper third and middle third of the right and left thighs respectively. CONCLUSION: Knowledge of the level of bifurcation and distribution of the sciatic nerve and its location is important. This nerve is commonly encountered by neurologists, orthopaedics, and anaesthesiologists. The uncommon anatomical findings described are relevant to surgeons to enable them to perform efficient surgical procedures and avoid errors.

LL body contour technique-A new way of gluteal contouring and augmentation with hyaluronic acid filler.

INTRODUCTION: Enhancing and altering body contours has increasingly been the focus of new technologies and techniques in aesthetic treatments. The buttocks are seen as a symbol of beauty, sensuality, and attraction. PATIENTS AND METHODS: The authors described a technique for female and male gluteal augmentation. It uses a special marking, a safe plan, and a specific product. The patients chosen for this technique wanted to have an augmentation or projection effect on the buttocks, but were not willing to undergo surgery. The product used was Sofiderm Subskin Aeskins. The plan of injection was the subcutaneous as no major blood vessels were found. RESULTS: The authors report good aesthetic results with the proposed technique. The patients reported a high degree of satisfaction. DISCUSSION: The product chosen has a high G prime and a larger molecule size, which accounts for resistance to deformation and a high lifting power. Thus, result can be visible in a large body area. As the anatomy between male and female buttocks are different, different techniques were used for each gender. CONCLUSION: The LL body contour technique for gluteal augmentation proved to be a minimally invasive technique, with quick results, without major risks and downtime.

Objectifying High-Definition Brazilian Buttock Lift Results Using the Buttock Assessment Tool.

BACKGROUND: The buttock is an essential feature of the female silhouette. This has led to the rise of the Brazilian butt lift as one of the most popular plastic surgery procedures in recent years. Despite this popularity, there remains no prevailing standard for the ideal buttock size and shape. In fact, a wide range of preferred sizes and shapes among the authors' patients has been observed. The authors hypothesized that age, religious affinity, and ethnic differences may demonstrate different buttock size and shape preferences. METHODS: The authors designed the buttock assessment tool, which utilizes digitally altered buttock sizes and shapes to determine desired buttock shape (upper, middle, and lower pole maximum fullness) and buttock size (waist-to-hip width ratio) for both the posteroanterior and lateral views. A survey of 422 patients was completed, evaluating variation of desired buttock size and shape based on patient age, cultural, and ethnic differences. RESULTS: There were significant differences in buttock size and buttock shape based on age, ethnicity, and religion. Hispanics and African Americans were twice as likely as Caucasians to request lower pole fullness in the posteroanterior view. Older respondents preferred a smaller buttock in both views. African Americans preferred a larger buttock compared to Caucasians in both views. Hispanics preferred a larger buttock in only the lateral view. Muslim respondents preferred a smaller buttock in the posteroanterior view. CONCLUSION: The Brazilian buttock assessment tool has become critical to understanding and delivering prospective Brazilian butt lift patients' goals by objectifying buttock size and shapes.

Deep Gluteal Syndrome: A Pain in the Buttock.

ABSTRACT: While buttock pain is a common complaint in sports medicine, deep gluteal syndrome (DGS) is a rare entity. DGS has been proposed as a unifying term referring to symptoms attributed to the various pain generators located in this region. While not all-inclusive, the diagnosis of DGS allows for focus on pathology of regionally associated muscles, tendons, and nerves in the clinical evaluation and management of posterior hip and buttock complaints. An understanding of the anatomic structures and their kinematic and topographic relationships in the deep gluteal space is pivotal in making accurate diagnoses and providing effective treatment. Because presenting clinical features may be unrevealing while imaging studies and diagnostic procedures lack supportive evidence, precise physical examination is essential in obtaining accurate diagnoses. Management of DGS involves focused rehabilitation with consideration of still clinically unproven adjunctive therapies, image-guided injections, and surgical intervention in refractory cases.

Gluteoperinealis muscle: a surgically important variation.

BACKGROUND: Anatomical variations are common in gluteal region. This report presents two cases of gluteoperinealis muscles detected during radiological imaging. CASE PRESENTATION: Our study was conducted on two patients. This report describes an accessory muscle detected in the gluteal region on MRI examination of a patient who admitted to our clinic after a firearm injury and a second patient examined with CT imaging who had signs of pelvic infection. In the first case, this accessory muscle originated bilaterally from the fascia of the gluteus maximus throughout its posteromedial side and was attached to the perineal body. In the second case, it extended forward from the fascia of the gluteus maximus muscle and inserted to the cavernous body of penis on the left side and to the perineal body on the right. In the literature, this accessory muscle has been described as the gluteoperinealis muscle being a rare variation. CONCLUSION: Considering the origin and insertion of the muscle, this variation may be important during the surgical operations of the gluteal and perineal regions.

Anatomic landmarks for a safe arthroscopic approach to the deep gluteal space: a cadaveric study / Hitos anatómicos para un abordaje artroscópico seguro del espacio glúteo profundo: un estudio cadavérico

SUMMARY: To determine the morphometric landmarks and anatomical variants relevant to the arthroscopic approach to the deep gluteal space. Twenty deep gluteal spaces from cadaveric specimens were dissected. The anatomical variants of the sciatic nerve (SN) were determined according to the Beaton and Anson classification. A morphometric study of the distances in the subgluteal space was carried out to define the anatomical references to achieve a safe arthroscopic approach for piriformis syndrome [GT-SN=Distance from greater trochanter (GT) to SN emergence; GT-IT=Distance from GT to ischial tuberosity (IT); GT-IGA=distance from GT to inferior gluteal artery (IGA) emergence; IT-SN=distance from IT to SN emergence; IT-IGA=distance from IT to IGA]. The SN showed the most frequent anatomical pattern with an undivided nerve coming out of the pelvis below the piriformis muscle (Beaton type A) in 16 specimens (80 %). The common peroneal nerve emergence in the subgluteal space through the piriformis muscle (PM) with the tibial nerve being located at the lower margin of the piriformis muscle (Beaton type B) was observed in 4 specimens (20 %). The morphometric measurements of the surgical area of study were: GT-SN=7.23 cm (±8.3); GT-IT=8.56 cm (±0.1); GT-IGA=8.46 cm (±0.97); IT-SN=5.28 cm (±0.73), IT- IGA=5.47 cm (±0.74). When planning surgery for the deep gluteal syndrome in adult patients, the fact that the emergence of the SN in the subgluteal space is approximately 7 cm from the greater trochanter and 5 cm from the ischial tuberosity must be considered.

RESUMEN: El objetivo del estudio fue determinar referentes morfométricos y variantes anatómicas relevantes en el abordaje artroscópico del espació subglúteo. Se disecaron veinte regiones glúteas procedentes de cadáver. Las variaciones anatómicas del nervio ciático (SN) se determinaron de acuerdo con la clasificación de Beaton y Anson. Se llevó a cabo un estudio morfométrico de distancias en el espacio subglúteo, con objeto de determinar referencias que permitan un abordaje artroscópico seguro del sindrome piriforme [GT-SN= distancia trocánter mayor (GT) a la emergencia del nervio ciático (SN); GT-IT= distancia GT a la tuberosidad isquiática (IT); GT-IGA= distancia GT a la emergen- cia de la arteria glútea inferior (IGA); IT-SN= distancia IT a la emergencia del SN; IT-IGA= distancia IT a la IGA]. El patrón más frecuente del SN fue su emergencia no dividida por el margen inferior del músculo piriforme (tipo A Beaton) en 16 especímenes (80 %). La salida del nervio fibular común a través del músculo piriforme (PM) con el nervio tibial localizado en el margen inferior del PM (tipo B Beaton) se observó en 4 especímenes (20 %). Las medidas en el área quirúrgica de estudio fueron: GT-SN= 7,23 cm ± 8,3; GT-IT= 8,56 cm ± 0,1; GT-IGA= 8,46 cm ± 0,97; IT-SN= 5,28 cm ± 0,73 IT-IGA= 5,47 cm ± 0,74. En la cirugía del síndrome glúteo profundo en adultos, debe considerarse que la sa- lida del SN hacia el espacio subglúteo tiene lugar aproximadamente a 7 cm del GT y a 5 cm de la IT.

Neuromuscular variations in the gluteal region - Embryological basis and clinical significance.

ABSTRACT: Piriformis, is a key muscle in the gluteal region. Under its lower border sciatic nerve and inferior gluteal nerves exit. During routine educational dissection of the lower limb, bilateral gluteal regions in fifteen cadavers (30 gluteal regions) focusing on the variations of inferior gluteal nerve and sciatic nerve with respect to piriformis muscle were observed in the department of anatomy, All India Institute of Medical Sciences, New Delhi, India. In one of the left sided specimens, inferior gluteal nerve had an abnormal course, piercing superior belly of piriformis muscle instead of emerging through the lower border of it along with variation of the sciatic nerve. The common peroneal component of the sciatic nerve was coming out between the two anomalous tendinous slips of the piriformis muscle, whereas the tibial component, emerged along lower border of the piriformis muscle bilaterally in the same cadaver. In the remaining cadavers, there were no variations of the inferior gluteal nerve with respect to the piriformis muscle. But in another cadaver, there was a similar variation of the sciatic nerve bilaterally. Inferior gluteal and sciatic nerves, when compressed by muscle belly or tendinous slips of the piriformis muscle, may cause lurching gait and sciatica respectively. Knowledge of the different variations of these peripheral nerves with respect to the piriformis muscle is important to clinicians and surgeons for the accurate diagnosis and intervention.

The infragluteal fold: An appraisal by MRI combined with an anatomic study.

PURPOSE: The gluteal region is a key element of beauty balance and sexual appearance. However, there is no clear anatomical description of the infragluteal fold, nor any classification exists allowing standardizing treatment of this area in case of jeopardisation. The purpose of this study was to perform an anatomical description of the infragluteal fold (IGF) matching radiological and anatomical findings in describing specifically raise of the fibrous component at the bone level. METHODS: Six volunteers (three males and three females) underwent an MRI scan (Siemens Aera® 1.5 T) of the pelvic region. T1 Vibe Morpho T2, Sag Space 3D, and Millimetric slices were performed in order to obtain a more detailed selection of the gluteal landmark. Trabecular connective tissue of the region was analyzed using Horos® ROI (region of interest) segmentation function. Four fresh cadavers (two males, two females, accounting for 8 hemipelvis) were dissected in order to compare the radiological findings. RESULTS: The infragluteal fold is a connectival fibrous band extending from the ramus of the ischium (but not involving the ischial tuberosity, for a length of 21 mm ± 2 and 21 mm ± 3), the apex of the sacrum (for a length of 13 ± 2 and 11 mm ± 2), and the coccyx (for a length of 19 mm ± 2 and 20 mm ± 2, all measures referring to volunteers and cadavers, respectively) reaching superficially the dermis of the medial one-third of the cutaneous fold. No significant difference was found between volunteer and cadaver group in MRI measurement of bony origins, or between MRI and cadaveric dissection measurements. CONCLUSION: Knowledge of this structure will define novel surgical techniques in infragluteal fold restoration.

A rare third head of the biceps femoris in the posterior thigh.

The occurrence of a third head of the biceps femoris is very rare. We encountered the case of a 90-year-old Japanese male cadaver with a third head of the biceps femoris in the posterior aspect of the thigh during dissection at Aichi Medical University in 2016. It originated from the proximal part of the femur and fused with the muscle belly between the long and short heads of the biceps femoris. Additionally, three muscle tendons were connected to the gluteus maximus. To the best of our knowledge, this is the first report on the third head of the biceps femoris demonstrating two origins, i.e., the proximal part of the femur and the insertion tendon of the gluteus maximus. Moreover, the third head, as well as the short head, of the biceps femoris was innervated by the muscular branch of the common peroneal nerve. Based on the origin and innervation, it can be believed that the third head of the biceps femoris is analogous to its short head and is related to the tenuissimus, a phylogenetic remnant. Therefore, we concluded that this third head is an intermediate muscle type of the tenuissimus and short head of the biceps femoris.

Poly-L-Lactic Acid for Gluteal Augmentation found to be Safe and Effective in Retrospective Clinical Review of 60 Patients.

BACKGROUND: Poly-L-lactic acid (PLLA) is a well-established biostimulator that induces neocollagenesis, allowing for volume loss correction. Although PLLA is FDA approved to treat mid-to-lower facial wrinkling, it has grown increasingly popular as a nonsurgical, minimally invasive procedure for soft-tissue volume augmentation of other extremities. However, research detailing PLLA buttock injections is still lacking. OBJECTIVE: The purpose of this study is to determine the safety and efficacy of PLLA for buttock augmentation. MATERIALS AND METHODS: A clinical retrospective review of 60 patients (ages 23-54 years) were followed for 2 years by 2 investigators. Patients underwent 1 to 3 treatments, spaced 4 to 6 weeks apart, and received 2 to 12 vials per session (based on the patient budget). Pretreatment and post-treatment photographs were assessed by the primary and secondary investigator in blinded and double-blinded surveys, respectively. The Global Aesthetic Improvement Scale was used to quantify improvements in volume, skin texture, and cellulite dimpling. RESULTS: Poly-L-lactic acid allows for visible volume amplification, improved skin texture, and softened cellulite dimpling in the buttocks when at least 20 vials are used. CONCLUSION: Poly-L-lactic acid is safe and effective for overall aesthetic enhancement of the buttocks if used in adequate quantity (minimum 20 vials) for all women, independent of age or the number of sessions.

Male Aesthetics for the Gluteal Area: Anatomy and Algorithm for Surgical Approach for Dynamic Definition Body Contouring.

BACKGROUND: Gluteal prominence is a unique characteristic that is widely acknowledged in female contouring but ignored in the male population. This study focuses on male gluteal aesthetics based on a muscular anatomical approach. METHODS: A retrospective review of gluteal contouring in men from January of 2012 to September of 2019 was conducted. Male body sculpting surgery in the gluteal area was performed in most cases. Patients were included according to preoperative assessment and the American Heart Association risk analysis. The gluteal area was divided into four main anatomical contouring zones and classified according to the procedure type. The follow-up period of 3 months to 6 years was included with photographs and medical assessment data. A nonstandardized satisfaction survey was performed postoperatively. RESULTS: The analysis included data from 374 consecutive gluteal dynamic definition liposculptures performed in men (mean age, 38.2 years; range, 20 to 66 years). Patients were treated according to the authors' new classification of deformities. Fat extraction, liposhifting, and fat grafting were performed on a regular basis to enhance and define the gluteal area. A satisfaction index of 92.5 percent was reported. Minor complications were reported: seroma, 0.2 percent; prolonged bruising, 1.3 percent; and swelling, 1.8 percent. No necrosis, burns, or infections were reported. CONCLUSIONS: Men have been increasingly requesting improvement and definition of the buttocks, and our novel algorithm allows for a reliable method in this regard. The high satisfaction index supports the natural and athletic results accomplished with our new approach.

Recommendation of the best site based on the distribution pattern of extramuscular and intramusular nerves for gluteal muscle injection / Recomendación del mejor sitio para la inyección del músculo glúteo basado en el patrón de distribución de los nervios extramusculares e intramusculares

To reveal the extra- and intramuscular nerve distribution patterns of the gluteus maximus, medius, and minimus, and to provide guidance for gluteal muscle injection in order to avoid nerve injury. Ten adult and 10 child cadavers were used. The superior and inferior gluteal nerves innervating the gluteus maximus, medius, and minimus were dissected, exposed, and sutured in-situ on the muscle. The three gluteal muscles were removed, and the distribution patterns of the intramuscular nerves were revealed by modified Sihler's nerve staining. The nerve distribution pattern was returned to the corresponding position in the body, and the patterns in the four quadrants of the buttock were analyzed. There were 3-12 extramuscular nerve branches of the gluteus maximus, medius, and minimus. After entering the muscle, these nerve branches arborized and anastomosed to form an arc-shaped, nerve-dense zone. The nerve distribution was most dense in the inferomedial region of the superolateral quadrant and the inferolateral region of the superomedial quadrant of the buttocks. The nerve distribution was relatively dense in the inferolateral region of the superolateral quadrant, and the medial region of the inferomedial quadrant. An arc-shaped, nerve-sparse zone in the superolateral and superomedial quadrants near the lower iliac crest accounted for about two-fifths of the two quadrants' limits. The arc-shaped, nerve-sparse zone in the superolateral quadrant is the preferred injection site, and the superomedial quadrant near the lower iliac crest is also recommended as a gluteal intramuscular injection region, free from nerve injury.

El objetivo de este trabajo fue revelar los patrones de distribución nerviosa extramusculat e intramuscular de los músculos glúteo máximo, medio y mínimo y proporcionar orientación para la inyección en la región glútea con el propósito de evitar lesiones nerviosas. Se utilizaron diez cadáveres adultos y diez niños. Los nervios glúteos superior e inferior que inervan a los músculos glúteo máximo, medio y mínimo fueron disecados, expuestos y suturados in situ en el músculo. Se extirparon los tres músculos glúteos y se revelaron los patrones de distribución de los nervios intramusculares mediante la tinción nerviosa de Sihler modificada. El patrón de distribución nerviosa se devolvió a la posición correspondiente en el cuerpo y se analizaron los patrones en los cuatro cuadrantes de la región glútea. Se encontraron 3 a 12 ramos nerviosos extramusculares de los músculos glúteo máximo, medio y mínimo. Después de ingresar al músculo, estas ramas nerviosas se arborizaron y anastomizaron para formar una zona densamente nerviosa en forma de arco. La distribución nerviosa fue de mayor densidad en la región inferomedial del cuadrante superolateral y en la región inferolateral del cuadrante superomedial de la región glútea. La distribución nerviosa era relativamente densa en la región inferolateral del cuadrante superolateral y en la región medial del cuadrante inferomedial. Una zona en forma de arco en los cuadrantes superolateral y superomedial y con escasa inervación, cerca de la cresta ilíaca representaba una parte de los límites de los dos cuadrantes. La zona de poca inervación en forma de arco en el cuadrante superolateral es el sitio de inyección preferido, y el cuadrante superomedial próximo a la cresta ilíaca también se recomienda como una región de inyección intramuscular glútea, libre de lesión nerviosa.

Core muscles thickness is not associated with knee frontal plane projection angle during single-leg squat in healthy people.

BACKGROUND: Core muscles play an important role in lower limb stability and alignment, with their weakness being associated with poor alignment and, consequently, with injuries. Despite muscle structure being critical to muscle strength production, we did not find studies associating the morphology of the core muscles and lower limb alignment during functional tasks. RESEARCH QUESTION: Is there association between thickness of core muscles (external oblique - EO, internal oblique - IO, transversus abdominis - TrA and gluteus medius - GMed) and lower limb alignment during the single-leg squat in healthy subjects? METHODS: Forty-six healthy participants (27 male and 19 female) performed the following evaluations: (i) measurements of muscle thickness of the EO, IO, TrA and GMed using ultrasound and (ii) measurements of lower limb alignment using the knee frontal plane projection angle (FPPA) during the single-leg squat. A Spearman rank correlation coefficient (rs) was performed between the thickness of selected core muscles (OE, OI, TrA and GMed) and the knee FPPA. In addition, a partial correlation (r) was performed, using sex, physical activity level and body mass index as control variables. RESULTS: We did not observe significant correlations between the knee FPPA and the thickness of the EO (rs = 0.194; p = 0.197), IO (rs = 0.182; p = 0.225), TrA (rs = 0.073; p = 0.627) and GMed (rs = -0.092; p = 0.542). When controlling for sex, physical activity level and body mass index, similar results were observed [EO (r = 0.157; p = 0.316), IO (r = 0.261; p = 0.092), TrA (r = 0.030; p = 0.850) and GMed (r = -0.144; p = 0.356)] SIGNIFICANCE: Our results demonstrated that core muscles' thickness is not associated with lower limb alignment during the single-leg squat in healthy people.

Seated buttocks anatomy and its impact on biomechanical risk.

AIM: The objective of this study was to describe the amount, types, and shapes of tissue present in the buttocks during sitting (i.e., seated buttocks soft tissue anatomy), and the impact of seated buttocks soft tissue anatomy on biomechanical risk. MATERIALS AND METHODS: The buttocks of 35 people, including 29 full-time wheelchair users with and without a history of pelvic pressure ulcers were scanned sitting upright on 3" of flat HR45 foam in a FONAR Upright MRI. Multi-planar scans were analyzed to calculate bulk tissue thickness, tissue composition, gluteus maximus coverage at the ischium, the contour of the skin, and pelvic tilt. RESULTS: Bulk tissue thickness varied from 5.6 to 32.1 mm, was composed mostly of adipose tissue, and was greatest in the able-bodied cohort. Skin contours varied significantly across status group, with wheelchair users with a history of pressure ulcers having tissue with a peaked contour with a radius of curvature of 65.9 mm that wrapped more closely to the ischium (thickness at the apex = 8.2 mm) as compared to wheelchair users with no pressure ulcer history (radius of curvature = 91.5 mm and apex thickness = 14.5 mm). Finally, the majority of participants presented with little to no gluteus coverage over their ischial tuberosity, regardless of status group. CONCLUSIONS: This study provides quantitative evidence that Biomechanical Risk, or the intrinsic characteristic of an individual's soft tissues to deform in response to extrinsic applied forces, is greater in individuals at greater risk for pressure ulcers.

Reporte de caso: origen del músculo piriforme a través de dos cabezas en forma de bíceps, propicia división del nervio isquiático en nervio fibular común y nervio tibial / Case report: origin of the piriformis muscle through two heads in the form of biceps, favorable division of the sciatic nerve in the common fibular nerve and tibial nerve

El músculo piriforme es un músculo pelvitrocantérico que recibe su nombre debido a su forma de pera, cuyo origen es de varios fascículos que se encuentran entre los forámenes anteriores del sacro, correspondiente a las segunda, tercera y cuarta vértebra. Estos fascículos se funden constituyendo un músculo aplanado, que se inserta en el trocánter mayor del fémur. Presenta una relación bien conocida con el nervio isquiático, el cual comúnmente emerge hacia la región glútea por el margen inferior de este músculo, sin embargo a través del tiempo, autores han descrito variaciones del paso de este nervio que podrían asociarse a alguna patología de compresión del nervio isquiático. En una disección rutinaria de dos individuos formolizados, uno femenino y otro masculino de la región glútea, encontramos que el músculo piriforme se originaba a través de dos cabezas, cada una con su propia fascia que se unían en un vientre común, en forma de bíceps y a través de un tendón cilíndrico se insertaban en la parte medial del trocánter mayor del fémur. El nervio isquiático se encontraba dividido, el nervio fibular común emergía a la región glútea a través de las cabezas, en tanto el nervio tibial por el margen inferior del músculo piriforme. Es importante comunicar las variaciones anatómicas para complementar el conocimiento de las mismas, las que pueden explicar ciertos trastornos físicos y dolorosos como el denominado síndrome del músculo piriforme.

The piriform muscle is a pelvitrochanteric muscle that gets its name due to its pear shape, whose origin are several fascicles located between the anterior foramina of the sacrum, corresponding to the second, third and fourth vertebrae. These fascicles are fused forming a flattened muscle, which is inserted into the greater trochanter of the femur. It has a well-known relationship with the sciatic nerve, which commonly emerges towards the gluteal region through the lower margin of this muscle, however over time, authors have described variations in the course of this nerve that could be associated with some compression pathology of the sciatic nerve. In a routine dissection of two formalized individuals, one female and one male, we found that the piriformis muscle originated through two heads, each with its own fascia that joined in a bicep-shaped common belly. Through a cylindrical tendon it is inserted into the medial part of the greater trochanter of the femur. The sciatic nerve was divided, the common fibular nerve emerged to the gluteal region through the heads, while in the tibial nerve divided through the inferior margin of the piriformis muscle. It is important to report on the anatomical variations to complement knowledge of these variations, which may explain certain physical and painful disorders such as the socalled piriformis muscle syndrome.

An exploration of the differences in hip strength, gluteus medius activity, and trunk, pelvis, and lower-limb biomechanics during different functional tasks.

The purpose of the study was to explore differences in the coronal biomechanics of the trunk, pelvis, hip, and knee joints, and gluteus medius muscle activity (GMed) during walking and step down from two riser heights. Joint kinematics and kinetics from 20 healthy participants were recorded using a 10-camera Qualisys system and force plates, and GMed EMG was recorded using a Delsys Trigno system. Hip abductor strength was measured using a hand-held dynamometer. Pelvic obliquity and lateral trunk bending excursions were significantly higher in walking than in step-down tasks. Significantly greater knee adduction moments were seen during both step-down tasks compared to level walking with significantly greater GMed activity. However, a significant interaction between side and task was seen for hip adduction moment, with step-down tasks showing lower hip moments than during walking, with greater peak hip moments being more apparent in the dominant limb. This suggests the GMed has a greater stabilizing role during the step-down tasks, although walking required a greater mechanical demand. Health professionals should expect to find less excursion of lateral trunk bending in step-down tasks compared to level walking and consider that GMed has different roles in these two tasks.

Influence of Age, Sex, and Body Mass Index on the Thickness of the Gluteal Subcutaneous Fat: Implications for Safe Buttock Augmentation Procedures.

BACKGROUND: The deep intramuscular approach during buttock augmentation with fat grafting has been associated with a significantly increased risk for pulmonary fat embolism. This study was designed to provide guidance for injection into the subcutaneous fat. METHODS: The authors investigated 150 Caucasian individuals with an equal distribution of men and women (n = 75 each) and a balanced distribution of age (n = 30 per decade: 20 to 29, 30 to 39, 40 to 49, 50 to 59, and 60 to 69 years) and body mass index (n = 50 per group: ≤24.9 kg/m, between 25.0 and 29.9kg/m, and ≥30 kg/m). Ultrasound-based measurements were conducted of the thickness of the total, superficial, and deep gluteal fatty layers. RESULTS: An increase in body mass index of 1.0 kg/m corresponded to an increase of 3 mm of the total gluteal subcutaneous fat of men and a 4-mm increase of the total gluteal subcutaneous fat in women. With increasing age, the thickness of the deep fatty layer increased, whereas with increasing body mass index the thickness of the superficial layer primarily increased. Formulas were generated to estimate the total thickness of the gluteal subcutaneous fatty layer for men [total thickness (in millimeters) = -33.56 + (age × 0.078) + (body mass index × 3.042)] and women [total thickness (in millimeters) = -56.997 + (age × 0.1) + (body mass index × 3.86)]. CONCLUSIONS: Knowing the total thickness of the gluteal subcutaneous fat (i.e., the safe space) allows surgeons to estimate their operating range for cannula motion even if no ultrasound machine is available during buttock augmentation with fat grafting. This can increase safety, potentially reducing the number of adverse events.

Structural Gender Dimorphism and the Biomechanics of the Gluteal Subcutaneous Tissue: Implications for the Pathophysiology of Cellulite.

BACKGROUND: This study was performed to investigate gender differences in gluteal subcutaneous architecture and biomechanics to better understand the pathophysiology underlying the mattress-like appearance of cellulite. METHODS: Ten male and 10 female body donors [mean age, 76 ± 16.47 years (range, 36 to 92 years); mean body mass index, 25.27 ± 6.24 kg/m (range, 16.69 to 40.76 kg/m)] were used to generate full-thickness longitudinal and transverse gluteal slices. In the superficial and deep fatty layers, fat lobule number, height, and width were investigated. The force needed to cause septal breakage between the dermis and superficial fascia was measured using biomechanical testing. RESULTS: Increased age was significantly related to decreased dermal thickness, independent of sex (OR, 0.997, 95 percent CI, 0.996 to 0.998; p < 0.0001). The mean number of subdermal fat lobules was significantly higher in male body donors (10.05 ± 2.3) than in female body donors (7.51 ± 2.7; p = 0.003), indicating more septal connections between the superficial fascia and dermis in men. Female sex and increased body mass index were associated with increased height of superficial fat lobules. The force needed to cause septal breakage in male body donors (38.46 ± 26.3 N) was significantly greater than in female body donors (23.26 ± 10.2 N; p = 0.021). CONCLUSIONS: The interplay of dermal support, septal morphology, and underlying fat architecture contributes to the biomechanical properties of the subdermal junction. This is influenced by sex, age, and body mass index. Cellulite can be understood as an imbalance between containment and extrusion forces at the subdermal junction; aged women with high body mass index have the greatest risk of developing (or worsening of) cellulite.