Ultrasonography of the normal donkey tarsus (equus asinus).

Tarsal joint illness is a frequent source of hind limb lameness due to the complex anatomy of the region and the presence of numerous bony and soft tissue structures. Proper lameness diagnosis aims to discover the structure provoking lameness. Ultrasonography documents valuable information of soft tissues and characterizes soft tissue injuries that have heretofore been difficult to obtain either noninvasively or via radiography. The objectives of the current study were to develop and describe a standardized ultrasonographic protocol for investigation of the tarsal region in donkeys. The donkey tarsal anatomy was investigated in 5 cadavers and the tarsi of 11 healthy lameness free adult donkeys were echographically investigated. The dorsal, plantar, lateral and medial aspects of the tarsal region were substantially evaluated at four anatomical landmarks in both the longitudinal and horizontal planes using a multi-frequency 5-12 MHz linear transducer. Sonoanatomy of the extensor and flexor tarsal tendons, collateral and plantar ligaments, and synovial pouches was delineated and described. Systematic echography of the tarsal region allowed accurate localization and thorough exploration of various soft tissues of clinical interest in the donkey tarsus. Sonograms provided in this study should serve as a reference database for tarsal ultrasonography in clinical circumstances.

Compositional, Structural, and Biomechanical Properties of Three Different Soft Tissue-Hard Tissue Insertions: A Comparative Review.

Connective tissue attaches to bone across an insertion with spatial gradients in components, microstructure, and biomechanics. Due to regional stress concentrations between two mechanically dissimilar materials, the insertion is vulnerable to mechanical damage during joint movements and difficult to repair completely, which remains a significant clinical challenge. Despite interface stress concentrations, the native insertion physiologically functions as the effective load-transfer device between soft tissue and bone. This review summarizes tendon, ligament, and meniscus insertions cross-sectionally, which is novel in this field. Herein, the similarities and differences between the three kinds of insertions in terms of components, microstructure, and biomechanics are compared in great detail. This review begins with describing the basic components existing in the four zones (original soft tissue, uncalcified fibrocartilage, calcified fibrocartilage, and bone) of each kind of insertion, respectively. It then discusses the microstructure constructed from collagen, glycosaminoglycans (GAGs), minerals and others, which provides key support for the biomechanical properties and affects its physiological functions. Finally, the review continues by describing variations in mechanical properties at the millimeter, micrometer, and nanometer scale, which minimize stress concentrations and control stretch at the insertion. In summary, investigating the contrasts between the three has enlightening significance for future directions of repair strategies of insertion diseases and for bioinspired approaches to effective soft-hard interfaces and other tough and robust materials in medicine and engineering.

The effect of hallux valgus on the anatomy of the nerves around the first metatarsal bone.

OBJECTIVE: To identify the variations in the location of the nerves that may be at risk in hallux valgus (HV) surgery, and to reveal whether these nerves are affected by the anatomical changes associated with HV. METHOD: In the formalin fixed, 46 lower extremities (19 female, 27 male) (9 normal, 14 mild HV, 21 moderate/severe HV), extensor hallucis longus tendon (EHL), deep plantar artery, medial dorsal cutaneous (MDCN), deep fibular (DFN), common plantar digital (CPDN) and proper plantar digital (PPDN) nerves were examined. The branches of MDCN extending to the medial side of foot were recorded in three segments. The positional topography of nerves according to EHL were analyzed on 360° circle and clock models. RESULTS: Sex-related differences observed in some parameters in direct measurements were not found in the clock model comparisons. In advanced HV angles (> 20°), DFN was closer to EHL in the distal part of the metatarsal bone, while there was no difference in the proximal. The intersection of the medial branch of the MDCN with the EHL was more proximal in HV cases than in normal feet. The location of the nerves in the clock pattern did not change in HV. Of the nerve branches reaching the medial side of the foot, 65.2% were in Part I, 71.7% in Part II, and 4.3% in Part III. CONCLUSION: Sex differences in the distance of the nerves to the EHL disappeared when the size effect of the cross-section of the first metatarsal bone region was eliminated with the clock model. Only in advanced HVA (>20°) (not in mild HV), the DFN being closer to the EHL distally and the intersection of the medial branch of the MDCN with the EHL in HV being more proximal than in normal can be interpreted as specific reflections of HV progress. The variations we revealed in the number of branches reaching the inside of the foot may explain the diversity of neuromas or nerve injuries associated with HV surgery.

Morphological differences between the dorsal and palmar septa of the first extensor compartment in relation to the brachioradialis and pronator quadratus.

BACKGROUND: The first extensor compartment of the wrist is known as a frequent site of stenosing tenosynovitis, referred to as de Quervain's disease. De Quervain's disease occurs more frequently in the dorsal part of the first extensor compartment than in the palmar part; however, the anatomical reason why the dorsal part is worse remains poorly elucidated. This study clarified the morphological differences between the dorsal and palmar parts by examining their relationship with the surrounding structures. METHODS: In this study, a total of 35 wrists from 23 Japanese cadavers were used. Twenty-five wrists were randomly assigned for macroscopic analysis, and the remaining 10 wrists were used for histological analysis. RESULTS: The palmar septum of the first extensor compartment was connected to the brachioradialis tendon and superficial head of the pronator quadratus and was histologically stout compared to the dorsal septum. Despite several anatomical variations, such as the septum between the abductor pollicis longus/extensor pollicis brevis and the multiple tendons of these muscles, the aforementioned characteristics of the fibrous sheath in the first extensor compartment were identical in all specimens. CONCLUSION: In contrast to the fragile structure of the dorsal septum, the stout structure of the palmar septum could be related to the low occurrence of symptoms of de Quervain's disease. The present results could play a role in revealing the pathogeny and establish the precise treatment for de Quervain's disease and provide an anatomical basis for kinesiological/biomechanical studies.

The tendon of the fibularis brevis muscle - Systematic overview and new classification system.

The fibularis brevis muscle belongs to the lateral compartment of the leg. It originates from the lower two-thirds of the lateral surface of the fibula bone and it also is attached to the anterior intermuscular septum. Its insertion is normally located on the tuberosity at the base of the fifth metatarsal bone, on its lateral side. However, distal attachment of this muscle is morphologically variable. Different variations have been identified and some classification systems have been created for both adults and foetuses. Based on various literature references, we have created a new classification system and compared the frequency of each type. The main aim of this review is to present morphological variations of the fibularis brevis tendon with their clinical significance, especially in autografting in case of surgical treatment of fibularis brevis tendon rupture. The clinical aspect of this pathology and some medical cases will also be presented.

Editorial Commentary: When Managing Patellofemoral Instability, Mind Your P's and Q's: Medial Patellofemoral Ligament Versus Medial Quadriceps Tendon Femoral Ligament Versus Medial Patellofemoral Complex.

Our understanding of patellar instability and the medial patellofemoral complex (MPFC) has evolved over the past 15 years. Despite advancements and appreciation of the anatomy and biomechanics of the MPFC, the best surgical treatment for recurrent patellar instability has yet to be determined. The goals of medial patellofemoral ligament (MPFL), medial quadriceps tendon femoral ligament (MQTFL), or MPFC reconstructions (with grafts from both the patella and quad to the femur) are to return patients back to activity and avoid complications such as recurrent instability, overconstraint, secondary arthrosis, and potential patellar fracture from surgical drill holes. Other considerations when managing recurrent instability include patella alta, hypermobility, and whether an osteotomy procedure is indicated. Although we always need to make good choices and mind our P's and Q's, the big question remains: Is MPFL, MQTFL, or MPFC the best choice for our patients?

A very rare case report: accessory head of the sartorius muscle.

The sartorius muscle belongs to the anterior compartment of the thigh. Morphological variations of this muscle are very rare, few cases being described in the literature. An 88-year-old female cadaver was dissected routinely for research and teaching purposes. However, an interesting variation was found during anatomical dissection. The proximal part of the sartorius muscle had the normal course, but the distal part bifurcated into two muscle bellies. The additional head passed medially to the standard head; thereafter, there was a muscular connection between them. This connection then passed into the tendinous distal attachment. It created a pes anserinus superficialis, which was located superficially to the distal attachments of the semitendinosus and gracilis muscles. This superficial layer was very wide and attached to the medial part of the tibial tuberosity and to the crural fascia. Importantly, two cutaneous branches of the saphenous nerve passed between the two heads. The two heads were innervated by separate muscular branches of the femoral nerve. Such morphological variability could be clinically important.

Very rare arrangement of the pes anserinus: potential clinical significance.

The pes anserinus superficialis is composed of the semitendinosus, gracilis and sartorius tendons. Normally, they all insert to the medial side of the tibial tuberosity, and the first two are attached superiorly and medially to the tendon of the sartorius muscle. During anatomical dissection, a new pattern of arrangement of tendons creating the pes anserinus was found. The pes anserinus comprised three tendons; the semitendinosus tendon was located superiorly to the gracilis tendon, and they both had distal attachments on the medial side of the tibial tuberosity. This seemed like the normal type, but the tendon of the sartorius muscle created an additional superficial layer, its proximal part lying just below the gracilis tendon and covering the semitendinosus tendon and a small part of the gracilis tendon. After crossing the semitendinosus tendon it is attached to the crural fascia significantly below the tibial tuberosity. Good knowledge of the morphological variations of the pes anserinus superficialis is necessary during surgical procedures in the knee region, especially anterior ligament reconstruction.

Two-headed extensor digitorum longus with coexisting additional tendinous slips.

The extensor digitorum longus is a source of much anatomic variation, mostly related with extra tendinous slips or their unusual insertions. This report describes a new configuration of the extensor digitorum longus with two heads and two main tendons which bifurcate into five slips. These slips undergo further divisions and establish connections between the each other. Our findings provide a greater insight into the intricacies of human morphology.

The anatomy of the extensor tendon insertion in the arthritic distal interphalangeal joint: a cadaveric study.

Dissection of arthritic cadaveric digits revealed an expanded extensor tendon footprint involving the dorsal osteophyte on the terminal phalanx. Osteophyte attachments can be safely released up to the width of a number 15 scalpel blade without risking the integrity of the extensor tendon.

The direct muscular origin of the semitendinosus: a pitfall in categorization of proximal hamstring tendon tears.

The ischial origin of the hamstring musculature is complex. While the conjoint tendon and semimembranosus are commonly discussed and understood by radiologists, there is a lesser-known origin of the semitendinosus along the inferior and medial surface of the ischium in the form of a broad direct muscular connection. This secondary origin is infrequently described in the radiology literature and is a potential pitfall during grading of semitendinosus injuries if the interpreting physician is unaware of its presence. In a proximal hamstring tendon tear, the direct muscular origin of the semitendinosus can be spared, torn along with the conjoint tendon, or remain intact and contribute to a vertical shearing injury of the semitendinosus myotendinous junction. Detailed knowledge of this anatomy and its imaging appearance in the setting of injury enables the reader to correctly diagnose these unique hamstring injuries.

Human navicular bone: a morphometric and morphological evaluation.

BACKGROUND: The composition of navicular joint complex is crucial to perform surgical interventions for multiple pathological foot aetiologies. The data on human navicular bone and its facets from Indian population remain scarce in literature. AIMS AND OBJECTIVES: To evaluate the morphometry and morphology of navicular bone. METHODOLOGY: A total of 77 (right: 40; left: 37) dried human navicular bones were used. The collected data were entered and analysed in SPSS software. RESULTS: The anteroposterior diameter of navicular bone on right side was 15.19 mm (13.92, 16.77) and on left side was 15.87 mm (13.83, 17.27). The transverse diameter on right and left sides were 34.21 mm (31.74, 36.6) and 33.59 mm (30.23, 35.43), respectively. The vertical diameter measured on the right was 22.31 mm (21.19, 23.94) and on left 22.53 mm (20.8, 24.24). Morphometric evaluation showed no significant difference between right and left navicular bones. The commonest shape for posterior facet was quadrilateral, on the right (62.5%) and left (40.5%). The most common shape of anterior facet for medial cuneiform is quadrilateral, on the right (85%) and left (89.1%). For intermediate cuneiform, triangular facet was common on the right side (72.5%) and on the left (59.5%). The lateral cuneiform facet was bean shaped on right side (72.5%) and quadrilateral on the left side (32.5%). There was a significant difference in shape distribution between right and left (P < 0.05). The median length of the groove for tibialis posterior tendon was 18.01 mm and 16.19 mm on right and left side, respectively. Cuboid facet was observed in 28 (70%) and 26 (65.9%) navicular bones on right and left sides, respectively. CONCLUSION: There is no significant difference between right and left bones with regards to morphometric parameters. Morphological evaluation revealed significant difference in the distribution of shape between right and left bones.

The accessory heads of the quadriceps femoris muscle may affect the layering of the quadriceps tendon and potential graft harvest lengths.

PURPOSE: The aim of the study was to assess the quadriceps femoris system for the presence of additional layers. METHODS: One hundred and twenty-eight lower limbs fixed in 10% formalin were examined. RESULTS: Five types of quadriceps tendon layering were found based on the accessory heads of the quadriceps muscle. Type I (55%)-represented by four heads and four layers, and it was something new because standard orthopaedic textbooks described quadriceps tendon as a structure composed of only three layers. Type II (27.4%)-the first four layers were the same as in Type 1, but the accessory tendon of the fifth head of the quadriceps femoris muscle had the deepest attachments. Type III (10.9%)-this type included 6 heads of quadriceps femoris. It consisted of five layers. Type IV (3.1%)-this type included 7 quadriceps femoris heads. This type consisted of only four layers. Type V (3.1%)-this type included 8 heads of the quadriceps femoris heads. This type consist of 5 layers. CONCLUSION: The findings of this study provide a detailed anatomy of the quadriceps tendon including the accessory tendons of the accessory heads of the quadriceps tendon. The accessory heads of the quadriceps femoris muscle contribute to the layering of the quadriceps tendon. The second conclusion of this study is the development of safe distances depending on the types. Not all types are perfect for harvesting-Type IV seems to be the safest type, in turn Type V the most dangerous.

A review on the use of porcine in tendon research.

PURPOSE OF REVIEW: Large animals have been increasingly employed in tendon research; the objective of this review was to summarize the employment of porcine in tendon research. RECENT FINDINGS: Literature before 2022-03-31 was searched using the following strategy: (pig[MeSH Terms]) AND (tendon[MeSH Terms]); (pig[MeSH Terms]) AND (tendon[title]); (tendon[MeSH Terms]) AND (porcine[title]); (tendon[title]) AND (porcine[title]); (tendon[MeSH Terms]) AND (pig[title]); (tendon[title]) AND (pig[title]); (tendon[MeSH Terms]) AND (swine[title]); (tendon[title]) AND (swine[title]). 296 studies were included in this review. There were wide application areas of porcine tendon, including tissue engineering tendons, training of surgical skills. Porcine tendon was used both in in vitro studies, such as anatomy, biomechanics, cytology, and material science as well as in in vivo studies. The research techniques of porcine tendon are relatively common. SUMMARY: In conclusion, pigs have been widely used as a good animal model of tendon research. However, the limitations of porcine tendon research (the lack of anatomical research and in vivo studies) should be given more attention in future studies.

Peroneus tertius revisited: The morphological variability of the bifurcated peroneus tertius insertion - An anatomical study.

BACKGROUND: The peroneus tertius muscle (PT) is one of the extensor muscles of the lower leg, often described as a variable separation from the extensor digitorum longus muscle (EDL). According to literature it has six different types of insertion, one of them (Olewnik Type IV) having two tendons inserting to the fifth metatarsal bone (FMTB). Morphometric data about this type of insertion is sparse, especially the relation between the two tendons, albeit the PT is suspected to contribute to stress fractures of the FMTB. Therefore, we examined this type of insertion to give detailed information on the tendons, the insertion points and the respective relations. METHODS: We examined 27 lower extremities of embalmed human bodies (12 paired, 15 single sided; 12 right and 15 left) with a distinguishable PT with two tendons inserting to the FMTB (Olewnik IV). The specimens were obtained of an undergrad dissection program, which in turn obtained them from a body donation program. After dissection of the PT and photo documentation in situ, resection and measurement of morphological properties of the tendons were performed with the PT attached to the fifth metatarsal bone. RESULTS: Results of the respective measurements yielded a wide range of variation, especially in the insertion point of the anterior tendon on the fifth metatarsal and the relation between the two tendons, but with no significant difference between sides or sex, except for the length of the posterior tendon between sex. The distance between the base of the FMTB and posterior tendon varies from 0 to 9 mm, with one outlier at 24 mm (mean = 3.9 ± 4.8 mm), the distance between the insertions from 0 to 15 mm (mean = 4.7 ± 4.7 mm), resulting in how far of the FMTB the anterior tendon reaches varying from 17 to 60 mm (mean = 39.6 ± 11.5 mm) or 22-98% (mean = 64 ± 19%). CONCLUSION: Our findings give a detailed overview of the morphological features the PTT can have, when attached with two tendons to the FMTB. Especially the varying relationship between those two insertions and varying point of the anterior insertion are of interest, as they might support its complex role in the occurrence of fractures of the fifth metatarsal by providing different amounts of torsional stress and its tendons can be used as tendon-grafts.

Morphological Classification of the Sagittal Tendon Plate in the Soleus Muscle in Japanese Cadavers / Clasificación Morfológica de la Lámina Tendinosa Sagital del Músculo Sóleo en Cadáveres Japoneses

SUMMARY: The human soleus muscle has attracted attention in the fields of sport science, rehabilitation medicine, etc. for improving exercise performance in training, preventing injuries, and rehabilitation. The sagittal tendon plate of the soleus muscle is particularly important in rehabilitation. Few studies, however, have evaluated the shape of the sagittal tendon plate in the human soleus muscle in detail and attempted to classify its variations based on its morphology. In this study, we conducted a detailed analysis of the morphology of the sagittal tendon plates in soleus muscle specimens from Japanese cadavers and constructed a morphology-based classification system and evaluated their frequencies of occurrence. First, the specimens were divided into those with a sagittal tendon plate that was visible on the anterior surface (pennate muscle group) and those without (non-pennate muscle group). Next, based on the "number" and "breadth" of the sagittal tendon plates, the pennate muscle group specimens were further classified into four classes: Class I (one tendon, thin), Class II (one tendon, slightly broad), Class III (one tendon, very broad), and Class IV (two tendons, thin). Subsequently, the specimens were further divided into three types based on the position where the sagittal tendon plate joined the Achilles tendon: median tendon type, lateral tendon type, and medial tendon type (a total 13 divisions). When 458 Japanese soleus muscle specimens were classified into these divisions, the occurrence frequencies of Class I-IV were 80.57 %, 4.59 %, 5.46 %, and 1.09 %, respectively. In Class I, the median tendon type was more frequent than the lateral and medial tendon types, accounting for 48.47 % overall. The classification types of the sagittal tendon plate and their respective occurrence frequencies shown in this study are expected to serve as fundamental data in implementing rehabilitation of soleus muscle.

El músculo sóleo humano ha atraído la atención de la ciencia del deporte, la medicina de rehabilitación, etc. para mejorar el rendimiento del ejercicio en el entrenamiento, prevenir las lesiones y rehabilitación. La lámina tendinosa sagital del músculo sóleo es particularmente importante en la rehabilitación. Sin embargo, pocos estudios han evaluado en detalle la forma de la placa lámina sagital en el músculo sóleo humano y han intentado clasificar sus variaciones en función de su morfología. Realizamos un análisis detallado de la morfología de las láminas de los tendones sagitales en muestras de músculo sóleo de cadáveres japoneses y construimos un sistema de clasificación basado en la morfología y, además, evaluamos su frecuencia de aparición. Los especímenes se dividieron en aquellos con una lámina de tendón sagital que era visible en la superficie anterior (grupo muscular pennado) y aquellos sin (grupo muscular no pennado). A continuación, según el "número" y el "ancho" de las láminas de los tendones sagitales, las muestras del grupo de músculos pennados se clasificaron en cuatro clases: Clase I (un tendón, delgado), Clase II (un tendón, ligeramente ancho), Clase III (un tendón, muy ancho) y Clase IV (dos tendones delgados). Posteriormente, las muestras se dividieron en tres tipos, según la posición donde la lámina del tendón sagital se unía al tendón calcáneo: tipo de tendón mediano, tipo de tendón lateral y tipo de tendón medial (un total de 13 divisiones). En estas divisiones se clasificaron 458 especímenes de músculo sóleo de indiviuos japoneses, las frecuencias de ocurrencia de Clase I-IV fueron 80,57 %, 4,59 %, 5,46 % y 1,09 %, respectivamente. En la Clase I, el tipo de tendón mediano era más frecuente que los tipos de tendón lateral y medial, representando el 48,47 % del total. Se espera que los tipos de clasificación de la lámina del tendón sagital y sus respectivas frecuencias de aparición, que se reportan en este estudio, sirvan como datos fundamentales para implementar la rehabilitación del músculo sóleo.

Cadaveric Analysis of Key Anatomic Structures of Athletic Pubalgia.

PURPOSE: This study proposes to establish in-depth inspection of the anatomic structures involved with the pathology of athletic pubalgia in a cadaver model. METHODS: Eight male fresh frozen cadavers were dissected in a layered fashion. The rectus abdominis (RA) and adductor longus (AL) tendon insertions were isolated to quantify the size of the anatomic footprint and distance from the surrounding anatomy. RESULTS: The RA insertional footprint was 1.65 cm (SD, 0.18) in width by 1.02 cm (SD, 0.26) in length, and the AL insertional footprint on the underside of the pubis was 1.95 cm (SD, 0.28) in length by 1.23 cm (SD, 0.33) in width. The ilioinguinal nerve was 2.49 cm (SD, 0.36) lateral to the center of the RA footprint and 2.01 cm (SD, 0.37) lateral to the center of the AL footprint. The spermatic cord and the genitofemoral nerve were just lateral to the ilioinguinal nerve and were 2.76 cm (SD, 0.44) and 2.66 cm (SD, 0.46) from the rectus and AL footprints, respectively. CONCLUSION: Surgeons should be cognizant of these anatomic relations during both initial dissection and tendon repair to optimize repair and avoid iatrogenic injury to critical structures in the anterior pelvis.

Internal Structural Connections in the Popliteus Tendon Complex with Posterior Cruciate Ligament and Clinical Implications / Conexiones Estructurales Internas en el Complejo Tendón Poplíteo con Ligamento Cruzado Posterior e Implicaciones Clínicas

SUMMARY: At present, the anatomical relationship the mid-portion of popliteus tendon complex (PTC) and the surrounding tissues is still unclear, especially its relationship to the posterior cruciate ligament (PCL). It affected the anatomical reconstruction of the posterolateral complex (PLC) injury. A total of 30 cases of the adult human knee joint fixed with formalin were used. Sagittal sections were made in 14 knee joints by the P45 plastination technique and dissection of 16 cases of knee joints. The P45 section revealed that the popliteus muscle fascia ran superiorly over the posterior edge of the tibial intercondylar eminence, and turned forward to be integrated into the PCL. Laterally, near the posterior edge of the lateral tibial plateau, the popliteus tendon penetrates through the articular capsule (AC), where two dense fibrous bundles were given off upwards by the popliteus tendon: one was the ventral fiber bundle, which ran superiorly over the posterior edge of the tibial plateau and then moved forwards to connect with the lateral meniscus; the dorsal fibers bundle ascended directly and participated in the AC. Meanwhile, the popliteus muscle dissection showed that at the posterior edge of the platform of the lateral condyle of the tibia, at the tendon-muscle transition, the PTC and AC were anchored to PCL.

En la actualidad, la relación anatómica entre la porción media del complejo tendinoso poplíteo (CTP) y los tejidos circundantes aún no está clara, especialmente su relación con el ligamento cruzado posterior (LCP). Esto afecta la reconstrucción anatómica de la lesión del complejo posterolateral (LCP). Se utilizaron un total de 30 casos de articulaciones de rodillas humanas de individuos adultos fijadas con formalina. Se realizaron cortes sagitales en 14 articulaciones de rodilla mediante la técnica de plastinación P45 y disección de 16 casos de articulaciones de rodilla. La sección P45 reveló que la fascia del músculo poplíteo discurría superiormente sobre el margen posterior de la eminencia intercondílea tibial y giraba hacia delante para integrarse en el LCP. Lateralmente, cerca del margen posterior de la platillo tibial lateral, el tendón poplíteo penetra a través de la cápsula articular (CA), donde el tendón poplíteo desprendió hacia arriba dos haces fibrosos densos: uno era el haz de fibras ventral, que corría superiormente sobre el margen posterior de la meseta tibial y luego se movió hacia adelante para conectar con el menisco lateral; el haz de fibras dorsales ascendía directamente y participaba en la CA. Por su parte, la disección del músculo poplíteo mostró que en el margen posterior del platillo del cóndilo lateral de la tibia, en la transición tendón-músculo, el CTP y el AC estaban anclados al LCP.

An overview of the osseous palmar sesamoid in Anura, with the particular case of some Rhinella species.

Background: Sesamoids are generally regarded as structures that are not part of the tetrapod body plan. The presence of a palmar sesamoid is assumed to serve as a distribution point for the forces of the flexor digitorum communis muscle to the flexor tendons of the digits, which are embedded in the flexor plate. It has been considered that the palmar sesamoid is present in most anuran groups, and it has been suggested that it acts by inhibiting the closing of the palm, preventing grasping. Typical arboreal anuran groups lack a palmar sesamoid and flexor plate, a pattern shared with other tetrapod groups, which can retain a reduced sesamoid and flexor plate. We focus on the anatomical structure of the Rhinella group, which includes species that present an osseous palmar sesamoid and climb bushes or trees to avoid depredation or escape dangerous situations, and can exhibit scansorial and arboreal behaviors. We also add data on the bony sesamoids of 170 anuran species to study the anatomy and evolution of the osseous palmar sesamoid within this amphibian group. Our objective is to bring an overview of the osseous palmar sesamoid in anurans, unveiling the relationship between this element of the manus, its phylogeny, and the anuran habitat use. Methods: Skeletal whole-mount specimens of Rhinella were cleared and double-dyed to describe the sesamoid anatomy and related tissues. We review and describe the palmar sesamoid of 170 anuran species from CT images downloaded from Morphosource.org, representing almost all Anuran families. We performed an standard ancestral state reconstruction by optimizing two selected characters (osseous palmar sesamoid presence, distal carpal palmar surface) along with the habitat use of the sampled taxa, using parsimony with Mesquite 3.7. Results: Our primary finding is that sesamoid optimization in the anuran phylogeny revealed that its presence is associated with certain clades and not as widespread as previously anticipated. Additionally, we will also be delving into other important outcomes of our study that are relevant to those working in the field of anuran sesamoids. The osseous palmar sesamoid is present in the clade Bufonidae-Dendrobatidae-Leptodactylidae-Brachicephalidae that we named as PS clade, and also in the archeobatrachian pelobatoid Leptobranchium, all strongly terrestrial and burrowing species, though with exceptions. The osseous palmar sesamoid is always present in Bufonidae, but varies in form and size, depending on the mode that they use their manus, such as in the Rhinella margaritifera which has a cylindrical one and also grasping abilities that involve closing the manus. The scattered presence of the bony palmar sesamoid among anuran clades raises the question whether this sesamoid can be present with a different tissular composition in other groups.

Imaging of Anatomical Variants of the Long Head Biceps Tendon.

Anatomical variants of the long head of biceps (LHB) tendon are widely discussed in the literature. As one of the few intra-articular tendons, magnetic resonance arthroscopy can quickly evaluate the proximal part of LHB morphology. It provides good assessment of both intra-articular and extra-articular portions of the tendons. In-depth knowledge about imaging of the anatomical LHB variants discussed in this article is useful preoperatively for orthopaedists and also helps avoid potential diagnostic misinterpretations.