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.

Morphology and ontogeny of carpus and tarsus in stereospondylomorph temnospondyls

Skeletal development is well known in temnospondyls, the most diverse group of Paleozoic and Mesozoic amphibians. However, the elements of carpus and tarsus (i.e., the mesopodium) were always the last bones to ossify relative to the other limb bones and with regard to the rest of the skeleton, and are preserved only in rare cases. Thus, in contrast to the other parts of the limb skeleton, little is known about the ontogeny and sequence of ossification of the temnospondyl carpus and tarsus. We intended to close this gap by studying the ontogenies of a number of Permo/Carboniferous stereospondylomorphs, the only temnospondyls with preserved growth series in which the successive ossification of carpals and tarsals can be traced. Studying the degree of mesopodial ossification within the same species show that it is not necessarily correlated with body size. This indicates that individual age rather than size determined the degree of mesopodial ossification in stereospondylomorphs and that the largest individuals are not necessarily the oldest ones. In the stereospondylomorph tarsus, the distal tarsals show preaxial development in accordance with most early tetrapods and salamanders. However, the more proximal mesopodials exhibit postaxial dominance, i.e., the preaxial column (tibiale, centrale 1) consistently started to ossify after the central column (centralia 2-4, intermedium) and the postaxial column (fibulare). Likewise, we observed preaxial development of the distal carpals in the stereospondylomorph carpus, as in most early tetrapods for which a statement can be made. However, in contrast to the tarsus, the more proximal carpals were formed by preaxial development, i.e., the preaxial column (radiale, centrale 1) ossified after the central column (centralia 2-4, intermedium) and before the postaxial column (ulnare). This pattern is unique among known early tetrapods and occurs only in certain extant salamanders. Furthermore, ossification proceeded from distal to proximal in the central column of the stereospondylomorph carpus, whereas the ossification advanced from proximal to distal in the central column of the tarsus. Despite these differences, a general ossification pattern that started from proximolateral (intermedium or centrale 4) to mediodistal (distal tarsal and carpal 1) roughly in a diagonal line is common to all stereospondylomorph mesopodials investigated. This pattern might basically reflect the alignment of stress within the mesopodium during locomotion. Our observations might point to a greater variability in the development of the mesopodium in stereospondylomorphs and probably other early tetrapods than in most extant tetrapods, possibly mirroring a similar variation as seen in the early phases of skeletogenesis in salamander carpus and tarsus.

[Injuries of the foot and ankle in winter sports]

Winter sports injuries of the foot and ankle are a relevant entity due to the high enthusiasm for alpine skiing and snowboarding. The condition of the footwear and rigidity of the binding have a significant influence on the pathobiomechanics of fracture development and have been shown to influence the frequency of knee and ankle injuries. Foot injuries are rare due to the sport-specific footwear with good padding and frequent hard shell casings.

Surgical Strategies for Eyelid Defect Reconstruction: A Review on Principles and Techniques

Reconstruction of eyelid defects, especially the posterior lamella, remains challenging because of its anatomical complexity, functional considerations, and aesthetic concerns. The goals of eyelid reconstruction include restoring eyelid structure and function and achieving an aesthetically acceptable appearance. An in-depth understanding of the complex eyelid anatomy and several reconstructive principles are mandatory to achieve these goals. Currently, there are multiple surgical treatment options for eyelid reconstruction, including different flaps, grafts, and combinations of them. This comprehensive review outlines the principles of reconstruction and discusses the indications, advantages, and disadvantages of currently available surgical techniques. We also propose our clinical thinking for solving specific clinical questions in eyelid reconstruction and offer perspectives on new potential methodologies in the future.

Distal leg structures of Zoraptera - did the loss of adhesive devices curb the chance of diversification?

The distal leg structures of Zoraptera are documented and discussed with respect to their functional morphology and evolutionary aspects. We investigated eight species using scanning electron microscopy. We analyzed material compositions of the tarsus in three representative species using confocal laser scanning microscopy. When possible, we included both sexes, wing morphs, and nymphs and compared the structures among them. The distal leg structure is unusually uniform across zorapterans regardless of the sex, morphs, and developmental stages. The observed features combine simplification with innovation. The former is likely partially correlated with cryptic microhabitats and miniaturization. Innovation includes a protibial cleaning organ. This is very likely an autapomorphy of Zoraptera. The tarsi are composed of two tarsomeres covered with setae. The pretarsus distally bears an unguitractor plate and well-sclerotized claws. The tarsomeres appear less-sclerotized than the covering setae. The articulation between the basitarsus and tarsomere 2 is hinge-like, implying that tarsomere 2 moves only mediolaterally. The simplified and specialized tarsal morphology is likely suitable for the typical zorapteran microhabitat, under bark. However, the irreversible complete loss of adhesive devices prevented zorapterans to make use of a broader spectrum of environments and was presumably one reason for the species paucity of the group.

Magnetic resonance imaging of the normal dromedary camel tarsus

Background

Magnetic resonance imaging (MRI) is the most versatile and informative imaging modality for the diagnosis of locomotor injuries in many animal species; however, veterinary literature describing the MRI of the dromedary camel tarsus is lacking. Our purpose was to describe and compare the MRI images of twelve cadaveric tarsi, examined in a 1.5 Tesla MRI scanner, with their corresponding anatomical gross sections. Turbo spin-echo (TSE) T1-weighted (T1), T2-weighted (T2), proton density-weighted (PD), and short tau inversion recovery (STIR) sequences were obtained in 3 planes. Tarsi were sectioned in sagittal, dorsal, and transverse planes. MRI images from different sequences and planes were described and compared with the anatomical sections.

Results

The soft and osseous tissues of the dromedary camel tarsus could be clearly defined on MRI images and corresponded extensively with the gross anatomic sections. The obtained MRI images enabled comprehensive assessment of the anatomic relationships among the osseous and soft tissues of the camel tarsus. Several structure were evaluated that cannot be imaged using radiography or ultrasonography, including the transverse inter-tarsal ligaments, the talocalcaneal ligament, the short dorsal ligament, branches of the short medial and lateral collateral ligaments and the tarsometatarsal ligaments. Specific anatomical features regarding the dromedary camel tarsus were identified, including the fused second and third tarsal bone, an additional bundle of the short medial collateral ligament connecting the talus and metatarsus and the medial and lateral limbs of the long plantar ligament.

Conclusions

MRI images provided a thorough evaluation of the normal dromedary camel tarsus. Information provided in the current study is expected to serve as a basis for interpretation in clinical situations.

Double reinsertion including Whitnall's ligament in aponeurotic ptosis surgery : Comparison of results following simple aponeurosis reinsertion surgery and a combined reinsertion of the aponeurosis to Whitnall's ligament for aponeurotic palpebral ptosis: a cohort study of 722 cases

Purpose

The results of a technique with a double reinsertion of the aponeurosis to the tarsus and aponeurosis to Whitnall’s ligament (ATW) were compared with a simple reinsertion of the aponeurosis to the tarsus (AT) in acquired aponeurotic palpebral ptosis surgery.

Methods

Analytical, observational, retrospective, cohort study. Seven hundred and twenty-two consecutive cases with acquired aponeurotic palpebral ptosis have been treated surgically between 2000 and 2012 and have been followed up for 5 years. The cases were divided into two cohorts according to the applied surgical technique (AT vs ATW).

Results

The mean postoperative MRD after 1 month in cohort AT was 1 mm lower than in ATW (3 ± 0.9 mm vs 4 ± 1 mm). The mean MRD in the long-term follow-up (5 years) was 1 mm lower in cohort AT than in ATW (2.9 ± 1.5 mm vs 3.9 ± 0.9 mm). The rate of long-term recurrence (5 years) was 15% higher in A-T than in A-T-W (20% vs 5%). 70.5% of the eyes studied intra-surgically presented gaps between the Whitnall ligament and the aponeurosis, an anatomical area that we describe as the upper transition zone (UTZ). In an independent analysis, only those patients with open UTZ were evaluated and it was observed that those operated with A-T-W presented elevations greater than 1 mm compared to those operated with the AT technique (4 ± 0.9 mm A-T-W vs 2.8 ± 1 mm A-T) and a much lower recurrence rate (5.4% A-T vs 38.09% A-T-W).

Conclusions

In our study, the A-T-W technique achieved better results in terms of palpebral elevation and fewer recurrences compared to the A-T technique in all cases studied with aponeurotic ptosis. However, it particularly demonstrates its superiority in patients with large gaps in the UTZ.

Percutaneous Plate Arthrodesis

Arthrodesis is an elective surgical procedure that aims at eliminating pain and dysfunction by promoting deliberate osseous fusion of the involved joint(s). Percutaneous plating can be used to perform carpal and tarsal arthrodeses in dogs and cats. After cartilage debridement is performed, the plate is introduced through separate plate insertion incisions made remote to the arthrodesis site and advanced along an epiperiosteal tunnel, and screws are inserted through the 3 existing skin incisions. The primary advantage of this technique is a decreased risk of soft-tissue complications, including postoperative swelling, ischemia, and wound dehiscence. Preliminary clinical results have been promising.

Complex Intratarsal Cyst with a Mixed Ciliated Respiratory-Type and Squamous Epithelial Lining

A 55-year-old woman developed a painless, non-ulcerated left upper eyelid swelling over 6 months. Examination disclosed a fluctuant mass that permitted movement of the eyelid skin over the lesion. A full-thickness eyelid resection contained a well-encapsulated cyst with milky contents that was predominantly located in the tarsus. The cyst's lining was partially composed of segments of ciliated respiratory-type and non-keratinizing squamous epithelia. Immunohistochemical evaluation with cytokeratins 17, 18, and 19 confirmed the staining pattern of a respiratory-type epithelial cell (whether or not cilia were present in the non-squamous epithelial zones). In the squamous region, entirely different cytokeratin results were obtained vis-a-vis the non-squamous regions of the lining. The current lesion is interpreted as congenital and representing an in situ persistence of embryonic ciliated glandular epithelium that normally exists only transitorily. A more remote possibility is that the lesion was the result of ectopic epithelial cells displaced from an adjacent sinus. A recurrence has not developed during 6 months of follow-up.

The insect unguitractor plate in action: Force transmission and the micro CT visualizations of inner structures

The unguitractor plate (UT) within insect tarsus was previously assumed to hold claws in a bent position with reduced muscular efforts due to the specific interlocking mechanism. In this study, the functional morphology of the unguitractor plate in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae) was examined using force measurements and the micro CT visualization of the UT position at different straining states of the retractor unguis muscle tendon. Pulling forces were applied in a controlled manner to the tendon and forces elicited by the claws to the stiff substrate were simultaneously recorded, in order to understand the force transmission mechanism between the tendon and claws through the UT. After claw bending and entanglement with the substrate, the claws were not released, until the tendon was relaxed to an average of 22% of the original applied force. The time delay in the returning of the claws to their original position was observed due to the frictional mechanism between the UT and corresponding microstructures of the pretarsus. This mechanism provides energy saving, when claws are engaged with the substrate. However, physical contact between the UT and the inner pretarsal wall was not observed in preparations of prestrained tendons in the micro CT, presumably due to the deformations caused by fixation and drying procedures.

The Jurassic Bajanzhargalanidae (Insecta: Grylloblattida?): New genera and species, and data on postabdominal morphology

The presumed phylogenetic link between extant ice-crawlers (Grylloblattidae = 'crown-Grylloblattida') and fossil species of the taxon concept Grylloblattida sensu Storozhenko (2002) is essentially based on postabdominal morphology. However, the fossil data are limited, and the interpretation is open to debate. Here we investigate a sample of a poorly known fossil 'grylloblattidan' family, the Bajanzhargalanidae, collected from the Daohugou locality (Middle Jurassic, China). We describe Sinonele fangi gen. nov., sp. nov., Sinonele hei gen. nov., sp. nov., Sinonele phasmoides gen. nov., sp. nov., and Sinonele mini gen. nov., sp. nov. Thanks to the abundance and exceptional preservation of the material, we could document wing venation intra-specific variability, provide cues to identify male and female individuals, describe and tentatively interpret various body structures of both sexes, and discuss them with a broad pterygotan phylogenetic perspective. The Bajanzhargalanidae exhibit a puzzling combination of postabdominal characters leaving us inconclusive on their affinities, or lack thereof, with crown-Grylloblattida. Our contribution suggests that a substantial effort will be needed to further investigate postabdominal structures from comparatively ancient fossil insects preserved as rock imprints, because of their broad morphological disparity.

An unusual eyelid mass: Tarsal dermoid cyst

We report the case of a 15-month-old boy who presented with a mass lesion of the right upper eyelid that had been present since birth and had slowly enlarged over the last 3 months. The lesion had minimal surrounding erythema simulating the appearance of a chalazion. Intraoperatively the lesion was noted to be firmly adherent to the underlying tarsus. The lesion was excised completely through an eyelid crease approach leaving the tarsus intact. The histopathology was consistent with dermoid cyst. To our knowledge, this is the third case of a tarsal dermoid cyst reported in the literature. Dermoid cyst should be included in the differential diagnosis of eyelid mass lesions, and particulary differentiated from a chalazion to avoid mismanagement that may lead to scarring, recurrence and inflammation. The excision of these lesions sparing the underlying tarsus can be possible.

RhoGAP68F controls transport of adhesion proteins in Rab4 endosomes to modulate epithelial morphogenesis of Drosophila leg discs

Elongation and invagination of epithelial tissues are fundamental developmental processes that contribute to the morphogenesis of embryonic and adult structures and are dependent on coordinated remodeling of cell-cell contacts. The morphogenesis of Drosophila leg imaginal discs depends on extensive remodeling of cell contacts and thus provides a useful system with which to investigate the underlying mechanisms. The small Rho GTPase regulator RhoGAP68F has been previously implicated in leg morphogenesis. It consists of on an N-terminal Sec14 domain and a C-terminal GAP domain. Here we examined the molecular function and role of RhoGAP68F in epithelial remodeling. We find that depletion of RhoGAP68F impairs epithelial remodeling from a pseudostratified to simple, while overexpression of RhoGAP68F causes tears of lateral cell-cell contacts and thus impairs epithelial integrity. We show that the RhoGAP68F protein localizes to Rab4 recycling endosomes and forms a complex with the Rab4 protein. The Sec14 domain is sufficient for localizing to Rab4 endosomes, while the activity of the GAP domain is dispensable. RhoGAP68F, in turn, inhibits the scission and movement of Rab4 endosomes involved in transport the adhesion proteins Fasciclin3 and E-cadherin back to cell-cell contacts. Expression of RhoGAP68F is upregulated during prepupal development suggesting that RhoGAP68F decreases the transport of key adhesion proteins to the cell surface during this developmental stage to decrease the strength of adhesive cell-cell contacts and thereby facilitate epithelial remodeling and leg morphogenesis.

Isolated dorsal dislocation of the tarsal naviculum

Isolated dislocation of the tarsal naviculum is an unusual injury, scarcely reported in the literature. The naviculum is surrounded by the rigid bony and ligamentous support hence fracture dislocation is more common than isolated dislocation. The mechanism and treatment options remain unclear. In this case report, we describe a 31 year old man who sustained an isolated dorsal dislocation of the left tarsal naviculum, without fracture, when he was involved in a motor vehicle collision. The reported mechanism of the dislocation is a hyper plantar flexion force applied to the midfoot, resulting in a transient disruption of the ligamentous support of the naviculum bone, with dorsal displacement of the bone. The patient was treated with open reduction and Krischner-wire fixation of the navicular after the failure of closed reduction. The wires were removed after 6 weeks postoperatively. Physiotherapy for stiffness and midfoot pain was recommended for 2 months. At 6 months postoperatively, limping, midfoot pain and weakness were reported, no X-ray abnormalities were found. The patient returned to his obvious activities with a normal range of motion.

Calcinosis cutis at the tarsus of the upper eyelid

Calcinosis cutis involves the inappropriate deposition of calcium within the dermis layer of the skin, and is often associated with rheumatoid disease. A 42-year-old woman presented for evaluation of a hard palpable mass on the left upper eyelid. After everting the eyelid, a large papillomatous mass with a broad base was identified on the superior area of the tarsus. The lesion was partially excised posteriorly under local anesthesia, and pathologists identified the mass as calcinosis cutis. The patient had no systemic or trauma history, and the serum levels of calcium and phosphorous were normal. Idiopathic calcinosis cutis should be included in the differential diagnosis for a protruding papillomatous mass of the tarsal plate, and surgical debulking could be a viable option for large protruding lesions, although more follow-up is necessary to monitor regrowth.