The peroneocuboid joint: morphogenesis and anatomical study

Anthropometric Analysis of Cuboid Bones in a South Indian Population

Purpose Cuboid bone and its fibromuscular supports maintain the lateral longitudinal arch in weight transmission during different gait cycle phases. Morphometry of the cuboid bone is essential for designing a cuboid prosthesis for foot reconstruction and establishing an individual's biological profile. The present study aims to assess the morphology and morphometry of the cuboid bone. Materials and methods The study used 103 cuboid bones (right 50, left 53) of unknown sex. Different shapes of cuboid articular facets were observed, and the morphometric parameters such as length, breadth, and height of cuboid, and the dimensions of articular facets in cuboid (calcaneal facet, fourth and fifth metatarsal facets, ecto-cuneiform facet, navicular facet, and facet for os peroneum) were analyzed. Results The mean length, breadth, and height of the cuboid bone were 33.69 ± 2.61 mm, 25.43 ± 2.87 mm, and 23.03 ± 2.43 mm, respectively. The mean transverse and vertical diameters were 23.22 ± 2.4 mm and 15.97 ± 1.85 mm, respectively. Facet for os peroneum was observed in 74.76% and for navicular bone in 26.2%. The mean transverse and vertical diameters were 7.16 ± 2.08 and 6.78 ± 1.78 mm, respectively. The depth of the peroneal groove was 4.30 ± 1.11 mm. Conclusion The morphometric data from the present study could assist in preoperative planning and designing of prostheses for foot reconstruction, and in establishing the biological profile of an individual, which can help the anthropologists in identifying the unknown remains.

Retracted os peroneum with partial integrity of the peroneus longus tendon

Painful os peroneum syndrome encompasses a spectrum of disorders associated with lateral foot and ankle pain. In the setting of an os peroneum fracture or diastasis of a partitioned os peroneum, marked displacement of the proximal fragment on radiographs is often used as an imaging surrogate for detection of a complete peroneus longus tendon tear. We present a case of a displaced proximal fragment of the os peroneum above the level of the ankle joint on radiographs and MRI associated with incomplete tear of the peroneus longus tendon. We hypothesize that such an injury pattern results from an anatomic prerequisite where the os peroneum occupies a portion of the cross-sectional diameter of the tendon. We suggest that the retracted proximal moiety of the sesamoid bone is the result of elastic recoil of delaminated fibers of the peroneus longus directly inserting on the os, whereas eccentric bundles of the tendon draping over the os remain in continuity. Although treatment implications are debatable, the case questions the assumption of a complete peroneus longus tear based on a retracted os peroneum on radiography and highlights the role of MRI in providing a full description.

Beyond the obvious: Exploring Os Tibiale Externum and Os Peroneum in Foot and Ankle Pain - A Case Series

Introduction

Accessory ossicles are well-corticated bony structures found close to bones or a joint. They may be unilateral or bilateral. The os tibiale externum is also known as accessory navicular bone, os naviculare secundarium, accessory (tarsal) scaphoid, or prehallux. It is found within the tibialis posterior tendon near its insertion on the navicular bone. The os peroneum is a small sesamoid bone located within the peroneus longus tendon, adjacent to the cuboid. We present a case series of five patients with accessory ossicles of the foot to demonstrate pitfalls in the diagnosis of foot and ankle pain.

Case Report

The case series includes four patients with os tibiale externum and one patient with os peroneum. Only one patient had symptoms related to os tibiale externum. The accessory ossicle in the rest of the cases was discovered incidentally after trauma to the ankle or foot. The symptomatic os tibiale externum was managed conservatively with analgesics and shoe inserts for medial arch support.

Conclusion

Accessory ossicles are considered developmental anomalies and they originate from ossification centers that have failed to fuse with the main bone. Clinical suspicion and awareness about the existence of the commonly occurring accessory ossicles of the foot and ankle are necessary. They can be a confounding factor in the diagnosis of foot and ankle pain. Failure to notice their presence might result in a misdiagnosis and unnecessary immobilization or surgery for the patients.

Morphological variability of the fibularis longus tendon in human fetuses

INTRODUCTION

The morphological variability of the fibularis longus tendon (FLT) in adults is well understood. However, no comprehensive classification exists in human fetuses. The goal of this study was to prepare the first comprehensive classification of the fibularis longus tendon based on its insertion in human fetuses.

MATERIAL AND METHODS

Forty-seven spontaneously-aborted human fetuses were examined: 38 male, 56 female, a total of 94 lower limbs (Central European population). Age ranged from18-38 weeks of gestation at death.

RESULTS

The classification comprised three types of FLT. The most common type was Type I (49%), characterized by the single distal attachment. This type was divided into two subtypes (A-B): A - the tendon inserts to the lateral tubercle of the base of the 1st metatarsal bone, B - the tendon inserts to the head of the 1st metatarsal bone. The second most type was Type II, characterized by a bifurcated distal attachment (24.5%). This type was divided into three subtypes (A-C): A - the main tendon inserts to the lateral tubercle of the base of the 1st metatarsal bone and the accessory band inserts to the medial cuneiform bone; B - the strong, main tendon inserts to both the base of the 1st metatarsal bone and medial cuneiform bone, including the first metatarsal-cuneiform joint, and the accessory bands inserts to the fourth interosseus dorsalis muscle; C - the main tendon inserts to the lateral tubercle of the base of the 1st metatarsal bone and the accessory band inserts to the first interosseus dorsalis muscle. The rarest type was Type III, characterized by a trifurcated distal attachment: the main tendon inserts to the lateral tubercle of the base of the 1st metatarsal bone and the first accessory band inserts to the medial cuneiform bone and the second accessory bands inserts to the first interosseus dorsalis muscle. The anterior frenular ligament was observed in 16% of all cases, and posterior frenular ligament in 6.4%.

CONCLUSION

The FLT displays high morphological variability. The proposed classification consists of three main types, with Type I and Type II divided into sub-types; it also provides additional data regarding its accessory tendon bands.

The Os Peroneum incidence - A cadaveric study

BACKGROUND

The Os Peroneum (OP) is a small sesamoid bone, which can be found in the Peroneus Longus Tendon (PLT) sheath, near the calcaneocuboid joint. Size and shape variability is quite common as well as a multipartite OP that can be found in some cases. Trying to explore and understand this variability, this study was carried out in order to provide us with answers about the presence and shape of OP in our specimens.

METHODS

Twenty cadaveric lower extremities were obtained according to the body donation program of our institution. Dissections were performed to expose the OP (when present) starting proximally at the origin of the PLT and Peroneal Brevis Tendon (PBT) finalizing at the insertion of the PLT in the first metatarsal.

RESULTS

In twenty feet, nine distinct OP were found, whilst six feet had a thickening of the tendon. On the remaining five foot, we did not identify an OP.

CONCLUSIONS

In this study, 45% of the feet analyzed had an OP. The authors believe the variability of OP prevalence reported in the literature can be associated with differences in its definition.

The peroneus longus muscle and tendon: a review of its anatomy and pathology

This article will review the anatomy and common pathologies affecting the peroneus longus muscle and tendon. The anatomy of the peroneus longus is complex and its long course can result in symptomatology referable to the lower leg, ankle, hindfoot, and plantar foot. Proximally, the peroneus longus muscle lies within the lateral compartment of the lower leg with its distal myotendinous junction arising just above the level of the ankle. The distal peroneus longus tendon has a long course and makes two sharp turns at the lateral ankle and hindfoot before inserting at the medial plantar foot. A spectrum of pathology can occur in these regions. At the lower leg, peroneus longus muscle injuries (e.g., denervation) along with retromalleolar tendon instability/subluxation will be discussed. More distally, along the lateral calcaneus and cuboid tunnel, peroneus longus tendinosis and tears, tenosynovitis, and painful os peroneum syndrome (POPS) will be covered. Pathology of the peroneus longus will be illustrated using clinical case examples along its entire length; these will help the radiologist understand and interpret common peroneus longus disorders.

Is there a relationship between the occurrence of frenular ligaments and the type of fibularis longus tendon insertion?

PURPOSE

The fibularis longus muscle (FLM) is located in the lateral compartment of the leg. Although the FLM presents high morphological variability, particularly the tendon, little is known of its insertion. Similarly, little information exists regarding the great diversity of the Frenular ligament. The main aim of the study was hence to characterize the morphology of the fibularis longus tendon (FLT) and its accessory bands, to classify it and to determine the incidence of frenular ligaments. I hypothesize that the presence of anterior/posterior frenular ligament can be closely correlated with a given type of fibularis longus tendon insertion.

METHODS

Classical anatomical dissection was performed on 100 lower limbs (50 female, 50 male) fixed in 10% formalin solution. The morphology of the insertion of the FLT and of the frenular ligaments was evaluated.

RESULTS

The FLM was present in all specimens. Three types of insertion were observed, the most common being Type I (49%): a single distal attachment in which the tendon inserts into the lateral tubercle of the base of the I metatarsal bone. The second most common type was Type II (40%): bifurcated distal attachment, the main tendon inserts into the lateral tubercle of the base of the I metatarsal bone. This group was divided into three subtypes (A-C), subtype (A) - the accessory band inserts into the medial cuneiform bone; subtype (B) - a strong, accessory band inserts into both the base of the I metatarsal bone and the medial cuneiform bone, including the first metatarsal-cuneiform joint; subtype (C) - the accessory band inserts into the first interosseus dorsalis muscle. The rarest type was Type III (9%), characterized by a single distal tendon, which fuses with other adjacent muscle tendons before insertion. The main tendon inserts into the lateral tubercle of the base of the I metatarsal bone; this group was divided into two subtypes (IIIA - fusion with the tibialis posterior tendon and IIIB - fusion with the adductor hallucis longus). The anterior frenular ligament was present in 49% of specimens, whereas the posterior frenular ligament joined the FLT to the long calcaneo-cuboid ligament and was present in 9%.

CONCLUSION

Both the fibularis longus tendon and frenular ligament present high morphological variability. The anterior frenular ligament is closely correlated with Type I of the proposed classification, while the posterior frenular ligament is associated with Type II b. Knowledge of particular types of insertion is essential for both clinicians and anatomists.

LEVEL OF EVIDENCE

- II basic science research.

The location of the peroneus longus tendon in the cuboid groove: sonographic study in various positions of the ankle-foot in asymptomatic volunteers

OBJECTIVE

To evaluate the normal location of the peroneus longus tendon (PL) in the cuboid groove in various ankle-foot positions by ultrasonography in asymptomatic volunteers.

MATERIALS AND METHODS

Ultrasonographic assessment of the PL in the cuboid groove was performed in 20 feet of ten healthy volunteers. Each PL was examined in five ankle-foot positions (i.e., neutral, dorsiflexion, plantar-flexion, supination, and pronation). The PL location was qualitatively categorized as "inside" when the PL was entirely within the cuboid groove, as "overlying" when some part of the PL was perched on the cuboid tuberosity, and as "outside" when the PL was entirely on the cuboid tuberosity. For quantitative evaluation of the PL location, the distance between the PL and the cuboid groove was measured. The width of the cuboid groove was measured in the neutral position.

RESULTS

The PL location did not significantly change with changes in the ankle-foot position. Qualitatively, an "overlying" PL was the most common type, regardless of the ankle-foot position. "Inside" PLs were found in only 35, 20, 30, 25, and 35% of feet in neutral, dorsiflexion, plantar-flexion, supination, and pronation positions, respectively. The quantitative PL location was also not significantly different among all ankle-foot positions and it was significantly negatively correlated with the cuboid groove width.

CONCLUSIONS

In healthy volunteers, 65% or more of the PLs were partially or completely located outside of the cuboid groove, regardless of the ankle-foot position. The PL location relative to the cuboid groove was related to the cuboid groove width.

Os peroneum imaging: normal appearance and pathological findings

The os peroneum (OP) is a small sesamoid bone located inside the peroneus longus tendon (PLT), close to the cuboid. The OP can be the cause of pain and can be associated with lesions of the PLT. OP involvement in PLT disorders is frequently misdiagnosed by radiologists. Painful os peroneum syndrome (POPS) refers to a variety of conditions presenting with pain localized on the lateral aspect of the cuboid area. The syndrome can be observed as a consequence of local acute trauma such as ankle sprains or chronic overuse. Because of its intra-tendinous location, in tears of the peroneus longus tendon, the OP can show changes in its morphology or position, depending on the location of the tendon’s tear. Based on the level of the PLT tears, we propose a classification in three subtypes: tears localized proximal to the os peroneum (type I), at its level (type II) or distal to it (type III). These tears present with different changes on OP morphology or location. The aim of this article is to review the normal anatomy, imaging appearance and differential diagnosis of disorders of the OP as well as post-treatment imaging.

Teaching points

• PLT tears can be classified in three subtypes according to OP location.

• POPS is characterized by pain on the lateral aspect of the cuboid.

• OP involvement in PLT disorders is frequently misdiagnosed by radiologists.

Spatiotemporal distribution of proliferation, proapoptotic and antiapoptotic factors in the early human limb development

Involvement of proliferation and apoptosis in the human limb development was analyzed electronmicroscopically and immunohistochemically in histological sections of 8 human embryos, 4(th) -10(th) week old, using apoptotic (caspase-3, AIF, BAX), anti-apoptotic (Bcl-2) and proliferation (Ki-67) markers, and TUNEL method. The data were analyzed by Mann-Whitney test, Kruskal-Wallis and Dunn's post hoc test. Initially, developing human limbs consisted of mesenchymal core and surface ectoderm with apical ectodermal ridge (AER). During progression of development, strong proliferation activity gradually decreased in the mesenchyme (from 78% to 68%) and in the epithelium (from 62% to 42%), while in the differentiating finger cartilages proliferation was constantly low (26-7%). Apoptotic caspase-3 and AIF-positive cells characterized mesenchyme and AER at earliest stages, while during digit separation they appeared in interdigital mesenchyme as well. Strong Bcl-2 expression was observed in AER, subridge mesenchyme and phalanges, while BAX expression charaterized limb areas undergoing apoptosis. Ultrastructurally, proliferating cells showed mitotic figures, while apoptotic cells were characterized by nuclear fragmentation. Macrophages were observed around the apoptotic cells. We suggest that intense proliferation enables growth and elongation of human limb primordia, and differential growth of digits. Both caspase-3 and AIF-dependant pathways of cell death control the extent of AER and numer of cells in the subridge mesenchyme at earliest developmental stages, as well as process of digit separation at later stages of limb development. Spatio-temporal co-expresson of Bcl-2 and BAX indicates their role in suppression of apoptosis and selective stimulation of growth during human limb morphogenesis.