Os intermetatarseum: a heritable accessory bone of the human foot

Os intermetatarseum presenting as splay foot; Case report and literature review

INTRODUCTION AND IMPORTANCE

This report described the management of a lady with a rare finding of a large size of Os intermetatarseum in a bizarre location. This unique condition resulted in a splay foot which was rarely discussed in the literature.

CASE PRESENTATION

A lady in her early fifth decade has complained of foot swelling and difficulty wearing shoes for the last two years. Her main concern was the worry of a malignant condition.

CLINICAL DISCUSSION

She had an unusually huge articulated lump in the third web space. Also, it showed a central foot splay. A full battery of radiological investigation gave a narrow list of possible differential diagnoses. The final diagnosis showed that it was Os intermetatarseum. Surgical treatment involved enucleating the mass and correcting foot splay using a mini-tight rope®. The histopathology report confirmed the diagnosis of Os intermetatarseum. The central forefoot splay was treated by a known surgical tool differently. Post-operatively she was put on physical therapy. Five years follow-up showed improved foot anatomy and functional outcomes with no recurrence.

CONCLUSION

Awareness of this rare condition as a differential diagnosis. Complete excisional biopsy of the lump will be a valid option for this condition, as well as using a mini-tight rope® in dealing with central foot splay.

Three cases of brachydactyly type E from two commingled tombs at the Late Intermediate period - Late Horizon site of Marcajirca, Ancash, Peru

OBJECTIVE

Here we present the first known examples of brachydactyly from an Andean archaeological context by describing the affected bones, presenting a differential diagnosis, and discussing the cultural implications of there being shortened metapodials in multiple tombs.

MATERIALS

3232 well-preserved tubular bones representing an MNI of 250 human adults.

METHODS

Each bone was visually inspected. Measurements were taken with an osteometric board, sliding calipers, and a flexible tape measure.

RESULTS

Of 1210 metapodials excavated from eight burial contexts, ten were atypically short.

CONCLUSIONS

The ten shortened elements represent an MNI of three individuals with brachydactyly from two tombs. The presence of at least two individuals with brachydactyly in one tomb adds support to a previous suggestion that tombs were used for familial interment. It is plausible that the third individual from a different tomb was related to the other two, and the different burial contexts may reflect postmarital practices.

SIGNIFICANCE

These cases offer insight into tomb use and underscore the importance of identifying rare developmental anomalies in the archaeological record as their presence may indicate genetic relationships within or among archaeological cemeteries.

LIMITATIONS

With commingled contexts and incomplete recovery of skeletal remains, individualizing the brachydactylous elements was not possible. There is also a lack of comparative data from other Andean sites.

SUGGESTIONS FOR FURTHER RESEARCH

Identify more Andean cases of brachydactyly to learn if the relatively frequent involvement of the first digit is more common among Andean skeletal samples than North American, or if it is unique to Marcajirca.

Os Intermetatarseum and Polymetatarsia Without Polydactyly: A Case Report

Nontraumatic bony abnormalities of the foot occur at different rates, according to the literature. However, it is uncommon to see rare variations presenting together in one patient. This article discusses two less common anomalies: fused os intermetatarseum and polymetatarsia without polydactyly. Etiology, symptomology, diagnosis, and treatment are reviewed, in addition to the relationship of the two conditions to each other. We then discuss a case where both anomalies are present at the same time in a 17-year-old patient.

Os intermetatarseum: An analysis of morphology and case reports of fracture

INTRODUCTION

The os intermetatarseum is an uncommon accessory ossicle of the foot located dorsally, between the bases of the first and second metatarsals that are usually asymptomatic. In the setting of trauma, this ossicle can clinically mimic a Lisfranc fracture-dislocation, a potentially disabling condition often requiring surgical intervention.

METHODS

In this study, 47 cases of os intermetatarseum were reviewed across several Western Australian (WA) Hospitals and characterised based on morphology. Any fractures were recorded, and their cases were reviewed.

RESULTS

The most common type of os intermetatarseum was freestanding at 63%, followed by the articulating type at 30%. Only 7% were of the fused type. Two acute fractures were identified on plain radiography and computed tomography (CT).

CONCLUSION

The distribution of os intermetatarseum subtypes in the WA population is consistent with previous radiological studies. The two cases of isolated acute os intermetatarseum fracture are described, the first to our knowledge, highlighting the need for increased awareness of this ossicle in the setting of foot trauma.

A Case Report of Congenital Hallux Valgus from an Incomplete Preaxial Polydactyly without a Supernumerary Digit

Introduction

While hallux valgus is a common deformity occurring in adults and adolescents, congenital hallux valgus is rare. There is a paucity of information available about the deformity and even less information about its cause. In fact, discrepancies exist within literature as to its etiology. This is a case report of bilateral congenital hallux valgus that appears to have been caused by preaxial polydactyly of the great toe, without a supernumerary digit, which to date has not been reported in literature. Markedly increased intermetatarsal and hallux valgus angles were present in both feet. Furthermore, bilateral interval improvement of the angulation occurred spontaneously without operative or non-operative intervention. This case reveals another potential cause of congenital hallux valgus not previously described. Our patient demonstrates that preaxial polydactyly could be another possible etiology of congenital hallux valgus. This case also demonstrates that magnetic resonance imaging (MRI) may be required for accurate diagnosis.

Case Report

The subject of this case report is a 6-month-old boy who presented with what appeared to be severe bilateral congenital hallux valgus. However, an MRI was suggestive of preaxial polydactyly without a supernumerary digit. At 26 months of age, clinical follow-up demonstrated that the deformity had improved and the patient was doing well clinically without intervention.

Conclusion

Congenital hallux valgus is an uncommon deformity. Our patient demonstrates that the etiology may be incomplete preaxial polydactyly without a supernumerary digit. Overtime, even without treatment, the deformity appeared to improve, and the patient had no clinical complaints. The lack of an accessory ossicle or supernumerary digit makes our patient's case unique.

Anatomical variation in the ankle and foot: from incidental finding to inductor of pathology. Part II: midfooot and forefoot

Accessory anatomical structures in the ankle and foot usually represent incidental imaging findings; however, they may also eventually represent a source of pathology, such as painful syndromes, degenerative changes, be the subject of overuse and trauma, or appear as masses and cause compression syndromes or impingement. This review aims to describe and illustrate the imaging findings related to the presence of accessory ossicles and muscles in the midfoot and forefoot through different techniques, with special attention on those variants that associate factors of clinical relevance or that would trigger challenges in the differential diagnosis.

Non-metric traits and anatomical variants that can mimic trauma in the human skeleton

This paper presents some of the more commonly encountered non-metric traits and minor anatomical variants in the adult human skeleton that can mimic or be mistaken for trauma. Distinguishing non-metric traits is contingent upon both a knowledge of potential non-metric traits as well as the normal developmental timing, location, and anatomy of maturational markers in the human skeleton. Distinguishing non-metric traits from trauma in dry bone is an essential component in establishing an accurate and thorough forensic analysis of human remains, especially as it deals with antemortem and perimortem trauma, and postmortem damage.

Three-Dimensional CT Findings of Os Calcaneus Secundarius Mimicking a Fracture

Os calcaneus secundarius is one of several accessory ossicles of the foot that have been identified as normal variants of skeletal development. It may cause ankle pain and may mimic an avulsion fracture of the anterior calcaneal process. A twenty-year-old male was admitted to our institution with right ankle pain following an inversion injury. An axial CT image of the patient's right ankle revealed a shape with smooth and sharp margins, identified as a well-corticated bone fragment in the subtalar region. A diagnosis of an accessory ossicle, os calcaneus secundarius, was made based on radiographic findings. As a result of this case, it is recommended that potential locations of the accessory bones should be well understood in order to prevent misdiagnosis and inappropriate surgical procedures. Os calcaneus secundarius must be considered when an apparent bone fragment or a suspicious fracture line at the anterior region of os calcaneus is demonstrated.

Forefoot: a basic integrated imaging perspective for radiologists

Imaging of the forefoot is increasingly requested for patients with metatarsalgia. Awareness with specific anatomic arrangements exclusive for the forefoot and widely variable pathologic entities associated with metatarsalgia helps the radiologist to tailor a cost-effective imaging approach. This will enable reaching a specific diagnosis as much as possible with subsequent proper patient management. This pictorial review aims to provide basic understanding for the different imaging modalities used in studying the forefoot. After that, certain anatomic arrangements exclusive for the forefoot are discussed. The final section of this review describes the imaging findings of some common forefoot problems.

Bilateral fused os intermetatarseum presenting as dorsal foot pain: a case report

PURPOSE

Os intermetatarseum is a rare accessory bone of the forefoot and usually situated between the base of the first and second metatarsals. Most of the cases are asymptomatic and diagnosed incidentally. Here, we report a rare form of os intermetatarseum presented with bilateral dorsal foot pain and to the authors' knowledge, it is the first case which includes computerized tomography (CT) and magnetic resonance imaging (MRI) findings.

METHODS

A 23-year-old male complained of localized bump at the dorsum of the both feet underwent bilateral anteroposterior foot radiograms which was unremarkable and then CT and MRI were performed.

RESULTS

MRI of both feet demonstrated osseous structures in relation with medial os cuneiforme. Computerized tomography demonstrated bilateral os intermetatarsea fused with medial os cuneiforme.

CONCLUSIONS

It is important for radiologist to know that os intermetatarseum can be presented as dorsal foot pain. Due to its position, it is difficult to demonstrate os intermetatarseum in plain radiographs, CT and MRI should be performed in clinically suggestive cases.

Normal genetic variation of the human foot: Part 2: Population variance, epigenetic mechanisms, and developmental constraint in function

Congenital deformities of the foot have been reported to correlate with regulatory epigenetic mechanisms that are also responsible for the timing and sequencing of developmental growth of the lower limb. Developmental variance of normal morphologic features has also been shown to vary between populations despite the retention of human foot characteristics. The molecular evidence for genetically controlled expressions of common evolved physical features is highly suggestive of regulatory control mechanisms that act together with developmental constraints to homogenize the retained functional characteristics of the foot. Genetic variance in morphologic features and functional plasticity when linked to morphometric change during gait may prove influential in clarifying kinematic and kinetic relationships.

Os intermetatarseum - A case report

Accessory ossicles and sesamoid bones are skeletal variations, more commonly seen in the region of foot and ankle. Most such accessory and sesamoid bones remain asymptomatic. However overuse and trauma can make such feet symptomatic. Knowledge of such bony ossicles is essential in the management of patients presenting with foot pain. Dorsal foot pain can be caused by a symptomatic Os intermetatarseum - an accessory ossicle found between the bases of first and second metatarsals and the medial cuneiform. Its incidence has not been well established because of insufficient appropriate multi-centric anatomical, radiological and orthopaedic studies. A case of dorsal foot pain in a soccer player, caused by an Os intermetatarseum is reported here. A brief review of the literature is also presented.

[The painful os intermetatarseum]

The os intermetatarseum is an uncommon accessory bone of the foot, usually found between the bases of the first and second metatarsal bones. Two cases of a painful os intermetatarseum in athletes are reported. Surgical excision of the os intermetatarseum relieved the pain in both patients. Case reports concerning athletes with a painful os intermetatarseum are rare. An os intermetatarseum should be taken under consideration when evaluating dorsal midfoot pain.

RETRACTED ARTICLE. Painful os intermetatarseum in athletes: a literature review of this condition is presented

Painful os intermetatarseum is a very rare condition. Gruber et al. first described os intermetatarseum in 1877. This condition is usually asymptomatic. One should consider painful os intermetatarseum as being a possible cause of dorsal foot pain in athletes. Surgical excision of the os intermetatarseum should be considered for those patients failing conservative treatment. Here, a literature review of this condition is presented.

Painful os intermetatarseum in athletes: report of four cases and review of the literature

INTRODUCTION

A painful os intermetatarseum, which described the compression of the deep peroneal nerve by an os intermetatarseum, is a very rare condition. The authors reported four cases of painful os intermetatarseum in athletes and reviewed the present literature.

CASE PRESENTATION

We present four cases of a painful os intermetatarseum in athletes, who complained of pain over the dorsum of their foot associated with paresthesias in the first web space. Surgical excision of the os intermetatarseum relieved the pain in all patients. All patients returned to previous sporting activities.

CONCLUSION

We should consider a painful os intermetatarseum as being the cause of dorsal foot pain in athletes, and surgical excision of the os intermetatarseum is effective for these patients.

Os acromiale: Population differences and their etiological significance

The os acromiale is an accessory bone resulting from failure of the acromial apophysis to fuse to the scapula. It is a relatively frequent defect affecting 4-18% of most large skeletal series. The etiology of os acromiale is poorly understood, and two competing hypotheses have been proposed: (1) that the accessory bone represents a genetic defect, and (2) that it results from mechanical stress on the developing acromion. In order to assess the evidence for these two hypotheses, os acromiale frequencies from a South African cadaver sample (n = 494) were compared to frequencies from a medieval Danish archaeological sample (n = 532). The South African frequency (18.2%) was significantly higher than the medieval Danish frequency (7.7%, p < 0.0001). These results mirror those of another study comparing African- and Euro-Americans, and tend to support the genetic hypothesis. However, a left side bias (72%) was also found among the South Africans (p = 0.013), lending some support to the mechanical stress hypothesis. Sex and age biases were also examined but were not found. In order to further test the mechanical hypothesis, the medieval Danes were divided into groups of higher and lower socioeconomic status based upon cemetery type. Lower status individuals were presumed to have engaged in strenuous labor activities more often and at a younger age than higher status individuals. However, comparison of these two groups failed to demonstrate a significant frequency difference (p = 0.105). Based on the results of this study, it is suggested that a third etiology combining a genetic predisposition for os acromiale with mechanical stress as the proximate cause should also be considered.

Phenotypic approaches for understanding patterns of intracemetery biological variation

This paper reviews studies of phenotypic inheritance and microevolutionary processes in archaeological populations using data on cranial and dental phenotypic variation, often referred to as paleogenetics or biodistance analysis. The estimation of biological distances between populations, or among individuals within populations, is one component of bioarchaeological research on past populations. In this overview, five approaches that focus on morphological variation within cemeteries are summarized: kinship and cemetery structure analysis, postmarital residence analysis, sample aggregate phenotypic variability, temporal microchronology, and age-structured phenotypic variation. Previous research, theoretical justifications, and methods are outlined for each topic. Case studies are presented that illustrate these theoretical and methodological bases, as well as demonstrate the kinds of inferences possible using these approaches. Kinship and cemetery structure analysis seeks to identify the members of family groups within larger cemeteries or determine whether cemeteries were kin-structured. Analysis of sex-specific phenotypic variation allows estimation of postmarital residence practices, which is important for understanding other aspects of prehistoric social organization. Analysis of aggregate phenotypic variability can be used to infer site formation processes or cemetery catchment area. The study of temporal microchronologies can be used to evaluate provisional archaeological chronologies or study microevolutionary processes such as adaptive selection or changing patterns of gene flow. Finally, age-structured phenotypic variation can be reflective of selection processes within populations or it can be used as a measure of morbidity, growth arrest, and early mortality within past populations. Use of phenotypic data as a genotypic proxy is theoretically sound, even at small scales of analysis.

The intermetatarsal articular facet of the first metatarsal bone in humans: a derived trait unique within primates

The occurrence and morphology of an intermetatarsal facet of the first metatarsal bone have been investigated in a series of 306 nonhuman primates representative of 40 genera, and in a series of 412 human metatarsal bones (dried bones) (215 left, 197 right). In nonhuman primates, no case of intermetatarsal facet was observed in the 306 first metatarsal bones studied. In humans, a well-defined intermetatarsal facet was observed in 127 out of the 412 bones (30.8%); no significant difference was observed between the left and right sides. The shape of the facet was elliptical, more or less elongated; it had a mean major axis (height) of 10.7 mm, and a mean minor axis (width) of 6.1 mm (extremes: 5 x 3 mm and 17 x 10 mm). The facet was located in the dorsal third of the lateral side of the first metatarsal in 103 out of 127 cases (81.1%), and in the middle third in 24 out of 127 cases (18.9%); it was never observed in the plantar third. The intermetatarsal facet was in connection with the proximal articular facet for the medial cuneiform in 68 out of 127 cases (53.5%), and it was separated from the proximal facet by a small nonarticular area or groove in 59 out of 127 cases (46.5%). The present observations suggest that the human first intermetatarsal facet is a derived trait unique within primates (autapomorphy) which is present in approximately one third of individuals. The appearance of this new articular facet in human evolution seems clearly related to the morphological modifications of the foot due to the acquisition of bipedalism, and more particularly to the loss of abductability of the hallux and its permanent adduction.