Imaging features of intraosseous lipomas of the calcaneus

We report two cases of intraosseous lipoma arising in the calcaneus of a 36-year-old and a 22-year-old women complaining of heel pain. Plain radiographs and computed tomography scans revealed cystic lesions in the calcaneus triangle. On magnetic resonance images, the lesions had high signal intensities on both T1-weighted and T2-weighted images, corresponding to adipose tissue. Histological examination revealed mature fat cells with small bone fragments. Curettage and bone grafting were performed. There was no recurrence identified on plain radiographs 2 years following the surgery.

Posterior facet talocalcaneal coalition

Posterior facet talocalcaneal coalition is one of the rarest forms of talocalcaneal coalition. When a posterior facet coalition occurs, it typically involves a majority of the posterior facet articular surface. The authors present a rare form of posterior facet talocalcaneal coalition in an 11- year-old girl. A brief review of the literature is provided, along with the case history, including radiographic findings and intraoperative and postoperative illustrations.

Osteodensitometry of human heel bones by MR spin-echo imaging: comparison with MR gradient-echo imaging and quantitative computed tomography

The aim of the study was to investigate whether quantitative magnetic resonance (MR) fast spin-echo (FSE) imaging with moderate spatial resolution enables osteodensitometry in peripheral yellow bone marrow. Signal intensities in T1-weighted FSE images from yellow bone marrow indicate the amount of adipose tissue per volume. The signal intensity in marrow regions with spongy bone was assessed and compared to signal intensity of pure fatty marrow (100%). Heel bones of 30 patients with suspected osteoporosis were analyzed and the FSE images were compared with results from parallel MR gradient-echo (GE) imaging and quantitative computed tomography (QCT) examinations. High correlation was found between FSE imaging and QCT [r = 0.91 in the dorsal region of interest (ROI); r = 0.86 in ventral ROI]. Linear correlation coefficients between GE imaging and QCT were slightly lower in the dorsal part (r = -0.86) and considerably lower in the ventral part (r = -0.68). Correlation between the two MR techniques amounted to r = -0.72/-0.61 (dorsal/ventral). The high correlation between FSE imaging and bone mineral density (BMD) allows possible clinical applications of FSE imaging for diagnosis of osteoporosis. Further improvements of the accuracy using reference phantoms might be possible.

Intraosseous lipoma of the calcaneus

BACKGROUND AND AIMS

Intraosseous lipoma of the calcaneus is thought to be a rare tumour. As most of the articles have been single case reports, we performed a meta-analysis to evaluate diagnostic and therapeutic procedures.

METHODS

Based on 54 cases located at the calcaneus, typical features and treatment were studied.

RESULTS

A predilection was seen for adults between 30 and 60 years of age. Males were affected in two of three cases. The lesions were found incidentally in 33%. Symptomatic cases presented with pain, and some patients showed additional tenderness or swelling. All calcaneal lipomas were located at the base of the neck of the calcaneus (Ward's triangle). Radiological appearance depends on the stage due to evolutionary changes of the tumour. Diagnosis can be established with CT or MRI, as both methods show fat-equivalent densities in the lesion. Pathological fracture has not been reported.

CONCLUSION

Continued observation in asymptomatic cases is a reasonable clinical approach. We propose surgical treatment with curettage and bone grafting only in symptomatic cases.

[Diagnostic image (42). Solitary bone cyst of the left calcaneus]

A 9-year-old boy presented with a painful left heel. A plain radiograph showed a lytic lesion with a benign appearance, with a simple bone cyst or an intraosseous lipoma as the most likely differential diagnostic possibilities. MRI demonstrated a simple bone cyst.

Tarsal Sinus: Arthrographic, MR Imaging, MR Arthrographic, and Pathologic Findings in Cadavers and Retrospective Study Data in Patients with Sinus Tarsi Syndrome

PURPOSE

To evaluate the tarsal sinus by using different imaging techniques and specialized planes.

MATERIALS AND METHODS

Magnetic resonance (MR) imaging of the tarsal sinus was performed in 10 cadavers. Conventional arthrography of the anterior and posterior subtalar joints was then performed. Tarsal sinus ligaments were evaluated further on initial and reconstructed MR arthrograms along and perpendicular to their axes. Pathologic correlation was performed in five specimens suspected of having tarsal sinus lesions on the basis of initial imaging findings. In 37 patients with a clinical diagnosis of sinus tarsi syndrome, MR images of the ankle were obtained before and after intravenous gadolinium-based contrast material administration and were reviewed to verify the integrity of the tarsal sinus ligaments.

RESULTS

Two complete and three partial cervical ligament (CL) tears and one complete interosseous talocalcaneal ligament (ITCL) tear were diagnosed with MR imaging. Only one complete and one partial CL tear were seen after evaluation of both initial and reconstructed MR arthrograms and confirmed with pathologic correlation. In 18 patients, the diagnosis was confirmed at MR imaging, which depicted ITCL and CL tears in 11 patients, isolated CL tears in three patients, ganglia in three patients, and pigmented villonodular synovitis in one patient.

CONCLUSION

Cadaveric study results indicate that initial and reconstructed MR arthrograms along and perpendicular to the ligament axes are potentially useful for further evaluation of individual tarsal sinus structures.

Compartment syndrome of the foot

The hindfoot compartment syndrome occurs in 10% of cases after calcaneal fracture. We analyzed the pathological anatomical reasons for this syndrome using the 10 feet from cadavers plastinated and cut into 4-mm thick sequential sections. CT scans of patients with calcaneal fractures were then compared with the anatomical findings. The key component of this compartment syndrome is the quadratus plantae muscle. The sustentacular calcaneal fragment causes bleeding from the bone or the medial calcaneal arteries into this compartment. The medial and lateral plantar nerves and vessels are then compressed between the quadratus plantae muscle and the short flexor digitorum muscle. Relieving pressure by surgical decompression of the quadratus plantae compartment via a medial or plantar approach is the recommended treatment.

Management of a patient with sarcoid calcaneitis and dactylitis

Dactylitis and calcaneitis developed in a patient with untreated sarcoidosis of the skin and lungs. Radiographs showed a defect in the second phalanx of the left middle finger. Radiographs of the feet were normal, but magnetic resonance imaging demonstrated a defect in the left calcaneus. Methylprednisolone therapy (1 g per day for 3 consecutive days) induced a dramatic improvement within 48 hours. Low-dose oral glucocorticoid therapy was given subsequently. One year later, a recurrent episode of dactylitis responded promptly to the same regimen. Maintenance therapy was given, and no further recurrences were noted during the four-year follow-up. Sarcoid bone lesions are uncommon and arise selectively in the small bones of the hands and feet. Involvement of the calcaneus is exceedingly rare, and its treatment is not standardized. In our patient, glucocorticoid therapy combined with methotrexate and hydroxychloroquine were effective in controlling the disease.

Age, gender, and fragility fractures are associated with differences in quantitative ultrasound independent of bone mineral density

Bone strength is determined by bone mineral density (BMD) and bone structure. Dual-energy X-ray absorptiometry (DXA) measures BMD. Whether quantitative ultrasound (qUS) measures a property of bone distinct from BMD is uncertain. To evaluate this, DXA and qUS were measured in 58 fracture patients and 428 controls. To study the independent effects of age and gender on qUS measurements and control for BMD by study design rather than statistical methods, subgroups from the normative database were created and intentionally matched by the same femoral neck (FN) BMD. Speed of sound (SOS; m/sec), broadband ultrasound attenuation (BUA; dB/MHz), and stiffness index (SI) were then compared in individuals matched by FN BMD but differing in age, gender, and presence or absence of fractures. The results are presented as percentage difference (mean +/- SD). Elderly women with the same FN BMD as young women had 1 +/- 2% lower SOS (p < 0.05), 8 +/- 15% lower SI (p < 0.05), and 4 +/- 9% lower BUA (p = 0.07). Elderly women with the same FN BMD as elderly men had 5 +/- 9% lower BUA (p < 0.05). Elderly men with the same FN BMD as young men had 1 +/- 2% lower SOS (p = 0.1), 5 +/- 14% lower SI (p = 0.2), and 1 +/- 9% lower BUA (n.s.). Young women with the same FN BMD as young men had 2 +/- 7% lower BUA (n.s.). Women with fragility fractures had 8 +/- 11% lower BUA (p < 0.001) and 13 +/- 22% lower SI (p < 0.01) than controls with no fractures matched by FN BMD, age, and gender. Men with fragility fractures had 13 +/- 12% lower BUA (p < 0.01) and 16 +/- 19% lower SI (p < 0.05) than controls with no fractures matched by FN BMD, age, and gender. Despite comparable femoral neck BMD, qUS measurements differed according to age, gender, and fracture status, suggesting that qUS may provide additional information independent of femoral neck BMD, such as differences in connectivity or other properties yet to be identified.

Talo-calcaneal relationship in clubfoot

Talo-calcaneal angles were measured on anteroposterior, stress dorsiflexion, and plantarflexion lateral radiographs of 75 normal feet and 145 clubfeet. The talus and calcaneum from 15 normal fetal limbs were dissected without disturbing the subtalar capsule. Anteroposterior and lateral radiographs of these specimens were also obtained. The long axes of the ossific nuclei and the long axes of the cartilaginous anlagen of the bones were marked, and the talo-calcaneal angles were measured. The talo-calcaneal angles were lower in clubfeet than in normal feet, but there was considerable overlap in the ranges of normal and clubfeet for all the angles measured. The lateral talo-calcaneal angles in normal feet were higher in dorsiflexion than in plantarflexion, whereas the converse was true in clubfeet. The talo-calcaneal angles measured from the axes of the ossific nuclei of the fetal specimens were higher than those measured from the axes of the cartilaginous anlagen. Using logistic regression analysis, a mathematical model was made to predict the probability of correction of clubfeet. A lateral talo-calcaneal angle difference (between the stress dorsiflexion and plantarflexion angles) of 20 degrees suggests that there is a 93% probability that the hindfoot deformity of clubfoot has been adequately corrected. A talo-calcaneal angle of 30 degrees or a talo-calcaneal index of 40 degrees does not ensure correction of clubfoot. A decrease of the talo-calcaneal angle by up to 10 degrees occurs as the child grows because of the alteration of the shape of the ossific nucleus of the talus that occurs normally with growth.

Frequency dependence of ultrasonic backscattering in cancellous bone: autocorrelation model and experimental results

The goal of this study is to model the frequency dependence of the ultrasonic backscatter coefficient in cancellous bone. A twofold theoretical approach has been adopted: the analytical theoretical model of Faran for spherical and cylindrical elastic scatterers, and the scattering model for weakly scattering medium in which the backscatter coefficient is related to the autocorrelation function of the propagating medium. The ultrasonic backscatter coefficient was measured in 19 bone specimens (human calcaneae) in the frequency range of 0.4-1.2 MHz. The autocorrelation function was computed from the three-dimensional (3D) microarchitecture measured using synchrotron radiation microtomography. Good agreement was found between the frequency dependence of the experimental (f3.38+/-0.31) and autocorrelation modeled (f3.48+/-0.26) backscatter coefficients. The results based on Faran theory (cylindrical Faran model: f2.89+/-0.06 and spherical Faran model: f3.91+/-0.04) show qualitative agreement with experimental data. The good prediction obtained by modeling the backscatter coefficient using the autocorrelation function of the medium opens interesting prospects for the investigation of the influence of bone microarchitecture on ultrasonic scattering.

[Bursitis tendinis calcanei in extensive calcaneus erosion]

INTRODUCTION

Mechanical and static stress as well as rheumatic diseases may cause retrocalcanear bursitis. Anatomic variants of the calcaneus predispose to this bursitis.

CASE

A 51-year-old woman being afraid of operation waited 2 years before undergoing bursectomy al her right heel. For this reason the increase of calcanear bone loss and its stabilisation by sclerosis is well documented in X-rays and MR images. A secondary synovialitis of the peroneal tendons decided completely after bursectomy. No signs of rheumatic disease were found.

CONCLUSION

The radiological, clinical and hisiological findings in long-persisting bursitis are often simular to those found in patients with rheumatic disease. Normal laboratory findings do not preclude an early stadium of rheumatic disease. For this reason, these patients had to be instructed to return if they develop further synovialitis to verify the diagnosis and to avoid delayed therapy.

[Solitary cyst of the calcaneus contemporary diagnostic possibilities: the results and treatment]

Bone remodeling within solitary cyst of the calcaneus has been investigated, its unique location underlined. Different theories behind its origin within the short bone like the calcaneus are discussed. The diagnosis might be supported by magnetic resonance imaging according to Greenfield data. At the final radiographic assessment according to the Neer criteria in majority of the patients incomplete healing with small osteoporotic areas has been found.

Plantar fasciitis and fascial rupture: MR imaging findings in 26 patients supplemented with anatomic data in cadavers

Understanding of the normal anatomy of the plantar aponeurosis (PA) and familiarity with pathologic conditions are required for an accurate evaluation of the patient with subcalcaneal heel pain. In this study, we evaluated the diagnostic capabilities of magnetic resonance (MR) imaging in the assessment of the PA with close anatomic correlation. Herein, we describe the MR imaging features of plantar fasciitis and fascial rupture in 26 patients. High-spatial-resolution MR imaging was performed in four cadaveric feet, and a prescribed imaging plane was used for depiction of the peroneal component of the PA. MR imaging delineated the anatomy of the PA and perifascial soft tissues. The peroneal component was best visualized in prescribed sagittal oblique images. Perifascial edema was the most common finding of plantar fasciitis, and it was remarkable in those cases with acute fascial rupture. MR imaging reliably delineated the anatomy of the PA and may allow precise localization and definition of the extent of involvement in disease processes.

Extracorporeal shock wave application for chronic plantar fasciitis associated with heel spurs: prediction of outcome by magnetic resonance imaging

OBJECTIVE

To clarify morphologic features associated with the clinical outcome of extracorporeal shock wave application (ESWA) in chronic plantar fasciitis.

METHODS

In this prospective study 43 patients (48 heels) with chronic courses of plantar fasciitis were clinically examined before and after repetitive low energy ESWA. Standard radiographs of the affected heels were obtained before ESWA to document the existence of a calcaneal heel spur. Magnetic resonance imaging (MRI) was performed before ESWA to evaluate abnormalities of the plantar fascia, the surrounding soft tissue structures, and bone marrow edema of the calcaneus.

RESULTS

After ESWA (mean followup 19.3 mo), clinical evaluation of all 48 heels revealed a statistically significant decrease in the mean visual analog scale score from 74.5 to 25.4. Using the Roles and Maudsley score (RM), an established scoring system for categorizing results of treatment following ESWA for patients with plantar fasciitis, patients could be divided into 2 groups, i.e., satisfactory clinical outcome of ESWA (grades 1 and 2 by RM scale; n = 36 heels) and unsatisfactory outcome (grades 3 and 4 by RM scale; n = 12 heels). While thickness of plantar aponeurosis, soft tissue signal intensity changes, and soft tissue contrast medium uptake did not correlate with clinical outcome, the presence of a calcaneal bone marrow edema was highly predictive for satisfactory clinical outcome (positive predictive value 0.94, sensitivity 0.89, specificity 0.8).

CONCLUSION

This study indicates that in patients with chronic plantar fasciitis, the presence of calcaneal bone marrow edema on pretherapeutic MRI is a good predictive variable for a satisfactory clinical outcome of ESWA.

High-speed spectroscopic imaging for cancellous bone marrow R(2)* mapping and lipid quantification

In this work an interleaved multiple-gradient-echo chemical shift imaging (IMGE-CSI) technique was designed, implemented and evaluated at 1.5 and 4T for high-resolution lipid quantification and R(2)* measurement in-vivo. The method is analogous to echo planar CSI but utilizes conventional gradient echoes, exploiting the principle of spectroscopic bandwidth extension by interleaving temporally offset gradient-echo trains. It is shown that IMGE-CSI is able to measure true fat volume fraction in oil/water mixtures with high accuracy, not possible with Dixon-type methods which approximate the spectrum as consisting of only two spectral components. Correlation of the CSI- derived volume fractions with volumetry afforded r(2) > 0.99 with a slope of 0.98. The method is shown to be able to quantify regional variations in bone marrow composition in vivo with a spatial resolution of 2.5 x 2.5 x 5 mm(3.) R(2)* was obtained by multi-line spectral curve fitting. For the measurement of R(2)* in cancellous bone marrow the method is shown to agree well with time-domain fitting techniques but is superior in instances where the marrow has both hematopoietic and fatty constituents. Finally, excellent inter-scan reproducibility (1% coefficient of variation for global means and medians) was achieved, yielding r(2) = 0.98 of the test-retest correlation for three scans in four test subjects. In conclusion, IMGE-CSI is found to enable highly accurate lipid quantification and measurement of cancellous bone marrow R(2)* at spatial resolutions and scan times typical of standard clinical protocols.

Osteolytic lesions of the tuber calcanei in two horses

Two adult horses were evaluated for chronic hind limb lameness. Nonseptic calcanean bursitis with associated focal osteolytic lesions at the point of insertion of the gastrocnemius tendon was diagnosed in each horse by physical and lameness examinations, radiography, ultrasonography, and synovial fluid analysis. Both horses underwent arthroscopic exploration and lavage of the affected bursa, and one horse also underwent surgical debridement of the osseous lesion. Both horses remained lame for 13 months after the surgical procedures. To our knowledge, osseous lesions of the calcaneus in horses with nonseptic calcanean bursitis have not been reported. The flexed proximoplantar-to-distoplantar tangential radiographic view of the calcaneus was essential in localizing the lesions, as was the sonogram in one horse. Arthroscopy provided a thorough evaluation of the bursa and associated tendons. On the basis of the outcome of these 2 horses, the prognosis for complete recovery for horses with this condition appears to be unfavorable. Surgical debridement of the osseous lesion was of no benefit and may have been detrimental.

Resection of talocalcaneal middle facet coalition. Interposition with a tensor fascia lata allograft: a case report

Tensor fascia lata is utilized in the management of complex soft-tissue injuries and defects, but has not been described in the literature in the use of tissue interposition with resection of talocalcaneal middle facet coalitions. This article is a case presentation of a resection of a middle facet coalition with interposition of an allograft of tensor fascia lata. At 14 months postoperative follow-up, range of motion of the subtalar joint was noted to be 20 degrees, and without pain or crepitus. There was no radiographic evidence of degenerative changes in Chopart's joint. The patient returned to all routine and sports activities without pain. He was satisfied with the outcome of the procedure.

Quantitative ultrasound and dual X-ray absorptiometry measurements of the calcaneus in patients on maintenance hemodialysis

It has been suggested that quantitative ultrasound measurements (QUS), which reflect mainly bone density, could be influenced by bone micro-architecture. The aim of the study was to assess whether the relationship of QUS to dual X-ray absorptiometry (DXA) would reflect abnormalities of bone structure observed in renal osteodystrophy. QUS and bone mineral density of the calcaneus (BMDc) were measured by DXA in 30 patients on maintenance hemodialysis and 34 age- and gender-matched controls. QUS parameters and BMDc were significantly lower in hemodialysis patients than in controls (speed of sound [SOS] and broadband ultrasound attenuation [BUA], p = 0. 030; stiffness, p = 0.003; BMDc, p = 0.006). Bone measurements were not correlated with serum parathyroid hormone (PTH). The regression lines of SOS, BUA, and stiffness to BMDc were not significantly different from that of the controls. When dividing the patients into two subgroups according to their median PTH (203 pg/mL), the slopes of the regression lines of BUA to BMDc were significantly different between these two subgroups (p = 0.052). The slope of the subgroup with PTH </= 203 pg/mL was significantly different from that of the controls (p = 0.030). In conclusion, QUS of the calcaneus can be used for bone assessment in patients on maintenance hemodialysis. The differences in the slopes of patients with a less pronounced degree of hyperparathyroidism compared with patients with a higher degree of hyperparathyroidism and to controls suggest that BUA of the calcaneus contains information on bone complementary to DXA measured at the same site. The clinical relevance of this finding is presently unclear.

Imaging ultrasonometry of the calcaneus: dependence on calcaneal area

The purpose of this study was (1) to investigate the dependence of broadband ultrasound attenuation (BUA) and speed of sound (SOS) measured in a circular region of interest (ROI) having a fixed size on calcaneal area and (2) to examine whether the normalization of ultrasonic variables for the area of the calcaneus provides better differentiation of diseased subjects from healthy individuals. Ultrasound variables were estimated in 169 healthy postmenopausal women (mean age 66.5 years, range 42-87 years) and 39 women with vertebral fractures (mean age 72.9 years, range 51-86 years). A minimum attenuation ROI, 15 mm in diameter, with a commercial imaging ultrasonometer was used. Significant relationships were found between both ultrasonic variables and calcaneal area (r2 = 0.06, P < 0.001 for BUA, r2 = 0.12, P < 0.0001 for SOS). Normalization of ultrasound variables (BUAn and SOSn) was based on the regression equations of the relationships among BUA, SOS, and calcaneal area. In a precision study, nine women were examined five times each to determine the errors arising from both the repositioning of the foot and selection of the calcaneal area. The reproducibility errors of BUA, SOS, BUAn, SOSn, and area were 0.87%, 0.20%, 1.07%, 0.27%, and 3.72%, respectively. Significant differences were found between the areas under the ROC curve for BUAn and BUA (area under the curve = 0.93 for BUAn versus 0.90 for BUA, P = 0.003) as well as for SOSn and SOS (area under the curve = 0.85 for SOSn versus 0.79 for SOS, P = 0.003). Normalization of ultrasound variables for calcaneal area improves the discrimination of clinical studies.

Evaluation of tendon-to-bone reattachment: a rabbit model

Two different tendon-to-bone reattachment methods were compared to assess tensile strength and histologic repair. After sharp dissection, rabbit Achilles tendons were reattached to the calcaneus by one of two methods: to abraded cortical bone (group 1) or into a cancellous bone tunnel (group 2). After surgery, each rabbit had its long-leg hip spica-cast in plantar flexion for 3 weeks. The rabbits' tendon-bone junctions were harvested 1, 2, 4, 6, and 12 weeks after surgery. Three rabbits were used for each repair method at each point in time: 2 for strength testing and 1 for histologic analysis. After this preliminary study, tensile strength was tested with another 14 rabbits 2 weeks after surgery. At each advancing point in time, in both groups, increasing tendon-bone strength was found. Ultimate tensile strength was equivalent for test rabbits (both methods after 6 weeks) and control rabbits. There was no significant difference between methods at any point in time. Blinded pathologic evaluation reported similar healing with both methods over time. With both methods, healing occurred with Sharpey fibers attached to the superficial cortex, with tendon resorption occurring in the bone tunnel. The simple method of cortical reattachment was shown to be equal to the more complex bone-tunnel reattachment.

Open reduction and augmentation of internal fixation with an injectable skeletal cement for the treatment of complex calcaneal fractures

OBJECTIVES

To describe the surgical handling, potential complications, and remodeling of an injectable, osteoconductive calcium phosphate cement (Norian SRS) for joint depression-type calcaneal fractures in humans, and to illustrate the clinical efficacy of this cement with special reference to early postoperative full weight bearing.

DESIGN

Prospective cohort study.

SETTING

Level I trauma centers in Bochum and Leipzig, Germany.

INTERVENTION

Thirty-six joint depression type calcaneal fractures in thirty-two patients were augmented with the calcium phosphate cement after standard open reduction with internal fixation. Postoperative full weight bearing was allowed progressively earlier, and as the study progressed, the last patients were bearing full weight as early as three weeks postoperatively. Biopsies for histologic analysis were performed at time of hardware removal after one year (seven biopsies) or in case of infection at time of debridement (five biopsies).

MAIN OUTCOME MEASURES

Clinical outcome was evaluated according to a calcaneal scoring system. Data were compared and statistically analyzed between patients with postoperative full weight bearing after eight to twelve weeks and three to six weeks, respectively. Histologic findings are described.

RESULTS

Cement injection averaged ten cubic centimeters and could easily be performed under fluoroscopic control. Progressively earlier full weight-bearing was achieved without loss of reduction. There was no statistical difference in clinical outcome scores in patients with full weight bearing before or after six weeks postoperatively. The infection rate was 11 percent, possibly related to the skin incisions. The biopsies from clinically satisfactory cases showed nearly complete bone apposition, areas of vascular penetration, and reversal lines illustrating progressive cycles of resorption and new bone formation. Biopsy specimens from infected cases showed bone and cement surrounded by either fibrous tissue or acute inflammation without extensive bone apposition.

CONCLUSIONS

Calcium phosphate cement augmentation of standard open reduction with internal fixation in joint-depression type calcaneal fractures allows postoperative full weight bearing as early as three weeks postoperatively. The injectable bone cement can easily be handled surgically under fluoroscopic control and has proved to be remodelable.

[Magnetic resonance tomography in sinus tarsi syndrome]

The sinus tarsi is a cone-shaped anatomical space in the hind foot that is bounded by the talus and calcaneus, the talonavicular and posterior sub-talar joint, and is continuous with the tarsal canal medially. The space courses from posteromedial to anterolateral, with the larger portion of the cone laterally situated. The sinus tarsi consists of fatty tissue, arterial anastomoses, joint recesses posteriorly, nerve endings, and five ligaments. These include the lateral, intermediate, medial roots of the inferior extensor retinaculum, the cervical ligament, and the interosseous ligament. The sinus syndrome is characterized by lateral foot pain, focal pain to palpation over the tarsal sinus, and hind foot instability. This chronic disease is related to a history of inversion trauma in the majority of patients. Magnetic resonance imaging (MRI) may be used in the evaluation of abnormalities associated with the sinus tarsi syndrome.