Proximal Plantar Plate of Lesser Toe Metatarsophalangeal Joint Vascular Supply.

BACKGROUND: The plantar plate is a major stabilizing structure of the metatarsophalangeal (MTP) joint with instability frequently occurring after a tear or attenuation of this structure. Commonly, a McGlamry elevator is used to strip the plantar plate from the plantar surface of the metatarsal to improve exposure of the MTP joint. The anatomy of the proximal plantar plate and vascular consequence of stripping the plantar plate from the metatarsal is not yet well understood. The purpose of this study is to describe the proximal attachment of the plantar plate anatomically and quantify the relative contribution of blood supply to the proximal plantar plate from both the metatarsal and the plantar fascia. METHODS: For anatomic evaluation, 6 lower extremity cadaver specimens without any gross evidence of foot and ankle deformity were utilized. For imaging analysis, 16 fresh frozen human adult cadaveric lower extremity specimens were used for this study, resulting in 35 MTP joints without deformity and 11 lesser MTP joints with cockup and/or crossover deformities. The specimens were prepared as described previously by Finney et al.5. RESULTS: From gross anatomic dissection, the plantar plate origin consists of a stout fibrous pedicle distinct from the surrounding synovial-type tissue that firmly anchors the plantar plate to the metatarsal. Based on nano-computed tomographic imaging, an average of 63.5% of the vascular supply to the proximal portion of the plantar plate entered from the metatarsal pedicle. The remaining 36.5% of the vascular supply entered from the plantar fascia. CONCLUSION: The proximal attachment of the plantar plate includes a stout fibrous pedicle anchoring the proximal portion of the plantar plate to the notch between the medial and lateral plantar condyles of the metatarsal head. The vascular supply of the proximal plantar plate is supplied from both the metatarsal pedicle and plantar fascia. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Gross anatomy, computed tomography, magnetic resonance imaging and bone mineral densitometry of the ovine metacarpo/metatarsophalangeal joint.

This study was aimed to provide anatomical atlas of the ovine metacarpo/metatarsophalangeal joints using computed tomography (CT) scan and magnetic resonance imaging (MRI), as well as to investigate bone mineral density (BMD) and morphometric features of this joint. The limbs of twenty adult Sanjabi sheep were examined. Imaging was performed using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner. The obtained images were correlated with corresponding anatomical sections. BMD was measured by Dual Energy X-ray Absorptiometry (DEXA) method. Also morphometric features included distance between metacarpal and metatarsal heads, width of metacarpal and metatarsal head, length, width and the height of the proximal sesamoid bones were measured. In MRI images, compact bones, ligaments and tendons showed less signal intensity (hypointense). The fatty tissue and bone marrow had more signal intensity (hyperintense), but articular cartilage and synovial fluid showed moderate signal intensity. BMD in the left hind limb was significantly higher than other three limbs (p ≤ 0.05). The length of proximal sesamoid bones in left forelimb was higher than right forelimb (p ≤ 0.05). The thickness of proximal sesamoid bones in left limbs was higher than those in their counterparts (p ≤ 0.05). The width of the medial head in the forelimbs was significantly greater than the hind limbs (p ≤ 0.05). The present results might be useful in managing the clinical techniques on this joint. Larger volume of the proximal sesamoid bones and wider medial head in the forelimbs compared to the hindlimbs impel this speculation that the centre of gravity is closer to the forelimbs.

Anatomical Study of the Accessory Tendon of the Extensor Hallucis Longus Muscle and Its Clinical Application.

BACKGROUD: The accessory tendon of the extensor hallucis longus (ATEHL) muscle is a common abnormal structure, and its clinical significance remains debatable. In this study, we provide the incidence of the ATEHL and characterize its morphological types in Asian cadavers and investigate its clinical applications. METHODS: The tendons from 50 adult cadaveric feet, fixed in 10% formalin, were analyzed. We measured the length and width of both the ATEHL and the extensor hallucis brevis (EHB). RESULTS: All dissected specimens had an ATEHL. The first metatarsophalangeal joint was surrounded by an accessory tendon that inserted onto the joint capsule and the dorsal base of the proximal phalanx. We classified the ATEHL into 3 types based on their directions. Differences in ATEHL type based on sex were not statistically significant. CONCLUSIONS: We found an ATEHL in all cadaveric specimens in this study. We surmise that the ATEHL acts as an antagonist with the EHB when the toe is extending, which might help prevent the occurrence of hallux valgus deformity.

Percutaneous Lateral Release in Hallux Valgus: Anatomic Basis and Indications.

In the last decade, minimally invasive or percutaneous surgery has evolved rapidly through the development of novel techniques. Treatment of hallux valgus deformity is one of the indications for percutaneous surgery, both for bony and soft tissue correction. The release of the structures on the lateral part of the first metatarsophalangeal joint (lateral release) is one of the best indications for percutaneous surgery in the forefoot. In this article, a detailed description of the anatomy of the metatarsophalangeal joint is provided, along with the indications and tips to perform a safe percutaneous lateral release.

Study on bio-inspired feet based on the cushioning and shock absorption characteristics of the ostrich foot.

As the main actuator of high-speed running, the ostrich feet are highly capable of cushioning and shock absorption. In this study, based on the elastic modulus scales and assembly order of the 3rd toe soft tissues and the functions of the metatarsophalangeal (MTP) joint, we designed fourteen bio-inspired feet. The impact process on loose sand was simulated on the finite element software Abaqus. Also the stress distributions and deformations of each component of the bio-inspired feet were clarified. With the peak acceleration as the index, the cushioning performances of the bio-inspired feet were compared on both loose sand and solid ground through height-variable impact tests. The 15-15-15 HA (hardness unit) bio-inspired foot showed lower peak acceleration and thereby better cushioning performance, but larger deformation, less-uniform stress distribution and thereby lower stability than the 15-35-55 HA bio-inspired foot. In fact, the silicon rubbers with different hardness degrees (which simulate the elasticity modulus scales of the digital cushions, fascia and skin) and the spring mechanism (which simulates the functions of the MTP joint) work as an "integrated system" of cushioning and shock absorption.

Nonsurgical Treatment for Hallux Abducto Valgus with Botulinum Toxin Type A.

BACKGROUND: Hallux abducto valgus (HAV) is a frequently seen abnormality of the first metatarsophalangeal joint. Limited conservative treatment options exist, making surgery the only definitive treatment option for a mild to moderate deformity. Since initially published in 2008, treatment of HAV with botulinum toxin injection has evolved as a potentially effective modality as shown in several subsequent independent studies. METHODS: Botulinum injection of two intrinsic foot muscles (extensor halluces brevis and flexor hallucis brevis) in addition to adductor hallucis under electrical stimulation is presented as an improvement to the original method. RESULTS: The additional muscle injections of botulinum resulted in an further reduction of the HAV deformity and associated pain. CONCLUSIONS: A significant improvement to the injection paradigm developed the author may prove to be more effective in reducing the HAV deformity and its associated pain.

High-Resolution MRI of the First Metatarsophalangeal Joint: Gross Anatomy and Injury Characterization.

The first metatarsophalangeal joint (MTPJ) is vital to the biomechanics of the foot and supports a weight up to eight times heavier than the body during athletic activities. The first MTPJ comprises osseous and cartilaginous surfaces along with a complex of supporting structures, including the dorsal extensor tendons, collateral ligaments, and a plantar plate complex. In contradistinction to the lesser MTPJ plantar plates, a single dominant fibrocartilaginous capsular thickening does not exist at the first MTPJ. Instead, the plantar plate complex comprises a fibrocartilaginous pad that invests the hallux sesamoids and is inseparable from the plantar capsule, the intersesamoid ligament, paired metatarsosesamoid and sesamoid phalangeal ligaments (SPLs), and the musculotendinous structures. Acute injury at the first MTPJ is typically secondary to forced hyperextension-turf toe-and can involve multiple structures. During hyperextension, the resulting forces primarily load the distal SPLs, making these structures more susceptible to injury. SPL injuries are best seen in the sagittal plane at MRI. Radiography can also aid in diagnosis of full-thickness SPL tears, demonstrating reduced sesamoid excursion at lateral dorsiflexed (stress) views. Hallux valgus is another common condition, resulting in progressive disabling deformity at the first MTPJ. Without appropriate treatment, first MTPJ injuries may progress to degenerative hallux rigidus. The authors detail the anatomy of the first MTPJ in cadaveric forefeet by using high-resolution 3-T and 11.7-T MRI and anatomic-pathologic correlation. Injuries to the plantar plate complex, collateral ligaments, and extensor mechanism are discussed using clinical case examples. Online supplemental material is available for this article. ©RSNA, 2020.

Evaluation of the Association Between Plantar Fasciitis and Hallux Valgus.

BACKGROUND: The windlass mechanism, first described by John Hicks in 1954, defines the anatomical and biomechanical relationship between the hallux and the plantar fascia. Hallux valgus (HV) and plantar fasciitis are the most common foot disorders, and, to date, no study has evaluated the relationship between these disorders. The purpose of this study was to determine the incidence of and factors associated with plantar fasciitis in patients with HV deformity. METHODS: In this prospective observational study, 486 patients with HV were divided into three groups according to stage of HV deformity. Patient sex, age, and body mass index were recorded. Presence of accompanying plantar fasciitis and heel spur was investigated by physical and radiographic examination. First metatarsophalangeal joint dorsiflexion of the affected side was measured. Patients with or without plantar fasciitis were also compared to evaluate factors associated with plantar fasciitis. RESULTS: Mean age and body mass index of the patients were significantly different among the three HV groups. The incidence of plantar fasciitis and heel spur significantly increased in correlation with the severity of HV deformity. Increased age and HV stage and decreased first metatarsophalangeal joint dorsiflexion were significantly associated with presence of plantar fasciitis in HV. CONCLUSIONS: In this study, the incidence of plantar fasciitis was significantly increased in correlation with the severity of HV deformity. Significant association was found between plantar fasciitis and HV, which are anatomically and biomechanically related to each other by the windlass mechanism.

Metatarsalgia: Assessment Algorithm and Decision Making.

Historically, metatarsalgia was approached as a forefoot condition, most often associated with hallux valgus. Consequently, surgical treatments were limited to that anatomic zone, disregarding more proximal structures. In order to assess this entity properly, it is necessary to consider anatomic and biomechanical factors, as well as general and local conditions of the affected patients. A thorough understanding of the multiple potential causal factors is essential to ensure selection of the optimal treatment.

Intra- and Interobserver Agreement in Hallux Valgus Angle Measurements on Weightbearing and Non-Weightbearing Radiographs.

The choice of treatment of hallux valgus deformity is influenced by angles measured on radiographs. Angles of interest are the hallux valgus angle (HVA), 1,2-intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA), as well as the presence of first metatarsophalangeal joint (MTPJ) subluxation. Guidelines for measuring those angles have been distributed by American Orthopaedic Foot and Ankle Society (AOFAS), although the influence of weightbearing on these angles and its clinical relevance is not clear. We conducted a study to determine the influence of weightbearing and the inter- and intraobserver agreement in the measurement. A total of 104 patients were enrolled in this study. Both weightbearing and non-weightbearing radiographs were obtained. In 2 rounds, 2 orthopedic surgeons and 2 musculoskeletal radiologists measured the angles in blinded digital radiographs according to AOFAS guidelines. Agreement on measurement of HVA, IMA, and DMAA in both weightbearing and non-weightbearing radiographs, as well as the presence of MTPJ subluxation, was calculated using the linear-weighted kappa coefficient and the intraclass correlation coefficient (ICC). Examiner agreement strength was defined according to the guidelines of Landis and Koch. HVA decreases significantly with weightbearing, whereas IMA significantly increases. The change in magnitude was 1° to 2° on average. No significant influence on DMAA could be noted. Interobserver agreement was excellent in both weightbearing and non-weightbearing radiographs for HVA (ICC 0.99 and ICC 0.99, respectively), IMA (ICC 0.98 and ICC 0.86, respectively), and DMAA (ICC 0.95 and ICC 0.97, respectively). The agreement on presence of subluxation was moderate to good (Fleiss kappa 0.50 to 0.63). Weightbearing alters forefoot geometry significantly. Adhering to AOFAS guidelines yields excellent interobserver agreement on HVA, IMA, and DMAA. First MTPJ subluxation presence is not an alternative for DMAA. The magnitude of change in IMA and HVA is small and therefore not clinically important. Both weightbearing and non-weightbearing radiographs can be used for determination of the correct treatment of hallux valgus deformity.

Establishing a common instantaneous center of rotation for the metatarso-phalangeal and metatarso-sesamoid joints: a theoretical geometric model based on specific morphometrics.

BACKGROUND: Previous research has identified separate sagittal plane instantaneous centers of rotation for the metatarso-phalangeal and metatarso-sesamoid joints, but surprisingly, it does not appear that any have integrated the distinctive morphological characteristics of all three joints and their respective axes into a model that collectively unifies their functional motions. Since all joint motion is defined by its centers of rotation, establishing this in a complicated multi-dimensional structure such as the metatarso-phalangeal-sesamoid joint complex is fundamental to understanding its functionality and subsequent structural failures such as hallux abducto valgus and hallux rigidus. METHODS: Based on a hypothesis that it is possible to develop an instantaneous center of rotation common to all four osseous structures, specific morphometrics were selected from a sequential series of 0.5-mm sagittal plane C-T sections in one representative cadaver specimen randomly selected from a cohort of nine, seven which were obtained from the Body Donation Program, Department of Anatomy, University of California, San Diego School of Medicine, and two which were in the possession of one author (MD). All mature skeletal specimens appeared grossly normal, shared similar morphological features, and displayed no evidence of prior trauma, deformity, or surgery. Specific C-T sections isolated the sagittal plane characteristics of the inter-sesamoidal ridge and each sesamoid groove, and criteria for establishing theoretical sesamoid contact points were established. From these data, a geometric model was developed which, to be accurate, had to closely mimic all physical and spatial characteristics specific to each bone, account for individual variations and pathological states, and be consistent with previously established metatarso-phalangeal joint functional motion. RESULTS: Sequential sagittal plane C-T sections dissected the metatarsal head from medial to lateral and, at approximately midway through the metatarsal head, the circular nature of the inter-sesamoidal ridge (crista) was isolated; other C-T sections defined, respectively, the elliptical characteristics of the tibial (medial) and fibular (lateral) sesamoid grooves in each specimen. A general plane model representing the most basic form of the joint was developed, and its center of rotation was established with a series of tangential and normal lines. Simplified tibial sesamoid and fibular plane models were developed next which, when combined, permitted the development of a spherical model with three separate contact points. Based on the morphometrics of each sesamoid groove and a more distally positioned tibial sesamoid, the model was modified to accurately define the center of rotation and one distinctive sagittal plane geometric and functional characteristic of each groove. CONCLUSION: Consistent with our hypothesis, this theoretical geometric model illustrates how it is possible to define an instantaneous center of rotation common to all three joints while simultaneously accounting for morphometric and spatial variability. This should provide additional insight into metatarso-phalangeal-sesamoid joint complex functionality and the physical characteristics that contribute to its failure.

A comparison of metatarsophalangeal joint center locations on estimated joint moments during running.

The forefoot functions as the base of support during late stance, rotating about the dual-axis of the metatarsophalangeal joints. Previous research has shown that joint axis definition affects estimated joint moments about the forefoot. However, little is known about how metatarsophalangeal joint center definition affects estimated joint kinetics. This study compared moments about the metatarsophalangeal joint using four different defined joint centers. There was a significant difference (p < .001) in peak moments between joint center definitions, differing by up to 0.488 N-m/kg for the slow and 0.878 N-m/kg for the fast running speeds tested. Additionally, there was a significant difference (p < .001) for when peak plantar flexor moment occurred during the slower running condition. The more posteriorly oriented joint centers resulted in higher moments and earlier onset of the plantar flexor moment. In addition to careful modeling of the metatarsophalangeal joint axis, it is recommended that joint center definition should be considered as well.

Normal magnetic resonance anatomy of the hind foot of Egyptian buffalo (Bubalus bubalis): A correlative low-field T1- and T2-weighted MRI and sectional anatomy atlas.

Buffaloes represent a major source of milk production, especially in developing countries including Egypt. The buffalo foot is frequently involved in a large proportion of lameness cases. The relatively small size and complexity of its structures often render the radiographic evaluation of the foot challenging. Magnetic resonance imaging (MRI) is a noninvasive imaging technique that is regarded as both safe and accurate for assessment of the foot disorders in both man and animals. The purpose of the current investigation was to describe the MRI anatomy of buffalo foot using cadaveric hind feet. The feet were subjected to consecutive MRI scanning using a 0.3 Tesla scanner. Both T1-weighted (T1-W) and T2-weighted (T2-W) spin-echo pulse sequences were applied in dorsal, sagittal and transverse planes. The heterogeneity of signal intensities noted amongst foot components allowed for clear differentiation of bones, tendons, ligaments, adipose tissue and synovial fluid. The T1-W images provided an excellent overview of the foot. They were valuable for visualizing the bones and the alignment of tendons and ligaments. The T2-W images were particularly useful for the evaluation of synovial structures such as tendon sheaths and joint cavities. A communication between the two plantar sacs of the metatarsophalangeal (fetlock) joints was evident in T2-W images. MRI findings were further confirmed using relevant gross anatomical sections. The present study establishes a detailed MRI anatomic reference of buffalo foot that could help veterinary researchers, clinicians and surgeons for increasing the accuracy of interpretation of foot MRI scans of both healthy and diseased animals.

Morphological, radiographic and computed tomographic evaluation of the metatarsophalangeal joint of the one-humped camel.

The camel digits have a complex structure with tendons, joints and ligaments. The objective of the study was to determine the anatomical features of the metatarsophalangeal joint and its puncture site in dromedary camel using anatomical dissection, radiography, computed tomography (CT) bone and soft tissue window scans and 3D reconstruction render volume of CT. The study used six adult camels of both sexes (three males and three females), aged 9-15 years (Mean ± SD equal 11.80 ± 2.59 years). The camel fetlock possesses two metatarsophalangeal joints, left and right ones. The study described in detail the bony structures, ligaments and joint capsule of the metatarsophalangeal joint. The straight sesamoidean ligament was recorded in the studied one-humped camel joints. The joint capsule exhibited two recesses: dorsal and plantar recess. This is the first study to report the dorsal recess as triangular in outline with one proximal recess and two distal recesses, and the plantar recess as having two proximal recesses and one distal recess. The soft tissues examined around the fetlock were the proper extensor tendon, superficial, deep digital flexor tendon, digital scutum, collateral ligaments and sesamoidean ligaments. The plantar and dorsal pouches were the sites of joint injection. The present findings regarding joint injection indicate the plantar approach through plantar recess to fetlock to be preferable than the dorsal one as we used the proximal sesamoid bones and suspensory ligament as landmarks to inject easily.

MR imaging-anatomical correlation of the metatarsophalangeal joint of the hallux: Ligaments, tendons, and muscles.

OBJECTIVE: To perform an MR imaging-anatomical correlation to elucidate the anatomy of muscles, tendons, and ligaments about the hallux as seen on MR imaging. MATERIALS AND METHODS: Four fresh and 4 embalmed cadaver specimens were used for this study. The embalmed specimens and one fresh specimen were dissected by three investigators. The fresh specimens were preserved deep frozen. They were thawed and imaged with a 3 T MR system. Proton density weighted images were obtained. The specimens were refrozen and sectioned with a band saw into 3 mm thick slices. RESULTS: Musculotendinous structures were equally well seen in the fresh and embalmed specimens. The capsular ligaments could best be studied in the fresh specimens. Proximal to the sesamoids the following muscle and tendon anatomy was delineated: the abductor hallucis tendon inserted on the medial sesamoid bone together with the medial belly of the flexor digitorum brevis; the adductor hallucis (transverse and oblique heads) inserted on the lateral sesamoid together with the lateral head of the flexor hallucis brevis. At the level of the sesamoid bones and distally, the ligaments making up the plantar plate were delineated, including the presesamoid band, the flexor hallucis longus pulley, the sesamometatarsal ligaments, the sesamophalangeal ligaments, and the capsular ligaments. CONCLUSION: MRI allows for accurate assessment of the complex anatomy of the hallux. At the level proximal to the sesamoids the muscle and tendon insertions are well demonstrated. At the level of the sesamoids and distally, the ligaments making up 'the plantar plate' are well demonstrated.

Correlation of Radiographic Measurements With Patient-Centered Outcomes in Hallux Valgus Surgery.

BACKGROUND:: Evaluation of patients undergoing hallux valgus surgery has historically emphasized radiographic angles and relationships. However, patient-reported outcomes are increasingly important as health care systems trend towards a "value-based" delivery approach. METHODS:: We conducted a retrospective analysis of pre-existing data in our practice to examine whether patient-reported outcomes after bunion surgery, determined via Foot and Ankle Outcome Scores (FAOS), correlated with radiographic parameters commonly measured in hallux valgus deformity. Pearson correlation statistics and simple and multiple linear regression models were used to identify important radiographic predictors. There were 80 patients (80 feet) with mean follow-up of 59.3 ± 11.6 weeks (median 55, range 45.7-96.3 weeks) with complete data. RESULTS:: No radiographic measurement/variable achieved anything more than a weak correlation with any of the FAOS subscale scores at final follow-up; the study's best was postoperative first-second intermetatarsal (IM) angle with sports and recreation scores ( r = -0.328, P = .005). There was no correlation found between change in hallux valgus angle, change in first-second IM angle, magnitude of preoperative hallux valgus angle or magnitude of preoperative first-second IM angle ( P > .05 for all). Furthermore, none of the study's final multivariable models achieved an R2 > 0.24, and nearly all fell between 0.10 and 0.17. CONCLUSION:: We conclude that radiographic angles were not well correlated with patient-centered outcomes in hallux valgus surgery. This study calls into question the current emphasis that is placed on x-ray values both pre- and postoperatively. LEVEL OF CLINICAL EVIDENCE:: Level III, comparative study.

Measuring Visualized Joint Surface in Hallux Metatarsophalangeal Arthroscopy.

BACKGROUND: Arthroscopy has been increasingly used to evaluate small joints in the foot and ankle. In the hallux metatarsophalangeal (MTP) joint, little data exist evaluating the efficacy of arthroscopy to visualize the articular surface. The goal of this cadaveric study was to determine how much articular surface of the MTP joint could be visualized during joint arthroscopy. METHODS: Ten fresh cadaveric foot specimens were evaluated using standard arthroscopy techniques. The edges of the visualized joint surface were marked with curettes and Kirschner wires; the joints were then surgically exposed and imaged. The visualized surface area was measured using ImageJ® software. RESULTS: On the distal 2-dimensional projection of the joint surface, an average 57.5% (range, 49.6%-65.3%) of the metatarsal head and 100% (range, 100%-100%) of the proximal phalanx base were visualized. From a lateral view of the metatarsal head, an average 72 degrees (range, 65-80 degrees) was visualized out of an average total articular arc of 199 degrees (range, 192-206 degrees), for an average 36.5% (range, 32.2%-40.8%) of the articular arc. CONCLUSION: Complete visualization of the proximal phalanx base was obtained. Incomplete metatarsal head visualization was obtained, but this is limited by technique limitations that may not reflect clinical practice. CLINICAL RELEVANCE: This information helps to validate the utility of arthrosocpy at the hallux metatarsophalangeal joint.

Ultrasonography, computed tomography and magnetic resonance imaging of the bovine metacarpo/metatarsophalangeal joint.

The aims of the present study were to describe the normal ultrasonographic, magnetic resonance imaging (MRI) and computed tomographic (CT) appearances of the bovine metacarpo/metatarsophalangeal (MCP/MTP) joints and to assess the normal cross-sectional dimensions of the superficial (SDFT) and deep (DDFT) digital flexor tendons. A systematic ultrasound examination was performed on the MCP/MTP joints of 22 healthy cattle and two bovine cadavers, and the cross-sectional dimensions of the SDFT and DDFT were recorded. The cadaveric MCP/MTP joints (n=8) were scanned using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner, injected with green latex and sectioned into transverse (n=4), sagittal (n=2) and dorsal (n=2) slices. Ultrasonographic, CT and MRI images were correlated with corresponding findings in anatomical dissections for the distal aspects of the third and fourth metacarpal/metatarsal bones, proximal aspects of the proximal phalanges, proximal sesamoid bones, lateral, common and medial digital extensor tendons, SDFT, DDFT, axial and abaxial collateral ligaments, suspensory, palmar/plantar, interdigital intersesamoidean and interdigital phalangosesamoidean ligaments, and collateral, cruciate and short sesamoidean ligaments. The axial and collateral sesamoidean ligaments could not be evaluated by ultrasonography. The articular cartilage, and the short and cruciate sesamoidean ligaments, were not identified in CT images. The cross-sectional dimensions of the SDFT and DDFT differed significantly between the forelimbs and hind limbs (P<0.05); there were no significant differences between the contralateral limbs. The annotated ultrasonographic, CT and MRI images are intended as a normal reference that could be useful for interpretation of clinical disease in the bovine MCP/MTP joint.

Anatomy and Physiology of the Lesser Metatarsophalangeal Joints.

Knowledge and command of anatomy is paramount to effectively treating disorders of the lesser metatarsophalangeal (MTP) joints. The osseous structures consist of the proximal phalanx of the toe and the metatarsal head. The soft tissues on the dorsum of the MTP joint include the joint capsule and the tendons of extensor digitorum longus and extensor digitorum brevis. The proper and accessory collateral ligaments form the medial and lateral walls and contribute to stability in the coronal and sagittal planes. The plantar plate forms the plantar border of the MTP joint and stabilizes the MTP joint against hyperextension and dorsal translation.

Partite hallux sesamoid bones: Relationship with sesamoid bones at other metatarsophalangeal joints.

Partite hallux sesamoids are clinically meaningful but their association with other sesamoids is not clear. The objective was to relate the prevalence of the partite hallux sesamoid bones to sesamoid bones at other metatarsophalangeal (MTP) joints. We conducted a retrospective review of plain radiographs of 7946 adult feet between November 2005 and September 2012 to identify partite hallux sesamoids and sesamoids at other MTP joints. Coexistence patterns of the partition and extra sesamoids were studied. Presence or absence of sesamoids at other MTP joints as well as sex and laterality were compared between the feet with and without partite hallux sesamoids using Pearson Chi-square test. Association between age and partition was evaluated using Spearman's correlation coefficient. Overall partite prevalence rate is 6.82%, and coexistence with extra MTP sesamoids was 0.42%. One pattern was partition in hallux sesamoid only, and 4 patterns were coexistence with extra sesamoids. The prevalence rates of partite hallux sesamoids were 7.17% (508/7081) and 3.93% (34/865) in feet without and with extra sesamoids, respectively. The relative risk of 1.889 (95% CI, 1.325-2.693) of partite hallux sesamoids was noted in feet without than with extra sesamoids (Χ2 = 12.759, P < 0.001). A negative correlation between age and distribution of partition was identified (r = -0.061, P < 0.001). Partition of hallux sesamoid bones is a developmental variation, it can coexist with sesamoids at other MTP joints following a certain pattern; and its prevalence rate is almost twice higher in feet without than with extra MTP sesamoids. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:34-38, 2018. © 2017 Wiley Periodicals, Inc.