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Running is a very popular activity, whether for competition or fitness. Breakdown injuries related to training errors, shoe wear, or change in intensity are frequently seen by the sports medicine physician. In order to understand and treat the pathologic situation, a fundamental understanding of the biomechanics of walking and running is essential. The treating practitioner must appreciate the distinct differences between the walking and running gait. These differences transcend a simple increase in speed of gait and include distinct changes in joint range of motion and electromyographic activity. Armed with this knowledge, the practitioner treating a breakdown injury can work to a solution based on scientific understanding rather than anecdotal information.

We studied the function of the first tarsometatarsal joint in 100 specimens of 53 cadavers. The study showed that an adduction and abduction movement described earlier was present only in approximately 10% of the specimens. Moreover, eversion of an average of 6.2 degrees often only occurs as a result of dorsal displacement of the joint surfaces of the first metatarsal in relation to the first cuneiform by an average of 2.6 mm. All other movements in the frontal, horizontal, and sagittal plane can be disregarded or are the result of this movement. New conclusions may be drawn from these results, especially with regard to subcapital osteotomies of the first metatarsal and the adductor transfer according to McBride in metatarsus primus varus. These findings challenge the value of the McBride transfer.

The structural component of the arches of the human foot were analyzed by a radiogrammetric method and multivariate statistical procedures. The right feet of 101 male university students were radiographed in the standing position from a lateromedial direction. 6 joint heights were measured directly on the radiographs. Factor analysis with varimax rotation showed 3 basic underlying factors for arch heights: (1) calcaneonavicular joint, cuneonavicular joint and first tarsometatarsal joint; (2) calcaneocuboidal joint and 5th tarsometatarsal joint and (3) subtalar joint. The first factor represented the medial longitudinal arch height, the second was associated with the lateral longitudinal arch height. No transverse factor indicating tarsometatarsal or transverse tarsal joints was found. Cluster analysis showed a similar configuration to that in factor analysis. Analysis suggested a key role of the subtalar joint which integrated both the medial and lateral longitudinal arch heights.

A description is given of the functional morphology of the intrinsic joints of the foot, with particular reference to the primates, and an attempt is made to define the key human derived features. In the human subtalar joint the compromise axis has become reoriented into a very elevated position and more nearly in line with the functional foot axis than it is in subhuman primates. This provides for torque of the talus, and so the supported body weight, about the axis, during the stance phase of gait. In the subhuman primates the very oblique subtalar axis is important in inverting the foot into a grasping attitude. In subhuman primates the transverse tarsal joint complex plays an important role in supination of the forefoot, which complements inversion at the subtalar joint complex in achieving the ideal grasping position. This movement is only rendered possible by a helical action at the subtalar joint complex. In man the calcaneocuboid joint has been remodelled so as to bring the lamina pedis into a close-packed position during the latter part of the stance phase of gait. The joints between the cuneiforms and the cuboids, and the associated tarsometatarsal joints show significant modifications in man.

In addition to loose connective tissue, fat and blood vessels, the sinus and canalis tarsi also contain the capsules for the intertarsal joints as well as several varyingly stable tracts of fibers which present themselves in varying planes and directions but are nevertheless in a discernible arrangement to one another. This arrangement of fibers was studied on the feet of 40 adults whereby five distinct and clearly definable bundles could be regularly dissected. Starting from the lateral side and going medialis of the retinaculum mm. extensorum inferius, also a lig. talocalcaneum obliquum and a lig. canalis tarsi. Microscopically, fibrocartilage is evidenced in the ligaments and retinacula near their points of attachment to the bone. The ligaments lying lateral to the axis of movements for the talocalcaneal joint restrain the inversion while the medially lying lig. canalis tarsi prevents the eversion.

This article focuses on nearly 50 years of research by various authors documenting function and motion of the midtarsal joint. Subtalar joint control of the midtarsal joint, axes of motion, and quantification of range of motion are examined. The evolution of the joint from primates to man and the associated changes in functional requirements are considered.

Displaced intra-articular fractures of the body of the os calcis are notorious causes of significant and prolonged disability. Treatment recommendations for these injuries have varied widely. An understanding of the anatomy and pathomechanics of the injury is important in treatment selection. Tongue-type and joint depression-type calcaneal fractures are subdivided on the basis of relations of the primary fracture line to the posterior facet. Treatment regimens are also based upon these relations and fracture classification. Choice of surgical approach depends upon the fracture pattern, including secondary comminution. The goal of operative treatment is to reestablish articular congruency, calcaneal width, and early range of motion. Operative treatment can be recommended for fractures that can be accurately reduced and rigidly transfixed. Nonoperative treatment is recommended for those fractures where accurate reduction is unattainable.

The prints of the subtalar articulation were studied in several positions. An original set allowed the fixation of the articulation under pressure and in the desired position. Contact areas of articular surfaces were coloured by Safranin 0. In inversion and eversion, the rate of incongruency of articular surfaces increased, while the contact was maximal in a mid-position, fixed by a passive blocking of the articulation. According to our results, the support is the main position transmitting the pressures during the gait when the talocrural joint is in motion; the inversion is the essential movement when the foot is not in contact with the ground.

Convex and concave articular cartilage from adult subtalar and midtarsal joints showed depressions over surface chondrocytes and linear arrays of surface fibres when examined by scanning electron microscopy (SEM). Full-thickness cartilage from concave surfaces contained significantly less collagen than cartilage from convex surfaces (40.8% vs. 47.4%, p less than 0.05). Plano-concave surfaces contained 44.7% collagen. Water and uronic acid content did not differ significantly for the different shapes. A higher collagen content in convex surfaces is consistent with the hypothesis that collagen networks in these surfaces are subjected to higher tensile stress under load than are those in concave ones.

These injuries are associated with considerable morbidity, and successful results depend on understanding the anatomy, understanding pathogenesis, and precise and careful treatment of this injury. Surgical treatment is discussed as well as arguments against the use of conservative treatment.

The curvature and extent of a joint surface largely determine the type and range of motion possible. The talonavicular surface anatomy of 10 human foot specimens has been determined quantitatively, and the data have been compared with the design parameters for a prototype prosthetic joint. It was found that, in general, the natural talus as compared with the navicular was slightly larger in surface area and in mean arc length, but slightly smaller in mean radius of curvature. The arc length of the joint was found to be generally slightly longer along an axis positioned from slightly medial of dorsal to slightly lateral of ventral. In contrast, no general orientation of the radius of curvature was observed. Also, it was found that the congruency between the talus and navicular surfaces, as indicated by corresponding radii of curvature, varied widely. In comparison to the human specimens, a previously designed prototype talonavicular prosthesis proved somewhat smaller in radius, arc length, and surface area. Experimental studies related to other prosthesis design parameters, besides type and range of motion, are in progress.

Eighty 25-week-old male broiler-breeder chickens were placed in pens with elevated slats for 16 weeks. A similar group of birds was housed on floor pens for comparison. The coxofemoral, stifle, and tibiotarsal joints and their supporting tendons and ligaments were examined grossly. Rearing heavy broiler-breeders on elevated slats did not result in grossly apparent arthritis, tendonitis, or tendon failure. Body weights and shank lengths and diameters were not markedly different. Microscopically, the broiler-breeders reared on slats had a lymphocytic synovitis with synovial cell hyperplasia involving the gastrocnemius and digital flexor tendons. The incidence and severity of the lesion increased with time.

Dissection reveals that the ball of the foot contains a connective tissue framework with transverse, vertical, and sagittal fibers, all connecting the skin with the proximal phalanges of the toes. Dorsiflexion of the toes tightens the framework and thereby restricts passive movements of the skin, enabling shear forces to be transferred to the skeleton. An electromechanical oscillator was constructed that applied oscillatory shear forces of constant amplitude (+/- 0.2 N) to the skin and at the same time measured the resulting motions. It was found that the toes should be dorsiflexed by 35--40 degrees to restrict skin mobility to 50 per cent and by 50 degrees to restrict it maximally. The results were compared to actual dorsiflexions of toes during walking. These dorsiflexions were measured on slow motion film and with still pictures with light tracks formed by light emitting diodes. Maximal dorsiflexion during push off was found to be 60 degrees for feet walking without shoes, 45--50 degrees for feet walking in soft shoes, and 25--30 degrees for feet walking in a stiff shoe of the minus-heel type. Dorsiflexion was further found significant for arch support and for the mechanics of the forefoot during push-off.

Considerable difficulty may be encountered in evaluation of the disrupted tarsometatarsal joint complex as seen in variations of fracture dislocations of the Lisfranc's joint. This report points out constant relationships between the tarsal and metatarsal bones as seen on the standard anteroposterior and medial oblique views. Awareness of these constant radiological relationships can help the operating surgeon reconstruct the normal anatomic alignment.

In this paper a critical comment is given on the generally accepted terminology for the structural and functional description of the tarsal joints and their motions. Attention is given to the terms established in the officially canonized Nomina Anatomica (NA) of the IANC as well as to the widely used terms in clinical literature. This terminology has been reviewed in the light of underlying kinematic concepts developed by investigators of tarsal joint motions as found in the original papers and in a number of widely used handbooks. Conflicting points of these concepts are briefly discussed while referring to the results of recent biomechanical research.

In Greyhounds, 2 plantar sesamoid bones were identified in radiographs taken of the intact tarsus and also of the tarsometatarsal fibrocartilage, that had been dissected free from the joints. Anatomic dissections defined the precise position of each sesamoid. A prominent sesamoid was present on the lateral side of the tarsometatarsal articulation in 50% of the tarsi; it is proposed that this bone be named the lateral plantar tarsometatarsal sesamoid bone. A smaller bone was detected on the medial side of the tarsometatarsal articulation in 27% of the tarsi; it is proposed that this bone be named the intra-articular tarsometatarsal sesamoid bone.