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The Lower Extremities
Published in Melanie Franklyn, Peter Vee Sin Lee, Military Injury Biomechanics, 2017
The talus rests on the anterior two-thirds of the calcaneus (Moore et al. 2011). The calcaneus is the largest and strongest bone of the foot and transmits the majority of the body weight from the talus to the ground. The posterior portion of the calcaneus serves as the insertion point for the Achilles tendon. The head of the talus is supported by the talar shelf of the calcaneus. It also articulates with the navicular. The navicular bone resides on the medial side of the foot and has three strongly concave proximal articular surfaces for each of the three cuneiform bones. The medial, middle and lateral cuneiforms articulate with the first, second and third metatarsal bones, respectively, via a tarsometatarsal joint. Residing medial of the cuneiform is the cuboid bone. The lateral cuneiform and navicular bones articulate with the medial surface of the cuboid bone. The cuboid bone also articulates with the fourth and fifth metatarsal bones forming the tarsometatarsal joint and with the calcaneus proximally at the calcaneocuboid joint. The metatarsals connect the tarsus to the 14 phalanges. Each phalange is constructed of three bones except the first phalange which consists of two bones (Moore et al. 2011).
Designing for Foot and Ankle Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The tarsal bones form the rear of the foot and can be subdivided into proximal bones and distal bones. The proximal bones include the calcaneus and the talus. The calcaneus is the largest tarsal bone. You can feel its solid structure at the back and bottom of your foot. The calcaneal (Achilles) tendon attaches to the calcaneus and extends to the strong muscles on the posterior of the leg. The talus, as the uppermost foot bone, interfaces with the bones of the leg above it, the tibia and the fibula, to form the ankle (talocrural joint). Find the joint by locating the intersection of the leg and the foot. Refer to the illustration of the lower limb in Chapter 5 if needed. Run your hands down the inside and outside length of your leg from about mid-calf until you feel two protrusions. On the medial side of your leg you will feel the medial malleolus which is the distal end of the tibia. Along the outside feel the lateral malleolus which is the most distal portion of the fibula. The medial malleolus is slightly higher. Because these protrusions of the ankle do not lie on the same transverse plane (parallel to the ground), the total circumference for footwear, like high-top, pull-on boots, should be designed to comfortably encircle both malleoli. The tibia transmits the weight of the body to the talus. The fibula, with the ankle ligaments, acts as a strut to stabilize the talus beneath the tibia. The talus is unusual, as no muscles attach to it (Hamill & Knutzen, 2003). The talus rests on the calcaneus below, forming the subtalarjoint. The ankle structure, while amazingly sturdy, is very flexible and also susceptible to sprains as described later in this chapter.
Musculoskeletal system
Published in David A Lisle, Imaging for Students, 2012
Fractures of the calcaneus may show considerable displacement and comminution, and may involve the subtalar joint. Boehler’s angle is the angle formed by a line tangential to the superior extra-articular portion of the calcaneus and a line tangential to the superior intra-articular portion. Boehler’s angle normally measures 25–40°. Reduction of Boehler’s angle in a setting of trauma is a useful sign of a displaced intra-articular fracture of the calcaneus; these fractures may otherwise be difficult to see on radiographs (Fig. 8.49).
A simple and effective 1D-element discrete-based method for computational bone remodeling
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Diego Quexada-Rodríguez, Kalenia Márquez-Flórez, Miguel Cerrolaza, Carlos Duque-Daza, Olfa Trabelsi, M.A Velasco, Salah Ramtani, Marie Christine Ho-Ba-Tho, Diego Garzón-Alvarado
The calcaneus bone is the largest tarsal bone and it is characterized by a cortex containing trabecular bone (Metcalf et al. 2018). Due to the mechanical stresses acting on the calcaneus, a set of trabecular groups are formed and play a crucial role in the biomechanics of this bone. These are important in orthopedic procedures and pathology treatments that compromise bone integrity such as in osteoarthritis therapy. The loading conditions were addressed as bone remodeling problems with the methodology proposed herein. The resulting trabecular groups resemble those seen in the calcaneus bone illustrated in Figure 16(c). As in the previous medical case, a set of main trabecular groups have been identified as displayed in Figure 16(b). These are in good agreement with anatomical studies regarding the biomechanics of calcaneus bone (Abboud 2018). The following trabecular motifs can be identified individually for the boundary conditions of (Belinha et al. 2012): thalamic group (1); inferior plantar group (2); anterior apophyseal group (3); anterior plantar group (4); posterior achillean group (5); and central triangular area of refracted bone (6). An aspect that calls attention in some of these groups is the appearance of single lines corresponding to long trabecular groups such as the anterior apophyseal group or the central triangular area of refracted bone; this “thinning” could mean that the particular group does not play a vital structural role for that specific case load.
Tibialis posterior muscle activity alteration with foot orthosis insertion measured by fine-wire electromyography
Published in Footwear Science, 2021
Hiroshi Akuzawa, Atsushi Imai, Satoshi Iizuka, Naoto Matsunaga, Koji Kaneoka
Running tasks were performed under three conditions: (1) barefoot, (2) footwear, and (3) footwear plus orthoses (orthoses). The running pace was set at 150 steps per minute. An electronic metronome measured the step pace for the participants. All participants wore the same type of footwear (Calcetto Le3, Asics, Japan) and prefabricated orthoses (Athlete grip 7, Winning One Inc., Japan) (Figure 2). The proper sizes of the footwear and orthoses were chosen for each participant. The upper layer of the prefabricated insole was made of poly microsuede, and the base material was ethyl vinyl acetate. The orthoses had three arch supports for the medial longitudinal, lateral longitudinal, and transverse arches. These arch supports prevented collapse of the arches. In addition, a heel cup of orthoses stabilised the calcaneus, preventing excessive rearfoot motions.
Comparison of plantar loads among runners with different strike patterns
Published in Journal of Sports Sciences, 2019
Zhen Wei, Zhiwang Zhang, Jiayi Jiang, Yu Zhang, Lin Wang
Maximum force was found to be much greater in the heel, midfoot and lesser toes regions during RFS running in our study. The results support those of recent studies indicating that the MF in the heel and midfoot were 87.6% and 27.3% higher in RFS runners (Daoud et al., 2012; Divert, Baur, Mornieux, Mayer, & Belli, 2005; Hamill & Gruber, 2017; Lieberman et al., 2010; Willson et al., 2014), respectively. The higher force in the heel and midfoot may be caused by higher vertical ground reaction force (VGRF) and greater impact transient. When the rearfoot initially touched the ground, extra impact peak can be observed in RFS runners on the plot of the VGRF versus time, whereas the two FSPs both had the second peak (called active peak) at the landing stage (Daoud et al., 2012; Kelly et al., 2018; Knorz et al., 2017). Additional impact peak force is believed to produce a shockwave from the heel and up to the knee, which may generate greater strains and stresses in the knee joint, and result in the greater possibility of anterior knee pain (Almeida et al., 2015; Knorz et al., 2017; Vannatta & Kernozek, 2015) and medial tibial stress syndrome (Almeida et al., 2015; Pohl, Mullineaux, Milner, Hamill, & Davis, 2008; Raissi, Cherati, Mansoori, & Razi, 2009). Together, the high-magnitude transient force to the heel may increase potential injuries in lower extremity skeletal tissues, especially causing calcaneal stress fractures (Almeida et al., 2015; Almonroeder et al., 2013), although the incidence rates seem lower compared with the tibial and patellofemoral joint injuries.