Tarsus
- Consists of seven tarsal bones: talus, calcaneus, navicular bone, cuboid bone, and three cuneiform bones.
1. Talus
- Transmits the weight of the body from the tibia to the foot and is the only tarsal bone without muscle attachments.
- Has a neck with a deep groove, the sulcus tali , for the interosseous ligaments between the talus and the calcaneus.
- Has a body with a groove on its posterior surface for the flexor hallucis longus tendon.
- Has a head , which serves as keystone of the medial longitudinal arch of the foot.
2. Calcaneus
- Is the largest and strongest bone of the foot and lies below the talus.
- Forms the heel of the foot, articulates with the talus superiorly and the cuboid anteriorly, and provides an attachment for the Achilles tendon.
- Has a shelf-like medial projection called the sustentaculum tali , which supports the head of the talus (with the spring ligament) and has a groove on its inferior surface for the flexor hallucis longus tendon (which uses the sustentaculum tali as a pulley).
3. Navicular bone
- Is a boat-shaped tarsal bone lying between the head of the talus and the three cuneiform bones.
4. Cuboid bone
- Is the most laterally placed tarsal bone and has a groove for the peroneus longus muscle tendon.
- Serves as the keystone of the lateral longitudinal arch of the foot.
5. Cuneiform bones
- Are three wedge-shaped bones that form a part of the medial longitudinal and proximal transverse arches.
- Articulate with the navicular bone posteriorly and with three metatarsals anteriorly.
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