At the foot the differences between humans and quadrupeds are most pronounced. In contrast to many four-legged friends, humans need a foot that rests on the ground with 2 or 3 points for a normal, safe stand. The foot is connected to the lower extremity by ankle joints.
A distinction is made between the upper ankle joint (OSG) and the lower ankle joint (USG). The upper ankle joint has the important task of rolling the foot. The lower ankle joint, on the other hand, is responsible for a better adaptation to inclined and uneven terrain.
The toes also serve this purpose, with which additional “clawing” is possible. Shocks are cushioned by the anatomical arch construction of the foot, which consists of several bones. Finally, it can be said that the mobility of the foot is made possible by the upper and lower ankle joint. Ankle joints as such are joints fixed or secured by ligaments.
The foot (Pes) consists of a total of 26 bones, which can be divided into 3 different areas: the tarsal root (tarsus) the metatarsus (metatarsus)
- The tarsus (root of the foot)
- The metatarsus
- The forefoot (antetarsus)
The tarsal can now be further subdivided: Hock bone (talus): The hock bone or talus carries the so-called trochlea or joint roll on its “bone body”. It forms the important joint connection of the upper ankle joint with the malleolar fork, an ankle fork or joint fork for the upper ankle joint. Directly behind the joint roller is the processus posterior tali, the bony process of the ankle bone.
In the lower ankle joint, however, the joint surfaces are formed by the talus head together with the scaphoid bone (Os navicular). Heel bone (calcaneus): The heel bone forms the largest and longest bone of the foot skeleton. The basic shape of the calcaneus is cubic and thus has 6 surfaces.
It rests on the ground with the tuber calcanei and is also involved in the formation of the lower ankle joint. The tendon of the Musculus flexor hallucis longus runs in a groove under a horizontal bone projection on the calcaneus. The actual function of the calcaneus is to act as a lever arm for the flexor muscles in the lower leg.
This bone also plays an important role in fractures (fractures). Thus, jumps from great heights often lead to fractures of this bone, which usually always have to be treated surgically. Scaphoid (Os naviculare): In simplified terms, the scaphoid is nothing more than a kind of bone disc that lies between the head of the talus and the three sphenoid bones.
These are called as follows: Ossa cuneiformia medial Ossa cuneiformia intermedium Ossa cuneiformia lateral The wedge shape of these bones is largely responsible for the anatomical transverse curvature of the foot. On their surfaces they form joints with the so-called Ossa metatarsi 1, 2 &3, which form the bony foundation of the metatarsus. Cuboid bone (Os cuboideum): The cuboid bone is a pyramid-shaped bone from the tarsal bone family.
It lies between the 4th /5th metatarsal and the heel bone mentioned above. Articular formations occur at the lateral front end of the heel bone and the Ossa metatarsi 4&5. On the underside of the bone there is also a groove in which the tendon of the musculus peroneus longus runs.
- Ossa cuneiformia medial
- Ossa cuneiformia intermedium
- Ossa cuneiformia laterale
The metatarsal bones (Ossa metatarsalia 1-5) form the metatarsus in its entirety. On the bones themselves, a distinction is made between the base, shaft and a spherical head. The latter then forms a joint with the base of the toes.
Here too, a systemic numbering system is used. Thus, the digitus pedis 1-5 can be distinguished, where the digitus pedis 1 represents the big toe (hallux) and the digitus pedis V the little toe. The structure of the toes 2-5 is the same.
They each consist of a base phalanx, a middle phalanx and an end phalanx. Just like the hand, the big toe consists of only 2 phalanges. Due to their reduced mobility, the skeleton of the toe is receded in comparison to the fingers of the hand.