What Is the Heel Bone?

It is the largest of the seven metatarsal bones and is located in the lower back of the foot, forming the metatarsus (heel).

It is the largest of the seven metatarsal bones and is located in the lower back of the foot, forming the metatarsus (heel).

Chinese name

Calcaneus

Foreign name

Calcaneus

Anatomical position

In the lower back

Aka

Heel bone

Calcaneus anterior calcaneus

The vertical line at the lowest point of the calcaneal groove is defined as the boundary between the front of the calcaneus and the body of the calcaneus, and the boundary between the medial side and the peroneal margin of the load bearing process. It is square in shape, with anterior talar articular surface and upper nodule on top, and saddle-shaped calcaneal articular surface in front. From the perspective of the internal trabecular structure, it is mainly the pressure trabecular below the anterior articular surface.

Calcaneus calcaneus body

The front of the body is bounded by the front, the top is bounded by the bottom of the mound, and the back is bounded by the tuberosity. The inner cortex of the calcaneal body is thicker than the outer side, and the surface is recessed by the main blood vessels, nerves and tendons at the bottom of the foot. From the perspective of internal bone structure, bone trabeculae are relatively rare.

Calcaneus calcaneus tuberosity

The calcaneus tuberosity has a rough surface and the front is connected to the thicker cortex. The lower half of the tuberosity is the calcaneal tubercle, where the Achilles tendon stops. From its internal trabecular structure, it is mainly the dense calcaneal tension trabecula.

Calcaneus calcaneus

The outer side of the calcaneal distance from the protrusion is bounded by the body. The upper surface is mainly the medial articular surface, and the load-bearing process is inclined outward to form a 27 ° upturn angle with the lowest part of the calcaneal groove. Around the load-bearing process there are strong triangular ligaments, intertalar ligaments, and anterior and posterior joint capsules of the subtalar joint.

Calcaneus calcaneus

A line is drawn from the lowest point of the calcaneal groove back to the lowest point behind the calcaneal body. The upper part of the line is the mound of the calcaneus, and the lower part is connected to the calcaneal body. The internal structure of the calcaneal mound is mainly a dense pressure trabeculae below the posterior articular surface.

Anatomical characteristics and clinical significance of each calcaneal anatomical division of the calcaneus

Anterior calcaneus:

The advent of CT has caused some authors to pay closer attention to the front of the calcaneus. Miric divides the articular surface from anterior to posterior, anterior articular surface, middle articular surface, and heel articular surface. From our anatomical division of the calcaneus, the appearance of the front of the calcaneus is basically similar to what Miric saw. The front and middle joints have a common joint cavity. However, if the front and middle articular surfaces are connected, the front part may include a part of the middle articular surface, and if the front and middle articular surfaces are separate and independent, the front of the calcaneus does not include the middle articular surface. The anterior part of the calcaneus is square, and the upper part of the calcaneus is involved in the inferior wall of the sacral sinus. The outer cortex is thinner. The internal trabecular bone is slightly rarer than the body. There is a "neutral triangle" where the trabecular bone is scarcely located below the calcaneal groove connected to the body. The original fracture line of a calcaneal fracture often begins here and extends inward. 51% to 68% of the calcaneal fractures involve the calcaneal joint. In some cases, dislocation of the calcaneal joint can also occur. For this type of fracture, the calcaneus and the sacrum often need to be fixed together to achieve a more reliable fixation effect.

Body of calcaneus :

The internal side of the calcaneus below the pitch process is recessed to the fibula to form the side wall of the sacral canal. The long extensor tendon, the posterior tibial arteriovenous and the posterior tibial nerve pass obliquely from the back up and down. It is difficult and inappropriate to place the steel plate inside. If the calcaneus fracture plate is placed on the outside, it is important to avoid damaging these important structures when the tired nail is drilled from the outside to the inside. The outer side of the calcaneal body is relatively flat, and the long and short peroneal tendons of the calcaneus and the lateral cutaneous nerve of the dorsal foot pass from the back to the front and down. According to the appearance of the inner and outer sides of the calcaneus, it is more convenient to place a steel plate on the outer side. The inner cortex of the calcaneal body is thicker and the outer cortex is thinner. Therefore, the inner side of the fracture is rarely collapsed, swollen and smashed, while the outer side is often collapsed, swollen and smashed. Although the outside of the calcaneus is severely collapsed and comminuted, it is possible to rely on the more complete and thicker cortical bone on the inner side for more reliable fixation. The internal structure of the calcaneal body is characterized by a distributed pressure trabecular bone. The fracture of the calcaneus caused by the vertical compression violence, because the dense bones of the hump collapse into the calcaneus, causing the swollen lateral wall of the calcaneus, the width of the calcaneus to increase, and the lateral malleolus colliding with the flared calcaneal lateral wall. Collapse and compression of the calcaneus body causes a reduction in the height of the calcaneus, shortening of the shaft length and horizontal length. According to our clinical data, after calcaneal fracture surgery reduction, the height and width of the body change significantly before and after surgery, which has significant statistical significance, and the horizontal and axial length of the calcaneus before and after surgery After the change is small, there is no significant statistical significance.

Calcaneal tuberosity:

The nodule at the back of the calcaneus is relatively thick. At the back, the protruding calcaneus tuberosity has a thickened cortical bone, which resists the compression force generated by the impact of the calcaneus and is the attachment point of the main muscle group . The shape behind the calcaneus looks like a triangle with a base underneath. The lower middle 1/3 of the back is the attachment of the Achilles tendon, which is separated from the upper 1/3 joint capsule. The upper third is usually smooth and has no Achilles tendon attachment. Therefore, if a tongue-shaped fracture block is formed at the upper 1/3, it can be displaced without being pulled by the Achilles tendon. When it is connected to the tongue-shaped fracture block formed at the middle and lower 1/3, this fracture block bears the third leg. The traction of the head muscles can cause significant upward displacement. The lower 1/3 is wider and is the meeting point of the plantar fascia and Achilles tendon. The inner structure of the tuberosity is mainly a densely distributed tension trabeculae. When the calcaneus fracture forms a tongue-type fracture block, or when the comminuted fracture occurs in the posterior part, the reduction is made by using the denser tuberosity of the bone to obtain a satisfactory reduction and reliable fixation.

Calcaneal distance projection:

The load-bearing process is connected to the middle of the thicker medial cortical bone of the calcaneus. It is composed of thicker cortical bone with cancellous bone in the middle. The shape is approximately parallelogram. The long side forms a certain forward angle with the long axis of the calcaneus. Its protrusion inwardly and upwardly forms the upturned angle of the load-bearing protrusion, forms the middle joint surface of the calcaneus on the upper side, and together with the inner wall of the calcaneus, forms a relatively strong inner load-bearing column. Vertical inversion injuries often cause splitting of the load gap. In a vertical compression type calcaneal fracture, the oblique original fracture line splits the calcaneus into two main fracture pieces, the anterior medial load fracture and the posterolateral trochanteric fracture. Around the load-bearing process, there are strong tendons, ligaments, and joint capsules attached, so that the load-bearing process is usually a static and non-displacement fracture, but it can also be displaced in very serious injuries. The articular capsule is mainly the joint capsule of the anterior and middle joints; the ligaments are mainly the calcaneal intertalar ligament, the cervical ligament, and the medial triangular ligament; the tendons are the toe longus flexor tendon and the long flexor tendon. Since the talus fracture block does not shift, the trochanteric fracture block is often pulled to displace the talus fracture block in order to achieve a good fracture reduction. The outer steel plate is used to fix 2 to 3 screws to the load-bearing protrusion according to the upturn angle of about 30 ° of the load-bearing protrusion, so that the fracture block can be reliably fixed.

Calcaneal mound:

Destotlz named the posterior articular surface the "mound" in 1937. Its shape is like a triangle with a base at the bottom, the cortical bone in the mound is thicker, and the internal radial trabeculae of the body are concentrated under the cortex of the mound, making the bone in the mound more dense. When the calcaneus is subjected to vertical compression violence, the humerus often rotates forward and downward and is compressed and collapses into the calcaneus, causing a significant decrease in the height of the calcaneus, which is about 8 mm lower on average. The mound constitutes an important subtalar posterior articular surface. Many authors recognize that the degree of comminution and reduction of the posterior articular surface is closely related to the effect of surgery. The mound is the main basis of the Gissane's and Bohler's angles. If the position of the mound changes, the Gissane's and Bohler's angles must change. Therefore, the correct reduction of the mound can usually restore the normal subtalar joint, Gissane's angle and Bohler's angle. After the reduction, the mound can be fixed to the load-bearing protrusion with a single screw or with screws on the outer steel plate.