Heel in Human Anatomy

The foot is a part of vertebrate anatomy that supports the animal's weight while still allowing it to move about on the ground. The foot is one of the most complicated structures in the human body. It has over 100 moving parts, including bones, muscles, tendons, and ligaments, that allow the foot to balance the body's weight on just two legs and support a variety of activities.

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The Heel Bone and Largest Bone in the Foot

The calcaneus is the bone that makes up the foot's heel. It's one of the tarsals, which are the bones that make up the foot and ankle. The calcaneus is the largest bone in the foot, and it serves as the base for the rest of the tarsals and metatarsals. When running or walking, the calcaneus hits the ground with each step. Two of the most common causes of foot pain are stress fractures of the calcaneus and inflammation of the plantar fascia ligament, which is attached to the calcaneus.

Heel Anatomy/ Parts of the Heel

One of the seven tarsal bones that make up the foot is the calcaneus. The calcaneus is a short bone, which means it is about the same length as it is large. The tarsals are all known to be small bones. The calcaneus is the largest bone in the foot and the largest of all the tarsals.

Trabecular bone makes up the majority of the calcaneus (spongy bone). The strength of the calcaneus is proportional to its density of trabecular bone. Owing to the stresses exerted on the calcaneus by walking and running, runners and those with higher body weight gain more bone density in the calcaneus.

Structure of Heel Anatomy - Parts of the Heel

The calcaneus(heel body part) is a difficult bone to understand because it has so many different textures, attachments, and insertion points.

The posterior (back) portion is the heel. The Achilles tendon insertion point is on the superior aspect (top) of the posterior part of the calcaneus. There are two bursae (fluid-filled sacs that act as cushions) in front (internal) and behind (external) the insertion point for the Achilles tendon. The middle surface of the posterior portion of the calcaneus is the insertion point of the calcaneal tendon.

The talus, a tarsal bone above the calcaneus, attaches to the most superior part of the calcaneus. The anterior talar articular surface, the middle talar articular surface, and the largest, the posterior talar articular surface, all articulate with the calcaneus.

The calcaneus articulates with the cuboid bone, another tarsal bone, on its entire anterior (front) surface. Around the calcaneus, there are several additional processes (protuberances) that serve as channels and insertion points for other tendons, as well as assisting with balance.

An apophysis (growth plate) is found near the bulbous surface of the posterior calcaneus in childhood. About the age of 15, the apophysis solidifies, or fuses. 2 It doesn't solidify in certain females until they're 18 years old. It doesn't finish ossifying (hardening into strong bone) in some males until they're 22 years old.

Location - Heel Muscle Anatomy

The calcaneus (heel body part) is found at the back (posterior) of the foot, near the heel. The calcaneus will serve as a fulcrum point for flexion and extension of the foot because of its position. When you raise your toes off the floor as you're about to tap your foot, you're flexing. When you press down on the gas pedal, you're extending.

Anatomical Variations

In medical images, the calcaneus can be seen in a variety of anatomical variations. Some of these may be linked to specific medical conditions, while others may not cause any discomfort and are only noticed because radiologists often notice them.

• A pseudofracture of the apophysis is a partly ossified apophyseal plate that looks like a fracture on an X-ray. This is a common calcaneus variation that does not need treatment.

• A congenital tarsal coalition is a connection between the tarsals, most commonly the calcaneus and talus, that prevents the tarsals from properly articulating. Ossification (bone fusion), fibrous tissue, or cartilage buildup may all contribute to the alliance. 

• Calcaneal pseudocysts, also known as calcaneal pseudotumors, are common natural variations in calcaneus images caused by variations in bone density. Calcaneal pseudocysts are normally only seen in children and disappear as they get older.

• A nutrient foramen (a hole that allows blood vessels to pass through) may form in the calcaneus' spongy bone. This is a natural but uncommon variation that is totally harmless.

Calcaneal Apophysitis

The most common cause of heel pain in children is calcaneal apophysitis. 6 It's an inflammation of the calcaneal apophysis brought about by repeated hits from running or jumping.

Bursitis

A bursa is a fluid-filled sac that serves as a buffer or bumper between potentially tender areas and irritated tissue. Bursitis is an inflammation of the bursae, which are usually located around the insertion points of tendons or between articulated tarsal bones such as the talus which is calcaneus and may cause heel or foot pain (talocalcaneal joint).

Plantar Fasciitis

The most common cause of heel and foot pain in adults is plantar fasciitis. 7 The plantar fascia tendon aids in maintaining the form of the foot's bottom (plantar surface). This widespread tendonitis affects many runners and is difficult to treat.

Stress Fractures

Stress fractures in the calcaneus may develop as a result of hitting the heel repeatedly. There are usually small cracks that cause foot pain. A stress fracture is rarely major, but since it is in the heel, it takes time to heal.

Avulsion Fractures

An avulsion fracture occurs when a tendon rips away from its insertion point. The tendon usually does not separate from the bone, but the bone to which it is attached may do so, hence the name.

The Achilles tendon and the plantar fascia tendon are the two main tendon insertion points on the calcaneus. Avulsion fractures are less common than Achilles tendon ruptures. The discomfort from a simple Achilles tendon rupture is felt more in the ankle or calf than in the heel.