Foot X-ray

What Is Foot Radiograph?

A foot radiograph or X-ray is a diagnostic imaging test that uses radiation to produce an image of the foot’s bones and soft tissues⁽¹⁾. An X-ray image shows darker shades for the muscles and soft tissues, and the bones appear white in the film image⁽²⁾.

Radiographs have been used to diagnose bone fractures, pneumonia, cancer, and arthritis⁽³⁾. Specifically, foot radiographs are used to detect dislocated joints and joint deformities and help diagnose symptoms, such as tenderness, foot pain, and swelling⁽⁴⁾.

An X-ray procedure may take at least 15 minutes. However, the radiation exposure may only take a second⁽⁵⁾. Typically, radiograph results are available in one to two days⁽⁶⁾.

While this imaging technique is generally safe, there are risks to consider before undergoing an X-ray. 

Pregnant women are advised not to do a radiograph due to its harmful effects on the developing fetus⁽⁷⁾.

Clinical Significance of Foot Radiograph

Foot X-rays are essential to understanding the symptoms of a bone injury or trauma⁽⁸⁾. An extremity X-ray also shows the image of the knee, hip, leg, ankle, arm, or foot to assess the damage caused by bone growths (tumors), infection, arthritis, or other bone diseases⁽⁹⁾. 

A study on the radiography of the foot and ankle suggested that a kind of X-ray called diffraction enhanced X-ray imaging (DEI) was able to produce an image detecting specific soft tissues based on the small differences in tissue densities⁽¹⁰⁾. 

These soft tissues include tendons, adipose tissue, and ligaments of the human ankle and foot⁽¹¹⁾. 

A 2003 article published in the International Society for Optics and Photonics cited that diffraction enhanced imaging (DEI) elicits a higher contrast X-ray image than the standard radiographs⁽¹²⁾.

However, a synchrotron, a cyclic particle accelerator, is used in doing DEI X-rays and can be quite expensive⁽¹³⁾. 

A research study conducted a radiographic assessment of a pediatric foot alignment and cited that radiographs are beneficial in examining the alignment of the foot⁽¹⁴⁾. 

Brief Anatomy of the Foot

The foot consists of 30 joints, 26 bones, and more than a hundred muscles⁽¹⁵⁾. These structures work cohesively to perform mobility functions, balance, and support⁽¹⁶⁾. 

The foot’s 26 bones are divided into 14 phalanges, seven tarsal bones, and five metatarsal bones⁽¹⁷⁾. 

Tarsal Bones

These bones are similar to the wrist’s carpal bones or the small bones that connect the hand to the forearm⁽¹⁸⁾. The tarsal bones are divided into three groups: intermediate tarsals, proximal tarsals, and distal tarsals⁽¹⁹⁾.

Located in between the proximal and distal bone is the boat-shaped navicular bone or the intermediate tarsals⁽²⁰⁾. It consists of an ovoid (egg-shaped) concave surface that joins at the head of the talus, the bone that comprises the lower part of the ankle⁽²¹⁾.

The proximal tarsal bones are made up of the calcaneus (the heel bone) and talus (ankle bone)⁽²²⁾. Talus, an irregularly shaped bone, connects the foot and the leg through the ankle joint⁽²³⁾. 

The calcaneus is found near the ankle at the back of the foot⁽²⁴⁾. The calcaneus is the foot’s largest bone, making it essential for weight stability and bearing⁽²⁵⁾.

Concurrently, the distal tarsal bone consists of a cuboid bone and a cuneiform⁽²⁶⁾. 

The cuboid bone is a short, square-shaped bone that is laterally located in the foot. The cuneiform bones are the three bones in the foot’s medial side that articulate with the navicular proximally through three separate facets.

Metatarsal Bones

These five long bones in the foot incorporate a shaft, a distal head, and a proximal base⁽²⁷⁾. 

Of all the metatarsals, the first metatarsal is the shortest and the thickest. This first metatarsal proximally links with the medial cuneiform at the base and distally connects with the sesamoid bones that protect tendons from wear and stress⁽²⁸⁾.

The second metatarsal bone has four articular facets at its base and is the longest of all the metatarsal bones⁽²⁹⁾. This bone connects with the lateral, intermediate, and medial cuneiforms and the third metatarsal⁽³⁰⁾.

The third metatarsal articulates with the lateral cuneiform and has a triangular base. It also links with the second and fourth metatarsals⁽³¹⁾.

The fourth metatarsal has three articular facets at the base, and it is smaller than the third metatarsal. This metatarsal has a quadrilateral facet that links with the cuboid⁽³²⁾.

The final metatarsal is the fifth metatarsal with a base linked to the fourth metatarsal medially and proximally with the cuboid⁽³³⁾. These metatarsals support body weight⁽³⁴⁾.

Gout typically occurs in the metatarsophalangeal joint (joint between metatarsal joint and proximal bones) due to a high level of crystal deposits in the surrounding tissues and joints and a high uric acid level in the blood⁽³⁵⁾.

Phalanges

The phalanges are located distally from the metatarsal bones⁽³⁶⁾. These phalanges are the bones of the toes⁽³⁷⁾.

Proximal phalanges are concave at the base and are dorsally convex⁽³⁸⁾. The proximal phalanges heads articulate with the bases of the middle phalanges⁽³⁹⁾.

The distal phalanges include a non-articular head and a broad base linking with the middle phalanges. These phalanges are smaller and flatter compared to the ones in the hand⁽⁴⁰⁾.

One known deformity of the phalanges is called claw toe, common among women and the elderly. Claw toes can occur with neuromuscular diseases like multiple sclerosis. People with this deformity may experience pain in the four lateral toes⁽⁴¹⁾.

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