Foot Anatomy

General Position and Characteristics
- Phalanges are classified as miniature long bones located distal to the metatarsals.
- They are numbered $1$ through $5$ , starting from the big toe (medial) to the little toe (lateral).
Articulations
- The five proximal phalanges articulate with their corresponding metatarsals.
- The first digit, known as the hallux or big toe, contains only two bones: a proximal phalanx and a distal phalanx.
- Digits $2$ through $5$ contain three bones each: a proximal phalanx, a middle phalanx, and a distal phalanx.
Morphological Features
- Base: The proximal portion of the bone, which is expanded to form a joint.
- Shaft: The body of the bone, which is characterized by a ventral concavity and a dorsal convexity.
- Head: The distal end of the bone, expanded to form a joint; this feature is present in all phalanges except the distal ones.

General Position and Characteristics
- Metatarsals are miniature long bones situated distal to the tarsal bones.
- They are numbered $1$ through $5$ in a medial-to-lateral direction.
Articulations
- First Metatarsal: Articulates with the medial ( $1^{st}$ ) cuneiform.
- Second Metatarsal: Articulates with the intermediate ( $2^{nd}$ ) cuneiform.
- Third Metatarsal: Articulates with the lateral ( $3^{rd}$ ) cuneiform.
- Fourth Metatarsal: Articulates with the cuboid.
- Fifth Metatarsal: Articulates with the cuboid.
Main Structural Features
- Base: The proximal end, expanded for articulation with the distal row of tarsal bones. The bases of the second through fifth metatarsals also articulate with each other.
- Shaft: Exhibits a ventral concavity and a dorsal convexity.
- Head: The distal end, which is rounded to facilitate articulation with the proximal phalanx.
Specialized Metatarsal Features
- First Metatarsal: This bone is notably larger and stronger than the others, serving as an important weight-bearing structure.
- Fifth Metatarsal: Possesses a prominent tubercle at its base which serves as a site for muscular attachment.
- Sesamoid Bones: Two sesamoid bones are located at the head of the first metatarsal.

General Characteristics
- Tarsal bones are short bones organized into proximal and distal rows.
- Their structural integrity is critical for supporting the weight of the body.
The Cuboid Bone
- This bone articulates with the calcaneus proximally.
- Distally, it articulates with the fourth and fifth metatarsals.
- Medially, it articulates with the lateral cuneiform.
Cuneiform Bones
- These are three small, wedge-shaped bones designated as follows:
- First ( $1^{st}$ ) or Medial Cuneiform.
- Second ( $2^{nd}$ ) or Intermediate Cuneiform.
- Third ( $3^{rd}$ ) or Lateral Cuneiform.
- They collectively articulate with the navicular bone proximally and the first through third metatarsals distally.
The Navicular Bone
- Featured on the medial side of the foot; its tuberosity is a prominent landmark that can be seen and felt.
- It serves as a central articulation point, connecting with the talus, the cuboid, and all three cuneiform bones.

The Talus
- Head: Features an oval convex surface for articulation with the navicular bone. The head also rests upon the sustentaculum tali of the calcaneus.
- Neck: A narrow region situated proximal to the head, containing the structure known as the sulcus tali.
- Body:
- Superiorly: Articulates with the distal end of the tibia.
- Laterally: Features an articular facet for the fibula.
- Medially: Provides a medial articular surface for the medial malleolus of the tibia.
- Inferiorly: Contains three distinct articular surfaces for articulation with the calcaneus.
The Calcaneus
- The calcaneus is defined by six distinct surfaces:
- Anterior Surface: Articulates with the cuboid bone.
- Posterior Surface: Forms the structure of the heel.
- Superior Surface: Consists of three articular facets for the talus and the sulcus calcaneus.
- Inferior Surface: Contains tubercles that provide attachment points for the plantar aponeurosis.
- Medial Surface: Features the sustentaculum tali, which supports the talus.
- Lateral Surface: Features the peroneal tubercle.