The navicular bone is a medial tarsal bone that articulates with the talus and cuneiforms.
The navicular bone is a boat-shaped tarsal bone located on the medial side of the midfoot. It acts as a keystone in the medial longitudinal arch and plays a central role in foot structure and mobility. It articulates with the talus posteriorly, the three cuneiforms anteriorly, and sometimes the cuboid laterally. The navicular also serves as the primary insertion point for the tibialis posterior tendon, contributing significantly to dynamic arch support and foot inversion.
The navicular is a small, oblong bone with a concave posterior surface and three smaller convex anterior facets. Its medial surface features a prominent tuberosity that serves as an important muscular attachment site. The bone is compact externally, with cancellous bone internally, adapted to distribute forces in the midfoot during weight-bearing and gait.
The navicular lies medially in the midfoot between the talus and the three cuneiform bones. It is situated distal to the talar head and proximal to the cuneiforms, and forms the central component of the medial longitudinal arch.
The navicular forms five or six articulations:
Bone | Joint | Joint Type |
---|---|---|
Talus | Talonavicular joint | Synovial ball-and-socket |
Medial cuneiform | Naviculocuneiform joint | Synovial plane |
Intermediate cuneiform | Naviculocuneiform joint | Synovial plane |
Lateral cuneiform | Naviculocuneiform joint | Synovial plane |
Cuboid (variable) | Naviculocuboid articulation | Synovial plane (if present) |
Several key ligaments attach to the navicular, providing joint stability and contributing to arch support.
Ligament | Attachment | Function |
---|---|---|
Plantar calcaneonavicular (spring) ligament | From sustentaculum tali (calcaneus) to navicular tuberosity | Supports head of talus and medial longitudinal arch |
Dorsal talonavicular ligament | Neck of talus to dorsal navicular | Stabilizes talonavicular joint |
Interosseous ligament | Between navicular and cuneiforms | Prevents joint separation |
Plantar ligaments | Navicular to cuneiforms and cuboid (if articulated) | Reinforce plantar arch |
The navicular serves as the main insertion point for the tendon of the tibialis posterior muscle, which is critical for arch maintenance and foot inversion.
Occasionally, a small portion of the flexor hallucis brevis or other intrinsic plantar muscles may have indirect attachments via surrounding fascia, but these are not primary insertions.
The navicular is supplied by branches from the:
Because of its articular cartilage coverage and minimal muscular attachments, vascularity is limited. This makes the navicular susceptible to avascular necrosis, particularly in its central zone.
Innervation is provided by:
The navicular is the last tarsal bone to ossify. It ossifies from a single center, which appears postnatally, typically around 3 years of age in girls and 4 years in boys.
Delayed ossification is a normal variant but may be mistaken for pathology in pediatric radiographs.