Navicular

Original Editor - Alex Benham

Top Contributors - Alex Benham, Lucinda hampton, Fasuba Ayobami and Kim Jackson

Description

The navicular bone is one of the seven bones which make up the tarsus of the Ankle and Foot. It is located on the medial aspect of the foot, next to the cuboid bone, anterior to the head of the talus and posterior to the cuneiform bones. It is one of the five bones of the midfoot.

Structure

The navicular is a small irregular bone with a shape being described as pyriform. [Golano]. Its posterior surface is concave and there are two faint ridges anteriorly to correspond with the articulation with the three cuneiform bones. There is a large protuberance on the inferomedial aspect of the navicular bone called the navicular tuberosity. [2 Palastaga ]This is

Function

Articulations

Acetabulum pedis The acetabulum pedis is the common name for the talocalcaneonavicular joint and forms the subtalar articular complex along with the posterior talocalcaneal joint. It has some of the morphological characteristics of a ball and socket joint which let to its name. [1] The skeletal structures included are the posterior articular surface of the navicular bone, and the anterior and middle articular surface of the calcaneus that articulate with the head and the anteromedial surface of the talus. These bones are stabilized by the plantar calcaneonavicular ligament (spring ligament) on the medial aspect and the lateral calcaneonavicular ligament (a component of the bifurcate ligament) on the lateral aspect.

Plantar calcaneonavicular ligament

The plantar calcaneonavicular ligament, otherwise known as the spring ligament is a group of ligaments that bond the calcaneus and the navicular to perform as a “socket” for the head of the talus. There are some controversies regarding the morphology of this ligament. While some former researchers believed that it made up of two fascicles of fibrocartilaginous component, more current studies describe that the spring ligament is composed of two different ligaments: the superomedial and the inferior calcaneonavicular ligaments. Some recent investigators even include the talonavicular fascicle of the superficial component of the deltoid ligament as a part of the spring ligament complex.[5][8][9]

The superomedial calcaneonavicular ligament, also known as the ligamentum neglectum, is a quadrangular ligament originally considered as the component of the tibiocalcaneonavicular ligament. It originates from the anteromedial margins os the sustentaculum tali which extended to the anterior margin of the calcaneal anterior articular surface. From its origin, the superomedial calcaneonavicular ligament concavely fans out to anterodorsolateral direction to a broad insertion at the margin of the navicular posterior articular surface. On the dorsal aspect, it attaches with the thick fibrocartilaginous surface that performs as the base of the fibrous tunnel of the posterior tibial tendon.[5][8][9]

The inferior calcaneonavicular ligament is a trapezoidal-shaped ligament that arises from the superior portion of the coronoid fossa of os calcis, just anterior to the sustentaculum tali. Its insertion is on the lateral aspect of the navicular beak on the plantar aspect of the navicular, just lateral to the superomedial calcaneonavicular ligament insertion. The inferior calcaneonavicular ligament performs as one of the main static stabilizers of the longitudinal arch of the foot.[5][8][9]

Bifurcate ligament

Also known as the Chopart ligament, the bifurcate ligament is a Y-shaped ligament that consists of two components that have different origins, which are the lateral calcaneonavicular ligament and the medial calcaneocuboid ligament. The lateral calcaneonavicular ligament originates from the lateral side of the anterior talar articular surface, anteromedially from the sinus tarsi. It courses anterodorsomedially and inserts in the superior segment of the lateral end of the navicular. Two bundles of fibers form this ligament. While the superior fibers are long, resistant, and lays superficial, the inferior fibers are short and rest deep. The medial calcaneocuboid ligament originates from the lateral side of the lateral calcaneonavicular ligament’s origin, on the anterior aspect of intermediary tubercle. It extended anteroinferior and attached to the dorsal side of the cuboid. Together, these fibers form a durable band that facilitates the lateral foot stabilization.[10][11]

Clinical relevance

Navicular Drop Test Navicular stress syndrome Accessory Navicular Bone

References

Epeldegui T, Delgado E. Acetabulum pedis. Part I: Talocalcaneonavicular joint socket in normal foot. J Pediatr Orthop B. 1995;4(1):1-10.

Anatomy, Bony Pelvis and Lower Limb, Navicular Bone Devindra Prapto; Mark A. Dreyer.