The navicular bone is a small bone found in the feet of most mammals.

Human anatomy

The navicular bone in humans is one of the tarsal bones, found in the

foot The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up o ...

. Its name derives from the human bone's resemblance to a small boat, caused by the strongly concave proximal articular surface. The term ''navicular bone'' or ''hand navicular bone'' was formerly used for the scaphoid bone, one of the carpal bones of the

wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...

. The navicular bone in humans is located on the medial side of the

, and articulates proximally with the talus, distally with the three cuneiform bones, and laterally with the

cuboid In geometry, a cuboid is a hexahedron with quadrilateral faces, meaning it is a polyhedron with six Face (geometry), faces; it has eight Vertex (geometry), vertices and twelve Edge (geometry), edges. A ''rectangular cuboid'' (sometimes also calle ...

. It is the last of the foot bones to start

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

and does not tend to do so until the end of the third year in girls and the beginning of the fourth year in boys, although a large range of variation has been reported. NavicularFracMark

The tibialis posterior is the only muscle that attaches to the navicular bone. The main portion of the muscle inserts into the tuberosity of the navicular bone. An

accessory navicular bone An accessory navicular bone is an accessory bone of the foot that occasionally develops abnormally in front of the ankle towards the inside of the foot. This bone may be present in approximately 2-14% of the general population and is usually asym ...

may be present in 2–14% of the general population.

Clinical significance

The human navicular is not a commonly broken bone but it breaks due to two reasons. The first mechanism is a stress fracture which happens commonly in athletes, and the other mechanism is a high energy trauma. The navicular bone is a keystone of the foot: it is part of the coxa pedis and articulates with the talus, first, second and third cuneiform, cuboid and calcaneus. It plays an important role in the biomechanics of the foot, helping in inversion, eversion, and motion; it is a structural link between midfoot and forefoot and it is part of the longitudinal and transverse arch of the foot.

Horse anatomy

The horse has a sesamoid bone called the navicular bone, located within the hoof, that lies on the palmar aspect of the coffin joint between the second phalanx and third phalanx ( coffin bone). The navicular bone in the horse is supported by the distal sesamoidean impar ligament and two collateral sesamoidean ligaments. The navicular bursa is located between the flexor surface of the navicular bone and the deep digital flexor tendon, which runs between the bursa and the distal phalanx. The central tarsal bone in the hock of the horse is homologous and analogous to the navicular bone of the human foot, and thus the navicular bone in the horse is a different structure from the

eponymous An eponym is a noun after which or for which someone or something is, or is believed to be, named. Adjectives derived from the word ''eponym'' include ''eponymous'' and ''eponymic''. Eponyms are commonly used for time periods, places, innovati ...

ly labeled bone in humans. The navicular region is an important structure in relation to lameness, particularly in the front feet, and is involved with a significant disease process called navicular disease or navicular syndrome. Recently much of the original literature concerning navicular disease has been called into question, particularly the significance of radiographic changes as a sole diagnostic criterion.Citing Clinical Anatomy and Physiology Laboratory Manual for Veterinary Technicians, Colville, Thomas and Bassert, Joanna M. 2008 Publ. Mosby/Elsevier, Canada. "Navicular Bone - The distal sesamoid bone of the horse. The navicular bone is located deep in the hoof behind the joint between the middle and distal phalanges." Navicular syndrome may be responsible for as much as 1/3 of all cases of lameness in horses, but radiographic changes in the navicular bone do not always provide a definitive diagnosis. Newer imaging techniques have shown that damage to the soft tissues in the region may be significant contributors to lameness and that multiple causes may result in visible lameness.

Notes

External links

3D printable navicular bone model
free download in STL format (Embodi3D.com) {{DEFAULTSORT:Navicular Bone Skeletal system Horse anatomy Bones of the foot Tarsal bones

Human anatomy

Clinical significance

Horse anatomy

See also

Notes

External links