Items tagged “ossicle”
26 results found
An os supratalare is an accessory ossicle of the foot located at the superior aspect of the talar head or neck. It has a reported incidence of ~1% (range 0.2-2.4%) 1. It is almost always asymptomatic. Differential diagnosis os supranaviculare is also anatomically seen in close proximity to th...
Os tibiale externum
An os tibiale externum, also known as an accessory navicular or os naviculare accessorium, is a large accessory ossicle that can be present adjacent to the medial side of the navicular bone. The tibialis posterior tendon often inserts with a broad attachment into the ossicle. Most cases are asym...
Os subfibulare is an accessory ossicle that lies at the tip of the lateral malleolus of the ankle and is rarely reported 1. Clinical presentation Os subfibulare are usually asymptomatic although they may eventually cause painful syndromes or degenerative change in response to overuse and traum...
An os subtibiale is a rare, genuine accessory ossicle and normal variant related to the posterior colliculus of the medial malleolus 1. It is present in ~1% of the population 5. Clinical presentation They usually are asymptomatic although they may eventually cause painful syndromes or degener...
The fabella is an accessory ossicle typically found in the lateral head of the gastrocnemius. It occurs in ~20% (range 10-30%) of the population 1. The fabella can also be fibrocartilaginous in nature and is occasionally found in the medial head of the gastrocnemius. The fabella articulates wi...
Sesamoids (or sesamoid bones) are focal areas of ossification within tendons as they pass over joints 1. They can also occur in ligaments and usually measure a few millimeters in diameter. Their function is purported to be to alter the direction of the tendon and modify pressure, thereby reducin...
Accessory ossicles are secondary ossification centres that are separate from the adjacent bone. They are usually round or ovoid in shape, occur in typical locations and have well defined smooth cortical margins on all sides. In most cases, they are congenital in origin, although they may occur ...
Ossicles of the wrist and hand
Diagnosis not applicable
Published 28 Jul 2013
Os supratrochleare dorsale
Os supratrochlear dorsale is an accessory ossicle of the elbow located in the olecranon fossa of the humerus 1. It may become symptomatic due to trauma during elbow extension and as such may require surgical removal 2. The differential diagnosis is an intra-articular loose body but the treatment...
Os radiostyloideum and triquetral fracture
Published 02 Oct 2013
Os radiostyloideum (or persistent radial styloid) is an accessory ossicle of the wrist located adjacent to the radial styloid process and lateral to the mid-portion of the scaphoid. This should not be confused with another bony ossicle in the wrist, os styloideum (part of a carpal boss), which...
The os supranaviculare is an accessory ossicle located at the proximal dorsal aspect of the navicular bone or talonavicular joint. It is also known as Piries bone, talonavicular dorsale or (dorsal) talonavicular ossicle and is present in ~1% of the population. Differential diagnosis An os sup...
The os intermetatarseum is an uncommon accessory ossicle of the foot occurring in ~4% (range 1-7%) of the population. Clinical presentation It is usually asymptomatic and an incidental finding although it can be a cause of dorsal midfoot pain. Gross anatomy The os intermetarseum is typical...
Sesamoid ossicles of the nuchal ligament
Sesamoid ossicles of the nuchal ligament are a relatively common anatomical variant that are usually asymptomatic and most commonly occur at the C5/6 or C6/7 vertebral levels. Epidemiology They occur in ~7.5% of the population, with a male predominance of 3:1 1. Radiographic features Plain...
Lateral malleolus avulsion fracture with os subfibulare
Published 09 Dec 2013
The hallux sesamoid bones are paired ossicles of the foot. They function as a fulcrum to increase the leverage of both flexor hallucis brevis and longus. Gross anatomy The hallux sesamoids are ovoid-shaped ossicles. There is a medial (tibial) and lateral (fibular) hallux sesamoid and are embe...
Os vesalianum (foot)
An os vesalianum is an accessory ossicle of the foot. Although asymptomatic, it may become symptomatic occasionally, causing lateral foot pain and requiring surgical excision 2. Gross anatomy It is formed as a result of failed fusion of the secondary ossification center of the metatarsal. It i...
Published 20 Feb 2014
The lunula is an accessory ossicle of the wrist. It lies in the TFCC, between the tip of the ulna styloid process and the triquetrum. It may be fused to the ulna styloid, giving it an elongated appearance. Differential diagnosis os triangulare: lies more radial ulna styloid fracture persist...
Medial malleolus ossicle
Published 26 Feb 2014