talar prominence is exaggerated with ...
- prominence is exaggerated with STJ prontation; reduced with STJ supination
- talar prominence = produced by head of talus
prominence located just distal to a possible talar head prominence, which is virtually unaffected by subtalar jt motion
- most commonly due to accessory ossicle
- becomes apparent at age 9-11 radiographically
three typical presentations of navicular prominence
type I: Represents a small ossicle just proximal to the navicular tuberosity, classified as a true sesamoid because it is within the tendon
type II: True accessory scaphoid appears radiographically as an extension of the navicular (its connection to the navicular is represented by a radiolucent zone which measures 1-3 mm.) The zone may be fibrous, cartilaginous, fibrocartilaginous, or partially osseous.
type III: Represents a true carnuate navicular or enlarged navicular tuberosity. (May be type II with an osseous bridge.)
sugery options for navicular prominence
type I: removal of ossicle from tendon by tendon splitting approach or reflection of post tib from talonavicular jt capsule and then removing ossicle
type II: excision of mobile fragment using adequate osseous exposure and c-arm.
type III: expose talonavicular jt and supinate subtalar jt to protect talar head. resection of tuberosity following normal contour of bone
what is dorsal bossing?
acquired disorder of the 1st tarsometatarsal joint
- presentation at 1st met-cuneiform jt may be medial or dorsal prominence
- may be secondary to hallux limitus or hallux valgus
- associated with charcot arthropathy
classification of dorsal bossing
type I: dorsal exostosis formation at 1st met cuneiform secondary to intermittent compression of bone. assoc with forefoot valgus plantarflexed 1st ray
type II: 1st met cuneiform exostosis located circumferentially associated with arthritic component. pt may have hx arthritis
type III: dorsal exostosis of 1st met cuneiform with angular malalignment. dorsiflexed = tendon imbalance, hallux limitus; plantarflexed - pes cavus; adducted - hallux abducto valgus
type IV: dorsal exostosis of 1st met cuneiform and involves lis franc's jt. assoc with arthritis w/i tarsometatarsal jt
type V: pseudo exostosis at 1st met cueniform secondary to pes cavus. results in shoe irritation
what is an accessory bone of the foot?
accessory bones of the foot are either normal parts or prominences of the tarsal bones that are abnormally separated from the main structure
ossicle located at base of 5th metatarsal
accessory bone located inferior to peroneal groove of the cuboid
- encompassed w/i tendon of peroneus longus (acutually considered a sesamoid and functions to assist movement of peroneus longus)
accessory boney process located on lateral process of posterior aspect of talus
- usually fuses with talus by age 18
- irritated by FHL