TERMS

Question 1

posterior 1/3 of the talar body is segmented off

Answer 1

talus bipartitus

Question 2

aka astralgus secundarius

Answer 2

os supratalare

Question 3

triangular shaped ossicle at the posterolateral margin of talus

aka talus accessorius/intermedium

frequency-14-25% of adults

os trigonum syndrome, called this if painful

Answer 3

os trigonum

Question 4

aka tuberis calcanei

Answer 4

os subcalcis

Question 5

usually symptomatic in young athletes

looks like the os trigonum

Answer 5

os supracalcaneum

Question 6

located in between calcaneus, talus, cuboid, and navicular

best seen on MO

usually b/l and can actually bridge the calcaneus and navicular

Ddx: beak fracture of calcaneus

Answer 6

Os calcaneus secundarium

Question 7

located at posterior end of sustentaculum tali

double ankle
limited STJ inversion
palpable submalleolar swelling
C sign on lateral radiograph

*medial ankle pain

Answer 7

Os sustentaculum

Question 8

can only be seen on MO view and never causes problems or symptoms

Answer 8

accessory calcaneal foramen

Question 9

comma shaped on AP, inclined cleft w/ dorsal triangular portion on LAT

frequently bilateral

painful in adults
rule out Kohlers, Mueller-Weiss, nonunion

Answer 9

bipartite navicular

Question 10

accessory bone only seen on LAT film , posterior superior navicular

Answer 10

os supranaviculare

Question 11

aka prehallux, accessory navicular, navicular secondarily

Answer 11

os tibiale externum

Question 12

located in or around the peroneus longus tendon

dislocated os peroneum can cause a PL rupture

POPS-painful os peroneum syndrome

Answer 12

os peroneum

Question 13

very rare, spherical accessory bone between cuboid and navicular

found on the plantar surface of cuboid

appears age 12 yrs

DDX: calcaneus secondarily

associated with a CN coalition

Answer 13

os cuboides secondarium

Question 14

at the intersection of the navicular, intermediate and lateral cuneiform

another physiologic variant is more common?

Answer 14

processes uncinatus

Os intercuneiform

Question 15

between the dorsal aspect of metatarsal bases 1 and 2

usually b/l, but there are lots of variations in size and shape

asymptomatic and common 
many theories:
-sesamoids
-vestigeal 6th digit
-developmental variant
-can be associated w/ met Primus varus or HAV in siblings

seen in AP view

Answer 15

os intermetatarseum

Question 16

accessory ossification center of the metatarsal

sclerotic looking bands at the lesser metatarsal base and 1st metatarsal bead

not pathologic, just might cause a long ray

pseudo epiphyses doesnt do longitudinal growth

Answer 16

pseudo epiphysis

Question 17

accessory epiphysis of 5th met base that is parallel or oblique to met shaft

located at PB tendon insertion

5th met apophysis and fractured styloid process are part of the DDx

Answer 17

os vesalianum