Keywords:
Education and training, Perception image, MR, Musculoskeletal system
Authors:
C. R. S. Costa1, R. Sampaio2, J. Pires2, J. Vasconcelos2; 1Vila Nova de Famalicão/PT, 2Porto/PT
DOI:
10.1594/essr2016/P-0095
Background
The term "cavus foot" concerns a range of foot shapes that have in common a high arch,
affecting one fifth to one quarter of the population.
1
Recently,
there has been an increasing interest in mild variation of the cavovarus deformity,
not associated with a neurological deficit.
This represents a slight degree of cavovarus deformity,
associated with characteristic symptoms.
Manoli and Graham came up with the term "subtle cavus foot",
but there are other terms in the literature such as mild,
nonneurologic or idiopathic cavus foot.
2
The leading deformity in subtle cavus foot is the plantar flexed first metatarsal,
which might be associated with peroneus longus hyperactivity,
the so called "peroneal overdrive".
The flexed first metatarsal reaches the ground first during foot-flat and heel-rise positions of the gait cycle,
not allowing the hindfoot to evert at the subtalar and midtarsal articulations.
Due to the tripod effect,
the foot and ankle will change into varus.
3 With time,
this results in overload of the outer border of the foot,
leading to ankle instability,
peroneal tendon pathology (tendinitis,
splitting,
recurrent dislocation or subluxation),
lesser metatarsal stress,
plantar fasciitis.4
Another anatomical issue consists of a gastrocnemius tightness,
deforming further the plantar flexed foot.
2
The aim of this study is to describe the findings on MRI of the ankle that help recognize mild cavus deformity,
the bone relationships in the tibia-talo-calcaneal unit,
the presence of calcaneus varus in coronal images and readily identify subtle image signs associated with this condition.