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Department
of Podiatry
Midtarsal
Joint
Anatomy
Functional unit consisting two separate joints:
- calcaneo-cuboid
- talo-navicular
Function
- adapt
to irregular terrain
- stabilise ('lock') the forefoot on the rearfoot
- absorb rotations of the rearfoot and keep forefoot in contact with
the ground
Midtarsal joint stability
Motion
is restricted by:
- distal projection of overhanging calcaneus
- ligamentous support: long and short plantar ligaments, calcaneo-navicular
(spring) ligament, bifurcate ligament
Axes of motion
- T-N
and C-C each have two triplanar axes which are similar and can be
considered to functionally be the same
Longitudinal axis
- pronation and supination
- predominantly frontal plane (inversion and eversion) motion
- absorb rotation of the rearfoot and adapt to irregular terrain
- opposite to STJ (ie: STJ pronation > LAMTJ supination)
- contraction of tibialis anterior will produce LAMTJ supination
Oblique axis
- pronation and supination
- predominantly sagittal plane (dorsiflexion / plantarflexion) and
transverse plane (abduction / adduction) motion
- lateral ground reaction forces pronate / lock / stabilise forefoot
on rearfoot
- contraction of peroneus longus locks the OAMTJ
Range of motion of the MTJ is unknown
Subtalar joint pronation increases the available ROM at the MTJ
Midtarsal
joint anomalies
Forefoot varus (this link is
here just to give you a better understanding of FF varus - the material
on the page is not examinable)
- osseus, congenital deformity of the MTJ in which the forefoot lies
in an inverted position relative to the rearfoot when the subtalar
joint is in its neutral position and the MTJ is locked
Forefoot valgus (this link is here
just to give you a better understanding of FF valgus - the material
on the page is not examinable)
- osseus, congenital deformity of the MTJ in which the forefoot lies
in an everted position relative to the rearfoot when the subtalar
joint is in its neutral position and the MTJ is locked.
Very common anomalies responsible for numerous lower limb pathologies
Summary
- MTJ consists of two joints: C-C and T-N
- function around two different axes
- LAMTJ: inversion / eversion
- OAMTJ: dorsi-plantar flexion, ab-adduction
- MTJ anomalies: forefoot varus and valgus
References
Michaud TC (1993) Foot orthoses and other forms of conservative
foot care. Williams and Wilkins, Baltimore, pp.9-14.
Root ML, Orien WP and Weed JH (1971) Clinical biomechanics: normal
and abnormal function of the foot. Clinical Biomechanics Corp,
Los Angeles, pp.26-62.
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