Anatomy of the Lateral Plantar Ligaments of the Transverse Metatarsal Arch -The Lateral Lisfranc Ligament

Jayatilaka L, Swanton E, Fisher A, Fisher L, Fischer B, Molloy A , Mason L

Background: The anatomy of the the lateral tarsometatarsal ligamentous structures are under investigated. A number of classifications have previously been proposed, noting homolateral and divergent subtypes of midfoot fracture dislocations. These subtypes indicate intact metatarsal connections of the middle and lateral rays, however little is understood in regards to these connections. There are currently no anatomical studies analysing the middle to lateral plantar ligamentous insertions. Our aim was to identify the plantar ligamentous structures of the lateral tarsometatarsal joints and their significance in tarso-metatarsal joint injuries.

Methods: We examined 10 cadaveric lower limbs that had been preserved for dissection at the Human Anatomy and Resource Centre at Liverpool University. The lower limbs were dissected to identify the plantar aspect of the transverse metatarsal arch.

Results: In all specimens, the short plantar ligament blended with a transverse metatarsal ligament (lateral Lisfranc) spanning from the 2^nd to the 5^th metatarsal. The separate short plantar ligament formed the floor of the peroneus longus canal. The transverse metatarsal ligament formed the basis of the roof and distal aspect of the peroneus longus canal. In addition, separate intermetatarsal ligaments were identifiable connecting each metatarsal. The short plantar ligament provides connection through the transverse metatarsal ligament, connecting the transverse and longitudinal arches of the foot.

Conclusion: The plantar ligamentous structures of the lateral tarsometatarsal joints are a combination of individual intermetatarsal ligaments and a transverse metatarsal ligament (Lateral Lisfranc). This explains the homogenous nature of a divergent tarsometatarsal joint injury and why middle and lateral columns move as one. The lateral Lisfranc ligament acts like a suspension bridge, storing energy during stance phase that could be released during propulsive phase. This study has clinical significance in the observation that in some cases lateral column instability can be overcome when the middle column is stabilised.