1218 SURFACE AND SURGICAL ANATOMY. 
the internal malleolus, at the anterior part of the hollow between it and the heel. 
In effusions into the ankle-joint the hollows in front and behind the malleoli are 
obliterated, and the extensor tendons are raised from the front of the joint. 
A finger’s breadth below the tip of the internal malleolus is the sustentaculum 
tali; 11 in. in front of the latter, and midway between the dorsal and_ plantar 
margins of the inner aspect of the foot, is the tubercle of the scaphoid (the inner 
landmark in Chopart’s amputation), which is generally visible, and always 
distinctly palpable. The calcaneo-astragaloid joint hes unmediately below the 
sustentaculum, while close above it the tendon of the tibialis posticus may 
be rendered visible, as it extends from behind the tip of the internal malleolus to 
the tubercle of the scaphoid. An inch and a half in front of the tubercle of the 
scaphoid is the joint between the internal cuneiform and the first metatarsal; the 
ridge at the base of the latter bone furnishes a good guide to the articulation. The 
first metatarso-phalangeal joint lies a little in front of the middle of the ball of the 
great toe. 
A finger’s breadth vertically below the tip of the external malleolus is the 
peroneal tubercle of the os calcis, and midway between the two is the calcaneo- 
astragaloid joint; the tubercle is, when present, a trustworthy guide to the level at 
which the two peronei tendons cross the outer surface of the os calcis. The greater 
process of the os calcis is felt in the triangular interval between the tendons of the 
Tibialis posticus 
Anterior border of lower end of tibia 
Line of ankle-joint 
Posterior tibial 
artery 
Flexor longus 
hallucis 
Tibialis anticus_ 
i Internal malleolus 
Tendo Achillis 
Head of astragalus__ 
Tubercle of scaphoid , 
od 
Flexor longus 
digitorum 
Tarso-metatarsal articulation 
First metatarso- 
phalangeal articulation 
Sustentaculum 
tali 
Fic. 821.—INNER ASPECT OF FOOT AND ANKLE. 
peroneus brevis and tertius; the calcaneo-cuboid joint—the outer landmark in 
Chopart’s amputation—is placed a little in front of the mid-point between the tip 
of the external malleolus and the base of the fifth metatarsal bone. To open the 
outer tarso-metatarsal articulations, the knife, entered behind the projecting base of 
the fifth metatarsal bone, should be directed forwards as well as inwards. On the 
dorsum of the foot the tarsal joints are obscured by the extensor tendons. The 
synovial membrane of the ankle-joint is prolonged on to the neck of the astragalus, 
and care must be taken to avoid opening the ankle-joint in performing Chopart’s 
amputation. 
The line of the tarso-metatarsal joints extends nearly | in. further forwards on 
the inner than on the outer border of the foot; between these points the joint- 
line takes a zigzag course on account of the second metatarsal bone extending 
backwards between the internal and external cuneiform bones. The joint between 
the second metatarsal and middle cuneiform is nearly } in. behind that between 
the first metatarsal and internal cuneiform, and nearly } in. behind that between 
the third metatarsal and the external cuneiform. The strong transverse inter- 
osseous ligament (Lisfranc’s ligament), which connects the outer surface of the 
internal cuneiform with the base of the second metatarsal, must be divided in 
the tarso-metatarsal amputation of Lisfranc. In order to preserve the insertions 
of the two tibial and the three peroneal muscles it is advisable, when possible, 
instead of disarticulating at “ Lisfranc’s joint,” to saw through the metatarsal bones _ 
just in front of their bases. 
