Ellipsoid/spheroidal joints.
Fibrous capsules surround each joint – thin dorsally and seperated from tendons by bursae. Capsule is contiguous with extensor hood expansion dorsally and plantar plate below.
Plantar Ligaments:
• Thick fibrous structures
Collateral ligaments:
• Strong round “cords” on both sides of joint.
• Attached to dorsal tubercle on side of head of metatarsal runs obliquely forward attaches to base of proximal phalanx.
Suspensory ligaments:
extensions from extensor expansion that descends on both sides of the joint to the plantar plate
Plantar plate:
• firm and flexible fibrocartilaginous plate plantar to metatarsal heads
• firmly attached to the base of the proximal phalanges
• composed mostly of type 1 collagen
• measures 20mm in length and 2mm in thickness
• acts as a ‘central’ attachment for ligaments and joint capsule
• attached to adjacent plantar plates by the deep transverse metatarsal ligament
• sometimes a sesamoid is invested in the plantar plate
Plantar plate and deep transverse metatarsal ligaments from a segmental ‘tie-bar’ across the forefoot
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