Joints and ligaments · Lower limb
Bifurcate ligament !
The bifurcate ligament is a Y-shaped band on the top outer midfoot, from the heel bone to the navicular and cuboid.
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What it is
A Y-shaped ligament on the top outer side of the midfoot, from the heel bone to the navicular and the cuboid.
What it does
Holds the front of the heel bone to the midfoot.
Key facts
- Attaches
- Dorsal anterior calcaneus to cuboid (calcaneocuboid part) and navicular (calcaneonavicular part)
- Function
- Stabilizes midtarsal (Chopart) joint; can avulse anterior calcaneal process
- Tight in
- Plantarflexion with inversion
Relations
- Superficial
- Belly of the extensor digitorum brevis and the inferior extensor retinaculum
- Deep
- Chopart joint: the calcaneocuboid and talonavicular joints
- Behind
- Sinus tarsi
- Medial
- Talonavicular ligament on the top of the talonavicular joint
How to find it
With the foot pointed and turned in, the anterior process of the calcaneus lies in the small hollow in front of the sinus tarsi, under the extensor digitorum brevis belly; point tenderness there separates this injury from an ATFL sprain.
Examination
- Point tenderness over the anterior calcaneal process, with pain on passive plantarflexion and inversion, suggests a bifurcate ligament sprain or avulsion fracture
On imaging
Lateral and oblique foot X-rays show an anterior process fracture as a fleck above the calcaneocuboid joint; it is often invisible on an ankle series. CT measures the fragment and joint involvement; MRI shows the ligament.
Common problems
- Sprained when the foot twists, often mistaken for an ankle sprain; it can pull off a small piece of the heel bone.
Clinical notes
- Anterior process fractures misread as ankle sprains can fail to unite and cause long-lasting lateral midfoot pain
- Calcaneonavicular coalition sits in the same place, between the anterior process and the navicular; on a lateral X-ray the elongated process looks like an 'anteater nose'
- Its calcaneocuboid limb is one of the main ties between the rear and middle rows of the tarsus, so Chopart sprains often tear it with the dorsal calcaneocuboid ligament
- Key ligament of Chopart (midtarsal) disarticulation: medially the joint line lies just behind the navicular tuberosity, and the joint only opens once this Y-shaped ligament is cut
Development
Calcaneonavicular coalition is a failure of segmentation; it usually becomes painful in early adolescence, when the bar ossifies and the hindfoot stiffens.
Test yourself
Think of the answer, then tap the question to see it.
What are the attachments of the bifurcate ligament?
From the dorsal anterior calcaneus to the cuboid (calcaneocuboid part) and the navicular (calcaneonavicular part).
Which fracture can occur through the bifurcate ligament, and why is it missed?
Avulsion of the anterior process of the calcaneus; it is often invisible on ankle X-rays.
Where is bifurcate ligament tenderness compared with ATFL tenderness?
In front of the sinus tarsi, further forward and lower than ATFL tenderness.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- ligamentum bifurcatum TA2 1931
- Official Spanish (DeCS)
- Ligamento bifurcado
- English (TA2)
- Bifurcate ligament
- Also called
- ligamentum bipartitum · Chopart's ligament
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Bony Pelvis and Lower Limb, Foot Joints; Anatomy of the Human Body (20th ed.): Intertarsal Articulations (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain; Anatomía humana (4.ª ed.), tomo 1, cap. 66: Pierna. Pie.
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Representative model, for educational purposes only.
