Fibularis Longus Tendon, Plantar View

Description

Plantarly oriented, the fibularis (peroneus) longus tendon is traced as it emerges from the lateral hindfoot and turns sharply anteriorly within the groove on the plantar surface of the cuboid. From that cuboid tunnel it runs obliquely across the midfoot, deep to the plantar soft tissues, toward its distal attachments on the base of the first metatarsal and medial cuneiform. The tendon lies inferior to the calcaneocuboid joint line and passes in close apposition to the cuboid’s plantar tuberosity, a relationship that explains the characteristic angular change in direction. A hard corner. That bend at the cuboid is where many clinically relevant problems concentrate, including longitudinal split tears, tenosynovitis, and irritation around an os peroneum embedded in the tendon, all of which can present as lateral plantar foot pain that worsens with resisted eversion and plantarflexion. Surgeons approaching peroneal tendon pathology, or reconstructing the lateral ankle and hindfoot, need this plantar course clear in mind to avoid iatrogenic injury and to understand how fibularis longus contributes to first-ray plantarflexion and support of the transverse arch. Radiologists also rely on this anatomy when following the tendon on ultrasound or MRI through the cuboid groove, where anisotropy and partial-volume effects can mimic tendinopathy if the expected turn is not appreciated. Use this illustration in gross anatomy and lower-limb biomechanics teaching, in podiatry and orthopedic surgery texts discussing lateral column pain and peroneal tendon disorders, and in clinical education materials for interpreting plantar midfoot imaging or planning tendon debridement and os peroneum excision. Anatomical accuracy verified by SciePro's Medical Advisory Board.