Atlas of Anatomy

26 Ankle & Foot

Bones of the Foot

Fig. 26.1   Subdivisions of the pedal skeleton
Right foot, dorsal view. Descriptive anatomy divides the skeletal elements of the foot into the tarsus, metatarsus, and forefoot (antetarsus). Functional and clinical criteria divide the pedal skeleton into hindfoot, midfoot, and forefoot.

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Fig. 26.2   Bones of the right foot

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Joints of the Foot (I)

Fig. 26.3   Joints of the foot
Right foot with talocrural joint in plantar flexion.

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Fig. 26.4   Proximal articular surfaces
Right foot, proximal view.

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Fig. 26.5   Distal articular surfaces
Right foot, distal view.

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Joints of the Foot (II)

Fig. 26.6   Talocrural and subtalar joints
Right foot. The talocrural (ankle) joint is formed by the distal ends of the tibia and fibula (ankle mortise) articulating with the trochlea of the talus. The subtalar joint consists of an anterior and a posterior compartment (the talocalcanean and talocalcaneonavicular joints, respectively)divided by the interosseous talocalcanean ligament (see p. 409).

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Fig. 26.7   Talocrural and subtaler joints: Sagittal section
Right foot, medial view.

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Fig. 26.8   Talocrural joint
Right foot.

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Joints of the Foot (III)

Fig. 26.9   Subtalar joint and ligaments
Right foot with opened subtalar joint. The subtalar joint consists of two distinct articulations separated by the interosseous talocalcanean ligament: the posterior compartment (talocalcanean joint) and the anterior compartment (talocalcaneonavicular joint).

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Fig. 26.10   Talus and calcaneus
The two tarsal bones have been separated at the subtalar joint to demonstrate their articular surfaces.

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Ligaments of the Ankle & Foot

image The ligaments of the foot are classified as belonging to the talocrural joint, subtalar joint, metatarsus, forefoot, or sole of the foot. The medial and lateral collateral ligaments, along with the syndesmotic ligaments, are of major importance in the stabilization of the subtalar joint.

Fig. 26.11   Ligaments of the ankle and foot
Right foot. See p. 406 for inferior view.

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Plantar Vault & Arches of the Foot

Fig. 26.12   Plantar vault
Right foot. The forces of the foot are distributed among two lateral (fibular) and three medial (tibial) rays. The arrangement of these rays creates a longitudinal and a transverse arch in the sole of the foot, helping the foot absorb vertical loads.

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Fig. 26.13   Stabilizers of the transverse arch
Right foot. The transverse pedal arch is supported by both active and passive stabilizing structures (muscles and ligaments, respectively).

Note: The arch of the forefoot has only passive stabilizers, whereas the arches of the metatarsus and tarsus have only active stabilizers.

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Fig. 26.14   Stabilizers of the longitudinal arch
Right foot, medial view.

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Muscles of the Sole of the Foot

Fig. 26.15   Plantar aponeurosis
Right foot, plantar view. The plantar aponeurosis is a tough aponeurotic sheet, thickest at the center, that blends with the dorsal fascia (not shown) at the borders of the foot.

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Fig. 26.16   Intrinsic muscles
Right foot, plantar view.

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Muscles & Tendon Sheaths of the Foot

Fig. 26.17   Deep intrinsic muscles
Right foot, plantar view.

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Fig. 26.18   Tendon sheaths and retinacula of the ankle
Right foot. The superior and inferior extensor retinacula retain the long extensor tendons, the fibularis retinacula hold the fibular muscle tendons in place, and the flexor retinaculum retains the long flexor tendons.

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Muscle Facts (I)

image The dorsal surface (dorsum) of the foot contains only two muscles, the extensor digitorum brevis and the extensor hallucis brevis. The sole of the foot, however, is composed of four complex layers that maintain the arches of the foot.

Fig. 26.19   Intrinsic muscles of the dorsum
Right foot, dorsal view.

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Fig. 26.20   Superficial intrinsic muscles of the sole
Right foot, plantar view.

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Muscle Facts (II)

Fig. 26.21   Deep intrinsic muscles of the sole
Right foot, plantar view.

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Fig. 26.22   Deep intrinsic muscles of the sole
Right foot, plantar view.

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