THE ANKLE AND THE FOOT Structure

THE ANKLE AND THE FOOTStructure • The foot provides (designed for) for support/shock absorbtion and propulsion. • Movements within the foot occur primarily at the subtalar and midtarsal joints. • The ankle serves to unite the foot and the leg.

Tibia Fibula Talus Sustentaculumtali Calcaneous Structure of the Ankle • Hinge joint • Articulation of talus with malleoli of tibia & fibula. • Bound together by ligaments. Fig 8.12

Ligamentous Reinforcement Lateral side • Anterior talofibular • Calcaneofibular • Posterior talofibular Fig 8.14

Deltoid • a. Calcaneotibial • b. Anterior talotibial d. Posterior talotibial • c. Tibionavicular Plantar calcaneonavicular Ligamentous Reinforcement Medial side • Deltoid • Calcaneotibial • Anterior talotibial • Tibionavicular • Posterior talotibial • Plantar calcaneonavicular Fig 8.13

Structure of the Foot • An elastic arched structure. • Talus is the keystone. • Comprised of two arches: • Longitudinal • Transverse Fig 8.15

Structure of the Foot • Longitudinal arch: • Heel to heads of five metatarsals. • Supported by the plantar fascia (maintains arch). • Transverse arch: • Side-to-side concavity. • Anterior tarsal bones & metatarsals. Fig 8.16

Subtalar Joint • Joint between underside of talus and upper & anterior aspects of calcaneus. • Plantar calcaneonavicular “spring ligament” helps support talus. Fig 8.17b

Foot Joints Midtarsal Joint (Chopart’s Joint): Consists of two articulations: • Calcaneocuboid: Nonaxial – permits only gliding. • Talonavicular: Modified ball-and-socket – permits restricted motion. Tarsometatarsal Joints: Movements are gliding. Intermetatarsal Joints: spreading or flattening. Metatarsophalangeal Joints: Modified condyloid joints (2 degrees of freedom). Interphalangeal Joints: Hinge joints (1 degree of freedom).

Movements of Foot at the Ankle, Tarsal, & Toe Joints Fig 8.20 Dorsiflexion Plantarflexion Inversion Eversion

MUSCLES OF THE ANKLE & FOOT Location: • 22 muscle of the ankle & foot are intrinsic. • 11 muscles are extrinsic.

MUSCLES OF THE ANKLE & FOOT Tibialis Anterior Function: dorsiflexes ankle & inversion. Peroneus Brevis Function: plantarflexes, eversion. Extensor Hallucis Longus Function: extends great toe & dorsi flexion Extensor Hallucis Brevis Function: extends great toe Extensor Digitorum Brevis Function: extends toes. Fig 8.21a

MUSCLES OF THE ANKLE & FOOT Extensor Digitorum Longus Function: extends toes & dorsi flexion, eversion Peroneus Longus Function: plantarflexes, eversion Peroneus Tertius Function: dorsiflexes & eversion. Fig 8.22

MUSCLES OF THE ANKLE & FOOT Gastrocnemius Function: powerful plantar flexor. • Fast twitch. • Allows one to rise on toes. • Advantageous leverage. • Crosses knee joint Fig 8.23

MUSCLES OF THE ANKLE & FOOT Soleus Function: Strong ankleplantar flexor. • Slow twitch. • Postural, static plantar flexion. Fig 8.24

MUSCLES OF THE ANKLE & FOOT Tibialis Posterior Function: plantar flexes tarsal joints, inversion when foot is plantar flexed. • Helps holds up longitudinal arch. Fig 8.25

MUSCLES OF THE ANKLE & FOOT Flexor Digitorum Longus Function: Flexes toes, plantar flexes, inversion. Flexor Hallucis Longus Function: flexes great toe, plantar flexes, inversion. Fig 8.26

Intrinsic Muscles of the Foot Fig 8.27 & 8.28

Intrinsic Muscles of the Foot Fig 8.29 & 8.30

Muscular Analysis of Fundamental Movements of the Ankle • Dorsiflexion: tibialis anterior, peroneus tertius, extensor digitorum longus, extensor hallucis longus. • Plantar flexion: gastrocnemius, soleus, peroneus. • Possible help from tibialis posterior, peroneus brevis, flexor digitorum longus, flexor hallucis.

Muscular Analysis of Fundamental Movements of the Tarsal Joints • Dorsiflexion: same as ankle. • Plantar flexion: tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus. • Inversion (Supination): tibialis anterior (when foot dorsiflexed)& tibialis posterior (when foot plantar flexed). • Eversion (Pronation): peroneus longus, brevis, & tertius.

Muscular Analysis of Fundamental Movements of the Toes • Flexion: flexor digitorum longus and flexor hallucis longus. • Extension: extensor digitorum longus and extensor hallucis longus.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Leg: Shin Contusions • Common based on exposed nature of tibia. • Usually from a direct blow. • May damage periosteum. • Shin guards are recommended in activities in which leg impacts are common.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Leg: Tibial Stress Injuries • Often called “shin splints”. • An overuse injury. • Repeated microtears where tibialis posterior or anterior attaches to tibia, inflammation. • Sprains in interosseous membrane. • Tenderness & pain on medial surface of tibia. • Rest, softer surface and supporting the arch are best treatment.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Leg: Fracture • Most common among the young. • Most common to lower 2/3 of fibula. • May result in instability of ankle joint. • Severity based on bone displacement: • More displaced - more severe.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Ankle: Strain • Due to impact that forces ankle beyond normal range. • Results in tearing at myotendinous junction. • May cause pain, weakness, possible deformity. Potentially very debilitating.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Ankle: Sprains • Usually associated with forceful inversion of the foot. • In this case the lateral ligaments stretched or torn, or may rupture. • Results in pain, swelling, disability.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Ankle: Fracture • Same causes as ankle sprains. • The majority occur to malleoli. • More serious fractures sometimes dislocate.

COMMON INJURIES OF THE LEG, KNEE AND ANKLE The Foot: Plantar Fasciitis • Pain and tenderness along the sole of the foot. • May be due to inflammation, micro tears, or rupture of the plantar fascia. • Is generally an overuse injury; lack of flexibility may be contributory. • Stretching has been shown to be helpful.

THE ANKLE AND THE FOOT Structure