Functional Anatomy of the Lower Extremity​ (ANKLE and FOOT))

Ankle (talocrural) and foot form a ________ unit​

complex

• mobile and stable

Bones in the ankle and foot

26 bones:​

7 tarsals​: Calcaneus​, Talus​, Navicular​, Cuboid​, and Medial, intermediate, and lateral cuneiforms ​

5 metatarsals​

14 phalanges​

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Arches in the foot

• Medial longitudinal arch is 15 to 18mm​: Level of navicular, which is the keystone of arch​

• Lower lateral longitudinal arch: 3 to 5mm from ground at level of cuboid ​

• Normal transverse arch: Angle formed between metatarsals and ground​

Functions of the foot and ankle

• Support of body weight with least expenditure of anatomical material​

• Protection for nerves and vascular supply ​

High arch or low arch can result in a variety of

dysfunctions ​

• Forces from foot are transferred to more proximal joints​

The foot is passively interlocked by action of

• Plantar aponeurosis (plantar fascia)​

• Long plantar ligament​

• Short plantar ligament​

• Plantar calcaneonavicular (spring) ligament​

The articular surfaces are particularly applicable to evaluation of the components of joint motion such as

glide, roll, spin, and interventions involving joint mobilizations

Ligamentous fibers direction is the key to

determining which motions are guided and limited​

The ankle joint (talocrural) consists of

Proximally and medially (internally): talus and the tibia ​

Laterally (externally): talus and the fibula ​

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Strong ligaments like anterior/posterior tibiofibular and interosseous tightly bind

the distal tibiofibular joint

• no synovial membrane

The bony attachments of ligaments in the foot and ankle

• Indicates the name of the ligament​

• Reveals the motions limited when the ligament is tight​

The Lateral Collateral ligament in the ankle is composed of what 3 bands ?

Anterior talofibular ligament​, Calcaneofibular ligament​, and Posterior talofibular ligament​

What are the medial ankle ligaments ?

Deltoid ligament or medial collateral ligament of ankle:​ Tibiocalcaneal ligament​, Tibionavicular ligament​, Posterior tibiotalar ligament​, and the Anterior tibiotalar ligament ​

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Anterior and Posterior muscle compartments are separated by the

tibia, fibula, and interosseous membrane between

Lateral Muscle Compartments are separated from

the other two compartments by:​ Strong fascial sheaths (intermuscular septa) → extend from fibula to superficial extent of muscle​

The Subtalar Joint consists of

• Anterior → biconcave calcaneal facet articulating with a biconvex talar facet on neck of talus ​

• Middle → sustentacular facet of talus with middle facet at sustentaculum tali of calcaneus​

• Posterior → biconvex calcaneal facet articulating with a biconcave posterior talar facet on body of talus​

Transverse Tarsal Joint​ consist of what 2 joints

• Talonavicular joint ​

• Calcaneocuboid joint​

Muscles that cross the transverse tarsal joints act around

a longitudinal and oblique axis producing the motions of: Plantar flexion-dorsiflexion, Inversion-eversion, Abduction-adduction​

The intertarsal Joints include

Three slightly convex navicular facets with the cuboid with the fifth ray​

Metatarsophalangeal Joints​ consists of

Biconvex metatarsal heads and biconcave proximal phalangeal bases ​

What are the motions of the Metatarsophalangeal Joints​

Plantar flexion / dorsiflexion​, Abduction / adduction​, and Circumduction​

Hallux has how many phalanges ?

2 : (IP Joint)

Toes 2-5 have how many phalanges?

3 : (PIP and DIP Joint)

What are the 3 cardinal planes of motion ?

Sagittal plane​: Flexion / extension​

Frontal (coronal) plane​: Abduction / adduction​

Transverse plane​: Internal & external rotation​

Rotation occurs about an axis _____________ to that plane​

perpendicular

The true mechanical axes of the joints of the foot complex _______ perpendicular to these cardinal planes​

are not

These motions occur in planes that pass through all three cardinal planes which is called

tri-planar motions

tri-planar motions combine

• Dorsiflexion, abduction, and eversion ​

• Plantarflexion, adduction, and inversion​

Pure rotation about an oblique axis results in the

same end position as three separate rotations in the cardinal planes​

Axis of motion at the ankle passes ​

just distal to medial and lateral malleoli

Axis of motion is ________ to all of the cardinal planes of motion​

oblique

Subtalar Joint Axis and Motion

• Gliding joint in supination​

• Hinge or uniaxial joint​

• Axis runs downward, posteriorly and laterally​: Motion of the STJ is tri-planar, providing pronation and supination​

Transverse Tarsal Joint functional articulation between

• Hindfoot (talus and calcaneus) ​

• Midfoot (navicular and cuboid)

Transverse Tarsal Joint Axis & Motion ​

• Plane or gliding joints​

• In supination:​ Navicular glides medially and inferiorly on the head of the talus, and Cuboid follows the navicular, moving medially and inferiorly on the calcaneus​

Foot regions include

Forefoot: ​Metatarsals​ and Phalanges​

Midfoot:​ Cuneiforms​, Cuboid​, and Navicular​

Hindfoot:​ Calcaneus​ and Talus​

Transverse Tarsal Joint Axis & Motion ​

Two axes of motion:​

Longitudinal axis is similar to the longitudinal component of the STJ axis​: Provide eversion and abduction or inversion and adduction ​

Oblique axis is similar to the axis of the ankle​: Contributes more to dorsiflexion and plantar flexion than to motions in the frontal and transverse planes​

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Tarsometatarsal Joint Axes & Motions ​is divided into 1st through 4th rays, more specifically?

1st ray: functional unit between the first metatarsal and medial cuneiform bones​ (Axis of motion: anterior, lateral & downward​)

2nd ray: between 2nd metatarsal & middle cuneiform​

3rd ray: between 3rd metatarsal & lateral cuneiform​

4th ray: 4th metatarsal & cuboid​

5th ray: 5th metatarsal & cuboid​ (Allows pronation & supination​)

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Joints of the foot are _____ and ______joints allowing motion in the sagittal and transverse planes​

condyloid or biaxial

Tarsometatarsal Joint Axes & Motions ​

Axes pass through the head of each metatarsal​ : Dorsiflexion / plantar flexion and Abduction / adduction

Interphalangeal Joint Axis & Motion ​are

hinge joints

• allow pure flexion and extension in the sagittal plane