Ankle Joint & Foot

What are the three main functions of the ankle joint and the foot?

(1) Acting as a shock absorber as the heel strikes the ground at the beginning of stance phase, (2) Adapting to the level (or unevenness) of the ground, & (3) Providing a stable base of support from which to propel the body forward.

How are the three arches maintained?

(1) the shape of the bones and their relation to each other, (2) the plantar ligaments and fascia, & (3) the muscles

The ankle joint allows approximately ____ degrees of plantar flexion and ____ degrees of dorsiflexion.

30-50 degrees of plantar flexion & 20 degrees of dorsiflexion.

Plantar fasciitis

A common overuse injury, resulting in pain in the heel.

Claw toe

Flexed PIP joint and flexed DIP joint.

List the muscles of the superficial posterior group:

Gastrocnemius, soleus, and plantaris muscles

Phalanges

Have the same composition as those of the hand.

Calcaneus (Tarsal Bone)

Largest and most posterior tarsal bone

True Ankle Joint

Made up of the distal tibia, which sits on the talus with the medial malleolus of the tibia fitting down around the medial aspect of the talus, and the lateral malleolus of the fibula, which fits down around the lateral aspect.

Forefoot

Made up of the five metatarsals and all the phalanges. This part of the foot adapts to the level of the ground. It is also the last part of the foot to make contact with the ground during stance phase.

Midfoot

Made up of the navicular, the cuboid, and the three cuneiform bones. The mechanics of this part of the foot provide stability and mobility as it transmits movement from the hind foot to the forefoot.

Name the landmarks of the tibia pertaining to the ankle:

Medial condyle, lateral condyle, crest, medial mallelous

The triplantar axis is essentially the axis of the ankle joint. It tips approximately ___ degrees from the transverse plane, ___ degrees from the sagittal plane, and ___ degrees from the frontal plane.

8 degrees (transverse plane), 82 degrees (sagittal plane), 20-30 degrees (frontal plane)

Hallux ridigus

A degenerative condition of the 1st MTP joint associated with pain and diminished range of motion.

Shin splints

A general term given to exercise-induced pain along the medial edge of the tibia, usually a few inches above the ankle to midway up the tibia. An overuse injury that can result from running on hard surfaces, running on tiptoes, and playing sports that involve a lot of jumping.

Metatarsalgia

A general term referring to pain around the metatarsal heads.

Medial tibial stress syndrome

A more specific term that includes anterior leg pain not associated with a stress fracture.

Plantigrade

A normal foot in that the sole is at right angles to the leg when a person is standing.

Mortise

A notch that is cut in a piece of wood to receive a projecting piece (tenon) shaped to fit.

Triple arthrodesis

A surgical procedure that fuses the talocalcaneal, calcanecuboid, and talonavicular joints. Provides medial-lateral stability of the foot and relieves pain at the subtalar joint, but inversion and eversion at the ankle are lost.

Inferior Tibiofibular Joint

A syndesmosis (fibrous union) between the concave distal tibia and the convex distal fibula. Not a synovial joint. Much of the ankle joint's strength depends upon a strong union at this joint.

In an open kinetic chain, with the leg fixed and the foot free to move, the angle of the joint axis causes the foot to do what?

Abduct during dorsiflexion and adduct during plantar flexion.

In an closed kinetic chain, with the foot fixed on the ground and the leg moves over it, the angle of the joint axis causes the foot to do what?

Adduct during dorsiflexion and abduct during plantar flexion.

Second-Fifth MTP Joints

Allow about 40 degrees of flexion/extension and only about 45 degrees of hyperextension.

Achilles tendonitis

An inflammation of the gastrocnemius-soleus tendon, is sometimes a precursor to a ruptured Achilles tendon.

Crest (Tibia)

Anterior and most prominent of the three borders

Third Metatarsal

Articulates with the third cuneiform.

Short Plantar Ligament

Assists the long plantar ligament, which also attaches the calcaneus to the cuboid. It mostly lies deep to the long plantar ligament.

Spring Ligament (Plantar Calcaneonavicular Ligament)

Attaches to the calcaneus and runs forward to the navicular. It is short and wide, and it is most important because it supports the medial side of the longitudinal arch.

Name the significant features and landmarks of the metatarsals:

Base, head, first, second, third, fourth, fifth

Plantar Fascia

Both longitudinal arches are supported by this, which runs from the calcaneus forward to the proximal phalanges. It acts as a tie-rod, keeping the posterior segments (calcaneus and talus) from separating from the anterior portion (anterior tarsals and metatarsal heads). Increases the stability of the foot and arches during weight-bearing and walking.

Name the 7 tarsal bones of the foot:

Calcaneus, calcaneal tuberosity, sustentaculum tali, talus, navicular, tuberosity of navicular, cuboid, cuneiforms

Morton's neuroma

Caused by abnormal pressure on the plantar digital nerves commonly at the web space between the 3rd and 4th metatarsals.

Turf toe

Caused by forced hyperextension of the great toe at the MTP joint. Commonly seen in football, baseball, or soccer players.

Hallux valgus

Caused by pathological changes in which the great toe develops a valgus deformity (distal end pointed laterally).

Subtalar (talocalcaneal) Joint

Consists of the inferior surface of the talus articulating with the superior surface of the calcaneus.

Metatarsophalangeal (MTP) Foot Joint

Consists of the metatarsal heads articulating with the proximal phalanges.

What is the arthrokinematics of the ankle during plantar flexion?

Convex talus glides anteriorly on the concave tibia.

What is the arthrokinematics of the ankle during dorsiflexion?

Convex talus glides posteriorly on the concave tibia.

The collateral ligament on the medial side is a triangular ___ whose apex is located along the tip of the medial malleolus. Its broad base spreads out to attach to the talus, navicular, and calcaneus in four parts.

Deltoid Ligament

Pronation

Describes a combination of dorsiflexion, eversion, and abduction.

Supination

Describes a combination of plantar flexion, inversion, and adduction.

Head (Metatarsal)

Distal end of each bone

At the triplantar axis, the lateral malleolus extends more ___ and lies more ___ than the medial malleolus.

Distally, Posteriorly

Lateral Malleolus (Fibula)

Enlarged distal end

Medial Malleolus (Tibia)

Enlarged distal medial surface

Head (Fibula)

Enlarged proximal end

Mallet toe

Extended PIP joint and flexed DIP joint.

The ___ muscles of the leg are found in groups of three or combinations of three and are located in four anatomical areas.

Extrinsic

What is the end feel of both dorsiflexion and plantar flexion at the ankle?

Firm (soft tissue stretch), which is due to the tension of the joint capsule, ligaments, and tendons.

What are the five motions of the MTP joints of the foot?

Flexion, extension, hyperextension, abduction, adduction.

Inversion and eversion occur in the ___ plane around the ___ axis.

Frontal plane around the sagittal axis.

What is the function of the joint capsule of the superior tibiofibular joint?

Functions to dissipate the torsional stresses applied at the ankle joint.

The 1st digit, the ___, has a proximal and distal phalanx but not middle phalanx.

Great Toe (Big Toe)

Fifth Metatarsal

Has prominent tuberosity located on lateral side of its base.

Name the landmarks of the fibula pertaining to the ankle:

Head, lateral malleolus

What are the three parts of the foot?

Hindfoot, midfoot, and forefoot

What motion is very important during the toe-off phase of walking?

Hyperextension

Eversion (subtalar/transverse tarsal joint)

Includes a combination of abduction, pronation, and dorsiflexion.

Inversion (subtalar/transverse tarsal joint)

Includes a combination of adduction, supination, and plantar flexion.

A strong ___ keeps the tibia and fibula together and provides a greater surface area for muscle attachment.

Interosseous membrane

The greater toe only has one phalangeal joint, the ____.

Interphalangeal Joint (IP)

Trimalleolar fractures

Involves both malleoli and the posterior lip of the tibia

Bimalleolar fracture

Involves both malleoli.

Tibia

Larger bone and is the only true weight-bearing bone of the leg. Triangular in shape, it's crest is located anteriorly.

During ankle plantar flexion, the leg ___ rotates on the foot. Why?

Laterally. Allowed because of the slight movement that is possible at the tibiofibular joints. It is an accessory movement that is not possible in an open chain.

The 2nd-5th digits, also called the four ___, each have a proximal, middle, and distal phalanx.

Lesser Toes

Transverse Tarsal Joint (Midtarsal Joint)

Made up of the anterior surfaces of the talus and calcaneus articulating with the posterior surfaces of the navicular and the cuboid. The motions of this joint link the hind foot and forefoot in inversion and eversion.

Hindfoot

Made up of the talus and calcaneus. In the gait cycle, it is the first part of the foot that makes contact with the ground, thus influencing the function and movement of the other two parts.

Medial Longitudinal Arch

Makes up the medial border of the foot, running from the calcaneus anteriorly through the talus, navicular, and three cuneiforms anteriorly to the 1st three metatarsals. Normally it never flattens or touches the ground.

What are the arches of the foot?

Medial longitudinal arch, lateral longitudinal arch, and transverse arch

Sustentaculum Tali (Tarsal Bone)

Medial superior part projecting out from the rest of the calcaneus, supporting the medial side of the talus. Three tendons loop around this projection, changing directions from the posterior leg to the plantar foot.

During dorsiflexion, the leg ___ rotates on the foot. With the foot fixed and the leg moving over it, the angle of the joint axis causes the leg to ___ rotate on the foot.

Medially, Medially

First MTP Joint

More mobile and allows 45 degrees of flexion and extension and 90 degrees of hyperextension.

Metatarsals

Numbered 1-5, starting medially. Normally, the 1st and 5th are weight-bearing bones, and the 2nd, 3rd, and 4th are not.

Name the O, I, A, & N for the peroneus tertius muscle:

O: distal medial fibula I: base of 5th metatarsal A: assists somewhat in ankle eversion and dorsiflexion N: deep peroneal nerve (L4, L5, S1)

Name the O, I, A, & N for the extensor hallucis longus muscle:

O: fibula and interosseous membrane I: distal phalanx of great toe A: extends 1st toe; assists in ankle inversion and dorsiflexion N: deep peroneal nerve (L4, L5, S1)

Name the O, I, A, & N for the extensor digitorum longus muscle:

O: fibula, interosseous membrane, tibia I: distal phalanx of four lesser toes A: extends four lesser toes, assists in ankle dorsiflexion N: deep peroneal nerve (L4, L5, S1)

Name the O, I, A, & N for the tibilalis posterior muscle:

O: interosseous membrane, adjacent tibia and fibula I: navicular and most tarsals and metatarsals A: ankle inversion; assists in plantar flexion N: tibial nerve (L5, S1)

Name the O, I, A, & N for the peroneus brevis muscle:

O: lateral distal fibula I: base of 5th metatarsal A: ankle eversion; assists in plantar flexion N: superficial peroneal nerve (L4, L5, S1)

Name the O, I, A, & N for the peroneus longus muscle:

O: lateral proximal fibula and interosseous membrane I: plantar surface of first cuneiform and metatarsal A: ankle eversion; assists in ankle plantar flexion N: superficial peroneal nerve (L4, L5, S1)

Name the O, I, A, & N for the tibialis anterior muscle:

O: lateral tibia and interosseous membrane I: first cuneiform and first metatarsal A: ankle inversion and dorsiflexion N: deep peroneal nerve (L4, L5, S1)

Name the O, I, A, & N for the gastrocnemius muscle:

O: medial and lateral condyles of femur I: posterior calcaneus A: knee flexion; ankle plantar flexion N: tibial nerve (S1, S2)

Name the O, I, A, & N for the flexor hallucis longus muscle:

O: posterior fibula and interosseous membrane I: distal phalanx of the great toe A: flexes great toe; assists in inversion and plantar flexion of the ankle N: tibial nerve (L5, S1, S2)

Name the O, I, A, & N for the plantaris muscle:

O: posterior lateral condyle of femur I: posterior calcaneus A: very weak assist in knee flexion and ankle plantar flexion N: tibial nerve (L4, L5, S1)

Name the O, I, A, & N for the flexor digitorum longus muscle:

O: posterior tibia I: distal phalanx of four lesser toes A: flexes the four lesser toes; assists in ankle inversion and plantar flexion of the ankle N: tibial nerve (L5, S1)

Name the O, I, A, & N for the soleus muscle:

O: posterior tibia and fibula I: posterior calcaneus A: ankle plantar flexion N: tibial nerve (S1, S2)

The motions of the subtalar and transverse tarsal joints occur on an ___ axis.

Oblique (triplantar)

Adduction/Abduction

Occur primarily in the forefoot and accompany inversion and eversion, respectively.

Dorsifexion

Occurs when the dorsal surface of the foot moves toward the anterior surface of the leg.

Ankle fracture

Often occurs when a person trips over an unexpected obstacle or falls from a height, and it usually involves a twisting component to the ankle. Lateral malleolus is most commonly involved.

Cuboid (Tarsal Bone)

On lateral side of the foot proximal (superior) to the fourth and fifth metatarsals and distal (inferior) to the calcaneus.

Lateral Ligament

On the lateral side of the ankle joint is a group of three ligaments, which connect the lateral malleolus to the talus and calcaneus.

Navicular (Tarsal Bone)

On the medial side in front of the talus and proximal to the three cuneiforms.

Calcaneus foot

One that is fixed in dorsiflexion.

Hammer toe

PIP is flexed and DIP is extended.

List the muscles of the lateral group:

Peroneus longus muscle, peroneus brevis muscle, peroneus tertius muscle

What type of joint is the superior tibiofibular joint and what motions does it allow?

Plane (synovial) joint that allows a small amount of gliding and rotation of the fibula on the tibia.

What type of joint is the subtalar joint, what is the DOF, and what motions are allowed?

Plane synovial joint with 1 degree of freedom and has motions of inversion/eversion, which occur around an oblique axis.

What are the motions of the ankle?

Plantar flexion, dorsiflexion, inversion, eversion, adduction, abduction.

Ankle sprains

Probably the most common injury among recreational and competitive athletes, and the lateral ligament is the most frequently injured ligament in these groups.

Tuberosity of Navicular (Tarsal Bone)

Projection on medial side of the navicular; easily seen on the medial border of the foot.

Calcaneal Tuberosity (Tarsal Bone)

Projection on posterior inferior surface of calcaneus

Each lesser toe (2-5) of the foot has a ___ & ___.

Proximal Interphalangeal (PIP) and a Distal Interphalangeal (DIP) Joint.

Base (Metatarsal)

Proximal end of each metatarsal

Lateral condyle (Tibia)

Proximal lateral end

Medial condyle (Tibia)

Proximal medial end

Varus

Refers to a position in which the distal segment is located toward the midline.

Valgus

Refers to a position in which the distal segment is situated away from the midline.

Pes cavus

Refers to an abnormally high arch

Transverse Arch

Runs from side to side through the three cuneiforms to the cuboid. The 2nd cuneiform is the keystone of this arch.

Lateral Longitudinal Arch

Runs from the calcaneus anteriorly through the cuboid to the fourth and fifth metatarsals. It normally rests on the ground during weight-bearing.

Plantar flexion and dorsiflexion occur in the ____ plane around the ____.

Sagittal plane around the frontal axis.

Talus (Tarsal Bone)

Sitting on the calcaneus, it is the second largest tarsal.

When the ankle moves in inversion/eversion, these motions are occurring primarily at the ____ & ____.

Subtalar & Transverse Tarsal Joints.

List the muscles of the extrinsic muscle group of the leg:

Superficial posterior, deep posterior, anterior and lateral groups/compartments

What are the two joints that provide little motion and are not part of the true ankle joint, but play a small role in the proper function of the ankle?

Superior and Inferior Tibiofibular Joints.

When the ankle moves in plantar flexion and dorsiflexion, these motions are occurring primarily at the _____.

Talocrural Joint

The bones of the foot include....

Tarsals, metatarsals, and phalanges.

True ankle joints are often described using a carpentry term:

Tenon & Mortise Joint

What is the point of reference for abduction and adduction?

The 2nd toe.

Superior Tibiofibular Joint

The articulation between the head of the fibula and the posterior lateral aspect of the proximal tibia.

During ankle plantar flexion, ....

The foot moves down and in (adduction).

During ankle dorsiflexion, .....

The foot not only comes up but also moves out slightly (abduction).

Equinus foot (horse's foot)

The hind foot is fixed in plantar flexion.

Long Plantar Ligament

The longest of the tarsal ligaments. Is more superficial than the spring ligament. It attaches posteriorly to the calcaneus and runs froward to attach on the cuboid and bases of the 3rd, 4th, & 5th metatarsals. It is the primary support of the lateral longitudinal arch.

Second Metatarsal

The longest; articulates with the second cuneiform.

Pes planus (flat foot)

The loss of the medial longitudinal arch.

In the ankle joint, what would be the mortise and what would be the tenon?

The malleoli of the tibia and fibula would be the mortise, and the talus would be the tenon.

Plantar Flexion

The movement toward the plantar surface of the foot.

Eversion

The raising of the lateral border of the foot, turning the forefoot outward.

Inversion

The raising of the medial border of the foot, turning the forefoot inward.

Cuneiforms (Tarsal Bone)

Thee in number and named the first through third, going from the medial toward the lateral side in line with the metatarsals. The first is the largest of the three.

First Metatarsal

Thickest and shortest metatarsal; located on the medial side of the foot. Articulates with the first cuneiform.

Describe the ankle joint's joint capsule.

This anteriorly and posteriorly but is reinforced by collateral ligaments on the sides.

List the muscles of the anterior group:

Tibialis anterior muscle, extensor hallucis longus muscle, extensor digitorum longus muscle

List the muscles of the deep posterior group:

Tibilalis posterior muscle, flexor hallucis longus muscle, flextor digitorum longus muscle

Fourth Metatarsal

Together with the 5th metatarsal, articulates with the cuboid.

Adduction and abduction occur in the ___ plane.

Transverse plane

Because the axis of rotation for the ankle joint is at an angle, it is considered ____.

Triplantar

What type of joint is the ankle joint?

Uniaxial hinge joint consisting of articulation between the distal end and medial malleolus of the tibia and the lateral malleolus of the fibula with the talus.