Ch20: Ankle Joint and Foot Flashcards
The leg (the portion of the lower extremity extending from the knee to the ankle) consists of the…
Tibia and Fibula.
What keeps the two bones together and provides a greater surface area for muscle attachment?
A strong interosseous membrane
Leg bones and interosseous membrane (anterior view).
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The Tibia
The larger of the two bones, is the only true weight-bearing bone of the leg. Triangular in shape, the tibia’s apex (crest) is located anteriorly.
The Fibula
The long, thin fibula is set back in line with the posterior surface of the tibia. Lateral to the tibia, the fibula forms a channel, with the interosseous membrane as the floor; this permits attachment of several muscles without distorting the shape of the leg.
Medial Condyle (Tibia)
Proximal medial end
Lateral Condyle (Tibia)
Proximal lateral end
Crest (Tibia)
Anterior and most prominent of the three borders
Right leg (lateral view). Note the posterior position of the fibula.
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Medial Malleolus (Tibia)
Enlarged distal medial surface
Head (Fibula)
Enlarged proximal end
Lateral Malleolus (Fibula)
Enlarged distal end
The bones of the foot include the…
Tarsals, metatarsals, and phalanges.
Calcaneus (Tarsal Bones)
Largest and most posterior tarsal bone
Calcaneal Tuberosity (Tarsal Bones)
Projection on the posterior inferior surface of the calcaneus
Calcaneal Tuberosity (Tarsal Bones)
Projection on the posterior inferior surface of the calcaneus
Sustentaculum Tali (Tarsal Bones)
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.
Talus (Tarsal Bones)
Sitting on the calcaneus, it is the second largest tarsal
Navicular (Tarsal Bones)
On the medial side, in front of the talus and proximal to the three cuneiforms
Tuberosity of Navicular (Tarsal Bones)
Projection on the medial side of the navicular; easily seen on the medial border of the foot
Cuboid (Tarsal Bones)
On the lateral side of the foot, proximal (superior) to the fourth and fifth metatarsals and distal (inferior) to the calcaneus
Cuneiforms (Tarsal Bones)
Three 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.
Metatarsals
Numbered 1 through 5, starting medially. Normally, the first and fifth metatarsals are weight-bearing bones, and the second, third, and fourth are not. We tend to stand on a triangle. Weight is borne from the base of the calcaneus to the heads of the first and fifth metatarsals.
Bones of the left foot (superior, lateral, and medial views).
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Base (Metatarsals)
Proximal end of each metatarsal
Head (Metatarsals)
Distal end of each bone
First (Metatarsals)
Thickest and shortest metatarsal; located on the medial side of the foot; articulates with the first cuneiform
Second (Metatarsals)
Longest; articulates with the second cuneiform
Third (Metatarsals)
Articulates with the third cuneiform
Fourth (Metatarsals)
Together with the fifth metatarsal, articulates with the cuboid
Fifth (Metatarsals)
Has prominent tuberosity located on the lateral side of its base
Phalanges
Of the foot have the same composition as those of the hand
The First Digit of the Foot (phalanges)
The great toe, has a proximal and distal phalanx but no middle phalanx.
The second through fifth digits of the foot (phalanges)
Aka the four lesser toes, each have a proximal, middle, and distal phalanx.
3 Parts of the foot
The Hindfoot, Midfoot, and Forefoot
The Hindfoot
Made up of the talus and calcaneus. In the gait cycle, the hindfoot is the first part of the foot that makes contact with the ground, thus influencing the function and movement of the other two parts.
The 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 hindfoot to the forefoot.
The Forefoot
Made up of the five metatarsals and all of 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.
Functional areas of the foot (superior view).
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Three Main Functions of the Ankle Joint and Foot
- Acting as a shock absorber as the heel strikes the ground at the beginning of stance phase
- Adapting to the level (or unevenness) of the ground
- Providing a stable base of support from which to propel the body forward.
Plantar Flexion
Movement toward the plantar surface of the foot. (Occurs in the sagittal plane around the frontal axis)
Dorsiflexion
Occurs when the dorsal surface of the foot moves toward the anterior surface of the leg. (Occurs in the sagittal plane around the frontal axis)
Movements of the ankle joint and foot in the frontal plane around the sagittal axis are called…
Inversion and Eversion
Inversion
The raising of the medial border of the foot, turning the forefoot inward.
Eversion
The opposite motion, is the raising of the lateral border of the foot, turning the forefoot outward.
Movements of the ankle joint and foot in the transverse plane are called…
Adduction and abduction. These motions occur primarily in the forefoot and accompany inversion and eversion, respectively.
Triplanar Motion of the Ankle Joint and Foot
Better defined using the terms supination and pronation. Depending on the particular joint, and the exact orientation of its axis, some of the cardinal plane component motions will predominate more than other. In reality, the axis of motion for each joint in the ankle region is oriented at an angle. Therefore, motion at any given joint happens in an oblique plane (not in a cardinal plane)
Ankle joint and foot motions.
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Supination
Describes a combination of plantar flexion, inversion, and adduction
Pronation
Describes a combination of dorsiflexion, eversion, and abduction
Valgus
Refers to a position in which the distal segment is situated away from the midline.
-Therefore, a calcaneal valgus is a position in which the distal (inferior) part of the calcaneus is angled away from the midline (
Varus
Refers to a position in which the distal segment is located toward the midline.
Calcaneal positions.
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Tibiofibular Joints
Two joints, with little motion, that are not part of the true ankle joint but that play a small role in the proper function of the ankle
Superior Tibiofibular Joint
The articulation between the head of the fibula and the posterior lateral aspect of the proximal tibia. It is a plane joint that allows a relatively small amount of gliding and rotation of the fibula on the tibia. Being a synovial joint, it has a joint capsule. Ligaments reinforce the capsule, and the joint functions to dissipate the torsional stresses applied at the ankle joint.
Inferior Tibiofibular Joint
A syndesmosis (fibrous union) between the concave distal tibia and the convex distal fibula. Because it is not a synovial joint, there is no joint capsule. However, fibrous tissue separates the bones and several ligaments that hold the joint together. Much of the ankle joint’s strength depends on a strong union at this joint.
What do the ligaments holding the inferior tibiofibular joint together allow?
Slight movement to accommodate the motion of the talus.
Talocrural Joint
The true ankle joint (talocrural joint or talotibial joint) is 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 of the talus.
This type of joint is often described using a carpentry term: (Talocrural Joint)
Tenon and mortise joint. A mortise is a notch that is cut in a piece of wood to receive a projecting piece (tenon) shaped to fit. Therefore, the malleoli of the tibia and fibula would be the mortise, and the talus would be the tenon. This joint connects the leg and foot and is responsible for controlling the majority of foot motion relative to the leg.
The two tibiofibular joints (anterior view).
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What kind of joint is the Ankle Joint?
The ankle is a uniaxial hinge joint consisting of an articulation of the talus with the distal end and medial malleolus of the tibia and the lateral malleolus of the fibula.
How many degrees of plantar flexion / dorsiflexion does the ankle joint allow?
The ankle joint allows approximately 30 to 50 degrees of plantar flexion and 20 degrees of dorsiflexion.
Because the axis of rotation at the ankle joint is at an angle, it is considered…
Triplanar, a term used to describe motion around an obliquely oriented axis that passes through all three planes.
During ankle dorsiflexion, the foot…
Mot only comes up but also moves out slightly (abduction).
During ankle plantar flexion, the foot moves…
Down and in (adduction).
The end feel of both dorsiflexion and plantar flexion is…
Firm and is classified as soft tissue stretch. This is due to the tension of the joint capsule, ligaments, and tendons.
Ankle joint (posterior view).
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Triplanar axis of motion for the left ankle joint. (A) Superior view. (B) Anterior view.
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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…
Abduct during dorsiflexion and adduct during plantar flexion.
In a closed chain, with the foot fixed and the leg moving over it, the angle of the joint axis causes the leg to…
Medially rotate on the foot. During ankle plantar flexion when the foot is fixed on the ground, the leg laterally rotates on the foot. This rotation is allowed because of the slight movement that is possible at the tibiofibular joints. It is an accessory movement much like the rotation of the CMC joint of the thumb. This rotation is not possible to do in an open chain
Arthrokinematics of the Ankle Joint
The convex talus glides posteriorly on the concave tibia during ankle dorsiflexion and glides anteriorly during ankle plantar flexion.
Subtalar, or talocalcaneal, joint
Consists of the inferior surface of the talus articulating with the superior surface of the calcaneus. It is a plane synovial joint with 1 degree of freedom. The motions of inversion and eversion occur around an oblique axis.
Open Kinetic Chain (Ankle and Foot Motions)
- Leg Fixed
- Foot Moves (Ankle Dorsiflexion: Foot abducts, Ankle Plantar Flexion: Foot Adducts)
Closed Kinetic Chain (Ankle and Foot Motions)
Foot Fixed
Leg Moves: (Ankle Dorsiflexion: Leg Medially Rotates, Ankle Plantar Flexion: Leg Laterally Rotates)
Arthrokinematic motion for ankle dorsiflexion/ plantar flexion.
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Subtalar joint (lateral view).
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Transverse Tarsal Joint
Made up of the anterior surfaces of the talus and calcaneus articulating with the posterior surfaces of the navicular and the cuboid, respectively. Although they lie next to each other, very little movement occurs between the navicular and the cuboid. The motions of the transverse tarsal joint link the hindfoot and forefoot in inversion and eversion.
Transverse tarsal joint (superior view).
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Motions occurring at both the subtalar and transtarsal joints.
Inversion (combination of adduction, supination, and plantar flexion) and Eversion (combination of abduction, pronation, and dorsiflexion)
What motions occur at the talocrural joint?
Plantar Flexion and Dorsiflexion
The combined motions of all these joints allow the foot to…
Assume almost any position in space. This is quite useful in allowing the foot to adapt to irregular surfaces such as those found when walking on uneven ground. For example, think about the many foot positions needed when climbing on rocks at the beach or in the mountains.
Metatarsophalangeal (MTP) Joints
Consist of the metatarsal heads articulating with the proximal phalanges. There are five joints allowing flexion, extension, hyperextension, abduction, and adduction
The first MTP joint
The most mobile. It allows approximately 45 degrees of flexion, 70 degrees of extension, and 90 degrees of hyperextension.
The second through fifth MTP joints
Allow about 40 degrees of flexion and extension and only about 45 degrees of hyperextension.
Hyperextension is very important during what phase of walking?
The toe-off phase of walking.
The point of reference for abduction and adduction of the foot joint is…
The second toe. Like the middle finger, the second toe abducts in both directions but adducts only as a return motion from abduction.
Joints of the phalanges of the foot (superior view). Note that the great toe has only two joints, whereas the four lesser toes have three.
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Toe motions.
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Proximal Interphalangeal (PIP) and a Distal Interphalangeal (DIP) Joint
Each of the lesser toes (2 through 5) of the foot has each these joints.
The foot has only one phalangeal joint called the…
Interphalangeal (IP) Joint
What kind of joint is the Ankle Joint
A synovial joint, has a joint capsule
Capsule of the Ankle Joint
Rather thin anteriorly and posteriorly but is reinforced by collateral ligaments on the sides. These collateral ligaments are actually groups of several ligaments.
Deltoid Ligament
The collateral ligament on the medial side is a triangular ligament 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
-Strengthens the medial side of the ankle joint, holds the calcaneus and navicular against the talus, and helps maintain the medial longitudinal arch.
Anterior Fibers of the Deltoid Ligament
Attach to the navicular (tibionavicular ligament).
Middle Fibers of the Deltoid Ligament
(Tibiocalcaneal Ligament) Descend directly to the sustentaculum tali of the calcaneus.
Posterior Fibers of the Deltoid Ligament
(Posterior Tibiotalar Ligament) Run backward to the talus.
Deep Fibers of the Deltoid Ligament
(Anterior Tibiotalar Ligament) Can barely be seen from the medial side because they are deep to the tibionavicular portion.
Ligaments of the right medial ankle. The four parts of the deltoid ligament.
Note that the dotted lines show the outline of the talus under the ligaments.
On the lateral side of the ankle joint is a group of three ligaments commonly and collectively referred to as the…
Lateral Ligament
What do the three parts of the Lateral Ligament connect?
The lateral malleolus to the talus and calcaneus.
The rather weak anterior talofibular ligament attaches the…
Lateral malleolus to the talus.
Posteriorly, the fairly strong posterior talofibular ligament runs almost horizontally to connect
The lateral malleolus to the talus.
In the middle is the long and fairly vertical calcaneofibular ligament that attaches the…
Malleolus to the calcaneus.
Ligaments of the right lateral ankle. The three parts of the lateral ligament.
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Arches of the Foot
Bc the foot is the usual point of impact with the ground, it must be able to absorb a great deal of shock, adjust to changes in terrain, and propel the body forward. To allow these actions to occur, the bones of the foot are arranged in arches. We stand on a triangle that distributes weight-bearing from the base of the calcaneus to the heads of the first and fifth metatarsals. Between these three points are two arches (medial and lateral longitudinal) at right angles to the third (transverse) arch
The main weight-bearing surfaces of the right foot (plantar view).
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The two longitudinal arches of the right foot:
(A) Medial longitudinal arch. (B) Lateral longitudinal arch.
Transverse arch of the foot (frontal view)
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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 first three metatarsals The talus is at the top of the arch; it is often referred to as the keystone because it receives the weight of the body. An essential part of an arch, the keystone is usually the central, or topmost, part. The arch depresses somewhat during weight-bearing and then recoils when the weight is removed. Normally, it never flattens or touches the ground.
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.
The Transverse Arch
Runs from side to side through the three cuneiforms to the cuboid. The second cuneiform is the keystone of this arch.
These three arches of the foot are maintained by
(1) the shape of the bones and their relation to each other, (2) the plantar ligaments and fascia, and (3) the muscles. The ligaments and fascia are perhaps the most important features.
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.
Support structures of the right foot and arches (medial view).
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Support structures of the right foot and arches (inferior view).
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Long Plantar Ligament
The longest of the tarsal ligaments, is more superficial than the spring ligament. It attaches posteriorly to the calcaneus and runs forward to attach on the cuboid and bases of the third, fourth, and fifth metatarsals. It is the primary support of the lateral longitudinal arch
Short Plantar Ligament
Assists the long plantar ligament and also attaches the calcaneus to the cuboid. It mostly lies deep to the long plantar ligament.
Plantar Fascia
- Superficially located and supports both longitudinal arches
- Runs from the calcaneus forward to the proximal phalanges and 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
The arches of the foot are also supported by muscles…
Mainly the invertors and evertors of the foot.
Which muscles give some support to the medial side of the foot.
The tibialis posterior, the flexor hallucis longus, and the flexor digitorum longus muscles all span the ankle posteriorly on the medial side, passing under the sustentaculum tali of the calcaneus.
Which muscles support the medial longitudinal arch of the foot?
The flexor hallucis longus and flexor digitorum longus muscles span the medial longitudinal arch and help support it.
Which muscles provide support to the transverse and lateral longitudinal arches of the foot?
The fibularis (aka peroneus) longus muscle spans the foot from the lateral to the medial side, providing support to the transverse and lateral longitudinal arches
Why do the intrinsic muscles of the foot provide more support than the extrinsic?
The intrinsic muscles provide more support than the extrinsics, because any motion will involve them. However, the total muscular support to the arches has been estimated to bear only about 15% to 20% of the total stress to the arches.
Plantar fascia (plantar view).
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Extrinsic Muscles of the Ankle and Foot
Originate on the leg and have vertical lines of pull in the leg, but the foot acts as a pulley to change their line of pull distally.
-Found in groups of three or combinations of three and are located in four anatomical areas. Those four anatomical areas also represent the four compartments of the leg, separated by heavy fascia.
Intrinsic Muscles of the Ankle and Foot
Originate on the tarsal bones and have both attachments distal to the ankle joint. Bc we do not use these muscles in the foot to perform intricate actions, they tend not to be as well developed as their counterparts in the hand. Their names tell a great deal about their location and action. All intrinsic muscles are located on the plantar surface, essentially in layers; the exceptions to this are the extensor digitorum brevis, the extensor hallucis brevis, and the dorsal interossei, which are between the metatarsals and dorsal to the plantar interossei
Muscles that cross the ankle anteriorly will cause what motion?
Dorsiflex the ankle and possibly extend the toes.
Muscles that cross the ankle posteriorly will produce what motion?
Plantar flex the ankle and possibly flex the toes.
The medial muscles of the ankle and foot will produce what motions?
Invert the ankle, and the lateral ones will evert.
Four Anatomical Areas of Leg Extrinsic Muscles
(1) Superficial Posterior, (2) Deep Posterior, (3) Anterior, and (4) Lateral groups/compartments
(All have proximal attachments on the femur, tibia, or fibula, and all cross the ankle joint)
Role of the Plantar Fascia in Supporting the Arch of the Foot
When the foot is pushing off for the next step, the ankle plantar flexors lift the calcaneus upward, pulling the ankle into plantar flexion while simultaneously extending the metatarsophalangeal (MTP) joints. The resulting increased tension on the plantar fascia causes the arch to rise (see figure). As the arch rises, it mechanically forces the foot into supination. The result of the foot being in supination creates the rigid lever necessary for push-off. This is known as the “windlass effect.” “Windlass” is a sailing term for a winch mechanism in which a rope is wound around a drum. In the foot, the plantar fascia is being wound around the metatarsal head.
Superficial Posterior Group (ankle and foot)
Includes the gastrocnemius, soleus, and plantaris muscles.
Gastrocnemius Muscle (Superficial Posterior Group)
Two-joint muscle that crosses the knee and the ankle. It is an extremely strong ankle plantar flexor and attaches by two heads to the posterior surface of the medial and lateral condyles of the femur. After descending the posterior leg superficially, it forms a common Achilles tendon (aka heel cord) with the soleus muscle and attaches to the posterior surface of the calcaneus. Although its major function is at the ankle, it does span the knee posteriorly and has a significant role at the knee.
Superficial Posterior Group (Extrinsic Muscles of the Ankle and Foot)
Muscle, Joint Crossing, and Possible Actions
- Gastrocnemius: Posterior (Plantar flexion)
- Soleus: Posterior (Plantar flexion)
- Plantaris: Posterior (Plantar flexion)
Deep Posterior Group (Extrinsic Muscles of the Ankle and Foot)
Muscle, Joint Crossing, and Possible Actions
- Tibialis posterior: Posterior, medial (Plantar flexion, inversion)
- Flexor digitorum longus: Posterior, medial (Plantar flexion, inversion, lesser toe flexion)
- Flexor hallucis longus: Posterior, medial (Plantar flexion, inversion, great toe flexion)
Anterior Group (Extrinsic Muscles of the Ankle and Foot)
Muscle, Joint Crossing, and Possible Actions
- Tibialis anterior: Anterior, medial (Dorsiflexion, inversion)
- Extensor hallucis longus Anterior, medial (Dorsiflexion, inversion, great toe extension)
- Extensor digitorum longus: Anterior (Dorsiflexion, lesser toe extension)
Lateral Group (Extrinsic Muscles of the Ankle and Foot)
Muscle, Joint Crossing, and Possible Actions
- Fibularis longus: Posterior, lateral (Eversion, plantar flexion)
- Fibularis brevis: Posterior, lateral (Eversion, plantar flexion)
- Fibularis tertius: Anterior (Eversion, dorsiflexion)
Gastrocnemius Muscle (OIAN)
O: Medial and lateral condyles of femur
I: Posterior calcaneus
A: Knee flexion and ankle plantar flexion
N: Tibial nerve (S1, S2)
Soleus Muscle
Large, one-joint muscle located deep to the gastrocnemius muscle. Originating on the posterior tibia and fibula, it spans the posterior leg, blending with the gastrocnemius muscle to form the large, strong Achilles tendon that inserts on the posterior calcaneus. Because the soleus muscle spans the ankle in the midline, its only function is to plantar flex the ankle.
Triceps Surae
(meaning “three-headed calf” muscle) Made up of the two heads of the gastrocnemius and soleus muscles
The gastrocnemius muscle (posterior view).
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The soleus and plantaris muscles (posterior view).
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Soleus Muscle (OIAN)
O: Posterior tibia and fibula
I: Posterior calcaneus
A: Ankle plantar flexion
N: Tibial nerve (S1, S2)
Plantaris Muscle
Long, thin, two-joint muscle with no significant function. It originates on the posterior surface of the lateral epicondyle of the femur, spans the posterior leg medially, and blends with the gastrocnemius and soleus muscles in the Achilles tendon. Theoretically, it should flex the knee and plantar flex the ankle. However, because of its size in relation to the prime movers of those actions, it is assistive at best. It is absent in one or both legs in some individuals. Similar to the palmaris longus in the hand, its long tendon is sometimes harvested when there is need for a tendon transplant for some other muscle. Its absence does not affect function.
Biomechanical Impact of a Heel Lift
Wearing a heeled shoe causes the calcaneus to be elevated during weight-bearing compared with the rest of the foot. This causes the gastrocnemius and soleus to be put on slack. Individuals who regularly wear high-heeled shoes can develop adaptive shortening of these muscles as a result
Plantaris Muscle (OIAN)
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)
Deep Posterior Group
Made up of the tibialis posterior, the flexor hallucis longus, and the flexor digitorum longus muscles. They all attach to the posterior tibia and/or fibula and all terminate in the foot. Because they all cross the ankle posteriorly, they can plantar flex it. However, because of their size in relation to the soleus and gastrocnemius muscles, their role is only assistive in ankle plantar flexion.
Tibialis Posterior Muscle
The deepest-lying posterior muscle. Its proximal attachment is on the interosseous membrane and adjacent portions of the tibia and fibula. It descends on the posterior aspect of the leg, looping around the medial malleolus to attach on the navicular with fibrous expansions to the cuboid, the three cuneiforms, the sustentaculum tali of the calcaneus, and the bases of the second through fourth metatarsals. Because the tibialis posterior muscle crosses the ankle medially and posteriorly, it can invert and plantar flex the ankle. As mentioned above, because of its size in relation to the other plantar flexors, it is only assistive in plantar flexion.
Tibialis Posterior Muscle (OIAN)
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)
Flexor Hallucis Longus Muscle
Situated mostly on the lateral side of the leg, it arises from the posterior fibula and interosseous membrane. Descends the leg posteriorly, loops around the medial malleolus through a groove in the posterior talus, and goes under the sustentaculum tali of the calcaneus. This muscle travels down the foot through the two heads of the flexor hallucis brevis muscle to attach at the base of the distal phalanx of the great toe. This distal attachment is similar to the flexor digitorum profundus and superficialis muscles in the hand.
-Flexes the great toe and assists in inversion and, to a lesser degree, assists in plantar flexion of the ankle.
The tibialis posterior muscle (posterior view). Note that the foot is in extreme plantar flexion.
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Flexor Hallucis Longus Muscle (OIAN)
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)
Flexor Digitorum Longus Muscle
Situated mostly on the medial side of the leg, it arises from the posterior tibia. It descends the leg posteriorly, loops around the medial malleolus, and runs down the foot, splitting into four tendons and inserting into the distal phalanx of the second through fifth toes. This muscle passes through the split in the flexor digitorum brevis tendon in a fashion similar to the flexor digitorum profundus muscle, which goes through the split in the flexor digitorum superficialis muscle in the hand. It flexes the four lesser toes and assists in inversion and plantar flexion of the ankle.
The flexor hallucis longus muscle (posterior view). Note that the foot is in extreme plantar flexion.
Dotted line denotes attachment along interosseous membrane.
Flexor Digitorum Longus Muscle (OIAN)
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)
Anterior Muscle Group
Made up of the tibialis anterior, the extensor hallucis longus, and the extensor digitorum longus muscles. They all attach proximally on the anterior lateral leg and cross the ankle anteriorly.
The flexor digitorum longus muscle (posterior view). Note that the foot is in extreme plantar flexion.
Dotted line denotes attachment along tibia.
Tibialis Anterior Muscle
Originates on the lateral side of the tibia and interosseous membrane, then descends the leg to insert medially on the first cuneiform and the base of the first metatarsal. It makes up most of the anterior lateral leg’s bulk. Bc the tibialis anterior muscle spans the ankle anteriorly and medially, it dorsiflexes and inverts the ankle.
From origin to insertion, the changing positions of the flexor digitorum longus, the tibialis posterior, and the flexor hallucis longus provide added strength (posterior and plantar views of leg and foot).
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Tibialis Anterior Muscle (OIAN)
O: Lateral tibia and interosseous membrane
I: First cuneiform and first metatarsal
A: Ankle inversion and dorsiflexion
N: Deep fibular nerve (L4, L5, S1)
Origin: Medial to Lateral (Deep Posterior Group)
Flexor digitorum longus (FDL)> Tibialis posterior (TP)> Flexor hallucis longus (FHL)
Medial Malleolus: Superior to Inferior (Deep Posterior Group)
Tibialis posterior (TP)> Flexor digitorum longus (FDL)> Flexor hallucis longus (FHL)
Insertion: Medial to Lateral (Deep Posterior Group)
Tibialis posterior (TP)> Flexor hallucis longus (FHL)> Flexor digitorum longus (FDL)
Extensor Hallucis Longus Muscle
A thin muscle lying deep to and between the tibialis anterior and the extensor digitorum longus muscles, originates on the fibula and interosseous membrane and inserts into the base of the distal phalanx of the great toe. Its primary function is to extend the great toe at the IP and then the MTP joints, but this muscle also assists in dorsiflexing and inverting the ankle.
The tibialis anterior muscle (anterolateral view).
Dotted line denotes attachment along interosseous membrane.
Extensor Hallucis Longus Muscle (OIAN)
O: Fibula and interosseous membrane
I: Distal phalanx of great toe
A: Extends first toe IP and MTP joints; assists in ankle inversion and dorsiflexion
N: Deep fibular nerve (L4, L5, S1)
Extensor DIgitorum Longus Muscle
The most lateral of the anterior muscles. It attaches to most of the anterior fibula, the interosseous membrane, and the lateral condyle of the tibia. It descends the leg to attach to the distal phalanx of the four lesser toes. The extensor digitorum longus muscle functions primarily to extend the second through fifth toes, but it also assists in dorsiflexing the ankle. It does not have an inversion/eversion role because it crosses the joint through the middle of that axis.
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 fibular nerve (L4, L5, S1)
The extensor hallucis longus muscle (anterolateral view).
Dotted line denotes attachment along interosseous membrane.
Lateral Group of Ankle and Foot Muscles
Consists of the fibularis longus, fibularis brevis, and fibularis tertius muscles. They all originate proximally on the fibula and run distally to the foot. Two cross the ankle joint posteriorly, and one crosses the ankle anteriorly. “Fibularis” more accurately described the anatomical locations of these muscles and nerves and will be used here.
Fibularis Longus Muscle
The most superficial of the fibular muscles. Arising from the proximal end of the fibula and interosseous membrane, it descends the lateral leg and loops behind the lateral malleolus along with the fibularis brevis muscle. At this point, the fibularis longus muscle goes deep, crossing the foot obliquely from the lateral to the medial side and inserting into the plantar surface of the first metatarsal and first cuneiform (Fig. 20-32). This distal attachment is very close to the attachment of the tibialis anterior muscle.
Stirrup of the Foot
The fibularis longus and tibialis anterior muscles together because the fibularis longus muscle descends the leg laterally before crossing the foot medially to join the tibialis anterior muscle. The tibialis anterior muscle descends the leg medially to meet the fibularis longus muscle, forming a U, or stirrup.
Crossing the foot as it does, the fibularis longus muscle provides some support to the lateral longitudinal and transverse arches of the foot. Its prime function is to evert the ankle, although this muscle can assist somewhat in ankle plantar flexion.
The extensor digitorum longus muscle (anterolateral view).
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Fibularis Longus Muscle (OIAN)
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 fibular nerve (L4, L5, S1)
The fibularis longus muscle (anterolateral view).
Dotted lines indicate location on plantar surface.
Fibularis Brevis Muscle (OIAN)
O:Lateral distal fibula
I: Tuberosity on base of fifth metatarsal
A: Ankle eversion; assists in plantar flexion
N: Superficial fibular nerve (L4, L5, S1)
The fibularis brevis and tertius muscles (anterolateral view).
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Fibularis Tertius Muscle (OIAN)
O: Distal medial fibula
I: Tuberosity on base of fifth metatarsal
A: Assists somewhat in ankle eversion and dorsiflexion
N: Deep fibular nerve (L4, L5, S1)
Plantar Flexion Prime Movers
Gastrocnemius, Soleus
Dorsiflexion Prime Movers
Tibialis anterior
Inversion Prime Movers
Tibialis Posterior (Tibialis anterior)
Eversion Prime Movers
Fibularis longus, fibularis brevis
Flexion of second through fifth toes Prime Movers
Flexor digitorum longus
Flexion of first toe Prime Movers
Flexor hallucis longus
Extension of second through fifth toes Prime Movers
Extensor digitorum longus
Extension of first toe Prime Movers
Extensor hallucis longus
No prime mover action
Plantaris, fibularis tertius
Dorsal Surface (Intrinsic Muscles of the Foot)
- Extensor Digitorum Brevis: Extends PIP joints of second through fourth digits
- Extensor hallucis brevis: Extends IP joint of first digit
Plantar Surface (Intrinsic Muscles of the Foot)
- Abductor hallucis: Abducts; Flexes IP of first toe
- Flexor digitorum brevis: Flexes PIP of digits second through fifth digits
- Abductor digiti minimi: Flexes; Abducts fifth digit
Second Layer (Intrinsic Muscles of the Foot)
- Quadratus plantae: Straightens diagonal line of pull of flexor digitorum longus
- Lumbricals: Flexes MPs; extends PIPs and DIPs
Third Layer (Intrinsic Muscles of the Foot)
- Flexor hallucis brevis: Flexes MP of first digit
- Adductor hallucis: Adducts; flexes first digit
- Flexor digiti minimi: Flexes PIP of fifth digit
Dorsal Surface/Fourth Layer- Deepest (Intrinsic Muscles of the Foot)
- Dorsal interossei: Abducts second through fourth digits
- Plantar interossei: Adducts third through fifth digits
Dorsal Surface (Innervation of the Intrinsic Foot Muscles)
Extensor digitorum brevis: Deep fibular
Extensor hallucis brevis: Deep fibular
Plantar Surface (Innervation of the Intrinsic Foot Muscles)
- Abductor hallucis: Tibial
- Flexor digitorum brevis: Tibial
- Abductor digiti minimi: Tibial
- Quadratus plantae: Tibial
- Lumbricals: Tibial
- Flexor hallucis brevis: Tibial
- Adductor hallucis: Tibial
- Flexor digiti minimi: Tibial
- Dorsal interossei: Tibial
- Plantar interossei: Tibial
Muscles of the posterior leg, superficial layer (posterior view, right leg).
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Middle layer of the posterior group. The middle section of the gastrocnemius muscle has been removed.
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Deep layer of the posterior group.
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Muscles of the right lateral group (lateral view).
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Muscles of the right anterior group (anterior view)
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Muscles of the plantar surface of the foot—first (superficial) layer (plantar view).
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Muscles of the plantar surface of the foot—second layer (plantar view).
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Muscles of the plantar surface of the foot—third layer (plantar view).
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Superficial Fibular Nerve
Innervates muscles on the lateral side of the leg
Deep Fibular Nerve
Innervates the fibularis tertius muscle which is the exception because it crosses the ankle anteriorly
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. Most commonly, inflammation of the periosteum causes the pain.
-An overuse injury that can result from running on hard surfaces, running on tiptoes, and playing sports that involve a lot of jumping
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.
Equinus Foot
(Horse’s foot) means that the hindfoot is fixed in plantar flexion.
Calcaneus Foot
One that is fixed in dorsiflexion.
Pes Cavus
efers to an abnormally high arch
Pes Cavus
efers to an abnormally high arch
Pes Planus
(flat foot) is the loss of the medial longitudinal arch
Hallux Valgus
Caused by pathological changes in which the great toe develops a valgus deformity (distal end pointed laterally).
Hallux Rigidus
A degenerative condition of the first MTP joint associated with pain and diminished range of motion.
Hammer Toe
The PIP is flexed and the DIP is extended (all MTP joints are hyperextended)
Mallet Toe
PIP joint is extended and DIP joint is flexed (all MTP joints are hyperextended)
Claw Toe
PIP joint and DIP joint are flexed (all MTP joints are hyperextended)
Muscles of the plantar surface of the right foot—fourth (deepest) layer.
(A) Plantar interossei. (B) Dorsal interossei.
Intrinsic muscles of the dorsum of the foot.
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Metatarsalgia
A general term referring to pain around the metatarsal heads. The individual often describes the pain as a bruise, or “like walking on pebbles.” The pain usually becomes worse with increased activity.
Morton’s neuroma
Caused by abnormal pressure on the plantar digital nerves commonly at the web space between the third and fourth metatarsals. This pressure can result in pain and numbness in the toe area that gets worse with activity such as running.
Turf Toe
Caused by forced hyperextension of the great toe at the MTP joint. It is commonly seen in football, baseball, and soccer players.
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. Lateral or inversion sprains occur when the foot lands in a plantar-flexed and inverted position. One or more of the lateral ligament’s three parts may be stretched or torn.
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. The lateral malleolus is most commonly involved.
Bimalleolar Fracture
Involves both malleoli
Trimalleolar Fractures
Involves both malleoli and the posterior lip of the tibia.
Plantar Fasciitis
A common overuse injury, resulting in pain in the heel. The plantar fascia helps to maintain the medial longitudinal arch and acts as a shock absorber during weight-bearing. The pain is usually located at the point where the fascia attaches to the calcaneus on the plantar surface.
Achilles Tendonitis
An inflammation of the gastrocnemius-soleus tendon, is sometimes a precursor to a ruptured Achilles tendon.
Ruptured Achilles Tendon
With a complete rupture, the individual loses the ability to plantar flex the ankle. To determine whether the tendon is intact, have an individual lie prone with the feet off the edge of the table. Squeeze on the muscle belly of the gastrocnemius muscle. If the tendon is intact, slight plantar flexion will occur, but no motion will occur if the tendon is ruptured.
Triple Arthrodesis
A surgical procedure that fuses the talocalcaneal, calcaneocuboid, and talonavicular joints. It provides medial-lateral stability of the foot and relieves pain at the subtalar joint, but inversion and eversion at the ankle are lost. Ankle dorsiflexion and plantar flexion remain because the talotibial joint has not been involved
When do stretching and strengthening occur?
Stretching is performed on relaxed muscles; and strengthening occurs when muscles contract
How do you stretch a two-joint muscle?
Stretch it over both joints at the same time within pain limits of that muscle.
How do you stretch a one-joint muscle?
When a two-joint muscle crosses the same joint, select a joint position that stretches a two-joint muscle over only one joint.
The excursion of a one-joint muscle being stretched will be…
Greater than the range allowed by the joint.
The excursion of a two-joint muscle is…
Less than the combined range allowed by both joints.
A muscle contraction is strongest if the muscle is…
Stretched before it contracts.
A muscle loses power quickly as it…
Shortens
Do one or two-joint muscles maintain their force of contraction for longer?
Two-joint muscles maintain their force of contraction for a longer period than a one-joint muscle. This is because they are able to elongate over one joint while shortening over the other joint.
