Ankle and Foot
What are the arthrokinematics for open chain movement at the talocrural joint?
Roll glide opposite since the ankle mortise is concave and it is the fixed segment with open chain movement.
Subtalar joint stabilizing tissue: eversion
STJ stabilizing tissue for eversion includes the tibiocalcaneal ligament, the tibionavicular ligament, and the spring ligament.
What movements occur at the MTP joints? What arthrokinematics for open chain movement? Closed chain?
Abduction/adduction (horizontal plane) and extension/flexion (sagittal plane). Extension of the first MTP joint is very important for gait. Roll and glide are the same for open chain movement because the fixed metatarsal head is convex. For closed chain movement in which the metatarsal head moves on the proximal phalanx, roll and glide are opposite because the fixed proximal phalanx has a concave surface.
With dorsiflexion/plantarflexion at the talocrural joint, why does the fibula move and not the tibia?
About 1/6 of the weight goes through the fibula and 5/6 goes through the tibia - it requires more force to move the tibia. In addition, the larger lateral facet is able to push the fibula superiorly as we move ventrally into the wider aspect on the talar dome. This provides that superior translation and lateral rotation of the fibula with dorsiflexion.
What is pes cavus?
An abnormally high arch is termed pes cavus. Pes cavus occurs due to supination in the hind foot and mid tarsal joint. To keep the forefoot in contact with the ground, the forefoot must pronate. These terms only qualitatively describe the arch and do not identify the mechanism. Top right picture: significant callus formation under the metatarsals. There is more of a medial arch than normal in the case of pes cavus. The rear foot includes the subtalar joint, the mid foot includes the the calcaneocuboid and talonavicualr joints. If these two areas are supinating, to avoid losing contact with the ground/shifting the BOS laterally, the forefoot has to pronate to keep the first, second, and third metatarsal heads on the ground. Supination in the hind foot and mid foot causes these individuals to be more susceptible to ankle sprains because they are shoving themselves over to the outside so it takes less force to damage the ligaments that limit inversion on the lateral side of the foot. There is already passive tension generated by the supinated position, so movement into additional inversion could stress the ligaments to the point that they enter the plastic region sooner than normal. Individuals with pes cavus are not able to absorb shock through the medial longitudinal arch very well. The shock is transmitted up to the next proximal structure until the force dissipates.
Dorsiflexors
Anterior tibialis, extensor hallucis longus, extensor digitorum longus Anything on the ventral side of the axis is a dorsiflexor. Extensor hallucis longus and extensor digitorum longus influence the toes greatly - they also cross the talocrural and subtalar joints so they have actions at those joints as well. Anterior tibialis is more of a pure dorsiflexor because it crosses fewer joints than the other two dorsiflexors.
What is the stabilizing tissue for the proximal tibiofibular joint?
Capsule, anterior and posterior proximal tibiofibular ligament, and the interosseous membrane.
What complications can occur with pes planus?
Complications of pes planus include plantar fasciitis, metatarsal stress fracture, bunions, and potential decrease in transfer of loads in the foot during gait. Plantar fasciitis refers to inflammation in the plantar fascia due to micro tears that have occurred from the structure being overstretched. Stretching the gastrocnemius and soleus can assist with plantarfasciitis. Bunions are associated with excessive pronation.
What are the three movements involved in pronation at the talocrural joint with open chain movement?
DABE: dorsiflexion, abduction, and eversion. With pronation, there is dorsiflexion (main movement) with a little bit of eversion and abduction (minor movements)
How does the shape of the talar dome affect the movement that occurs at the tibiofibular joint with dorsiflexion at the talocrural joint?
Dorsiflexion and plantar flexion are the main movements that can occur at the talocrural joint. With dorsiflexion, we have to consider the shape of the talar dome. The picture shows the tibia and fibula on either side of the talus, which is a wedge like structure that is thicker ventrally than it is dorsally. The red line drawn in the picture represents the maximum/full dorsiflexion taking place at the talocrural joint where the tibia and fibula move on the dome of the talus. The tibia and fibula move into the widest part of the talus that stops further movement - the bones have to spread apart even further to get greater dorsiflexion.
What are the main and minor movements at the talocrural joint (as a result of the oblique axis)?
Dorsiflexion and plantarflexion in the sagittal plane are the main movements. The minor movements include eversion and abduction and inversion and adduction (they occur in the frontal and horizontal planes).
What is the function of the mid tarsal joint during weight bearing rearfoot pronation?
During WB rearfoot pronation, the mid tarsal joint can supinate or the mid tarsal joint can pronate - it depends on what is needed for the particular situation. Bottom figure is showing reaerfoot pronation. Since pronation is occurring with weight bearing (closed chain), there is calcaneal eversion, talar plantarflexion, and talar adduction. The issue is that if nothing changes in the forefoot through the mid tarsal joint, the lateral metatarsal heads would come up off the ground due to the rear foot pronation without any compensation. This would cause a loss of BOS and a fall would likely occur. With rearfoot pronation, you can get supination at the mid tarsal joint to keep as large of a BOS as possible. This keeps the lateral metatarsal heads on the ground to maintain the BOS.
What happens if the individual with forefoot varus starts biking?
Forefoot varus means that not all of the metatarsals are in contact with the ground. In order to have the largest BOS possible, all of the metatarsals need to be in contact with the ground. In order to get all of the metatarsals on the ground, the rearfoot is forced into pronation. By pronating the rearfoot (closed chain/WB), there is adduction of the talus an internal rotation of the tibia. Internal rotation of the tibia lends itself to an increase in genu valgum. Without compensation from an orthotic, there is varus/valgus force going through the knee as the individual is biking. This can start to wear down the joint over time. By wearing an orthotic, all of the metatarsal heads are in contact with the surface of the orthotic. This prevents pronation of the rearfoot so there is no internal rotation of the tibia and no increase in genu valgum.
Midtarsal joint function during weight bearing rearfoot supination
During WB rearfoot supination, the mid tarsal joint can pronate or the mid tarsal joint can supinate. For the STJ and the midtarsal joint, the close packed position is supination - this means that all of the ligaments are tight in supination. With supination of the rearfoot, the mid tarsal can pronate to keep the metatarsal heads on the ground. The bottom picture shows supination (inversion of the calcaneus). If there was inversion of the calcaneus and no movement through the mid tarsal joint to affect the forefoot, the first, second, and possibly third metatarsal heads would lift off of the ground so only the lateral side of the foot would remain in contact with the ground (loss of BOS). Initially with supination of the rearfoot we can get pronation through the mid tarsal joint. However, as supination continues in the rearfoot, the ligaments become tight (those that cross the STJ and mid tarsal joint). Once the ligaments tighten at the STJ, the passive tension is translated to the mid tarsal joint, which will pull it into supination as well. Initially as the rearfoot is supinating, it is starting to stretch out the ligaments that limit inversion. As the passive tension is developing, the mid tarsal joint is still able to pronate. However, as the rearfoot supination continues, the passive tension can cause the STJ to lock up and transmit the passive tension to the mid tarsal joint which starts to lock the mid tarsal joint/pull it into supination. In this case, this is occurs due to rearfoot mechanics rather than a change in terrain.
Medial longitudinal arch during static weight bearing
During static weight bearing, the body pushes the talus inferiorly, which spreads out the calcaneus and metatarsal heads. The plantar fascia stretches minimally. If the load is increased or the fascia is overstretched, intrinsic and extrinsic muscles will need to contract to support the arch. Looking at the foot print, notice that the medial longitudinal arch has disappeared because there is contact of the skin on the medial side with the ground. Normally, we just have body weight pushing the talus inferiorly and the plantar fascia stretches minimally. When there is a load placed upon us in addition to body weight, there is greater force pushing down on the ventral and dorsal aspects of the arch to stretch the plantar fascia - it has to stretch more before the passive tension is able to equal the force of the weight that is pushing down on it. It is possible for someone to have overstretched plantar fascia so it requires more movement/stretching to start to increase the passive tension. Then the intrinsic and extrinsic muscles need to contract to support the arch.
True or false: the rearfoot contains the talocrural joint
FALSE - the rearfoot does NOT contain the talocrural joint. The rearfoot only includes the subtalar joint. The talocrural joint is not considered part of the rearfoot because the joints of the foot only include the bones of the foot. The talocrural joint includes the tibia and the fibula.
Flexible vs rigid pes planus
Flexible pes planus occurs when the medial longitudinal arch is lost during weight bearing but it is present in non weight bearing. There is always some medial longitudinal arch lost in weight bearing, but not to the extent of an individual with pes planus. Rigid pes planus occurs due to an osteologic issue. There is pes planus in weight bearing and in non weight bearing. The intrinsic and extrinsic muscles have to work to help support the arch as much as possible.
Plantar flexors
Gastrocnemius, soleus, tibialis posterior, flexor hallucis longus, flexor digitorum longus, peroneus brevis, peroneus longus 80% of plantar flexion torque comes from the gastrocnemius and soleus. Tibialis posterior inserts on structures around the transverse arch. This is an extrinsic muscle that could pull the medial arch up or superiorly which could help individuals who have a pes planus foot structure in weight bearing. Peroneus bervis/peroneus longus function differently in the frontal plane than the other plantar flexors - they are everters and the rest of the plantar flexors are inverters. Peroneus longus functions at the first ray and it influences what is taking place at that particular toe (the big toe). By holding down the big toe, peroneus longus helps create a rigid lever for the foot and guides translation of weight through the big toe.
What is hallux valgus?
Hallux valgus is progressive lateral deviation of the first toe. In this picture, the metatarsal has actually spun so the plantar surface is now facing medially - you can see the sesamoid bones which should be directly on the plantar surface. Every time the person flexes the MTP joint, whether through flexor hallucis longus/brevis, it pulls the sesamoid bones and pulls the toe even further into hallux valgus.
For a patient with talocrural range of motion limitations, which glides would you assess?
If an individual has ROM limitations at the talocrural joint, the main movements to consider are plantarflexion and dorsiflexion. You should assess ventral and dorsal glides.
What is the function of the mid tarsal joint when we are standing on uneven terrain?
If we are standing on an odd surface, the mid tarsal joint could pronate during rearfoot pronation to keep the large BOS. The pronation or supination that can occur is dependent on the surface you are standing on. If you are standing on carpet or a flat surface, you would need the mid tarsal joint to supinate to go with the rear foot pronation to keep the large BOS.
What are potential cases of pes planus?
Looking at the most dorsal aspect of the calcaneus - this is where the achilles tendon attaches. If there is a force vector from the achilles tendon (combination of soleus and gastrocnemius), this pulls the calcaneus into a plantar flexed position. By moving into a plantar flexed position, the calcaneus is lifted into a position that can minimize the medial longitudinal arch. Working on stretching the achilles tendon to minimize the passive force that goes through the calcaneus at rest can improve the condition.
What is mid tarsal joint function based on?
Midtarsal joint function is based on terrain and functional needs. The foot needs to be able to conform to the terrain it is standing on. The individual who is standing on the rock - the mid tarsal joint helps the foot conform to the shape of the rock by amplifying the movements of the talocrural/subtalar joints. The mid tarsal joint helps us combine the forefoot to the rearfoot to maintain the greatest BOS possible for whatever conditions the foot needs to deal with.
Subtalar joint arthrokinematics
Most consider the subtalar joint to be a plane joint. However, there are three articulations between the talus and the calcaneus. The medial and anterior articulations are considered plane joints while the posterior articulation is a condyloid joint with the calcaneus having a convex surface. With open chain inversion there is a lateral glide - the calcaneus is moving on the fixed talus - the talus has a concave surface that articulates with the convex calcaneus. With open chain eversion, there is a medial glide.
Ankle/foot triplanar movement: non-weightbearing (NWB) supination
Non-weightbearing supination involves calcaneal plantarflexion, calcaneal adduction, and calcaneal inversion (PADI). The calcaneus is moving with non-weightbearing (open chain) supination. This means the distal segment is moving - the distal segment in the STJ is the calcaneus in relation to the talus.
What are the three movements involved in supination at the talocrural joint with open chain movement?
PADI: plantarflexion, adduction, and inversion. The main movement is plantarflexion and the minor movements are adduction and inversion.
Everters
Peroneus longus, peroneus brevis, extensor digitorum longus Peroneus longus has the biggest influence on gait mechanics
What is pes planus?
Pes planus refers to a diminished medial longitudinal arch that occurs due to pronation in the hind foot. The pes planus can be classified as flexible or rigid. Pes planus requires active muscle contraction from intrinsic and extrinsic muscles. In this picture, there is no arch whatsoever. Their footprint would like like a rectangle/close to it because the foot is in full contact with the ground. This is problematic for absorbing shock - the plantar fascia is not able to assist with the shock absorption.
Muscles and movement of the foot
Plantarflexion, dorsiflexion, eversion, and inversion There are two axes we have to consider: the subtalar and the talocrural axes. There are oblique axes that allow for three movements to occur at the same tine. This picture divides the foot into quadrants - there is a ventral and dorsal quadrant with regard to the mediolateral axis of the talocrural joint. Anything in front of the axis will cause dorsiflexion and anything behind the axis will cause plantarflexion. For the anterior-posterior axis of the subtalar joint, anything on the inside of the foot (closest to midline of the body) will cause inversion and any muscles on the fibular side will cause eversion.
Inverters
Posterior tibialis, flexor digitorum longus, flexor hallucis longus, anterior tibialis, gastrocnemius, soleus All of these except for anterior tibialis cause plantar flexion.
What glides are required to get the sagittal plane osteokinematic movements at the talocrural joint? What stabilizing tissue would limit the extremes of those respective glides?
Sagittal planes movements at the talocrural joint include dorsiflexion and plantarflexion, which require dorsal or ventral glides. Ligaments that limit dorsiflexion: posterior tibiotalar, posterior talofibular, and calcaneofibular ligaments (these ligaments limit a dorsal glide) Ligaments that limit plantarflexion: tibionavicular and anterior talofibular ligaments (these ligaments limit a ventral glide).
What is the stabilizing tissue for the IP joints?
Stabilizing tissue for the IP joints includes the capsule and collateral ligaments. Just because there are collateral ligaments does not mean that there is movement in that plane. The collateral ligaments limit the extremes of horizontal movement - the IP joints do not physiologically move in the horizontal plane - they only move in the sagittal plane. You could have some external force that pushes the joint into a valgus or varus position - the collateral ligaments would limit this.
Rays of the foot: 2nd ray
The 2nd ray is recessed on the foot - it serves as an axis for the foot for MTP abduction/adduction. In addition, it provides stability for weight bearing and gait. The second ray of the foot is the most stable - this is the midline of the foot. The second ray provides stability because the base of the second metatarsal is wedged between the first and third cuneiforms so there's not much mobility at all. This helps with weight bearing and gait :)
What is the function of the IP joints?
The IP joints allow for smooth weight transfer to the contralateral extremity during gait. In addition, they stabilize the body during static stance.
What is the joint type of the interphalangeal (IP) joints? What movements occur at these joints?
The IP joints are hinge joints that allow for movement in the sagittal plane (flexion/extension). The arthrokinematics are roll glide same for open chain movement because the head of the metatarsal is fixed and it is convex. The IP joints help with gripping the floor to try to prevent ventral translation. As you start to move S2 dorsally, the COM shifts dorsally so the body dorsiflexes to translate the body toward the BOS. Leaning forward as much as you can without the heels coming up - the toes dig into the ground to try to prevent the forward leaning through the MTP and IP joints.
What type of joint are the MTP joints?
The MTP joints are condyloid joints. The head of the metatarsal is convex, so whether in the sagittal plane or horizontal plane, roll and glide are in the same direction for open chain movement.
What is the function of the MTP joints?
The MTP joints extend as weight comes forward to assist with push off in gait. The first MTP joint is most important for gait.
What is the stabilizing tissue for the distal tibiofibular joint?
The anterior and posterior tibiofibular ligaments and the interosseous membrane. Note that there is not a capsule at the distal tibiofibular joint because it is not a diarthrodial joint like the proximal tibiofibular joint.
What is the most commonly sprained ligament in the ankle?
The anterior talofibular ligament is most commonly sprained - ankle sprains typically involve plantar flexed, inverted ankle position.
What are the functions of the arches in the foot?
The arches in the foot protect nerves, blood vessels, and muscles during weight bearing. They modify forces from above and below. The arches are the first thing that contact the ground. We normally strike the ground with the heel first, and then the foot comes down into a flat position. In the flat position, the weight is absorbed through the arch to modify forces. Conversion of the flexible foot to a rigid lever for propulsion during gait. Adapt to changes in supporting surface.
What type of movements can occur at the talocrural joint and what are they termed?
The axis is deviated from the mediolateral axis - it is an oblique axis. Since there is deviation toward the vertical axis and anterior axis, movements come in that are normally associated with those axes. The movements around the oblique axis at the talocrural joint are known as pronation and supination. As a result of the oblique axis (slight deviations away from the mediolateral axis), plantarflexion/dorsiflexion are the main movements at the sagittal plain, but there are also minor movements of abduction/adduction and inversion/eversion.
STJ stabilizing tissue: inversion
The calcaneofibular ligament limits inversion The cervical ligament and interosseous talocalcaneal ligament mostly limit inversion, but they also limit extremes of all movements
What is the stabilizing tissue for the talocrural joint on the medial side and what movement(s) do they limit?
The deltoid ligament (MCL) - contains three ligaments: Tibiocalcaneal ligament: only limits eversion Posterior tibiotalar ligament: limits eversion and dorsiflexion Tibionavicular ligament: limits eversion and plantarflexion All of these ligaments limit eversion - the posterior tibiotalar also limits dorsiflexion and the tibionavicular ligament also limits plantarflexion (look at where the ligaments are and picture how they would be stretched with these movements).
What type of joint is the distal tibiofibular joint?
The distal tibiofibular joint is a synarthrosis. There is minimal movement at this joint.
Rays of the foot: first ray
The first ray is the most mobile of the rays. It provides an element of flexibility to the medial longitudinal arch. It allows the medial side of the foot to conform better around irregularities of walking surface. With hallux rigidus, there is limitation of motion at the first metatarsophalangeal (MTP) joint.
How is the foot separated? Which joints are contained in each segment of the foot?
The foot is separated into there segments: rearfoot/hindfoot, mid foot, and forefoot. Rearfoot/hindfoot: subtalar joint Midfoot: mid tarsal joint Forefoot: metatarsophalangeal joint and interphalangeal joint
What happens with forefoot valgus variation of the mid tarsal joint?
The forefoot is everted in relationship with the rearfoot. This will affect gait mechanics. With forefoot valgus, the rearfoot is in natural position - there is not pronation or supination of the rearfoot (STJ). There is a difference in positioning for the metatarsal heads known as forefoot valgus. As soon as you step down, the first metatarsal head contacts the ground first and it will push everything out laterally. An individual could be prone to lateral ankle sprains because of this - need to get the metatarsal heads down to keep the BOS.
What is the stabilizing tissue for the talocrural joint on the lateral side and what movement(s) do they limit?
The lateral collateral ligament contains three ligaments: Posterior talofibular: limits inversion and dorsiflexion Calcaneofibular: limits inversion and dorsiflexion Anterior talofibular: limits inversion and plantarflexion All of these limit inversion.
What bones does the lateral longitudinal arch include?
The lateral longitudinal arch includes the calcaneus, the cuboid, and the fifth metatarsal.
What is the main bony stabilizing tissue at the talocrural joint? What movement does it limit?
The lateral malleolus serves as a bony block that limits eversion. There are fewer eversion ankle sprains than inversion ankle sprains due to this bony block. It is possible to generate enough force to fracture the lateral malleolus, but that is no longer a sprain.
What are the main movements that occur at the STJ? What are the minor movements?
The main movements at the subtalar joint include eversion/inversion and abduction/adduction (frontal and horizontal planes). The minor movements include dorsiflexion and plantarflexion. They talocrural joint and subtalar joint complement each other nicely. The talocrural joint has a lot of movement in the sagittal plane while the subtalar joint has only a little movement. The TCJ has little movement in the horizontal and frontal plane while the STJ has a lot of movement in these planes.
Explain what happens to the tibia and the medial longitudinal arch with weight bearing (closed chain) pronation at the subtalar joint
The medial longitudinal arch drops because with the talar movement of plantarflexion, the talus pushes directly into the plantar fascia. Recall that pes planus occurs when we have very little medial longitudinal arch - it can be rigid or flexible. When the talus adducts, it internally rotates the tibia. The vertical axis of the talus is causing a rotation. For the foot, horizontal movement is rotation, but it is where the head of the talus either points toward midline of the body or away from midline of the body. Toward midline of the body refers to adduction of the talus. If the head of the talus points away from the midline of the body, it is talar abduction.
What bones does the medial longitudinal arch include?
The medial longitudinal arch includes the calcaneus, talus, navicular, medial cuneiform, and first metatarsal.
Medial longitudinal arch
The medial longitudinal arch is the primary shock absorber and load bearing structure of the foot. It is supported by active muscle force and passive force. Plantar fascia is the primary support for the medial longitudinal arch. The spring ligament can help the medial arch by the mid tarsal joint.
What arches are present in the foot?
The medial longitudinal arch, the lateral longitudinal arch, and the transverse arch.
Describe the mid tarsal joint in relation to the movement of the talocrural and subtalar joints
The mid tarsal joint amplifies the movement of the talocrural and subtalar joints. Recall that the talocrural and subtalar joints complement each other - one's major movement is the other's minor movement and vice versa.
Discuss the mid tarsal joint function
The mid tarsal joint amplifies the movements of the talocrural and subtalar joints. Motion from the longitudinal axis adds to the inversion/eversion of the subtalar joint. Motion from the oblique axis adds to the plantarflexion and dorsiflexion of the talocrural joint. If we need to amplify inversion/eversion, then we use movement along the longitudinal axis of the mid tarsal joint. If we need to amplify sagittal plane or horizontal plane movement, we would use movement along the oblique axis of the mid tarsal joint. What movement needs to be amplified depends on what the individual is doing and what type of surface they are working with.
Midtarsal joint
The mid tarsal joint links the hind foot and the forefoot. The mid tarsal joint allows the forefoot to stay in contact with the ground after hind foot movement. The mid tarsal joint involves two separate joints: the talonavicular (TN) joint and the calcaneocuboid (CC) joint The mid tarsal joint helps to keep as large of a BOS as possible with regard to the metatarsals. The calcaneus is 1 point of about 3 that are in contact with the ground in standing. The first and fifth metatarsal heads are the other points. If the metatarsal heads come off of the ground, this decreases the BOS.
Midtarsal joint movement around the oblique axis
The oblique axis is above and medial to the anterior-posterior axis. The main movements about this axis are dorsiflexion/plantarflexion and abduction/adduction. This is different than what we have seen with other joints - normally, frontal and horizontal plane movements have been lumped together and sagittal planes movements were separate. In this case, the sagittal and horizontal plane movements are considered together and the frontal plane movement is considered separately.
Calluses
The picture on the right side shows excessive pronation - there is collapse on the medial side. Forte foot refers to the front of the foot. The eversion of the foot causes the big toe to abduct and go into a valgus position - resulting in a hallux valgus deformity. The metatarsal moves toward from midline of the body and the big toe moves away from the midline of the body. As weight is moving forward, we step off of the foot to move it into swing - typically push off through the big toe (why extension of the big toe is so important for gait). Hallux valgus deformity shifts weight transmission - it moves weight from first metatarsal to the second and third resulting in abnormal weight bearing. There is rubbing against the shoe that occurs to create a callus.
What is the stabilizing tissue for the MTP joints? What movements do they limit?
The plantar plate and the collateral ligaments. The plantar plate limits hyperextension and the collateral ligaments limit movement toward the fibula or movement toward the tibia.
What type of joint is the proximal tibiofibular joint?
The proximal tibiofibular joint is a plane joint. Since this is a diarthrodial joint, there is some movement available.
What type of joint is the talocrural joint?
The talocrural joint is a modified hinge joint. There is not pure sagittal plane movement (same with the knee). The main movement at the talocrural joint is dorsiflexion/plantarflexion in the sagittal plane, but there are also minor movements of abduction/adduction and inversion/eversion. Since movement can occur in other planes beside the sagittal plane, this is a modified hinge joint.
Picture of previously discussed mid tarsal joint stabilizing tissue
The talonavicular (deltoid ligament) is shown
What bones does the transverse arch include?
The transverse arch is formed by the cuboid, cuneiforms, and bases of the metatarsals.
Arches
The transverse arch is located differently between these two pictures. The bottom picture shows the transverse arch at the level of the cuneiforms, cuboid, and base of metatarsals. The top picture shows the transverse arch at the head of the metatarsals. We will use the location in the bottom picture.
What type of joint is the subtalar joint (STJ)?
There are three articulations between the talus and the calcaneus: two in the front and one in the back. Two of these articulations are considered plane joints and one is considered a diarthrodial joint that allows for roll and glide. The oblique axis at the subtalar joint gives major movements and minor movements. The axis is above the AP axis and medial to the AP axis, so the main movements are in the frontal and horizontal planes and the minor movement is in the sagittal plane.
Midtarsal joint movement around the longitudinal axis
There is a longitudinal axis that runs through the mid tarsal joint - it is above and medial to the anterior-posterior axis. The main movements about this axis are eversion and inversion.
What can occur with hallux rigidus?
There is a rigidity in the first ray that does not allow for much movement - this forces things out to the lateral side of the foot where there is movement. With a flexible/normal first ray, it is easy to accommodate to uneven surfaces. We can assess the flexibility/mobility of the first ray by locking down rays 2-5 and moving the first ray into DF or PF to see how much mobility there is and compare it to the other foot to look for any discrepancies.
How can movement at the foot impact the body?
This picture shows that the left foot is pronating/moving into a pes planus position. This moves the tibia into internal rotation. The internal rotation at the tibia causes the femur to go into internal rotation which creates an increase in genu valgum at the knee. Note: there is more internal rotation at the tibia than at the femur. The distal segment moves more and drags the proximal segment along with it - the femur lags slightly behind the movement of the tibia. With the knee valgus that is created, there is a hip drop on the side of increased pronation which then causes a shift in side bending toward the hip in stance. This results in unequal shoulder height which means the head has to correct/compensate in order to look straight ahead. This is an example of how an issue of the foot can manifest all the way up in the cervical spine.
What is the resultant tibiofibular joint movement with dorsiflexion at the talocrural joint?
This picture shows the facets on the talus. The medial facet is much smaller than the lateral facet. So, the lateral facet and the ventral aspect of the dome are larger. With dorsiflexion at the talocrural joint, the fibula translates superiorly and laterally rotates.
Medial longitudinal arch
This picture shows the inside of the arch of an individual who is standing still. The body weight comes down and pushes onto the talus. The talus pushes through the navicular bone, first cuneiform, and first metatarsal and down through the calcaneus. In between these, there is a vector that represents the plantar aponeurosis. By pushing down on these structures, the aponeurosis is stretched. Eventually, the passive tension of the aponeurosis will equal the force of the body weight pushing down on the talus. In addition to these passive structures, there is active muscle force that can be generated. The first line of defense is through the plantar aponeurosis as well as through the Windlass mechanism - by pushing down on the ventral and dorsal structure (dorsal structure is calcaneus and ventral structure is the navicular, first cuneiform, and first metatarsal), we pull and stretch out the plantar aponeurosis to minimize the shock that takes place. In addition, the spring ligament can catch the head of the talus as it moves into plantar flexion - the spring ligament can assist with stability at the mid tarsal joint.
Midtarsal joint: stabilizing tissue
Tibionavicular ligament (deltoid) Bifurcate ligament - attaches the calcaneus to the navicular and cuboid (shown at the red star) Dorsal calcaneocuboid ligament Spring ligament: forms the floor of the mid tarsal joint Plantar fascia Long plantar ligament Short plantar ligament (plantar calcaneocuboid)
What are the functions of the ankle and foot?
To provide a structural supporting platform for the body, to absorb shock from the ground reaction forces, to be able to adjust to different terrains, to convert transverse torque from the lower extremity, to become a rigid lever capable of forward propulsion.
Progression of hallux valgus from mild to severe
Watch for pronation that is lasting too long into the stance phase. The individual will collapse down through the medial longitudinal arch as they push through the big toe and get extension plus abduction from the midline of the body. If the individual is pronating, an orthotic might help minimize some of the pronation to prevent exacerbation of the issue.
Ow!
Wearing improper footwear that squeezes the toes can irritate the nerves and cause inflammation. A Morton's neuroma may develop due to the irritated nerve.
STJ Arthrokinematics
When looking at frontal plane movements, make sure you identify what is considered medial and what is considered lateral. This helps us understand what roll/glide is going on. If the plantar surface of the foot is pointing away from the midline of the body, this is termed eversion. When the plantar surface of the foot points toward the midline of the body, this is inversion. With open chain inversion, we have a lateral glide and with open chain eversion, we have a medial glide. You can see the concave area of the talus that is fixed with open chain movement (highlighted and pointed out by the purple arrow)
Forefoot varus - a variation of the mid tarsal joint
With forefoot varus, the forefoot is inverted as compared to the rearfoot. This will change gait mechanics. Notice that there is a line drawn parallel to the floor and the rearfoot is in neutral position (there is no eversion or inversion of the rearfoot). The rearfoot is perpendicular to the line that is drawn parallel to the floor, so it is in neutral position. The other line that is connecting all of the metatarsal heads is not in line with the floor. There is a supination that has taken place at the forefoot. The individual has forefoot varus.
Ankle/foot triplanar movement: non-weight bearing (NWB) pronation
With non-weight bearing (NWB) pronation, there is calcaneal dorsiflexion, calcaneal abduction, and calcaneal eversion (DABE).
Using PADI/DABE to understand closed chain/WB pronation and supination
With open chain pronation/supination at the subtalar joint, it is all calcaneal movement that is occurring (the distal calcaneus is moving on the proximal talus). The calcaneal movements are explained by DABE for pronation and PADI for supination. You can still use DABE and PADI to understand closed-chain movement. The frontal plane - eversion/inversion (E and I) stay the same with closed chain movement. The DAB and PAD, on the other hand, have to be relative movements of the calcaneus based off of what the talus does in closed chain pronation or supination. It is the talus that is moving on the calcaneus in the horizontal and sagittal planes.
What is the resultant tibiofibular joint movement with plantarflexion at the talocrural joint?
With plantarflexion at the talocrural joint, the fibula translates inferiorly and rotates medially.
Figure demonstrating mid tarsal joint function
With pronation occurring at the STJ through medial rotation of the leg, the transverse tarsal joint is free to (A) supinate slightly to maintain the relatively fixed position of the forefoot segment; (B) pronate slightly as occurs in normal standing; or (C) supinate substantially to maintain appropriate weight bearing of the forefoot segment on uneven terrain.
Midtarsal joint function with WB rearfoot supination: figure
With supination occurring at the subtalar joint through lateral rotation of the leg, the transverse tarsal joint has limited ability to pronate to maintain the relatively fixed position of the forefoot segment (A); Will begin to supinate with a greater range of subtalar supination and lateral rotation of the leg (B); or will fully supinate along with a fully supinated subtalar joint and maximal lateral rotation the superimposed leg (C)
Spring ligament (stabilizing tissue of the subtalar joint that limits eversion)
With the spring ligament, as the head of the talus tries to plantar flex with pronation, the ligament will catch the head of the talus and limit how much the medial longitudinal arch drops.
Ankle/foot triplanar movement: weight bearing (WB) pronation
With weight bearing (WB) pronation, the calcaneus everts (valgus), the talar head adducts - the tibia rotates medially, and the talar head plantar flexes - the medial arch drops. Notice that one of the movements is calcaneal movement. For pronation or supination in open or closed chain movement (WB/NWB), the frontal plane is calcaneal movement (eversion or inversion). In the horizontal and sagittal planes, the talus moves on the calcaneus. It is not a pure closed chain movement - it is closed chain for two of the three planes, but for one it is not (frontal plane). Since two out of the three planes involve the proximal segment moving on the distal segment, we call this closed chain (WB) pronation. With WB pronation, the calcaneus everts. If we think about DABE in open chain, we can use this to deduce movements in closed chain pronation. You can still drop down the E for eversion because the calcaneus is the segment that is moving in the frontal plane. The DAB parts are referring to calcaneal movement. Since it is the talus moving instead with WB pronation, we have to think about relative calcaneal movements that are occurring using this acronym. The talus plantar flexes and to give a relative dorsiflexion of the calcaneus and the talus adducts to give a relative abduction of the calcaneus.
Ankle/foot triplanar movement: weight bearing (WB)/closed chain supination
With weight bearing (WB) supination, the calcaneus inverts (varus), the talar head abducts - the tibia rotates laterally, and the talar head dorsiflexes - the medial arch rises.
How can shoe creases indicate the presence of hallux rigidus?
You can look at shoe wear patterns to get an idea of what type of force is going through the shoe as the individual walks. There is normally a transverse crease across the shoe because the force is equally distributed among the rays. With hallux rigidus, the big toe is not conforming to uneven surfaces because it is not flexible, so it shoves all the force off to the lateral side of the foot - this is indicated by an obliquity to the crease on the shoe. The crease shows where the shoe is flexing to allow for propulsion. Note: the shoe crease only provides a clue that the individual might have hallux rigidus.