•Ankle

LOs

• Describe the blood and nerve supply of shoulder, elbow, hip and knee joint and the mechanics of all large joints in the limbs with emphasis on the special features that help to maintain their stability and movements

• Describe the joints and movements of the hand and foot with movements of fingers and toes in relation to the insertions and actions of the muscles and tendons which affect them.

What is Ankle

• The ankle, or talocrural region, is the region where the foot and the leg meet.

• The ankle includes three joints: • the ankle joint proper or talocrural joint, • the subtalar joint, and • the Inferior tibiofibular joint.

• The term ankle is used to describe structures in the region of ankle joint complex

• Ankle joint complex include–Ankle joint–Subtalar joint–Inferior tibio-fibular joint

• The bony architecture of the ankle consists of :

• Tibia, Fibula and Talus and Calcaneum

• The true ankle joint is composed of 3 bones:

• Tibia and fibula forming the superior part– Tibia which forms the medial portion – Fibula which forms the lateral portion

• Talus forming the inferior part

• Ankle joint is formed where the leg joins the foot

• Talo-crural joint• Crus [Latin word] is leg (knee to foot) • Crura is plural of crus• Crural is pertaining to leg

• It is a synovial hinge joint that connects the distal ends of tibia and fibula with the superior surface of talus bone

• The articulation between tibia and talus bears more weight than between fibula and talus.

• The articular surface of tibia is referred to as the plafond.

• Plafond (French for "ceiling"),

• The true ankle joint is responsible for • up (dorsiflexion) and • down (planter flexion) motion

of the foot.

–dorsiflexion consists in the approximation of the dorsum of foot to the front of leg–Angle decreases

–while in plantar flexion the heel is drawn up and the toes pointed downward–The angle increases

• Beneath the true ankle joint is the second part of the ankle, the subtalar joint, which consists of the talus on top and calcaneus on the bottom.

• The subtalar joint allows side to side motion of the foot.

Talus bone

• Name the bones articulating with talus bone?

• Tibia• Fibula• Navicular bone• Calcaneum

• Talus bone (Latin for ankle) is the first bone in the tarsal bones in the foot. It forms the lower part of the ankle joint.

• It also articulates with calcaneus below and navicular in front.

• Through these articulations, it transmits the entire weight of the body to the foot

• Talus is the second largest of the tarsal bones, • It is also one of the bones in the human body

with the highest percentage of its surface area covered by articular cartilage.

• Though irregular in shape, the talus can be subdivided into three parts.

• Facing anteriorly, the head carries the articulate surface for navicular bone, and the neck, the roughened area between the body and the head, has small vascular channels

• The body features several prominent articulate surfaces:

• On its superior side is the trochlea tali flanked by the articular facets for the two malleoli.

• The ankle mortise, the fork-like structure of the malleoli, holds these three articular surfaces in a steady grip, which guarantees the stability of the ankle joint.

• The mortise and tenon joint has been used for thousands of years by woodworkers around the world to join pieces of wood, mainly when the adjoining pieces connect at an angle of 90°.

• In its basic form it is both simple and strong.

• Diagram of a mortise (on left) and tenon joint

• The superior articular surface of talus is concave from side-to-side and convex anterio-posteriorly

• It is broad anteriorly and narrow posteriorly

In full dorsiflexion

• The broad anterior area is grasped by ankle mortise

• This requires widening of the malleolar gap through

• Slight lateral rotation of fibula by stretching at inferior tibiofibular syndesmosis and gliding at superior tibiofibular joint

• Proximal or superior tibiofibular articulation is a plane synovial joint between lateral condyle of tibia and the head of fibula

• The contiguous surfaces of the bones present flat, oval facets covered with cartilage and connected together by articular capsule and anterior and posterior ligaments

In full plantar flexion

• The posterior smaller area is in contact with ankle mortise

• Even in this position eversion and inversions are not possible in true ankle joint

• The true ankle joint is true hinge joint

• However, because the trochlea is wider in front than at the back (approximately 5-6 mm) the stability in the joint vary with the position of the foot:

• With the foot dorsiflexed (toes pulled upward) the ligaments of the joint are kept stretched, which guarantees the stability of the joint;

• but with the foot plantarflexed (as when standing on the toes) the narrower width of the trochlea causes the stability to decrease

• Normally in standing and walking the ankle joint is plantar flexed and remains unstable

• Behind the trochlea is a posterior process with a medial and a lateral tubercle separated by a groove for the tendon of flexor hallucis longus.

• Exceptionally, the lateral of these tubercles forms an independent bone called os trigonum or "accessory talus".

• On the bone's inferior side, three articular surfaces serve for the articulation with calcaneus, and

• several non-articular surfaces exist for the attachment of ligaments

Blood supply

• The Talus bone lacks a good blood supply. Because of this, healing a broken talus can take longer than most other bones.

• most blood supplied to the head and neck of the talus arises from the dorsalis pedis artery;anastomosis within sinus tarsi & tarsal canal form major blood supply to the talar head;

• artery of the sinus tarsi:- peroneal artery- from peroneal artery comes branches to posterior process & branch to form artery of sinus tarsi;- dorsalis pedis artery- supplies branches to dorsal talar neck & branch to form artery of sinus tarsi;

• artery of sinus canal:- branch of posterior tibial forms anastomotic sling inferior to talus from which branches arise to enter talar neck;- deltoid branches usually arise from the artery of the tarsal canal & supply the medial third of the body;- main artery supplying blood to the body of the talus is the artery of the tarsal canal

• The major blood supply to the body was provided by the artery of the tarsal canal.

• The deltoid and sinus tarsi vessels provided significant minor sources of vascularity.

anastomoses around the ankle

• The ankle joint receives its blood supply form malleolar rami of the anterior and posterior tibial and peroneal arteries.

• One with a broken talus may not be able to walk for many months without crutches and will further wear a walking cast or boot of some kind after that.

• Medial malleolus is a bony process extending distally off the medial tibia.

• The distal-most part of fibula is called lateral malleolus.

• Together, the malleoli, along with their supporting ligaments, stabilize the talus underneath the tibia

• The bony arch formed by the tibial plafond and the two malleoli is referred to as the ankle mortise.

• The joint surface of all the bones in the ankle are covered with articular cartilage.

• Malleolus (Latin, "small hammer") is the bony prominence on each side of the ankle.

• Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg.

• The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia.

• The lateral malleolus is the prominence on the outer side of the ankle, formed by the lower end of the fibula.

Ligaments

• The ankle joint is bound by the strong• Deltoid ligament • and three lateral ligaments: • Anterior talofibular ligament• Posterior talofibular ligament• Calcaneofibular ligament

• The major ligaments of the ankle are: • Anterior tibiofibular ligament, which connects the

tibia to the fibula; • Lateral collateral ligaments, which attach the fibula

to talus and calcaneus and gives the ankle lateral stability; and,

• Deltoid ligaments, which connect the tibia to the talus and calcaneus and provide medial stability.

Deltoid ligament

• Supports the medial side of joint• Proximally , it is attached to the medial

malleolus • Distally, it is attached to four places – Sustentaculum tali of calcaneus – Calcaneonavicular ligament– Navicular tuberosity– Medial surface of talus

• Deltoid ligament is a strong, flat, triangular band, attached, above, to the apex and anterior and posterior borders of medial malleolus.

• The Deltoid ligament is composed of – Anterior Tibiotalar Ligament, – Tibiocalcaneal Ligament, – Posterior Tibiotalar Ligament, and – Tibionavicular Ligament.

• It consists of two sets of fibers, superficial and deep

• Its middle portion, together with the calcaneofibular ligament, binds the bones of the leg firmly to the foot, and resists displacement in every direction.

• Its anterior and posterior fibers limit extension and flexion of the foot respectively, and the anterior fibers also limit abduction

• Anterior and posterior talofibular ligaments support the lateral side of the joint from lateral malleolus to the posterior and anterior ends of talus.

• Calcaneofibular ligament is attached at the lateral malleolus and to the lateral surface of calcaneum.

• Ligamentous support is more important during plantar flexion

• Deltoid ligament is very strong

• It usually resists a force which fractures the malleolus, to which it is attached.

Tibiofibular ligament

• Though it does not span across the ankle joint itself, the syndesmotic ligament makes an important contribution to the stability of ankle.

• This ligament spans the syndesmosis (the articulation between the medial aspect of distal fibula and the lateral aspect of the distal tibia.

• An isolated injury to this ligament is often called high ankle sprain.

Nerve supply

• The ankle joint receives its nerve supply from deep peroneal, saphenous, sural and tibial nerves.

• Occasionally, the superficial peroneal nerve also supplies the ankle joint.

Syndesmosis

• Syndesmosis [Gr. syn with + desmos a band]• It is a slightly movable articulation where the

contiguous bony surfaces are united by an interosseous ligament, as in inferior tibiofibular joint.

• If the syndesmosis is torn apart as result of bone fracture, surgeons will sometimes fix the relevant bones together with a syndesmotic screw, temporarily replacing the syndesmosis.

• The screw inhibits normal movement of the bones and, thereby, the corresponding joint. When the natural articulation is healed, the screw is removed

• The bony architecture of ankle joint is most stable during dorsiflexion.

• A sprained ankle is more likely to occur when the ankle is plantar-flexed.

• The classic ankle sprain involves anterior talofibular ligament.

• The posterior talofibular ligament assists the calcaneofibular in resisting the displacement of the foot backward, and deepens the cavity for the reception of the talus

• The anterior talofibular is a security against the displacement of the foot forward, and limits extension of the joint.

• Anterior talofibular ligament is also most commonly-injured ligament during inversion sprains.

• Another ligament that can be injured in a severe ankle sprain is calcaneofibular ligament.

• Symptoms of ankle fracture are similar to those of ankle sprain i.e. pain or even more severe.

• It is rare for ankle joint to dislocate in the presence of ligamentous injury alone. However, in fracture the talus can become unstable and dislocate.

• People may complain of ecchymosis (bruising). • Diagnosis is typically by X-ray.

• These components of ankle, along with the muscles and tendons of lower leg, work together to handle the stress the ankle receives during walking, running and jumping.

Movements

• When the body is in the erect position, the foot is at right angles to the leg

• dorsiflexion consists in the approximation of the dorsum of the foot to the front of the leg, while in extension the heel is drawn up and the toes pointed downward

• The range of movement varies in different individuals from about 50° to 90°

Axis

• Axis of rotation is not horizontal• It slopes downward and laterally• It passes through the lateral surface of talus

just below the apex of the triangular articular area and

• through the medial surface at a higher level just below the concavity of the comma-shaped articular area

• The transverse axis about which movement takes place is slightly oblique

• It passes through the malleoli just above their apices

• Lateral, posterior, inferior (plantar) to medial, anterior, superior (dorsal)

• 8 degree from transverse plane• 82 degree from sagittal plane• 20 to 30 degree from coronal plane

• Dorsiflexion

• The axis changes during movements, for the upper convexity of talus is not the arc of a circle rather of an ellipse

• Plantar flexion

• This axis corresponds to the deviation of malleoli in ankle mortise

• Largest deviation from the sagittal plane so the dominant movements will be dorsiflexion and plantar flexion

• Frontal plane movements relatively less

• The malleoli tightly embrace the talus in all positions of the joint, so that any slight degree of side-to-side movement which may exist is simply due to stretching of the ligaments and slight bending of the body of the fibula

• The superior articular surface of the talus is broader in front than behind.

• In dorsiflexion, therefore, greater space is required between the two malleoli.

• This is obtained by a slight outward rotatory movement of the lower end of the fibula and a stretching of the ligaments of the syndesmosis;

• this lateral movement is facilitated by a slight gliding at the proximal tibiofibular articulation, and possibly also by the bending of the body of the fibula

• The movements of inversion and eversion of the foot, together with the minute changes in the form by which it is applied to the ground or takes hold of an object in climbing, etc., are mainly effected in the tarsal joints

Transverse tarsal joint

• The joint which enjoys the greatest amount of motion being that between the talus and calcaneus behind and the navicular and cuboid in front.

• This is often called the transverse tarsal joint, and it can, with the subordinate joints of the tarsus, replace the ankle-joint in a great measure when the latter has become ankylosed

• The transverse tarsal joint or midtarsal joint is formed by the articulation of calcaneum with cuboid, and the articulation of talus with navicular bone

• The movement which takes place in this joint is more extensive than that in the other tarsal joints, and consists of a sort of rotation by means of which the foot may be slightly flexed or extended, the sole being at the same time carried medially (inverted) or laterally (everted)

• Extension of the foot (plantar flexion) upon the tibia and fibula is produced by the Gastrocnemius, Soleus, Plantaris, Tibialis posterior, Peronæi longus and brevis, Flexor digitorum longus, and Flexor hallucis longus;

• dorsiflexion, by the Tibialis anterior, Peroneus tertius, Extensor digitorum longus, and Extensor hallucis longus

• The line of gravity passes behind the cervical vertebrae, in front of the thoracic vertebrae, behind the lumbar vertebrae, behind the hip joint, in front of the knee joint, one to two inches in front of the ankle joint.

• Stability requires continuous action by soleus • Stability increases with leaning forward involving

gastrocnemius and vice versa

• In backward sway • When line of gravity becomes posterior to the

transverse axis of ankle joints• The plantar flexors relax and the dorsiflexors

contract

• From the upright position, with the foot at right angle to the leg, active plantar flexion of about 200 is produced by gastrocnemius and soleus, assisted by long flexor tendons and the long and short peronei.

• Active dorsiflexion of about 100 is produced by tibialis anterior, the long toe extensors and peroneus tertius.

• The degree of passive movements possible is approximately double the above

• It should be clear that the Extensor digitorum longus and Extensor hallucis longus are extensors of the toes, but flexors of the ankle; and that the Flexor digitorum longus and Flexor hallucis longus are flexors of the toes, but extensors of the ankle