Presentation on theme: "FOOT TARSALS, METATARSALS & PHALANGES The human foot is a complex structure containing 26 bones, 33 joints and more than 100 tendons, muscles, and ligaments."— Presentation transcript:
FOOT TARSALS, METATARSALS & PHALANGES The human foot is a complex structure containing 26 bones, 33 joints and more than 100 tendons, muscles, and ligaments.
Tarsus = ankle Proximal region of the foot 7 tarsal bones Talus: ankle bone Calcaneus: heel bone Navicular: ‘like a little boat’ 3 Cuniform bones: wedge shaped - lateral, intermediate, medial Cuboid: cube shaped
Ankle Talus is the only bone that articulates with the fibula and tibia to form the ankle joint [talocrural joint] tibia medial malleolus Fibula lateral malleolus During walking the talus distributes about half the weight to the calcaneus the rest to the other tarsal bones
Metatarsus 5 metatarsal bones: numbered I – V [ 1 – 5] medial to lateral Each has a proximal base, an intermediate shaft and a distal head articulate proximally with the first second and third cuneiform bones and the cuboid to form the tarsometatarsal joints Articulate distally with the phalanges to form the metatarsophalangeal joint
Phalanges [digits] Numbered I – V medial to lateral Each phalanx : proximal base, intermediate shaft and distal head. Hallux: has two phalanges [proximal & distal] Other toes have three phalanges: proximal, middle and distal Interphalangeal joints [between phalanges]
Sesamoid bones are always present at the metatarsophalangeal joint of the great toe. Function: protect the tendon that flexes the toe, [flexor hallicus longus/brevis] by protecting it from the body's weight. At the upper and forepart of the medial surface of the calcaneusis a horizontal eminence, the sustentaculum tali, which gives attachment to a slip of the tendon of the Tibialis posterior.
Arches of Foot Two arches held by tendons & ligaments Allow foot to support weight of the body: ball of foot – 40% weight. Heel – 60% weight Leverage for walking Fully developed by age 13 Longitudinal arch: medial and lateral parts Transverse arch
The longitudinal arch of the foot is higher on the medial side, where it forms the instep as can be seen on a foot-print. It is made up of the 1st three digits and their metatarsals, the cuneiforms, the navicular bone and the talus. The lateral longitudinal arch is made up of digits 4 and 5 and their metatarsals, the cuboid and the calcaneum. It is much shallower than the medial arch. The transverse arch of the foot is primarily formed by the 5 metatarsal bones.
Every ligament that connects the bones of the foot plays a part in the maintenance of the arches, but some which pass across two or more joints are especially important. Among these are the long plantar ligament, the plantar calcaneocuboid ligament and the plantar calcaneonavicular ligament, on which the head of the talus rests. While the normal tone of the small intrinsic muscles of the foot also plays an essential part in keeping the arches intact, the long muscles which are inserted by tendons into the bones of the foot have an even more important role. These are the tendon of the tibialis anterior muscle, the tendon of the tibialis posterior muscle, the tendon of the peroneus longus and the tendons of the flexor hallucis longus and flexor digitorum longus muscles. Finally, more superficially, the plantar aponeurosis also plays an important part in maintaining the medial longitudinal arch.
Once the skin of the sole of the foot has been removed, there is a very dense organized layer of deep fascia that runs down the middle of the sole; this is the plantar aponeurosis. There is also deep fascia covering the medial and lateral muscle groups but it has been removed in this image. The plantar aponeurosis is thought to help maintain the medial longitudinal arch of the foot.
Plantar Fasciitis:"heel spurs“: an overuse injury affecting the sole or flexor surface (plantar) of the foot. A diagnosis of plantar fasciitis means you have inflamed the tough, fibrous band of tissue (fascia) connecting your heel bone to the base of your toes. Higher risk: female, overweight, a job that requires a lot of walking or standing on hard surfaces; walk or run for exercise, especially if you have tight calf muscles that limit how far you can flex your ankles. People with very flat feet or very high arches are also more prone to plantar fasciitis. starts gradually with mild pain at the heel bone often referred to as a stone bruise. more likely to feel it after (not during) exercise. The pain classically occurs again after arising from a midday lunch break. If you don't treat plantar fasciitis, it may become a chronic condition. You may not be able to keep up your level of activity and you may also develop symptoms of foot, knee, hip and back problems because of the way plantar fasciitis changes the way you walk.
In order for these flexor and extensor tendons to perform their duty properly, they must be kept close to the bones of the ankle. The structures that keep them close are the retinaculae: superior extensor retinaculum flexor retinaculum inferior extensor retinaculum
the superior and inferior peroneal retinaculaem keep the tendons of the peroneus longus and brevis close to the lateral malleolus.
After the plantar aponeurosis has been removed you can see the muscles that make up the first layer of the sole of the foot and the arteries and nerves entering the foot. The muscles of the first layer are: abductor hallucis flexor digitorum brevis abductor digiti minimi
When the flexor digitorum brevis is removed, the muscles of the second layer can be seen: accessory flexor (quadratus plantae) lumbricals tendons of the flexor digitorum longus from which the lumbricals arise
The muscles of the third layer include the: flexor hallucis brevis adductor hallucis oblique head transverse head flexor digiti minimi brevis
The fourth layer of muscles are the: dorsal interossei (dab) meaning dorsal abduct plantar interossei (pad) meaning plantar adduct At this level, you can also see the tendon of the peroneus longus crossing the sole of the foot.