foot antomy

7/29/2019 Foot antomy

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FOOT

TARSALS, METATARSALS &

PHALANGES

The human foot is a complex structure containing 26bones, 33 joints and more than 100 tendons, muscles,

and ligaments.
http://mrl.nyu.edu/~ajsecord/hatching/images/bones.png


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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


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Ankle

Talus is the only bone that articulates withthe fibula and tibia to form the ankle joint[talocrural joint]

tibia medial malleolus Fibula lateral malleolus

During walking the talus distributes abouthalf the weight to the calcaneus the rest tothe other tarsal bones


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Metatarsus

5 metatarsal bones: numbered I V [ 15] 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 cuboidto form the tarsometatarsal joints

Articulate distally with the phalanges toform the metatarsophalangeal joint


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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]


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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.


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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


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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.


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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 calcaneocuboidligament 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 thetendon 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.


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Once the skin of the sole of the foot

has been removed, there is a verydense 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.


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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.


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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


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the superior and inferior peroneal

retinaculaem keep the tendons of

the peroneus longus and brevis

close to the lateral malleolus.


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After the plantar aponeurosis has beenremoved 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


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When the flexor digitorum brevis is

removed, the muscles of thesecond layer can be seen:

accessory flexor (quadratus plantae)

lumbricals

tendons of the flexor digitorum longus

from which the lumbricals arise


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The muscles of thethird layer

include the:

flexor hallucis brevis

adductor hallucis

oblique head

transverse headflexor digiti minimi

brevis


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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.


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foot antomy

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