Download MBBS Arches of the Foot Lecture PPT

ARCHES OF THE FOOT
SKELETON OF THE FOOT

? The skeleton of the foot from behind forward

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consists of the following bones:

? Tarsals
? Metatarsals

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? Phalanges

? TARSAL BONES
? These are short bones & arranged in three rows:

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(a)Proximal row Talus and calcaneus.

(b) Middle row Navicular.

(c) Distal row Three cuneiforms (medial,

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intermediate, and lateral) and cuboid.

? METATARSAL BONES
? These are five miniature long bones.
? The five metatarsal bones together constitute the

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metatarsus.

? They are numbered from medial to lateral sides as

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first, second, third, fourth, and fifth.

? PHALANGEAL BONES
? The phalangeal bones are miniature long bones.
? They are 14 in number in each foot--two for the

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great toe and three for each of the other four toes.
? The foot performs two major functions
1. It acts as a pliable platform to support the body

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weight during standing position.

? For this function foot is designed in the form of

elastic arches.

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? These arches are segmented so that they can

sustain the stress of weight and thrusts at the

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optimum level.
2. It acts as a lever to propel the body forward during

walking, running, and jumping.

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? For this function, the foot is so constructed that it is

transformable in a lever.

? The segmented arched lever converts the foot into

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a spring, which is ideally suited for its functions.
? The foot and its bones are

divided into three

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anatomical and functional

segments:

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1.Hindfoot consists of talus

and calcaneus.

2.Midfoot consists of

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navicular, cuboid,&

cuneiforms.

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3.Forefoot consists of

metatarsals and

phalanges.

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? The skeleton of the foot is arched both

longitudinally and transversely, with the concavity

directed towards the plantar surface.

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? The presence of arches makes the sole concave

both anteroposteriorly and transversely
? During the standing position, the weight of the

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body is distributed among three points:


(a) Posteroinferior tuberosity of the calcaneum (heel)

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(b) Head of first metatarsal, and

(c) Head of fifth metatarsal

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Factors Maintaining the Arches of the

Foot

? The devices used

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to support a stone

bridge are:

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1. Shape of stones.
2. Intersegmental

ties (staples).

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3. Slings.
4. Tie beams
TYPES OF ARCHES
LONGITUDINAL ARCHES

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? Each longitudinal arch has: (a) two pillars, (b) a

summit, and (c) joints.

? MEDIAL LONGITUDINAL ARCH

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? Formed by the calcaneum, talus, navicular, three

cuneiforms, and medial three metatarsals

? Pillars

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1. Posterior pillar medial half of calcaneum.
2. Anterior pillar heads of the medial three

metatarsals.

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? Summit
? The talus lies at the summit of this arch. Therefore,

the talus is the keystone of this arch.

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? Joints
? The main joints of the medial longitudinal arch are

talocalcaneonavicular and subtalar joints.

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? LATERAL LONGITUDINAL ARCH

? Formed by the calcaneum cuboid and lateral two

metatarsals.

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? It is characteristically low and almost touches the

ground.

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? It is involved in receiving and supporting the body

weight during walking and running.

? Pillars

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? Posterior pillarlateral tubercle of the calcaneum
? Anterior pillarheads of the lateral 2 metatarsals.

? Summit
? Lies at the level of articular facets on the superior

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surface of the calcaneum.

? Joints
? The main joint of the arch is calcaneocuboid joint.

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FACTORS MAINTAINING THE LONGITUDINAL ARCHES

? Factors Maintaining the Medial Longitudinal Arch
? Bones
? The sustentaculum tali partly support the head of talus.

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? Ligaments
(a) Plantar calcaneonavicular ligament (spring ligament)

which provides dynamic support to the head of talus

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(b) Interosseous ligaments connecting the adjacent bones
(c) Interosseous talocalcanean ligament, connecting these

bones.

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? These ligaments act as intersegmental ties.

? Muscles, tendons, and aponeurosis
1. Acting as slings (suspending arch from above):
? The tendon of tibialis posterior lying below the

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spring ligament provides supports to the head of

talus and suspends the arch from above.

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? The flexor hallucis longus muscle, has three

functions to support the medial longitudinal arch.

(a) It stretches the arch like the string of a bow.

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(b) It supports the calcaneus by passing underneath

the sustentaculum tali.

(c) It supports the talus by passing along its posterior

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groove

? The tendon of tibialis anterior also exerts a sling

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action.

? 2. Acting as tie beams (structures which prevent

separation of the pillars):

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? The medial part of the plantar aponeurosis and

abductor hallucis assisted by the flexor hallucis

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brevis act as tie beam to maintain the height of

the medial longitudinal arch.
? Factors Maintaining the Lateral Longitudinal Arch
? Bones

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? The proper shaping of the distal end of calcaneus and

proximal end of cuboid. The cuboid is the keystone of

longitudinal arch.

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? Ligaments
1. Short plantar ligament: broad and thick.
It lies deep to the long plantar ligament and supports

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the calcaneocuboid joint from below.

2. Long plantar ligament: long and supports the joints

between the calcaneum, cuboid, and relate metatarsals

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? These ligaments act as intersegmental ties.


? Muscles, tendons, and aponeurosis

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1. Acting as tie beams:
? The lateral part of the plantar aponeurosis and the

intrinsic muscles of the little toe (lateral part of the

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flexor digitorum brevis, abductor digiti minimi

brevis, and flexor digiti minimi brevis) function as

tie beams of this arch.

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2. Acting as slings: The tendons of peroneus brevis

and peroneus tertius, which are inserted on the

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base of the fifth metatarsal, act as weak slings

from above.

? The tendon of peroneus longus supports the

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cuboid bone from above through its pulley-like

action
Differ. between the medial and lateral longitudinal arches

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Medial longitudinal arch

Lateral longitudinal arch

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Formed by more bones and more joints Formed by less bones and less joints

Characteristic feature is resiliency

Characteristic feature is rigidity

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Higher and more mobile

Lower and less mobile

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Involved in propulsion during

Involved in receiving and supporting the

locomotion

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body weight

(initiating the next step during walking)
Summit is formed by the talus

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Summit is formed by the calcaneum

Main joint is talocalcaneonavicular joint Main joint is calcaneocuboid

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(the most vulnerable part of the arch)

(the most vulnerable part of the arch)
TRANSVERSE ARCHES

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? Anterior Transverse Arch

? Formed by the heads of the metatarsals.

? It is a complete arch because during standing

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position the heads of first and fifth metatarsals

come into contact to the ground and form the

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two ends of the arch.
? Posterior Transverse Arch
? Formed by greater parts of

the tarsus and metatarsus.

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? It is an incomplete arch

because only its lateral end

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comes into contact with

the ground during standing

position.

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? The complete dome is

formed when the two feet

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are brought together
Factors Maintaining the Transverse Arches

? Bones
? Tarsal and metatarsal bones maintain the concavity

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on the plantar aspect of the foot skeleton.

? Ligaments
? Superficial and deep transverse metatarsal

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ligaments at the heads of metatarsals function as

intersegmental ties to maintain the shallow arch at

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the heads of metatarsals.
? Muscles and tendons
1. Acting as tie beams:
The tendons of peroneus longus and tibialis

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posterior support the transverse arch as tie beam.

2. Acting as slings:
The peroneus tertius and peroneus brevis on the

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lateral side and tibialis anterior on the medial side

support the transverse arch as slings.

3. Acting as intersegmental ties:

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The dorsal interossei act as intersegmental ties.
FUNCTIONS OF THE ARCHES

1. Distribute the body weight to the weight-bearing

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points of the sole

2. Act as shock absorber during jumping by their

spring like action

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3. The medial longitudinal arch provides a

propulsive force during locomotion.

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4. The lateral longitudinal arch functions as a static

organ of support and weight transmission.

5. The concavity of the arches protects the nerves

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and vessels of the sole.
CLINICAL CORRELATION

? Flat foot (pes planus):

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? Commonest problem of foot.
? It occurs due to collapse of medial longitudinal arch.
? During long periods of standing the plantar aponeurosis

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and spring ligament are overstretched.

? As a result, the support of the head of talus is lost and

is pushed downward between the calcaneus and the

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navicular bones. This leads to flattening of the medial

longitudinal arch with lateral deviation of the foot.

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? The effects of the flat foot are:

(a) The person usually has clumsy shuffling gait due

to the loss of spring in the foot.

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(b) Liable to trauma due to loss of the shock

absorbing function.

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(c) The compression of the nerves and vessels of the

sole is due to the loss of concavity of the sole.

? The compression of the communication between

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the medial and lateral plantar nerves leads to

neuralgic pain in the forefoot (metatarsalgia).
? High arched foot (pes cavus)

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? The exaggeration of the longitudinal arch of the

foot causes pes cavus.

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? This usually occurs because of a contracture

(plantar flexion) at the transverse tarsal joint.

When the patient walks with a high arched foot

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there is dorsiflexion of the metatarsophalangeal

joints and the plantar flexion of th interphalangeal

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joints of the toes.