ARCHES OF FOOT
CHAPTER
12
ARCHES
OF THE FOOT
Arches of foot helps in
a)
Proportional distribution of body weight to the ground.
b)
Acts as segmented lever to help in propulsive mechanism.
Arches of foot are
a)
Longitudinal arch
b)
Transverse arch
Longitudinal arch – it is subdivided into medial and lateral arches
Medial longitudinal arch:
Bones forming the arch are: calcaneus, talus, navicular, three
cuneiform and medial three meta tarsal bones up to their heads.
Summit of
the arch
– trochlear upper surface of talus
Posterior
pillar – medial
tubercle of calcaneus
Anterior
pillar – heads of
the medial three meta tarsal bones.
Most vulnerable part of the medial arch – head of talus – received in front by the concave surface of the navicular bone, below by the sustentaculum tali of the calcaneus and by the spring ligament between them.
Factors maintaining the medial
longitudinal arch of foot:
a)
Shape of the bones- wedge shaped cuneiform bones and
the head of the talus which acts as key stone
b)
Tie beams- medial part of plantar aponeurosis,
abductor halucis, medial part of flexor digitorum brevis and longus tendon of
flexor halucis longus, flexor halucis brevis.
c)
Intersegmental tiers: Spring ligament on the upper surface
of which rests the head of talus.
d)
Sling and sustentacular: Tibialis anterior acts as sling and tibialis
posterior acts as sustentacular support.
Lateral longitudinal arch
Bones
forming the arch are;
Calcaneus, cuboid, fourth and fifth metatarsal bones up to their heads.
Summit of
the arch: Subtalar
joint or upper surface of calcaneus
Posterior
pillar:
Medial tubercle of the calcaneus
Anterior pillar: Heads of the fourth and fifth
metatarsal bones
Most vulnerable part of the arch: Calcaneocuboid joint
Factors maintaining the lateral
longitudinal arch:
a)
Shape of the bones: Calcanean angle of cuboid maintains
the upward tilt of the calcaneus
b)
Tie beams: lateral part of the plantar
aponeurosis.
c)
Intersegmental tiers: The long and short plantar
ligaments acts as tiers
d)
Sling and sustentacular: Tendons of peroneus brevis and
tertius act as sling and tendon of peroneus longus act as sustentacular
support.
Transverse arches
When the medial borders of both feet
are approximated, a complete transverse arch is formed.
The transverse arches are made of a
series of arches involving the bases of metatarsal bones, cuboid and three
cuneiform bones.
Factors maintaining the
transverse arches of foot:
a)
Shape of bones: wedge shaped cuneiform bones and
bases of the middle three metatarsal bones.
b)
Tie beams: Tendons of peroneus longus and
tibialis posterior
c) Intersegmental tiers: dorsal interossei, oblique and transverse
heads of abductor hallucis muscles.
d)
Sling: tibialis anterior on medial side and
peroneus brevis and terries on lateral side.
Applied anatomy
1)
Pes planus: t flat foot is caused by the
abnormal distribution of body weight on to the arch such as rapid increased in
body weight.
2)
Pes cavus: it is an exaggeration of the
longitudinal arch of foot.
Comments
Post a Comment