Foot

Surface landmarks of the foot

Surface landmarks of the left foot

1

Medial malleolus
2

Great saphenous vein and saphenous nerve
3

Tibialis anterior
4

Extensor hallucis longus
5

Extensor digitorum longus
6

Lateral malleolus
7

Extensor digitorum brevis
8

Dorsalis pedis artery
9

Dorsal venous arch
10

Fibularis ( peroneus ) longus and brevis
11

Small saphenous vein and sural nerve
12

Tendo calcaneus
13

Flexor hallucis longus
14

Posterior tibial artery and tibial nerve
15

Flexor digitorum longus and tibialis posterior
16

Tuberosity of calcaneus
17

Sesamoid bones under head of first metatarsal
18

Base of first metatarsal
19

Head of fifth metatarsal
20

Tuberosity of base of fifth metatarsal
21

Tuberosity of navicular

Definitions of movements are as follows:

•

Extension: from the Latin for straightening out, but as far as the ankle and foot are concerned it means bending the foot and/or toes upwards, and is also known as dorsiflexion.
•

Flexion: from the Latin for bending. In the ankle and foot it means bending the foot and/or toes downwards, which is also known as plantarflexion.
•

Abduction: from the Latin for moving away. In the foot it means spreading the toes apart (the corresponding movement of the fingers is much more extensive).
•

Adduction: from the Latin for moving towards. In the foot it means drawing the toes together.
•

Inversion: from the Latin for turning in—turning the foot so that the sole faces more inwards (medially).
•

Eversion: from the Latin for turning out—moving the foot so that the sole faces more outwards (laterally) (a more limited movement than inversion).

For further details see pp. 87 and 99 .

1

Tendo calcaneus
2

Flexor hallucis longus
3

Posterior tibial artery and tibial nerve
4

Flexor digitorum longus and tibialis posterior
5

Medial malleolus
6

Great saphenous vein and saphenous nerve
7

Tibialis anterior
8

Extensor hallucis longus
9

Head of first metatarsal
10

Sesamoid bone
11

Tuberosity of navicular
12

Sustentaculum tali
13

Tuberosity of calcaneus
14

Small saphenous vein and sural nerve
15

Fibularis (peroneus) longus and brevis
16

Lateral malleolus
17

Extensor digitorum brevis
18

Extensor digitorum longus
19

Tuberosity of base of fifth metatarsal
20

Head of fifth metatarsal

•

Pulsation in the dorsalis pedis artery ( p. 78 , 14 ) is normally palpable between the tendons of extensor hallucis longus ( 8 ) and extensor digitorum longus ( 18 ), on a line from the midpoint between the medial and lateral malleoli to the proximal end of the first intermetatarsal space. However, the artery is absent in about 12% of feet (see p. 79 ).
•

Pulsation in the posterior tibial artery ( 3 ) is normally palpable behind the medial malleolus ( 5 ), 2.5 cm in front of the medial border of the tendo calcaneus.
•

The sustentaculum tali ( 12 ) is palpable about 2.5 cm below the tip of the medial malleolus ( 5 ).

Skeleton of the foot

Bones of the left foot, from above

The talus and calcaneus remain articulated with each other but the remainder have been disarticulated.

1

Calcaneus
2

Talus
3

Navicular
4

Medial cuneiform
5

Intermediate cuneiform
6

Lateral cuneiform
7

Cuboid
8

First metatarsal
9

Second metatarsal
10

Third metatarsal
11

Fourth metatarsal
12

Fifth metatarsal
13

Proximal phalanx of great toe
14

Distal phalanx of great toe
15

Proximal phalanx of second toe
16

Middle phalanx of second toe
17

Distal phalanx of second toe

•

Bones of the tarsus

Calcaneus

Talus

Navicular bone

Cuboid bone

Medial, intermediate and lateral cuneiform bones
•

Bones of the metatarsus

First to fifth metatarsal bones, numbered from medial to lateral
•

Bones of the toes or digits

Phalanges—a proximal and a distal phalanx for the great toe; proximal, middle and distal phalanges for each of the second to fifth toes
•

The hindfoot consists of the talus and calcaneus.
•

The midfoot consists of the navicular, cuboid and cuneiform bones.
•

The forefoot consists of the metatarsal bones and phalanges.
•

Sesamoid bones —two always present in the tendons of flexor hallucis brevis. For others see pp. 44 , 46 .
•

Origin and meaning of some names associated with the foot are as follows (some older names for bones are given in parentheses):

Tibia:	Latin for a flute or pipe; when held upside down, the shin bone has a fanciful resemblance to this wind instrument.
Fibula:	Latin for a pin or skewer; the long thin bone of the leg. Adjective fibular or peroneal, which is from the Greek for pin (see the last note on p. 3 ).
Tarsus:	Greek for a wicker frame, in the basic framework for the back of the foot.
Metatarsus:	Greek for beyond the tarsus; the forepart of the foot.
Talus: (astragalus)	Latin (Greek) for one of a set of dice; viewed from above the main part of the talus has a rather square appearance.
Calcaneus: os calcis, ( calcaneum )	From the Greek for heel; the heel bone.
Navicular : (scaphoid)	Latin (Greek) for boat-shaped; the navicular bone roughly resembles a saucer-shaped coracle.
Cuboid:	Greek for cube-shaped.
Cuneiform:	Latin for wedge-shaped.
Phalanx:	Greek for a row of soldiers; a row of bones in the toes. Plural phalanges.
Sesamoid:	Greek for shaped like a sesame seed.
Digitus:	Latin for finger or toe. Digiti and digitorum are the genitive singular and genitive plural—of the toe(s).
Hallux:	Latin for the great toe. Hallucis is the genitive singular—of the great toe.
Dorsum:	Latin for back; the upper surface of the foot. Adjective dorsal.
Plantar:	Adjective from planta, Latin for the sole of the foot.

Articulated bones of the left foot

1

Calcaneus
2

Talus
3

Navicular
4

Medial cuneiform
5

Intermediate cuneiform
6

Lateral cuneiform
7

Cuboid
8

First metatarsal
9

Second metatarsal
10

Third metatarsal
11

Fourth metatarsal
12

Fifth metatarsal
13

Proximal phalanx of great toe
14

Distal phalanx of great toe
15

Proximal phalanx of second toe
16

Middle phalanx of second toe
17

Distal phalanx of second toe
18

Sesamoid bones

Ossification of Foot Bones

All the tarsal bones are ossified from one primary center: calcaneus at the third fetal month, talus at the sixth fetal month, cuboid just before or just after birth, lateral cuneiform at 1 year, medial cuneiform at 2 years, intermediate cuneiform and navicular at 3 years.

The calcaneus is the only tarsal bone to have a secondary center: a thin plate of bone on the posterior surface, appearing at about 7 years and fusing during puberty.

The metatarsal bones and phalanges have primary centers for their shafts at the second to fourth fetal months, and one secondary center: at the base of the first metatarsal and bases of all the phalanges, but at the heads of the other metatarsals. These begin to ossify at 2 to 6 years and fuse at about 18 years.

All dates given are subject to considerable variation, and ossification tends to occur earlier in females.

•

During the preparation of dried bones, the hyaline cartilage on articulating surfaces is lost, so that when rearticulating bones an exact fit is not possible. The thickness of the cartilage on joint surface is best appreciated in sections of bones, as on pp. 20 , 21 and 92–104 .
•

The talus ( 2 ) is the uppermost foot bone, forming the ankle joint with the tibia and fibula. For details see pp. 52 , 61 .
•

The calcaneus ( 1 ) is the most posterior and the largest foot bone, forming the heel. For details see pp. 62 , 63 .
•

The navicular bone ( 3 ) lies in front of the talus, on the medial side of the foot. For details see p. 64 .
•

The cuboid bone ( 7 ) lies in front of the calcaneus, on the lateral side of the foot. For details see p. 64 .
•

The three cuneiform bones —medial, intermediate and lateral ( 4 , 5 and 6 )—lie in front of the navicular bone. For details see p. 65 .
•

The first, second and third metatarsal bones ( 8 , 9 and 10 ) are in front of the three cuneiforms, and the fourth and fifth metatarsal bones ( 11 and 12 ) are in front of the cuboid bone. For details see pp. 66 , 67 .
•

The phalanges ( 13–17 ) are the bones of the toes. Each proximal phalanx articulates with the head of a metatarsal bone. Each phalanx has a base (at the proximal end), body and head (at the distal end). The body is convex on the dorsal (upper) surface, and concave on the plantar surface. See pp. 42 , 50 .

Attachments of muscles and major ligaments to the bones of the left foot

1

Tendo calcaneus
2

Plantaris
3

Area for bursa
4

Extensor digitorum brevis
7

Fibularis (peroneus) brevis
8

Fibularis (peroneus) tertius
13

Abductor hallucis
14

Extensor hallucis brevis
15

Extensor hallucis longus
16

Extensor digitorum longus and brevis
17

Extensor digitorum longus
21

Abductor digiti minimi
22

Flexor digitorum brevis
23

Quadratus plantae
24

Long plantar ligament
25

Plantar calcaneocuboid (short plantar) ligament
26

Plantar calcaneonavicular (spring) ligament
27

Tibialis posterior
28

Tibialis anterior
29

Flexor hallucis brevis
30

Flexor digiti minimi brevis
31

Adductor hallucis
32

Flexor hallucis longus
33

Flexor digitorum longus
34

Opponens digiti minimi (occasional part of 30 )
35

Fibularis ( peroneus ) longus

Sesamoid and accessory bones

Sesamoid Bones

The patella is by far the largest sesamoid bone in the lower limb and its close association with tendons and a bony joint (the knee) gives a conceptual focus as to the function of sesamoid bones.

In the Foot:

•

They usually vary in shape and size but in general are ovoid and normally only a few millimeters in diameter ( p. 44 , B18 ).
•

They are not always ossified but may consist of fibrous tissue or cartilage, or a combination of all three.
•

They are usually found embedded in tendons at the point where the tendons angle acutely around bony surfaces to their point of insertion ( p. 92 , 16 and p. 93 , 33 ).
•

Sesamoids have articular cartilage on the surface which is in direct relationship to the bone that they are proximate to.

Although not proved, it is thought that sesamoid bones protect tendons from wear, and by their strategic position to joints, alter the angle of insertion of a tendon into bone and thus provides a greater mechanical advantage to the joint.

Accessory Bones

Bones within the human body gradually begin to form during the early developmental phases of the fetus by the initial formation of central areas of ossification within the cartilaginous and membranous skeleton. These ossified areas continue to grow, unite and eventually form solid adult bones, some during late childhood and some as late as early adulthood.

On occasions however the centres of ossification fail to fuse completely, often at the ends of bones, and thus a separate (accessory or supernumerary) bone is formed.

The foot is a common place for accessory bones to form and there are common sites for them to occur. It is important to be aware of their possible presence because on a radiographic image they can be easily mistaken for a fractured bone or ‘chip’.

Common accessory bones in the foot are:

•

Dorsum of foot
- Os intercuneiforme
- Os talonaviculare dorsale
- Os calcaneus secondarius
- Os intermetatarsal I
•

Posterior part of foot
- Os trigonum
•

Lateral part of foot
- Os calcaneus secondarius
- Os vesalianum pedis
•

Medial part of foot
- Os tibiale externum (Os naviculare accessorium)
- Os sustentaculi
•

Plantar aspect (sole) of foot
- Pars peronea metatarsalis I
- Os cuboides secondarius

Common locations of sesamoid ( red ) and accessory ( blue ) bones

Articulated bones of the left foot

1

Body of calcaneus
2

Sustentaculum tali part of calcaneus
3

Body of talus
4

Head of talus
5

Navicular
6

Tuberosity of navicular
7

Medial cuneiform
8

Intermediate cuneiform
18

Sesamoid bone
19

Lateral cuneiform
20

Cuboid
25

Tarsal sinus

•

When standing (as can be seen from the imprint of a wet foot on the floor or when viewed through a glass plate—see p. 39 , F ) the parts of the foot in contact with the ground are the heel, the lateral margin of the foot, the pads under the metatarsal heads and the pads under the distal part of the toes.
•

The medial margin of the foot is not normally in contact with the ground because of the height of the medial longitudinal arch (see pp. 50 and 51 ). In flat foot the medial arch is lower with an increasingly large imprint on the medial side.
•

The body weight when standing is borne by the tuberosity of the calcaneus and the heads of the metatarsals, especially the first (with the sesamoid bones underneath it) and the fifth. As the foot bends forward in walking the other metatarsal heads take increasingly more of the load. With further raising of the heel the toe pads become pressed to the ground and so take some of the weight off the metatarsals.
•

Although the forearm and hand have many muscles similar in name and action to those of the leg and foot, their normal use in everyday life is different. In the upper limb the muscles work from above to produce intricate movements of the thumb and fingers in a free limb. In the lower limb the toes must be stabilized on the ground so that muscles can work from below to produce the propulsive movements of walking.

Bones of the left longitudinal arches, transverse tarsal joint and other joints

•

The bones of the medial longitudinal arch ( A ) are the calcaneus, talus, navicular, the three cuneiforms and the medial three metatarsal bones.
•

The bones of the lateral longitudinal arch ( B ) are the calcaneus, cuboid and the two lateral metatarsal bones.
•

The transverse arch is formed by the cuboid and cuneiform bones and the adjacent parts of the five metatarsals (those of each foot forming one half of the whole arch). At the level of the metatarsal heads the arched form is no longer present.
•

The medial longitudinal arch is higher than the lateral.
•

While the shape of the individual bones determines the shapes of the arches, the maintenance of the arches in the stationary foot (standing in the normal upright position) depends largely on the ligaments in the sole (where they are larger and stronger than those on the dorsum). As soon as movement occurs the long tendons and small muscles of the sole assume importance in maintaining the curved forms.
•

The many joints of the foot contribute to its function as a flexible lever, and the word arch suggests an architectural rigidity that does not exist.
•

On the medial side the plantar calcaneonavicular ligament (spring ligament) is of particular importance in supporting the head of the talus, and other structures that help to maintain the medial arch include the plantar aponeurosis, flexor hallucis longus, tibialis anterior and posterior, and the medial parts of flexor digitorum longus and brevis.
•

The transverse tarsal joint (midtarsal joint) is the collective name for two joints—the calcaneocuboid joint, and the talonavicular part of the talocalcaneonavicular joint.

1

Calcaneus
2

Talus
3

Navicular
4

Medial cuneiform
5

Intermediate cuneiform
6

Lateral cuneiform
7

First metatarsal
8

Second metatarsal
9

Third metatarsal
10

Phalanges of great toe
11

Phalanges of second toe
12

Phalanges of third toe
13

Cuboid
14

Fourth metatarsal
15

Fifth metatarsal
16

Phalanges of fourth toe
17

Phalanges of fifth toe
18

Talocalcanean joint
19

Talonavicular part of talocalcaneonavicular joint
20

Cuneonavicular joint
21

Intercuneiform joints
22

Tarsometatarsal joints (cuneometatarsal and cuboideometatarsal)
23

Intermetatarsal joints
24

Metatarsophalangeal joints
25

Interphalangeal joints
26

Calcaneocuboid joint
27

Cuboideonavicular joint
28

Cuneocuboid joint

Skeleton of the foot

Bones of the left foot, from above

The talus and calcaneus remain articulated with each other but the remainder have been disarticulated.

1

Calcaneus
2

Talus
3

Navicular
4

Medial cuneiform
5

Intermediate cuneiform
6

Lateral cuneiform
7

Cuboid
8

First metatarsal
9

Second metatarsal
10

Third metatarsal
11

Fourth metatarsal
12

Fifth metatarsal
13

Proximal phalanx of great toe
14

Distal phalanx of great toe
15

Proximal phalanx of second toe
16

Middle phalanx of second toe
17

Distal phalanx of second toe

•

Bones of the tarsus

Calcaneus

Talus

Navicular bone

Cuboid bone

Medial, intermediate and lateral cuneiform bones
•

Bones of the metatarsus

First to fifth metatarsal bones, numbered from medial to lateral
•

Bones of the toes or digits

Phalanges—a proximal and a distal phalanx for the great toe; proximal, middle and distal phalanges for each of the second to fifth toes
•

The hindfoot consists of the talus and calcaneus.
•

The midfoot consists of the navicular, cuboid and cuneiform bones.
•

The forefoot consists of the metatarsal bones and phalanges.
•

Sesamoid bones —two always present in the tendons of flexor hallucis brevis. For others see pp. 44 , 46 .
•

Origin and meaning of some names associated with the foot are as follows (some older names for bones are given in parentheses):

Tibia:	Latin for a flute or pipe; when held upside down, the shin bone has a fanciful resemblance to this wind instrument.
Fibula:	Latin for a pin or skewer; the long thin bone of the leg. Adjective fibular or peroneal, which is from the Greek for pin (see the last note on p. 3 ).
Tarsus:	Greek for a wicker frame, in the basic framework for the back of the foot.
Metatarsus:	Greek for beyond the tarsus; the forepart of the foot.
Talus: (astragalus)	Latin (Greek) for one of a set of dice; viewed from above the main part of the talus has a rather square appearance.
Calcaneus: os calcis, ( calcaneum )	From the Greek for heel; the heel bone.
Navicular : (scaphoid)	Latin (Greek) for boat-shaped; the navicular bone roughly resembles a saucer-shaped coracle.
Cuboid:	Greek for cube-shaped.
Cuneiform:	Latin for wedge-shaped.
Phalanx:	Greek for a row of soldiers; a row of bones in the toes. Plural phalanges.
Sesamoid:	Greek for shaped like a sesame seed.
Digitus:	Latin for finger or toe. Digiti and digitorum are the genitive singular and genitive plural—of the toe(s).
Hallux:	Latin for the great toe. Hallucis is the genitive singular—of the great toe.
Dorsum:	Latin for back; the upper surface of the foot. Adjective dorsal.
Plantar:	Adjective from planta, Latin for the sole of the foot.

Articulated bones of the left foot

1

Calcaneus
2

Talus
3

Navicular
4

Medial cuneiform
5

Intermediate cuneiform
6

Lateral cuneiform
7

Cuboid
8

First metatarsal
9

Second metatarsal
10

Third metatarsal
11

Fourth metatarsal
12

Fifth metatarsal
13

Proximal phalanx of great toe
14

Distal phalanx of great toe
15

Proximal phalanx of second toe
16

Middle phalanx of second toe
17

Distal phalanx of second toe
18

Sesamoid bones

Ossification of Foot Bones

All the tarsal bones are ossified from one primary center: calcaneus at the third fetal month, talus at the sixth fetal month, cuboid just before or just after birth, lateral cuneiform at 1 year, medial cuneiform at 2 years, intermediate cuneiform and navicular at 3 years.

The calcaneus is the only tarsal bone to have a secondary center: a thin plate of bone on the posterior surface, appearing at about 7 years and fusing during puberty.

The metatarsal bones and phalanges have primary centers for their shafts at the second to fourth fetal months, and one secondary center: at the base of the first metatarsal and bases of all the phalanges, but at the heads of the other metatarsals. These begin to ossify at 2 to 6 years and fuse at about 18 years.

All dates given are subject to considerable variation, and ossification tends to occur earlier in females.

•

During the preparation of dried bones, the hyaline cartilage on articulating surfaces is lost, so that when rearticulating bones an exact fit is not possible. The thickness of the cartilage on joint surface is best appreciated in sections of bones, as on pp. 20 , 21 and 92–104 .
•

The talus ( 2 ) is the uppermost foot bone, forming the ankle joint with the tibia and fibula. For details see pp. 52 , 61 .
•

The calcaneus ( 1 ) is the most posterior and the largest foot bone, forming the heel. For details see pp. 62 , 63 .
•

The navicular bone ( 3 ) lies in front of the talus, on the medial side of the foot. For details see p. 64 .
•

The cuboid bone ( 7 ) lies in front of the calcaneus, on the lateral side of the foot. For details see p. 64 .
•

The three cuneiform bones —medial, intermediate and lateral ( 4 , 5 and 6 )—lie in front of the navicular bone. For details see p. 65 .
•

The first, second and third metatarsal bones ( 8 , 9 and 10 ) are in front of the three cuneiforms, and the fourth and fifth metatarsal bones ( 11 and 12 ) are in front of the cuboid bone. For details see pp. 66 , 67 .
•

The phalanges ( 13–17 ) are the bones of the toes. Each proximal phalanx articulates with the head of a metatarsal bone. Each phalanx has a base (at the proximal end), body and head (at the distal end). The body is convex on the dorsal (upper) surface, and concave on the plantar surface. See pp. 42 , 50 .

Attachments of muscles and major ligaments to the bones of the left foot

1

Tendo calcaneus
2

Plantaris
3

Area for bursa
4

Extensor digitorum brevis
7

Fibularis (peroneus) brevis
8

Fibularis (peroneus) tertius
13

Abductor hallucis
14

Extensor hallucis brevis
15

Extensor hallucis longus
16

Extensor digitorum longus and brevis
17

Extensor digitorum longus
21

Abductor digiti minimi
22

Flexor digitorum brevis
23

Quadratus plantae
24

Long plantar ligament
25

Plantar calcaneocuboid (short plantar) ligament
26

Plantar calcaneonavicular (spring) ligament
27

Tibialis posterior
28

Tibialis anterior
29

Flexor hallucis brevis
30

Flexor digiti minimi brevis
31

Adductor hallucis
32

Flexor hallucis longus
33

Flexor digitorum longus
34

Opponens digiti minimi (occasional part of 30 )
35

Fibularis ( peroneus ) longus

Sesamoid and accessory bones

Sesamoid Bones

The patella is by far the largest sesamoid bone in the lower limb and its close association with tendons and a bony joint (the knee) gives a conceptual focus as to the function of sesamoid bones.

In the Foot:

•

They usually vary in shape and size but in general are ovoid and normally only a few millimeters in diameter ( p. 44 , B18 ).
•

They are not always ossified but may consist of fibrous tissue or cartilage, or a combination of all three.
•

They are usually found embedded in tendons at the point where the tendons angle acutely around bony surfaces to their point of insertion ( p. 92 , 16 and p. 93 , 33 ).
•

Sesamoids have articular cartilage on the surface which is in direct relationship to the bone that they are proximate to.

Although not proved, it is thought that sesamoid bones protect tendons from wear, and by their strategic position to joints, alter the angle of insertion of a tendon into bone and thus provides a greater mechanical advantage to the joint.

Accessory Bones

Bones within the human body gradually begin to form during the early developmental phases of the fetus by the initial formation of central areas of ossification within the cartilaginous and membranous skeleton. These ossified areas continue to grow, unite and eventually form solid adult bones, some during late childhood and some as late as early adulthood.

On occasions however the centres of ossification fail to fuse completely, often at the ends of bones, and thus a separate (accessory or supernumerary) bone is formed.

The foot is a common place for accessory bones to form and there are common sites for them to occur. It is important to be aware of their possible presence because on a radiographic image they can be easily mistaken for a fractured bone or ‘chip’.

Common accessory bones in the foot are:

•

Dorsum of foot
- Os intercuneiforme
- Os talonaviculare dorsale
- Os calcaneus secondarius
- Os intermetatarsal I
•

Posterior part of foot
- Os trigonum
•

Lateral part of foot
- Os calcaneus secondarius
- Os vesalianum pedis
•

Medial part of foot
- Os tibiale externum (Os naviculare accessorium)
- Os sustentaculi
•

Plantar aspect (sole) of foot
- Pars peronea metatarsalis I
- Os cuboides secondarius

Common locations of sesamoid ( red ) and accessory ( blue ) bones

Articulated bones of the left foot

1

Body of calcaneus
2

Sustentaculum tali part of calcaneus
3

Body of talus
4

Head of talus
5

Navicular
6

Tuberosity of navicular
7

Medial cuneiform
8

Intermediate cuneiform
18

Sesamoid bone
19

Lateral cuneiform
20

Cuboid
25

Tarsal sinus

•

When standing (as can be seen from the imprint of a wet foot on the floor or when viewed through a glass plate—see p. 39 , F ) the parts of the foot in contact with the ground are the heel, the lateral margin of the foot, the pads under the metatarsal heads and the pads under the distal part of the toes.
•

The medial margin of the foot is not normally in contact with the ground because of the height of the medial longitudinal arch (see pp. 50 and 51 ). In flat foot the medial arch is lower with an increasingly large imprint on the medial side.
•

The body weight when standing is borne by the tuberosity of the calcaneus and the heads of the metatarsals, especially the first (with the sesamoid bones underneath it) and the fifth. As the foot bends forward in walking the other metatarsal heads take increasingly more of the load. With further raising of the heel the toe pads become pressed to the ground and so take some of the weight off the metatarsals.
•

Although the forearm and hand have many muscles similar in name and action to those of the leg and foot, their normal use in everyday life is different. In the upper limb the muscles work from above to produce intricate movements of the thumb and fingers in a free limb. In the lower limb the toes must be stabilized on the ground so that muscles can work from below to produce the propulsive movements of walking.

Bones of the left longitudinal arches, transverse tarsal joint and other joints

•

The bones of the medial longitudinal arch ( A ) are the calcaneus, talus, navicular, the three cuneiforms and the medial three metatarsal bones.
•

The bones of the lateral longitudinal arch ( B ) are the calcaneus, cuboid and the two lateral metatarsal bones.
•

The transverse arch is formed by the cuboid and cuneiform bones and the adjacent parts of the five metatarsals (those of each foot forming one half of the whole arch). At the level of the metatarsal heads the arched form is no longer present.
•

The medial longitudinal arch is higher than the lateral.
•

While the shape of the individual bones determines the shapes of the arches, the maintenance of the arches in the stationary foot (standing in the normal upright position) depends largely on the ligaments in the sole (where they are larger and stronger than those on the dorsum). As soon as movement occurs the long tendons and small muscles of the sole assume importance in maintaining the curved forms.
•

The many joints of the foot contribute to its function as a flexible lever, and the word arch suggests an architectural rigidity that does not exist.
•

On the medial side the plantar calcaneonavicular ligament (spring ligament) is of particular importance in supporting the head of the talus, and other structures that help to maintain the medial arch include the plantar aponeurosis, flexor hallucis longus, tibialis anterior and posterior, and the medial parts of flexor digitorum longus and brevis.
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The transverse tarsal joint (midtarsal joint) is the collective name for two joints—the calcaneocuboid joint, and the talonavicular part of the talocalcaneonavicular joint.

1

Calcaneus
2

Talus
3

Navicular
4

Medial cuneiform
5

Intermediate cuneiform
6

Lateral cuneiform
7

First metatarsal
8

Second metatarsal
9

Third metatarsal
10

Phalanges of great toe
11

Phalanges of second toe
12

Phalanges of third toe
13

Cuboid
14

Fourth metatarsal
15

Fifth metatarsal
16

Phalanges of fourth toe
17

Phalanges of fifth toe
18

Talocalcanean joint
19

Talonavicular part of talocalcaneonavicular joint
20

Cuneonavicular joint
21

Intercuneiform joints
22

Tarsometatarsal joints (cuneometatarsal and cuboideometatarsal)
23

Intermetatarsal joints
24

Metatarsophalangeal joints
25

Interphalangeal joints
26

Calcaneocuboid joint
27

Cuboideonavicular joint
28

Cuneocuboid joint

Foot bones

Left talus

1

Head with articular surface for navicular
2

Neck
3

Trochlear surface of body, for inferior surface of tibia
4

Surface for medial malleolus
8

Surface for lateral malleolus
9

Anterior calcanean articular surface
10

Surface for plantar calcaneonavicular (spring) ligament
11

Middle calcanean articular surface
12

Sulcus tali
13

Posterior calcanean articular surface
14

Lateral process

Talus

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The uppermost foot bone, forming the ankle joint with the tibia and fibula.
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Formerly known as the astragalus.
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Articular facets on the upper surface and sides for the tibia and fibula, on the under surface for the calcaneus, and on the anterior surface (head) for the navicular.
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Unique among the foot bones in having no muscles attached to it.