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The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges Phalanges Bones that make up the skeleton of the fingers, consisting of two for the thumb, and three for each of the other fingers. Hand: Anatomy. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons that allow for flexibility as well as dynamic and static support. The foot has 3 primary arches and multiple ligaments that are essential to its structure. The arches are important in absorbing weight during standing, walking, and running and the ability to adapt to uneven terrain during locomotion.
Last updated: Jan 17, 2024
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The 26 bones of the foot are divided into 3 groups: tarsals, metatarsals, and phalanges Phalanges Bones that make up the skeleton of the fingers, consisting of two for the thumb, and three for each of the other fingers. Hand: Anatomy.
From superior to inferior and from medial to lateral in a right foot: Talus, Calcaneus, Navicular, Medial cuneiform, Intermediate or middle cuneiform, Lateral cuneiform, Cuboid
The joints of the foot, from proximal to distal, include the following articulations.
Subtalar or talocalcaneal joint Talocalcaneal joint Formed by the articulation of the talus with the calcaneus. Ankle Joint: Anatomy:
Transverse tarsal or midtarsal joint Midtarsal Joint Ankle Joint: Anatomy:
Tarsometatarsal or Lisfranc joints:
Metatarsophalangeal joints:
The foot has 3 primary arches and multiple supporting ligaments.
The plantar arches function to distribute and absorb the body weight, provide the foot with elasticity Elasticity Resistance and recovery from distortion of shape. Skeletal Muscle Contraction and resilience during locomotion, adapt to uneven surfaces, and protect the neurovasculature on the plantar surface.
Medial view of the foot featuring the arches of the foot
Image by Lecturio.The plantar ligaments are essential in the maintenance of the functional integrity of the arches on the sole of the foot.
Plantar view of the foot featuring the numerous plantar ligaments
Image by Lecturio.Plantar fascia or aponeurosis:
Note how the deep fascia is continuous with the
plantar fascia, which is thickened centrally as the toughened plantar aponeurosis. The aponeurosis has bands and intermuscular septa that divide the sole of the foot into 3 compartments: medial, lateral, and central.
Aside from the tendons of the extrinsic muscles from the anterior compartment of the leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy ( extensor hallucis longus Extensor hallucis longus Leg: Anatomy, extensor digitorum Extensor digitorum Forearm: Anatomy, tibialis anterior Tibialis anterior Leg: Anatomy, and peroneus tertius Peroneus tertius Leg: Anatomy), which pass under the extensor retinaculum, only 2 intrinsic muscles exist on the dorsum of the foot:
Muscle | Origin | Insertion | Innervation | Function |
---|---|---|---|---|
Extensor digitorum Extensor digitorum Forearm: Anatomy brevis | Calcaneus | Long extensor tendons of the extensor digitorum longus Extensor digitorum longus Leg: Anatomy (EDL) for digits 2–4 | Deep fibular nerve (L4, L5, S1 S1 Heart Sounds) | Extends the distal interphalangeal joints Interphalangeal joints Hand: Anatomy of digits 2–4 and aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS the EDL |
Extensor hallucis brevis | Proximal phalanx of the hallux (1st digit) | Extends hallux and aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS the extensor hallucis longus Extensor hallucis longus Leg: Anatomy |
Deep layer of the dorsum of the foot
Image by Lecturio.Superficial layer of the dorsum of the foot
Image by Lecturio.The intrinsic muscles of the plantar surface, or sole, of the foot both originate and insert within the foot. These muscles produce the fine movements of the digits and support the arches of the foot during standing, walking, and running. Commonly, the plantar muscles of the foot are organized into 4 layers, from superficial to deep:
Muscle | Origin | Insertion | Innervation | Function |
---|---|---|---|---|
Abductor hallucis | Tuberosity of calcaneus and plantar aponeurosis | Base of proximal phalanx of the hallux | Medial plantar nerve ( S3 S3 Heart Sounds) | Abducts and flexes the 1st digit |
Flexor digitorum brevis | Middle phalanges Phalanges Bones that make up the skeleton of the fingers, consisting of two for the thumb, and three for each of the other fingers. Hand: Anatomy of digits 2–5 | Flexes digits 2–5 | ||
Abductor digiti minimi Abductor digiti minimi Hand: Anatomy | Base of proximal phalanx of digit 5 | Lateral plantar nerve ( S3 S3 Heart Sounds) | Abducts and flexes digit 5 |
Most superficial layer of the muscles of the sole of the foot
Image by Lecturio.Muscle | Origin | Insertion | Innervation | Function |
---|---|---|---|---|
Quadratus plantae | Medial and lateral aspect of the calcaneus | Lateral margin of the tendons of the flexor digitorum longus Flexor digitorum longus Leg: Anatomy (FDL) | Lateral plantar nerve ( S1 S1 Heart Sounds– S3 S3 Heart Sounds) | Assist flexion Flexion Examination of the Upper Limbs of digits 2–5 with the FDL |
Lumbricals Lumbricals Hand: Anatomy | Tendons of the flexor digitorum longus Flexor digitorum longus Leg: Anatomy | Medial aspects of digits 2–5 |
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2nd most superficial layer of the muscles of the sole of the foot
Image by Lecturio.Muscle | Origin | Insertion | Innervation | Function |
---|---|---|---|---|
Flexor hallucis brevis | Cuboid and lateral cuneiform | Base of the proximal phalanx of the 1st digit | Medial plantar nerve ( S3 S3 Heart Sounds) | Flexes the proximal phalanx of the 1st digit |
Adductor hallucis |
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Lateral plantar nerve (deep branch, S3 S3 Heart Sounds) | Adducts the 1st digit | |
Flexor digiti minimi brevis Flexor digiti minimi brevis Hand: Anatomy | Base of the 5th metatarsal | Base of the proximal phalanx of the 5th digit | Lateral plantar nerve (superficial, S3 S3 Heart Sounds) | Flexes the proximal phalanx of the 5th digit |
Muscle | Origin | Insertion | Innervation | Function |
---|---|---|---|---|
Plantar interossei Interossei Hand: Anatomy | Medial surface of the 3rd–5th metatarsals | Medial surface of the proximal phalanx of digits 3–5 | Lateral plantar nerve ( S3 S3 Heart Sounds) | Adducts digits 3–5 and flexes metatarsophalangeal joints |
Dorsal interossei Dorsal interossei Hand: Anatomy | Adjacent surfaces of the 1st–5th metatarsals |
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Abducts digits 2–4 and flexes metatarsophalangeal joints |
Deepest layer of the muscles of the sole of the foot
Image by Lecturio.Alternatively, the intrinsic muscles of the plantar surface, or sole, of the foot can be divided into 3 groups, using the medial, lateral and central compartments of the foot. These compartments are formed by the deep fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis or plantar aponeurosis.
Primarily from branches of the tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy and the deep fibular nerve.
Innervation of the plantar surface:
The tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy branches into the medial and lateral plantar nerves at the ankle within the tarsal tunnel.
Innervation of the dorsal surface:
Innervation of the dorsal and plantar portions of the foot
Image by Lecturio.Posterior tibial artery:
Oblique view of the plantar aspect of the foot showing the branches of the posterior tibial artery
Image by Lecturio.Anterior tibial artery:
Anterior view of the dorsal foot demonstrating the anterior tibial artery to the dorsalis pedis artery and its branches
Image by Lecturio.Venous drainage of the foot begins with the digital veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology, which run proximally to form both a deep plantar venous arch and a dorsal venous arch. These veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology drain into the leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy via the anterior and posterior tibial veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology and the peroneal vein.
Foot deformities Foot deformities Foot deformities in children include congenital or acquired malformations of the feet. Two common examples are talipes equinovarus, commonly known as clubfoot, and metatarsus adductus, also called metatarsus varus. Foot Deformities