1Kaan Yücel M.D., Ph.D.

FOOTIN 30 QUESTIONS

EXAM OF THE LOWER EXTREMITIES

From A Practical Guide to Clinical Medicine

University of California, San Diego

INTRODUCTION TO FOOTRegion of the lower limb distal to ankle joint

Subdivided into Ankle Metatarsus Digits

Superior surface (dorsum of foot) Inferior surface (sole)

INTRODUCTION TO FOOT Body's point of contact with the ground Provides a stable platform for upright stance. Supports the body weight and provides leverage for walking and running. Unique -constructed in the form of arches, adapt its shape to uneven surfaces. Serves as a resilient spring to absorb shocks, such as in jumping.

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IN 10 QUESTIONS

SKIN &

SUBCUTANEOUS TISSUE

1…skin of the footSkin of the dorsum of the foot thinner and less sensitive than that of the sole

The subcutaneous tissue is loose deep to the dorsal skin

Edema most marked on the dorsal skinespecially anterior to and around the

medial malleolus

Entire sole is sensitive (“ticklish”), especially the thinner-skinned area underlying the arch of the foot.

Ticklish?gargalesis

Neurosci Res. 2010 Dec;68(4):285-9. Neurogenesis in the dentate gyrus of the rat hippocampus enhanced by tickling stimulation with positive emotion.

Thin where it is continuous proximally with the inferior extensor retinaculum.

Over the lateral and posterior aspects of the foot continuous with the plantar fascia, the deep fascia of the sole.

Plantar fascia holds the parts of the foot together, helps protect the sole from injury, and helps support the longitudinal arches of the foot.

2. Deep fascia of the foot & Plantar fascia

Midfoot and forefoot Medial compartment of the sole

Central compartment of the sole

Lateral compartment of the sole

Forefoot 4th compartment interosseous compartment of the foot

Dorsal compartment of the foot5th compartment between dorsal fascia of the foot & tarsal bones & dorsal interosseous fascia of the midfoot and forefoot

3. Compartments by the deep fascia

http://home.comcast.net/~wnor/soleoffoot.htm

Transverse section of the foot: 1, lateral compartment; 2, central compartment; 3, medial compartment; 4, interosseous compartment. Arrows indicate the high-pressure areas that often lead to foot ulceration.

Formed on the posteromedial side of the ankle by: A depression formed by

Medial malleolus of tibia Medial &posterior surfaces of talusInferior surface of sustentaculum tali Medial surface of calcaneus

Overlying flexor retinaculum

4. Tarsal tunnel

Contents from ant. to post. (Tom Dick ANd Harry)•Tibialis posterior tendon •Flexor digitorum longus tendon •Posterior tibial artery •Tibial nerve •Flexor hallucis longus tendon

Attaches above to medial malleolus below to calcaneus

2 compartments on the posterior surface of medial malleolus for tibialis posterior & flexor digitorum longus tendonsLaterally posterior tibial artery ,veins & tibial nerve through tarsal tunnel into sole of footLateral to tibial nerve tendon of flexor hallucis longus

5. Flexor retinaculum

Pulse of posterior tibial artery through flexor retinaculum midway between medial malleolus and calcaneus

Prevent tendon bowing during extension of the foot and toes

Superior extensor retinaculum Superior to the ankle

Attached to anterior borders of the fibula & tibia

Inferior retinaculum Y-shapedAttached to lateral side of calcaneus

6. Extensor retinacula

Extensor digitorum longus & fibularis tertius tendons

Medially Dorsalis pedis artery

Extensor hallucis longus tendon tibialis anterior tendon

pass under extensor retinacula

Bind the tendons of fibularis longus & fibularis brevis

to lateral side of the foot

Superior fibular retinaculum Between lateral malleolus & calcaneus

Inferior fibular retinaculum Attaches to lateral surface of calcaneus around fibular trochlea

7. Fibular (Peroneal) retinacula

A thickening of deep fascia in the sole of the foot

A thick central part Weaker medial and lateral parts

Tougher, denser, and elongated than palmar aponeurosis

Anchored to the medial process of calcaneal tuberosity

Supports the longitudinal arch of the foot & protects deeper structures in the sole

8. Plantar aponeurosis

Flexor digitorum longus, flexor digitorum brevis, & flexor hallucis longus tendons enter fibrous digital sheaths on plantar aspect of digits. Formed by fibrous arches & cruciate (cross-shaped) ligaments Hold the tendons to the bony plane and prevent tendon bowing when the toes are flexed.

9. Fibrous sheaths of toes

Extensor digitorum longus, extensor digitorum brevis, and extensor hallucis longus expand over the proximal phalanges to form complex dorsal digital expansions ("extensor hoods"). Many of the intrinsic muscles of the foot insert here. This allows the forces from these muscles to be distributed over the toes

10. Extensor hoods

to cause flexion of the metatarsophalangeal joints while at the same time extending the interphalangeal joints.

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IN 4 QUESTIONS

MUSCLESOF THE FOOT

20 individual muscles of the foot14 located on the plantar aspect2 on the dorsal aspect4 intermediate in position

Plantar muscles function primarily as a group during the support phase of stance, maintaining the arches of the foot

Few delicate functions compared to hand muscles

Concerned with supporting the arches of the foot

Extensor digitorum brevisAttached to a roughened area on the superolateral surface of the calcaneus lateral to the tarsal sinus

Extensor hallucis brevis The part of the muscle associated with the great toe

Muscles in the dorsum

Deep fibular nerve

Muscles in the soleOrganized into four layers From superficial to deepor plantar to dorsal

First layerMedial to lateralAbductor hallucis Flexor digitorum brevis Abductor digiti minimi

Second layerQuadratus plantae Lumbrical muscles Third layerFlexor hallucis brevis Adductor hallucisFlexor digiti minimi brevis Fourth layer

Dorsal & plantar interossei

Lumbricals

Functions & innervations of the muscles of the foot 1st layerAbductor hallucis

Flexor digitorum brevisAbductor digiti minimi

Medial plantar nerve (S2, S3)

Lateral plantar nerve (S2, S3)

2nd layer

Quadratus plantae

3rd layerFlexor hallucis brevis

Adductor hallucis deep branchFlexor digit minimi brevis superficial branch

4th layer

Plantar interossei (three muscles)Adduct digits (2-4) and flex metatarsophalangeal jointsDorsal interossei (four muscles)Abduct digits (2-4) and flex metatarsophalangeal joints

Assists flexor digitorum longus in flexing lateral four digits

Flex proximal phalanges, extend middle & distal phalanges of lateral four digits

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IN 5 QUESTIONS

ARTERIESOF THE FOOT

Terminal branches of anterior tibial artery & posterior tibial artery dorsalis pedis artery & plantar arteries

Posterior tibial artery in the sole divides into

lateral & medial plantar arteries

Lateral plantar artery +Dorsalis pedis artery Deep plantar arch

Supply of the foot

Lateral plantar arteryMajor branches of the deep plantar archDigital branch to lateral side of little toe 4 plantar metatarsal arteries3 perforating arteries

Medial plantar arteryPasses deep to the abductor hallucisEnds by joining the digital branch of the deep plantar arch Superficial branch

Lateral & medial plantar arteries

Major source of blood supply to forefoot

Continuation of anterior tibial artery

Begins midway between malleoli

Runs deep to inferior extensor retinaculum between extensor hallucis longus & extensor digitorum longus tendons on the dorsum of the foot

Dorsalis pedis artery

Passes inferiorly as deep plantar artery

Joins deep plantar arch in the sole of the foot.

Branches lateral and medial tarsal branches arcuate artery first dorsal metatarsal artery

Dorsalis pedis artery

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IN 2 QUESTIONS

VEINSOF THE FOOT

As in the rest of the lower limb, there are both superficial and deep veins in the foot.

Unlike the leg and thigh, however, the venous drainage of the foot is primarily to the major superficial veins

Dorsal digital veins Dorsal metatarsal veins

Dorsal venous arch of the foot

Dorsal venous network of the foot

Medial side Lateral side

Great saphenous vein

Small saphenous vein

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IN 8 QUESTIONS

NERVESOF THE FOOT

Tibial nerve Deep fibular nerve Superficial fibular nerve Sural nerve Saphenous nerve

Tibial nerve All intrinsic muscles of the foot except for the extensor digitorum brevis, innervated by the deep fibular nerve

Deep fibular nerve often also contributes to innervation of the first and second dorsal interossei.

Enters the foot through tarsal tunnel posterior to medial malleolus

Lateral to posterior tibial artery

Medial calcaneal branches heel

Midway between medial malleolus & heel

large Medial plantar nerve smaller Lateral plantar nerve

Tibial nerve

Compared to lateral plantar nerve, supplies more skin area but fewer muscles.

Its distribution to both skin and muscles of comparable to that of the median nerve in the hand.

Medial plantar nervesLarger & more anterior terminal branch Arises deep to the flexor retinaculum Major sensory nerve in the sole

Skin on most of the anterior two-thirds of the sole and adjacent surfaces of the medial three and one-half toes, which includes the great toe. Four intrinsic muscles- abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and the first lumbrical.

Smaller & more posterior terminal branch

Also courses deep to the abductor hallucis but runs anterolaterally between the 1st and 2nd layers of plantar muscles, on the medial side of the lateral plantar artery.

Ends @ lateral compartment, dividing into superficial and deep branches.

Lateral plantar nerve

Superficial branch Two plantar digital nerves

(one common and one proper)

Skin of the plantar aspects of the lateral one and a half digits, the dorsal skin and nail beds of their distal phalanges, and skin of the sole proximal to them.

Lateral plantar nerve

Passes deep to extensor retinaculum

Enters dorsal aspect of the foot on the lateral side of dorsalis pedis artery.

Muscles on dorsum of the foot

When finally emerges as a cutaneous nerve, so far distal in the foot ;

small area of skin remains available for innervation: web of skin between and contiguous sides of the 1st and 2nd toes

Divides into two dorsal digital nerves

Deep fibular nerve

Emerges as a cutaneous nerve about two thirds of the way down the legSkin on the anterolateral aspect of leg Divides into Medial and intermediate dorsal cutaneous nerves Most of the skin on the dorsum of the foot

Terminal branches Dorsal digital nerves (common & proper) Skin of the proximal aspect of the medial half of the great toe & that of the lateral three and a half digits.

Superficial fibular nerve

Cutaneous branch of tibial nerve Originates high in the leg

Sural nerve formation: Medial sural cutaneous nerve (from the tibial nerve) Sural communicating branch of common fibular nerve

Accompanies small saphenous vein Enters the foot posterior to the lateral malleolus ankle joint & skin on the lateral side of the foot and dorsolateral surface of the little toe.

Sural nerve

• Longest & most widely distributed cutaneous branch of the femoral nerve

•Only branch to extend beyond the knee

•Originates in the thigh

Skin and fascia on the anteromedial aspect of the leg, ankle joint

Skin along the medial side of the foot as far anteriorly as the head of the 1st metatarsal , medial side of the proximal foot

Saphenous nerve

Medially Saphenous nerve distally to the head of 1st metatarsal

Superiorly (dorsum of foot)

Superficial (primarily) Deep fibular nerves

Inferiorly (sole of foot) Medial & lateral plantar nerves

Laterally Sural nerve

Cutaneous innervation of the foot

Posteriorly (heel)Medial & lateral calcaneal branches of tibial & sural nerves, respectively

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LYMPHATIC DRAINAGEOF THE FOOT

Medial superficial lymphatic vesselsmedial side of the dorsum & sole of the foot Accompany great saphenous vein

Lateral superficial lymphatic vessels lateral side of the dorsum & sole of the foot Accompany small saphenous vein

Deep inguinal lymph nodes

Iliac lymph nodes