Chapter 18: The Foot
Overview
Sports injuries occur frequently to the foot. The complicated anatomy requires a great deal of strength, flexibility, and coordinated movement. Complaints about foot injuries by athletes call for careful physical examination.
Common acute injuries are heel and instep bruises, arch strains, and sprains of the midfoot, forefoot, and great toe. Fractures can occur to all areas of the foot.
In addition to therapy modalities, the use of rehabilitative exercise is important for managing foot conditions.
Understanding foot biomechanics is essential to help fully understand chronic and overuse stress injuries in the foot, ankle, and lower leg. There must also be an understanding of the foot, ankle, and lower leg as part of a linkage system.
Chronic and overuse foot conditions can lead to stress problems in the lower extremities. Common chronic problems occur to the arches of the foot, toes, and forefoot. The bunion, a common chronic condition, occurs when the great toe becomes deflected laterally. Metatarsalgia also is a chronic condition of the forefoot. Other problems include deformities such as hammer or clawed toes, bony outgrowths, heel bursitis, heel spurs, tendinitis, and stress fractures.
The coach and athletic trainer should be well aware of potential foot problems and should be capable of identifying, ameliorating, or preventing them whenever possible.
Introduction:
A. The function of the foot is critical in running, jumping and changing directions
B. The foot must act as a shock absorber to dissipate ground reaction forces, and must act as a rigid lever to propel the body forward, backward or to the side
C. Due to its complex nature, recognition and management of the foot presents a challenge to the athletic trainer
I. Foot Anatomy
1. Bones
a. Foot consists of 26 bones: 14 phalangeal, 5 metatarsal and 7 tarsal, also 2 sesamoid bones beneath the first metatarsal
b. Toes
1. Designed to give wider base for balance and for propelling the body forward
2. First toe has 2 phalanges the remaining toes have 3
3. Sesamoids under the first metatarsal (in the flexor hallucis tendon) assist with reducing pressure in weight bearing, increase the mechanical advantage of the flexor tendons of the great toe, act as sliding pulleys for tendons
c. Metatarsals
1. Five bones that lie between and articulate with the tarsals and the phalanges
2. Ligamentous arrangement gives elasticity to the foot in weight bearing
3. MTP joints permit hinge action of phalanges
4. First metatarsal functions as the main weight bearing support during walking and running
d. Tarsal Bones
1. Calcaneous
A. Largest tarsal bone; supports the talus and shapes the heel
B. Main functions: convey the body weight to the ground and serves as attachment of Achilles Tendon and plantar structures
2. Talus
A. Situated above the calcaneous; consists of the body, neck and head
B. Trochlea articulates with the medial and lateral malleoli to form the ankle joint
C. Dorsiflexion is limited due to talus being narrower posteriorly than anteriorly
3. Navicular
A. Anterior to the talus on the medial aspect of the foot
B. Articulates with the three cuneiform bones
4. Cuboid
A. On the lateral aspect of the foot
B. Articulates posteriorly with the calcaneous and anteriorly with the fourth and fifth metatarsals
5. Cuneiforms
A. Three cuneiforms located between the navicular and the base of the three metatarsals on the medial aspect of the foot
2. Arches of the Foot: Arches provide support in weight bearing, absorb shock, and provide space on plantar surface of blood vessels, nerves, and muscles
a. Anterior Metatarsal Arch
1. Shaped by the distal heads of the metatarsals
b. Transverse Arch
1. Extends across the cuboid, and the internal cuneiform
2. Protects the soft tissue and increases foot mobility
c. Medial Longitudinal Arch
1. Originates on medial border of the calcaneous and extends forward to the distal head of the first metatarsal
2. Main supporting ligament = plantar calcaneonavicular ligament (spring ligament)
3. Tendon of the posterior tibialis muscle helps to support the plantar calcaneonavicular ligament
d. Lateral Longitudinal Arch
1. On outer aspect of the foot, formed by the calcaneous, cuboid and fifth metatarsal bone
3. Plantar Fascia (Plantar Aponeurosis)
a. Thick white band of fibrous tissue originates on the medial tubercle of the calcaneous and ends at the proximal heads of the metatarsals
b. Supports the foot against downward forces
4. Articulations
a. Interphalangeal Joint
1. Designed for flexion and extension
2. Reinforced by collateral ligaments
b. Metatarsophalangeal Joint
1. Condyloid type joints permitting flexion, extension, adduction and abduction
c. Intermetatarsal Joint
1. Sliding joints: include two sets of articulations
d. Tarsometatarsal Joint
1. Formed by junction of the bases of the metatarsal bones with the cuboid and all three cuneiforms – allows for some gliding
2. Also known as the Lisfranc’s joint
e. Subtalar Joint
1. Articulation between the talus and calcaneous
2. Allows for inversion, eversion, pronation, and supination
3. In weight bearing pronation refers to combined movement of talar plantarflexion and adduction and calcaneal eversion
4. In weight bearing supination refers to combined movement of talar dorsiflexion, abduction and calcaneal inversion
f. Midtarsal Joint
1. Consists of the calcaneocuboid and the talonavicular joint
2. Directly related to the subtalar joint – if subtalar joint is pronated, the midtarsal joints become hypermobile, if supinated then the midtarsal joint is hypomobile
5. Muscles and Movement
a. Dorsiflexion: tibialis anterior, extensor digitorum longus, extensor hallucis longus and peroneus tertius
b. Plantarflexion: Gastrocnemius, soleus, plantaris, peroneus longus, peroneus brevis, tibialis posterior, flexor hallucis longus and flexor digitorum longus
c. Inversion, Adduction and Supination: Tibialis posterior, flexor digitorum longus, flexor hallucis longus, tibialis anterior and extensor hallucis longus
d. Eversion, Abduction and Pronation: Peroneus longus, peroneus brevis, peroneus tertius and extensor digitorum longus
e. Hallucis muscles move the great toe
f. Digitorum muscles move digits 2-5
g. Movements of Phalanges
1. Flexion of second, third, fourth and fifth distal phalanges: flexor digitorum longus and quadratus plantar
2. Flexion of middle phalanges: flexor digitorum brevis
3. Flexion of proximal phalanges: lumbricales and the interossei
4. Flexion of great toe: flexor hallucis longus
5. Extension of middle phalange: abductor hallucis and abductor digiti quanti, lumbricales and interossei
6. Extension of distal phalanges: Extensor digitorum longus, extensor hallucis longus and extensor digitorum brevis
6. Nerve Supply and Blood Supply
a. Tibial nerve supplies the muscles on the back of the leg and the plantar aspect of the foot
b. Common peroneal nerve supplies the front of the leg and the foot
7. Blood Supply
a. Major portion of blood is supplied by the anterior and posterior tibial arteries
2. Structural Deformities
3. Excessive Pronation
a. Prolonged pronation one of major causes of stress injuries
b. In pronated foot cuboid loses its mechanical advantage as a pulley and the peroneus longus tendon no longer stabilizes the first ray effectively
c. Prolonged pronation does not allow the subtalar joint to resupinate, thus there is less power for push-off
d. Injuries occurring from excessive pronation include: stress fractures of the second metatarsal, plantar fasciitis, posterior tibial tendonitis, achilles tendonitis, tibial stress syndrome and medial knee pain
4. Excessive Supination
a. Excessive supination at heel strike does not allow subtalar joint to unlock – foot remains rigid
b. Cuboid becomes hypomobile – increasing tension on the peroneus longus tendon
c. Foot cannot absorb ground reaction forces efficiently
d. Injuries seen include: inversion ankle sprains, tibial stress syndrome, peroneal tendonitis, IT band friction syndrome and trochanteric bursitis
II. Prevention of Foot Injuries
1. Selecting Appropriate Footwear
a. Pronators need stability and firmness to reduce excess motion (need board lasted, straight lasted shoe, with good rearfoot control)
b. Supinators need cushioning and flexibility as foot is too rigid (need slip lasted or combination lasted, curve lasted shoe)
III. Foot Assessment
1. Obtain a thorough history
2. Observation
3. Look for structural Deformities (bunions, check for forefoot varus/valgus deformities, check for rearfoot varus/valgus deformities, flexibility of first ray)
4. Look at shoe wear patterns
a. pronators wear out the front of the shoe under the second metatarsal, supinators wear out the outside of the shoe. All have excessive wear on the lateral heel due to heel strike
5. Palpation of bony and soft tissue structures
6. Pulses (posterior tibial and dorsalis pedis arteries)
7. Special Tests
a. Tinel’s sign: tap over the posterior tibial nerve – numbness, tingling and paresthesia may indicate tarsal tunnel syndrome
b. Morton’s Test: Transverse pressure on metatarsal heads causing sharp pain in forefoot, may indicate presence of neuroma or metatarsalgia
8. Neurological Assessment
a. Check reflexes (achilles = S1) and cutaneous distribution
IV. Recognition and Management of Specific Injuries
1. Injuries to the Tarsal Region
a. Fractures of the Talus
b. Fractures of the Calcaneous
c. Calcaneal Stress Fracture
d. Sever’s Disease (Apophysitis of the Calcaneous)
e. Retrocalcaneal Bursitis
f. Heel Contusion
g. Cuboid Subluxation
h. Tarsal Tunnel Syndrome
i. Lisfranc Injury (Tarsometatarsal Fracture/Dislocation)
2. Injuries to the Metatarsal Region
a. Pes Planus Foot
b. Pes Cavus Foot
c. Longitudinal Arch Strain
d. Plantar Fasciitis
e. Jones Fracture
f. Metatarsal Stress Fracture
g. Hallux Valgus Deformity (Bunion) and Tailor’s Bunions (Bunionettes)
h. Sesamoiditis
i. Metatarsalgia
j. Metatarsal Arch Strain
k. Morton’s Neuroma
3. Injuries to the Toes
a. Sprained Toes
b. Turf Toe
c. Fractures and Dislocations of Phalanges
d. Morton’s Toe
e. Hallux Rigidus
f. Hammertoe, Mallet Toe or Claw Toe
g. Overlapping Toes
h. Subungual Hematoma (blood under toenail)