Understanding Foot Anatomy and Conditions for Injury Prevention

1. Foot Conditions Chapter 19

2. Anatomy

4. Anatomy (Cont’d) • Forefoot • Metatarsals and phalanges; numerous joints • Support and distribute body weight throughout the foot

5. Anatomy (cont.) • Midfoot • Navicular, cuboid, 3 cuneiforms; numerous joints • Talocalcaneonavicular joint (TCN) • Talus moves simultaneously on calcaneus and navicular • Combined action of talonavicular and subtalar joint • Close-packed position—supination

6. Ligaments supporting the midfoot and hindfoot region Anatomy (cont.)

7. Anatomy (cont.) • Hindfoot • Calcaneus and talus • Talocrural joint (ankle joint) • Articulation of talus, tibia, and fibula • Close-packed position—dorsiflexion • Medial ligament—deltoid • Lateral ligament—anterior talofibular; posterior talofibular; calcaneofibular

8. Hindfoot Subtalar joint Behaves as a flexible structure Axis of rotation of the subtalar joint lies oblique in the sagittal and frontal planes Anatomy (cont.)

9. Anatomy (cont.) • Plantar arches • Support and distribute body weight • Longitudinal arch— medial and lateral • Transverse arch • Ligaments • Spring (calcaneonavicular) • Long plantar • Short plantar

10. Anatomy (cont.) • Plantar arches • Plantar fascia

11. Anatomy (cont.) • Muscles • Lateral and medial view

12. Anatomy (cont.) • Muscles • Posterior view

13. Anatomy (cont.) • Muscles • Intrinsic muscles of the foot – dorsal view

14. Anatomy (cont.) • Muscles • Intrinsic muscles of the foot – plantar view

15. Anatomy (cont.) • Nerves • Sciatic nerve • Tibial nerve • Common peroneal nerve — deep and superficial peroneal nerves • Femoral — saphenous

16. Anatomy (cont.) • Blood supply • Femoral artery • Popliteal • Anterior and posterior tibial • Anterior tibial • Dorsal pedal

17. Kinematics • Gait cycle • Consists of alternating periods of single-leg and double-leg support • Requires a set of coordinated, sequential joint actions of the lower extremity

18. Kinematics (cont.) • Motions • Toe — flexion and extension • Ankle (subtalar) — dorsiflexion and plantarflexion • Foot and ankle • Inversion and eversion • Pronation and supination

19. Kinetics • Bones subject to several loading patterns • Running • Foot sustains forces 2–3× body weight • Bones are typically 2–4× strength needed • Repeated forces—stress fractures • Foot deforms during weight bearing • Absorbing a smaller force of longer duration than if it were rigid • Deformation causes storage of mechanical energy in the stretched tendons, ligaments, and plantar fascia

20. Injury Prevention • Physical conditioning • Strengthening • Extrinsic muscles • Intrinsic muscles • Flexibility • Achilles tendon • Footwear • Demands of sport; wear shoe for its intended purpose • Proper fit • Protective equipment • Taping; braces; orthotics

21. Toe and Foot Conditions • Foot Deformities • Pes cavus • High arch and rigid foot • Pes planus • Flatfoot and mobile foot • Associated with common injuries (refer to Box 19.1)

22. Toe and Foot Conditions (cont.) • Toe deformities • Hallux rigidis • Degenerative arthritis in first MTP • S&S • Tender, enlarged first MTP joint • Loss of motion • Difficulty wearing shoes with an elevated heel • Hallmark sign—restricted toe extension • Management: shoe modification

23. Toe and Foot Conditions (cont.) • Toe deformities • Hallux valgus • Thickening of the medial capsule and bursa, resulting in severe valgus deformity of great toe • Asymptomatic or symptomatic • Treatment—symptomatic

24. Toe and Foot Conditions (cont.) • Hammer toe • Extension of MTP joint, flexion at PIP joint, and hyperextended at the DIP joint • Claw toe • Hyperextension of MTP joint and flexion of DIP and PIP joints • Mallet toe • Neutral position at MTP and PIP joints, flexion at DIP joint • Difficult to treat conservatively

26. Toe and Foot Conditions (cont.) • Turf toe • Sprain of the plantar capsular ligament of 1st MTP joint • Mechanism: forced hyperflexion or hyperextension of great toe • Acute or repetitive overload • Valgus ↑ susceptibility • S&S • Pain, point tenderness, and swelling on plantar aspect of MP joint • Extreme pain with extension • Potential for tear in flexor tendons or fracture of sesamoid bones • Management: standard acute; rest; protection from excessive motion

27. Toe and Foot Conditions (cont.) • Ingrown toenail • Preventable with proper hygiene and nail care • Edge of nail grows into lateral nail fold and surrounding skin • Nail margin reddens; painful • Paronychia—fungal or bacterial infection • Management: refer to Application Strategy 19.2

28. Toe and Foot Conditions (cont.) • Metatarsalgia • General discomfort around the metatarsal heads • Constant overloading leads to flattening of transverse arch • Contributing factors—intrinsic and extrinsic (refer to Box 19.2) • Management: activity modification; footwear examination; strengthening exercises

29. Toe and Foot Conditions (cont.) • Bunion • Medial aspect of MTP joint of great toe; lateral aspect of the 5th toe • Thickening of capsule and bursa • Due to constant rubbing against inside of shoe • S&S (as condition worsens) • Lateral shift of great toe • Rigid, nonfunctional hallux valgus deformity • Once deformity occurs, little can be done to correct condition

30. Toe and Foot Conditions (cont.) • Retrocalcaneal bursitis • Due to external pressure—constrictive heel cup, coupled with excessive pronation or varus hindfoot • “Pump bump” • Management: standard acute; shoe modification; AT stretching

31. Foot Contusions • Trauma to the midfoot or forefoot: need to rule out fracture and damage to extensor tendons • Hindfoot—heel bruise • Thick padding of adipose tissue—does not always suffice • Stress in running, jumping, changing directions • S&S • Severe pain in heel • Unable to bear weight • Management: cold; heel cup or doughnut pad • Condition may persist for months

32. Toe and Foot Sprains • IP & MP joints • Sprains of MP and IP joints of the toes may occur by tripping or stubbing the toe • S&S • Pain, dysfunction, immediate swelling • Dislocation—gross deformity • Management—strapping

33. Toe and Foot Sprains (cont.) • Midfoot sprains • Mechanism: severe dorsiflexion, plantarflexion, or pronation • More frequent in activities in which the foot is unsupported • S&S • Pain and swelling is deep on medial aspect of foot • Weight bearing may be too painful • Management: standard acute; limited weight bearing

34. Overuse Conditions • Plantar fasciitis • Extrinsic and intrinsic risk factors • S&S • Pain with first steps in the morning • Point tenderness at medial calcaneal tubercle • ↑ pain with passive extension of great toe and ankle dorsiflexion • ↑ pain with weight bearing • Pain relieved with activity, but recurs after rest • Management: standard acute; refer to Application Strategy 19.4

35. Neurologic Conditions • Plantar interdigital neuroma (Morton’s neuroma) • Trauma or repetitive stress → abnormal pressure on plantar digital nerves • Common—web space between 3rd and 4th metatarsals; less common, between 2nd and 3rd metatarsals

36. Neurologic Conditions (cont.) • S&S • Sensation of having a stone in the shoe that worsens when standing • Tingling or burning, radiating to the toes, along with intermittent symptoms of a sharp shock-like sensation • Pain subsides when activity is stopped or when the shoe is removed; desire to remove the shoe and massage foot—classic sign • Management: metatarsal pad; broad, soft-soled shoe with a low heel

38. Neurologic Conditions (cont.) • Tarsal tunnel syndrome • Posterior tibial nerve (or branch) constricted beneath fibrous roof of foot flexor retinaculum • Often linked to excessive pronation or excessive valgus deformity • S&S • Pain at medial malleolus radiating into sole and heel • Paresthesia, dysesthesia, or hyperesthesia in nerve distribution • + Tinel’s sign • Management: rest; NSAIDs; orthoses; gradual return to activity

40. Foot and Lower Leg Fractures • Repetitive microtraumas → apophyseal or stress fractures • Tensile forces associated with severe ankle sprains → avulsion fractures of 5th metatarsal • Severe twisting → displaced and undisplaced fractures in foot, ankle, or lower leg

41. Foot and Lower Leg Fractures (cont.) • Freiberg's disease • Avascular necrosis of 2nd metatarsal head • Active adolescents ages 14–18 • Sever's disease • Traction-type injury of calcaneal apophysis • Seen in ages 7–10 • S&S • Heel pain with activity • + “squeeze” test • + Sever’s sign • Decreased heel cord flexibility • Management: standard acute; physician referral

42. Foot and Lower Leg Fractures (cont.) • Stress fractures • Often seen in running and jumping, especially after significant ↑ training mileage; change in surface, intensity, or shoe type • Common sites • 2nd metatarsal • Sesamoid bones • Navicular • Calcaneus • Tibia and fibula

43. Foot and Lower Leg Fractures (cont.) • S&S • Pain begins insidiously; ↑ with activity and ↓ with rest • Pain usually limited to fracture site • Pain with percussion, tuning fork, or ultrasound • Management: standard acute; physician referral

45. Foot and Lower Leg Fractures (cont.) • Avulsion fractures • Eversion sprain—deltoid ligament avulses portion of distal medial malleolus • Inversion sprain—plantar aponeurosis or peroneus brevis tendon avulses base of 5th metatarsal (type II) • Jones fracture • Type I transverse fracture into the proximal shaft of 5th metatarsal at junction of diaphysis and metaphysis • Often overlooked in conjunction with a severe ankle sprain • Complications: nonunions and delayed unions are common • Management: standard acute; physician referral

47. Phalanges/ metacarpals Standard S&S Relatively minor Tarsal fractures LisFranc injury Disruption of tarsometatarsal joint, with or without associated fracture Caused by a severe twisting injury Foot and Lower Leg Fractures (cont.)

48. Foot and Lower Leg Fractures (cont.) • 1st metatarsal dislocated from 1st cuneiform; other 4 metatarsals are displaced laterally, usually in combination with fracture at base of 2nd metatarsal • History of severe midfoot pain, paresthesia, or swelling in midfoot region with variable flattening of arch or forefoot abduction

50. Foot and Lower Leg Fractures (cont.) • Lateral process of talus • Due to traumatic ankle sprain • Persistent ankle pain; inability to walk for long periods • Posterior fracture to talus • Forced plantarflexion • Pain with running, jumping; resisted plantarflexion and great toe flexion • Neck of talus • Forced dorsiflexion • May compromise blood supply to talus