Anatomy of the Foot Quiz

Chapter 19: Ankle Joint and Foot

• Chapter covers the anatomy, function, and pathologies of the leg, ankle, and foot
• Chapter objectives include describing the leg, ankle, and foot; identifying osteokinematic and arthrokinematic movements, normal end feels, bones/landmarks, ligaments/unique structures; and the effects of active/passive insufficiency on range of motion (ROM)

Function of Leg, Ankle, and Foot

• Transmission of forces from body to support surface and vice versa
• Base of support (BOS)
• Ability to accommodate various support surfaces, including irregular ones.
• Plantigrade position: plantar surface of foot is perpendicular to the leg when standing (normal)

Ankle Joint and Foot Anatomy

• Ankle Joint:
  • Talocrural joint (made up of the tibia, talus, and fibula)
• Foot:
  • Hindfoot, midfoot, forefoot (including phalanges) and regions of foot
    • Forefoot: metatarsals (5), phalanges (14)
    • Midfoot: cuboid, navicular, three cuneiform bones
    • Hindfoot: talus, calcaneus

Ankle and Foot Joints

• All joints are synovial joints
• Distal tibiofibular joint
• Ankle joint = talocrural joint (talus/tibia/fibula)
• Subtalar joint = Talocalcaneal joint (Hind Foot)
• Transverse Tarsal (Midtarsal) joint = Talonavicular and Calcaneocuboid joints
• Intertarsal Joints: 10 (between talus, calcaneus, navicular, cuboid, and cuneiforms)
• Tarsometatarsals: 5
• Intermetatarsals: 8
• Metatarsophalangeal: 5
• Interphalangeal: 9

Osteokinematic Motions

• Anatomists use cardinal planes to describe movements
• Clinicians use oblique axis of motion to describe movements
• Descriptions of ankle movements are used by clinicians

Movements

• Plantar flexion (0-50)/dorsiflexion (0-20) (sagittal plane, frontal axis)
• Inversion (0-35)/eversion (0-15) (frontal plane in sagittal axis)
• Adduction/abduction – movement of forefoot toward/away from midline (transverse plane in vertical axis)
• Triplanar Motions: Supination (PF, INV, and ADD); Pronation (DF, EV, and ABD)

Arthrokinematic Motions

• Open Kinetic Chain:
  • Dorsiflexion: Convex surface of talus rolls anteriorly and glides posteriorly on concave surface of tibia
  • Plantar flexion: Convex surface of talus rolls posteriorly and glides anteriorly on concave surface of tibia
• Closed Kinetic Chain: Concave moving on convex = same direction
• Ankle end feel = firm all directions
• Talocrural: Close-packed = full dorsiflexion (DF); Open-packed = 10 degrees of plantar flexion (PF); Capsular pattern = PF > DF
• Movement between bones of foot (talus, calcaneus, navicular, cuboid, three cuneiforms, tarsometatarsal, intermetatarsal joints) is minimal and planar
• End feel = firm all directions

Movements (Foot Motion)

• Metatarsophalangeal joint (MTP): Flexion/extension, abduction/adduction
• Interphalangeal joints (PIP/DIP/IP): Flexion/extension

Metatarsophalangeal Joint (MTP)

• Condyloid joint with two degrees of freedom
• Flexion/extension (sagittal plane about frontal axis)
• Abduction/adduction (transverse plane about vertical axis)
• Reference point is second metatarsal
• Open chain = concave on convex; Flexion = roll/glide inferiorly; Extension = roll/glide superiorly
• Closed chain = convex on concave; Extension = roll superior, glide inferior
• Abduction/adduction: open chain = concave on convex, roll/glide same direction as motion relative to second metatarsal

Interphalangeal (IP) Joints

• Hinge joint with one degree of freedom
• Flexion/extension in a sagittal plane about a frontal axis
• Concave on convex – same direction roll/glide

Bones and Landmarks

• Tibia: Medial condyle, lateral condyle, crest, medial/lateral plateau, tibial tuberosity, interosseous membrane, medial malleolus
• Fibula: Head, lateral malleolus
• Tarsals (7): Calcaneus (calcaneal tuberosity, sustentaculum tali), Talus, Navicular (navicular tuberosity), Cuboid, Cuneiforms (3)
• Metatarsals (5): Base, head
• Phalanges (14): Base, head

Joints – Tibiofibular

• Superior Tibiofibular joint: Synovial plane joint; little motion
• Inferior Tibiofibular joint: Synovial; makes up talocrural joint; convex distal fibula and concave distal tibia; held together by fibrous ligaments; slight motion; tibia is weight-bearing

Joints – Talocrural

• Uniaxial weight-bearing hinge joint
• “Horseshoe” or “mortise and tenon” (talotibial, talofibular, tibiofibular joints)

Joints – Hind Foot/Subtalar

• Plane synovial joint
• Inversion / eversion and part of supination/pronation

Joints – Hindfoot Positions

• Neutral, Valgus (WB load into arch/medial foot), Varus (WB load onto lateral foot)

Joints – Transverse Tarsal

• Synovial “midtarsal” joint
• Talus and calcaneus to navicular and cuboid; separation of hindfoot and midfoot
• Accommodate to surfaces; gliding motions

Midfoot

• Includes remaining intertarsal joints: talocalcaneonavicular, calcaneocuboid, cuneonavicular, cuboideonavicular, intercuneiform, and cuneocuboid
• Synovial plane joints; minimal motion: roll and glide
• Numerous ligaments support joints and limit motion

Joints – Foot – MTP, IPS

• Metatarsophalangeal joints (MTP = 5)
• Proximal interphalangeal joints (PIP = 4)
• Distal interphalangeal joints (DIP = 4)
• Interphalangeal joint (1)

Functional Aspects of the Foot

• Forefoot (metatarsals [5], phalanges [14]): Adapts to ground; assists with propulsion
• Midfoot (navicular, cuboid, cuneiform [3]): Provides mobility and stability; adapts to ground
• Hindfoot (talus, calcaneus): Contacts ground first; influences gait

Unique Structures of the Foot (Arches)

• Arches (3): Medial longitudinal (Talus = keystone), Lateral longitudinal (Cuboid = keystone), Transverse (Middle cuneiform = keystone)
• Arches supported by ligaments, fascia, and muscles

Support Structures of the Foot and Arches

• Diagrams show the 1st and 5th metatarsals and the calcaneus

Ligaments (Tibiofibular)

• Anterior Tibiofibular ligament
• Posterior Tibiofibular ligament
• Calcaneofibular ligament

Ligaments (Medial Ankle)

• Deltoid ligament (4 parts):
  • Tibionavicular lig
  • Tibiocalcaneal lig
  • Anterior Tibiotalar lig
  • Posterior Tibiotalar lig
• Stabilize medially including medial arch
• Very stable

Ligaments (Medial Foot)

• Spring ligament (plantar calcaneonavicular lig) - Maintains medial longitudinal arch
• Long Plantar Ligament - Maintains lateral arch
• Short Plantar Ligament -Helps support Long Plantar ligament

Ligaments (Lateral Ankle)

• Lateral “collateral” ligament (3 parts):
  • Anterior talofibular
  • Calcaneofibular
  • Posterior talofibular
• Commonly injured – Inversion sprain
• Ant. Talofibular, calcaneofibular, Posterior talofibular

Ligaments (Plantar Surface)

• Plantar ligaments and aponeurosis
• Spring ligament (medial support)
• Long plantar ligament (lateral support)
• Short plantar ligament (support long plantar lig)
• Plantar aponeurosis (fascia)

Plantar Fascia

• Anterior plantar surface of calcaneus to proximal phalanges
• Supports longitudinal arches
• Increases foot stability during weight-bearing

Role of Plantar Fascia (Windlass Effect)

• PF and MTP Ext
• Increase fascial tension
• Locks bones of arch in place
• Creates rigid foot; Push-off

Muscles (Extrinsic muscles of the leg, ankle, and foot)

• Superficial posterior group:
• Gastrocnemius: plantar flexion, knee flexion
• Soleus: plantar flexion
• Plantaris: plantar flexion, knee flexion
• Deep posterior group:
• Tibialis posterior: plantar flexion, inversion
• Flexor digitorum longus: MTP and IP flexion, plantar flexion, inversion
• Flexor hallucis longus: MTP and IP great toe flexion, plantar flexion, inversion
• Anterior Group:
• Tibialis anterior: dorsiflexion, inversion
• Extensor hallucis longus: MTP and IP great toe extension, dorsiflexion, inversion
• Extensor digitorum longus: MTP and IP of four lesser toes extension, dorsiflexion
• Lateral Group:
• Fibularis longus: eversion, plantar flexion
• Fibularis brevis: eversion, plantar flexion
• Fibularis tertius: eversion, dorsiflexion

Muscles (Intrinsic muscles on plantar surface)

• Four layered intrinsic muscles
• First layer: Abductor hallucis, Flexor digitorum brevis, Abductor digiti minimi
• Second layer: Quadratus plantae, Lumbricals
• Third layer: Flexor hallucis brevis, Adductor hallucis
• Fourth layer: Dorsal interossei, Plantar interossei

Muscles of the Ankle and Foot

• Diagrams show anatomical relations to other structures
• Tables/graphics show innervation and actions of the bones

Dermatomes

• Diagrams showing root levels and peripheral nerve (skin) innervation.

Common Ankle Pathologies

• Shin splints: inflammation of periosteum of tibia, overuse injury
• Ankle sprain (lateral – often inversion sprain; medial)
• Calcaneal (Achilles) tendonitis: inflammation of calcaneal tendon
• Ruptured calcaneal tendon
• Ankle fracture (lateral malleolus, bi-malleolar, tri-malleolar)
• Calcaneal valgus/varus
• Equinus foot: hindfoot fixed in PF
• Calcaneal foot: hindfoot fixed in DF
• Pes cavus: High medial longitudinal arch
• Pes planus: Flat medial longitudinal arch
• Hallux valgus: Lateral deviation of great toe
• Hallux rigidus: Degenerative condition of the first MTP joint
• MTP pain; loss of range of motion
• Hammer toe: PIPs flexed and DIPs extended
• Mallet toe: PIPs extended and DIPs flexed
• Claw toe: PIP and DIPs both flexed
• Metatarsalgia: pain at metatarsal heads; Morton's neuroma: between 3rd and 4th metatarsals, plantar digital nerves, pain with WB
• Turf toe: force hyperextension of the great toe MTP
• Plantar fasciitis: overuse injury, pain in heel during weight-bearing
• Fractures: toes and metatarsals

Test your knowledge on the anatomy and function of the foot with this quiz focused on joints, ligaments, and movements. Answer questions about the subtalar joint, midfoot function, and more. Perfect for students of anatomy and physical therapy!