Lower Leg, Angle, Foot, and Toes Sports Med

What does the Anterior Talofibular Ligament (ATF) do?

- Connects anterior fibula to talus near sinus tarsi

- Tight in plantarflexion

- Resists inversion in plantarflexion

- Prevents anterior translation of talus on tibia

What does the Calcaneofibular Ligament (CF) do?

- Connects lateral malleolus to calcaneus

- Resists subtalar inversion

What does the Posterior Talofibular Ligament do?

- Connects posterior fibula to talus and calcaneus

- Strongest of the three lateral ankle ligaments

- Prevents posterior translation of talus on tibia

What is the Deltoid Ligament and its function?

- Provides medial ankle support

- Limits eversion

- Restrains lateral rotation and translation of tibia on navicular

What are the 4 bands of the Deltoid Ligament and their functions

- Anterior & Posterior Tibiotalar Ligaments → limit eversion

- Tibiocalcaneal Ligament → limits eversion

- Tibionavicular Ligament → resists lateral rotation & translation of tibia on navicular

What makes the ankle joint stable?

- It is a hinge joint

- Medial & lateral displacement prevented by malleoli

- Ligament arrangement limits inversion & eversion at subtalar joint

- Square shape of talus adds stability

- Most stable in dorsiflexion, least stable in plantar flexion

What is the normal range of motion of the ankle?

- 10° dorsiflexion → 50° plantarflexion

- Normal gait: 10° dorsiflexion & 20° plantarflexion (with knee fully extended)

- Ankle function depends on rearfoot & subtalar joint action

- Critical link in kinetic chain

What are the main functions of the foot and toes?

- Provide diversity in tasks

- Standing → stable platform

- Rigid lever in toe-off

- Shock absorption

- Adaptive structure

What bones make up the foot and toes?

- Tarsals: talus, calcaneus, navicular, 3 cuneiforms, cuboid

- Metatarsals

- Phalanges

- Also has intrinsic and extrinsic muscles

What bones form the rearfoot and what is its function?

- Formed by calcaneus and talus

- Provides stability & shock absorption

- Serves as lever arm for Achilles during plantarflexion

- Calcaneus = largest tarsal bone

What are the functions and components of the midfoot and forefoot?

Midfoot:

- Shock absorber for the foot

- Composed of navicular, 3 cuneiforms, cuboid

Forefoot:

- Formed by 5 metatarsals + 14 phalanges

- Acts as lever during pressing phase of gait

What are the 3 groups of tarsal ligaments?

- Thin dorsal tarsal ligaments

- Relatively thick plantar tarsal ligaments

- Interosseous tarsal ligaments (named for bones they attach to)

What bones and joints make up the subtalar joint?

- Formed by superior calcaneus & inferior talus

- Has 3 articulations

- Tarsal canal crosses obliquely between talus & calcaneus

- Provides 1 degree of freedom (inversion/eversion)

- No muscular attachment to talus

What movements really occur at the subtalar joint?

- Often described as inversion & eversion

- Actually combined movements:

Supination = inversion + adduction + plantarflexion

Pronation = eversion + abduction + dorsiflexion

What joints (and their function) connect the rearfoot to the forefoot?

- Talocalcaneonavicular joint

- Calcaneocuboid joint

- Function: allow load transfer to forefoot during gait

What joints make up the forefoot?

- Tarsometatarsal joint (Lisfranc’s joint): junction between midfoot & forefoot

- 5 MetaTarsals articulate with midfoot bones in a gliding manner

- Proximal & distal intermetatarsal joints: between MT bases & heads

What are the articulations in the forefoot with toes?

- MetaTarsals articulate with toes → flexion, extension, rotation

- All toes (except 1st toe) have 2 interphalangeal joints

What are the two groups of foot muscles?

Intrinsics: 4 layers (superficial, middle, deep, interosseous)

Extrinsics: cross the talocrural and subtalar joints

Which muscles are in the superficial layer of the foot intrinsics?

- Abductor hallucis

- Abductor digiti minimi

- Flexor digitorum brevis

What do the superficial layer muscles do?

- Abductor hallucis: abducts & flexes great toe (1st digit)

- Abductor digiti minimi: abducts & flexes little toe (5th digit)

- Flexor digitorum brevis: flexes lateral 4 toes (at PIP joints)

Which muscles/tendons are in the middle layer of the foot intrinsics?

- Quadratus plantae

- Tendons of flexor hallucis longus (FHL)

- Tendons of flexor digitorum longus (FDL)

What do the middle layer muscles do?

- Quadratus plantae: assists FDL in flexing lateral 4 digits

- FHL tendon: flexes great toe, supports medial arch

- FDL tendon: flexes lateral 4 digits, supports longitudinal arches

Which muscles are in the deep layer of the foot intrinsics?

- Flexor hallucis brevis

- Adductor hallucis

- Flexor digiti minimi brevis

What do the deep layer muscles do?

- Flexor hallucis brevis: flexes proximal phalanx of great toe

- Adductor hallucis: adducts great toe, helps maintain transverse arch

- Flexor digiti minimi brevis: flexes proximal phalanx of 5th digit

Which muscles are in the interosseous layer of the foot intrinsics?

Plantar interossei (3 muscles)

Dorsal interossei (4 muscles)

What do the interossei do?

Plantar interossei (PAD): adduct digits 3–5 toward 2nd toe

Dorsal interossei (DAB): abduct digits 2–4 away from 2nd toe

What are the extrinsic muscles of the foot and what joints do they cross?

- Cross the talocrural and subtalar joints

Include:

- Extensor hallucis longus

- Extensor digitorum longus (toe extension, dorsiflexion)

- Tibialis anterior & posterior

- Peroneals

- Gastrocnemius & soleus

What does the Extensor Digitorum Longus (EDL) do in the foot?

- Extends toes

- Assists in dorsiflexion of ankle

- Provides weak eversion

What does the Flexor Hallucis Longus (FHL) do in the foot?

- Assists in plantar flexion of ankle

- Flexes great toe

- Contributes to adduction and inversion of foot

What does the Flexor Digitorum Longus (FDL) do in the foot?

- Plantar flexes ankle

- Flexes lateral 4 toes

- Inverts foot

What bones form the Medial Longitudinal Arch (MLA)?

- Calcaneus

- Talus

- Navicular

- First cuneiform

- First metatarsal

What supports and stabilizes the Medial Longitudinal Arch (MLA)?

- Spring ligament (calcaneonavicular ligament)

- Plantar fascia (primary support)

- Allows greater movement than other arches

What bones form the Lateral Longitudinal Arch (LLA)?

- Calcaneus

- Cuboid

- Fifth metatarsal

What are the features of the Lateral Longitudinal Arch (LLA)?

- Lower and more rigid than medial arch

- Continuation of medial longitudinal arch

What structures form the Transverse Metatarsal Arch (TMA)?

- Formed by lengths of metatarsals & tarsals

- Shaped by concavity of inferior surface of metatarsals

- 2nd metatarsal = apex of arch

What supports the Transverse Metatarsal Arch (TMA)?

- Intermetatarsal ligaments

- Transverse head of adductor hallucis