PT 500 Foot and Ankle PDF

1 PT 500: Human Anatomy Foot and Ankle 1. Osteology of the Foot and Ankle A. Structure i. Hindfoot 1. Calcaneus a. Calcaneal tuberosity b. Fibular trochlea c. Sust...

1 PT 500: Human Anatomy Foot and Ankle 1. Osteology of the Foot and Ankle A. Structure i. Hindfoot 1. Calcaneus a. Calcaneal tuberosity b. Fibular trochlea c. Sustentatculum tali 2. Talus a. Head and neck b. Body c. Tubercles d. Groove for FHL ii. Midfoot 1. Cuboid a. Groove for FL 2. Navicular a. Tubercle 3. Cuneiforms (3) a. Medial b. Intermediate c. Lateral iii. Forefoot 1. Metatarsals (5) 2. Phalanges iv. Sesamoid Bones 1. Within tendon of FHB 2. Wt bear/ Protect FHL tendon B. Terminology i. A ray is a metatarsal and its related cuneiform, or cuboid (for 4th and 5th MTs) ii. Clinically, a ray is often referred to as including the related phalange as well Section 1  2 Section 1  3 2. Arthrology of the Ankle and Foot A. Talocrural Joint i. Classification 1. Synovial joint, variably classified as a hinge, modified hinge, sellar, uniaxial, or mortise 2. Inferior aspect of tibia and fibula form the mortise into which the trochlea of the talus fits 3. The mortise is wider anteriorly than posteriorly due to the shape of the inferior tibia 4. The medial maleolus is more anterior than the lateral 5. The talus has two articular surfaces for the tibia (superior and medial) and one lateral facet for the fibula ii. Joint capsule 1. The joint capsule runs from the tibia and fibula to the neck of the talus 2. The capsule is thinner anteriorly 3. The ligaments strengthen the capsule medially and laterally Section 1  4 iii. Ligaments Medial Collateral (Deltoid) Ligament Proximal Ligament Attachment Distal Attachment Limits Ant Tibiotalar medial malleolus deep to ant talus eversion & plantarflexion Post Tibiotalar medial malleolus post talus eversion & plantarflexion Tibionavicular medial malleolus navicular eversion & plantarflexion Calcaneus Tibiocalcaneal medial malleolus eversion & plantarflexion (sustentaculum tali) Lateral Collateral Ligament Proximal Ligament Attachment Distal Attachment Limits Ant Talofibular Lateral malleolus ant talus (horizontal) inversion Post Talofibular Lateral malleolus post talus inversion & dorsiflexion Calcaneofibular Lateral malleolus lateral calcaneus inversion & dorsiflexion & PF Section 1  5 iv. Additional Ankle Joint supports (non-ligamentous) 1. Retinacula a. General Description i. Thickenings of crural fascia ii. Provide joint reinforcement iii. Facilitate efficient movement by preventing tendons running under them from bowstringing (hold tendons in appropriate path) b. Components i. Superior and inferior extensor retinacula on dorsal aspect of joint ii. Superior and inferior peroneal (fibular) retinacula on lateral aspect of joint 1. Often torn or stretched in inversion injuries iii. Flexor retinacula on medial aspect of joint 1. Thick fascia 2. Has been implicated in impingement syndromes (tarsal tunnel) 2. Muscles a. Lateral reinforcement i. Peroneus (fibularis) longus and brevis 1. Passing posterior to lateral malleolus 2. Plantar flex and evert ankle b. Dorsal Reinforcement i. Tibialis anterior, extensior hallucis longus, extensor digitorum longus, peroneus tertius 1. Dorsiflex ankle c. Posterior Reinforcement i. Gastrocnemius, Soleus, Plantaris 1. Plantarflex ankle 2. Weakness can result in lack of heel off during gait d. Posterior Medial Reinforcement i. Tibialis posterior, flexor digitorum longus, flexor hallucis longus 1. Plantar flex ankle 2. Medial support Section 1  6 Section 1  7 v. Motions 1. Dorsiflexion a. Trochlea of talus glides posteriorly, malleoli forced apart b. Fibula glides posteriorly and superiorly c. Dorsiflexion with eversion = closed packed position 2. Plantarflexion a. Most unstable position: (10-15 degrees PF = loose packed) vi. Blood and Nerve Supply 1. Malleolar branches of anterior tibial, posterior tibial and fibular arteries 2. Branches of Tibial and Deep Fibular Nerve innervate the talocrural joint Section 1  8 B. Subtalar Joint (Talocalcaneal Joint) i. Classification/Structure 1. Two articulations of talus on calcaneus (planar synovial) a. Large Posterior Facets (anatomical subtalar joint) i. Concave talus, Convex calcaneus b. Anterior i. Head of talus articulates with anterior calcaneus and navicular (TCN joint) 2. Sinus Tarsi a. Space between anterior and posterior talocalcaneal articulation b. Contains Interosseus talocalcaneal ligament Section 2  9 ii. Ligaments 1. Interosseus Talocalcaneal a. In sinus tarsi b. Above sustentaculum tali 2. Cervical Ligament a. Neck of talus to calcaneus (anterolateral to interosseus ligament) i. Limits inversion and possibly extreme eversion 3. Talocalcaneal Ligaments a. Medial b. Lateral c. Posterior 4. Medial and Lateral Collateral Ligaments (see Talocrural Joint) iii. Movements 1. Primarily associated with inversion and eversion a. May comprise as much as 75% of eversion/inversion 2. Due to the oblique axis of the joint, motion is actually a combination of a. Plantar/Dorsiflexion b. Inversion/Eversion c. Adduction/Abduction iv. Neurovascular Supply 1. Talus is covered on most surfaces by articular cartilage, and thus has poor vascular supply a. Can be vulnerable to avascular necrosis in the case of intraarticular fractures Section 2  10 C. Transverse Tarsal Joints i. Talocalcaneonavicular Joint (TCN) 1. Description/Structure a. Head of talus articulates with navicular and sustentaculumm tali b. Synovial Joint c. Spheroidal, Ovoid, Compound, or Multiaxial d. Joint axis is angled superomedially from the A-P axis e. Considered part of “Transverse Tarsal” joint with Calcaneocuboid joint 2. Ligaments a. Planter Calcaneonavicular Ligament (Spring ligament) i. Sustentaculum tali to navicular ii. Limits eversion iii. Strong ligament iv. Contributes to support of longitudinal arch of foot Section 3  11 ii. Calcaneocuboid 1. Structure a. Sellar/Saddle joint b/t anterior Calcaneus and Cuboid i. Moore describes it as planar jt) 2. Ligaments a. Long Plantar Ligament i. Plantar surface of calcaneus to groove on cuboid and bases of MTs ii. Helps maintain longitudinal arch iii. Peroneus longus tendon passes deep to Long and Short plantar ligaments b. Short Plantar Ligament (Plantar Calcaneocuboid) i. Anterior inferior calcaneus to inferior surface of cuboid ii. Helps maintain longitudinal arch c. Dorsal Calcaneocuboid d. Calcaneocuboid portion of bifurcated ligament iii. Motions 1. The Transverse Tarsal joints further contribute to the motions of pronation and supination a. Pronation and supination are compound movements, involving motion of the talocrural, subtalar and Transverse Tarsal joints b. These Motions assist with converting rotational forces to forward propulsion c. Also assist with adaptation to varying surfaces, and shock absorption Pronation Supination Open Chain pronation Open Chain supination Talocrural Dorsiflexion Talocrural plantarflexion Calcaneal eversion Calcaneal Inversion Foot abduction Foot adduction 2. The axes of the TCN and Calcaneocuboid joints are positioned in such a way that when the calcaneus is inverted, the axes cross and the motion in the midfoot is substantially reduced (midfoot locked) 3. When the calcaneus is everted, the axes are parallel and allow freer motion in the midfoot (midfoot unlocked) a. This related to the destabilizing aspect of excessive pronation (or lack of re- supination) during terminal stance in the gait cycle Section 3  12 Modified from Moore, K, 2010 D. Cuneonavicular Joint i. Structure 1. Gliding synovial joints 2. Navicular facet slightly convex 3. One joint capsule for articulation with 3 cuneiform bones ii. Motions 1. Gliding movements in conjunction with Transverse Tarsal motion in pronation and supination E. Cuboideonavicular Joint i. Structure 1. Fibrous syndesmoses 2. Ligaments a. Supported by strong interosseus ligament b. Reinforced by dorsal and plantar cuboideonavicular ligaments ii. Motions 1. Some gliding Section 3  13 F. Tarsometatarsal Joints i. Structure 1. Planar synovial joints 2. Ligaments a. Reinforced by dorsal, plantar and interosseus cuneometatarsal ligaments ii. Motions 1. Invloved in pronation and supination twists of the foot a. Helps keep foot (especially 1st ray) in contact with the floor during hindfoot inversion/eversion 2. Medial tarsometatarsal joint (First Ray) allows more motion a. Contributes to dorsiflexion and plantarflexion in gait 3. Second tarsometatarsal joints (2nd MT and all of the cuneiforms) is strong, only slightly moveable, and prone to injury (March Fractures) 4. Lateral Tarsometatarsal Joint involves MTs 4 and 5 articulating with cuboid G. Intermetatarsal Joints i. Structure 1. Planar, gliding joints 2. Ligaments a. Reinforced b/t MT 2-5 with dorsal, plantar and interosseus ligaments b. Metatarsal ligament is strong and also reinforces the transverse arch ii. Motions 1. Gliding, accessory movement H. Metatarsal Phalangeal Joints i. Structure 1. Ovoid, ellipsoid, or condyloid 2. Ligaments a. Plantar, collateral and deep transverse metatarsal ligaments ii. Motions 1. Flexion/extension 2. Abduction/Adduction 3. Circumduction I. Interphalangeal Joints i. Structure 1. Hinge joints 2. Ligaments a. Medial and Lateral Collateral Ligaments ii. Motions 1. Flexion/Extension Section 3  14 3. Arches of the Foot A. Arches Medial Longitudinal Arch Bones Keystone Supports Posterior Tibialis FHL FDL Calcaneus Tibialis Anterior Abductor Hallucis Talus Plantar Calcaneonavicular Navicular Talus or Talonavicular Joint ligament (Spring) Cuneiforms (3) Common supports with lateral MTs 1-3 arch o Plantar Aponeurosis o Quadratus Plantae muscle o FDB o FIbularis Longus Lateral Longitudinal Arch Bones Keystone Supports Fibularis Brevis Fibularis Tertius Abductor Digiti Minimi Short Plantar Ligament (Plantar calcaneocuboid Calcaneus ligament) Cuboid Cuboid or Calcaneocuboid Joints Long Plantar Ligament MTs 4 and 5 Common supports with medial arch o Plantar Aponeurosis o Quadratus Plantae muscle o FDB o FIbularis Longus Transverse Tarsal Arch Bones Keystone Supports Fibuarlis longus Tibialis Posterior 3 cuneiforms Long Plantar Ligament 2nd Cuneiform cuboid Short Plantar Ligament Spring Ligament Plantar Fascia Transverse Metatarsal Arch Bones Keystone Supports Adductor Hallucis (transverse MT heads 2nd MT head) Intermetatarsal ligaments Section 4  15 B. Characteristics of the Arches i. General Functions 1. Absorb weight a. Shock absorbing in loading phase of gait b. Act as a resilient spring to absorb energy in loading and release energy in terminal stance 2. Allow movement a. Allows the foot to function in shock absorbing and as a rigid lever for propulsion 3. Provide passage for neurovascular structures 4. Weight Bearing a. Body weight is distributed between the calcaneus and the forefoot i. Forefoot contacts include: 1. Medial Forefoot: two sesamoids and head of first MT (carries most of forefoot weight) ii. Lateral Forefoot: Heads of lateral four MTs (provide balance) ii. Shape of the arches is due to: 1. Shape of the bones 2. Plantar Fascia 3. Ligaments 4. Muscular Supports (help keep bones approximated) iii. Muscular Strength is stronger in plantarflexion/inversion than dorsiflexion/eversion, to compensate for the tendency to dorsiflex/evert in stance Modified from: Moore, K. Clinically Oriented Anatomy, 2010 Section 4  16 4. Fascia and Soft Tissues of the Foot A. Dorsal Surface i. Blood Vessels 1. Dorsalis Pedis Artery a. Palpable b/t tendon of tibialis anterior and extensor hallucis longus (medially) and the tendon of extensor digitorum longus to the 2nd digit (laterally) (ie first intermetatarsal space) b. Distal continuation of anterior tibial artery ii. Nerves 1. Superficial Peroneal/Fibular Nerve a. Innervates skin of dorsum of foot 2. Deep Peroneal/Fibular Nerve a. Innervates skin of first interdigital space 3. Sural Nerve a. Innervates skin of lateral aspect of foot iii. Muscles 1. Tendons of Extrinsic Muscles (see leg notes for details) a. Tibialis Anterior b. Extensor Digitorum Longus c. Extensor Hallucis Longus d. Peroneus longus, brevis, and tertius 2. Intrinsic extensors (see chart in anterior leg notes for details) a. Extensor Digitorum Brevis b. Extensor Hallucis Longus Modified from: Moore, K. Clinically Oriented Anatomy, 2010 Section 5  17 B. Plantar Surface i. Skin 1. Epithelium a. Thickened with stratum corneum b. Adapted for increased forces during weight bearing 2. Hypodermis a. Specialized pockets of adipose tissue enclosed in thick, deep, fibrous septae b. Acts as “shock absorber” cushion ii. Deep Fascia (Plantar Fascia/Aponeurosis) 1. Thickened fibrous band inserting on calcaneus 2. Splits anteriorly to insert onto each digit a. Split around digital tendons b. Insert on fibrous digital sheaths 3. Thick vertical septae run dorsally into sole of foot, partitioning it into three compartments a. Medial: Abductor Hallucis, FHB, tendon of FHL, Medal plantar nerves and vessels b. Central: FDB, Tendons of FHL and FDL, Quadratus Plantae, Lumbricals, Adductor Hallucis, Lateral plantar nerve and vessels c. Lateral: Abductor Digiti Minimi, Flexor Digiti Minimi Brevis 4. Acts as tie beam for longtiduinal arches Modified from: Moore, K. Clinically Oriented Anatomy, 2010 Section 5  18 iii. Vascular Supply 1. Terminal Divisions of Posterior Tibial Artery (passes around medial malleolus) a. Medial Plantar Artery b. Lateral Plantar Artery Modified from: Moore, K. Clinically Oriented Anatomy, 2010 iv. Innervation 1. Terminal Divisions of Tibial Nerve (passes around medial malleolus) a. Medial Plantar Nerve b. Lateral Plantar Nerve Section 5  19 Section 5  20 5. Intrinsic Muscles of the Foot 1st Plantar Layer Muscle Origin Insertion Action Innervation Medial tuber calcanei Medial side base of prox abduct great toe Medial Plantar n Abductor Hallucis Flexor retinaculum phalanx great toe flex great toe S2 S3 Plantar aponeurosis Medial tuber calcanei Bothsides of middle Medial Plantar n Flexor Digitorum Brevis Intermuscular septa Flex toes 2-5 Phalanges digits 2-5 S2 S3 Plantar aponeurosis Medial and lateral tuber calcanei Lateral base prox Abduct 5th toe Lateral plantar n Abductor Digiti Minimi Plantar aponeurosis phalanx 5th toe Flex 5th toe S2 S3 Intermuscular septa 2nd Plantar Layer Muscle Origin Insertion Action Innervation assist in flexing Medial and Lateral surf Lateral plantar n Quadratus Plantae tendon of FDL toes 2-5 of Calcaneus S2 S3 (helps align pull) Medial sides of bases Flex MTP 1st = Medial Plantar n Lumbricals Tendons of FDL of prox phalanges 2-5 Extend IP rest= lateral plantar n Extensor expansions S2 S3 FDL tendons FHL tendons Section 6  21 3rd Plantar Layer Muscle Origin Insertion Action Innervation Plantar surf cuboid and Base of prox phalanx Flex prox phalanx Medial Plantar n Flexor Hallucis Brevis lateral cuneiforms great toe (both sides) great toe S1 S2 Flexor Digiti Minimi Brevis base of 5th MT prox phalanx digit 5 Flex prox phalanx 5 Lateral Plantar n S2 S3 Adductor Hallucis Lateral side of base Adduct great toe Deep br lateral plantar n Oblique head Bases MT 2-4 prox phalanx great toe support trans arch S2 S3 Lateral side of base Adduct great toe Deep br lateral plantar n Transverse head Plantar lig of MTP jts prox phalanx great toe support trans arch S2 S3 Tibialis Posterior Tendon Peroneus Longus tendon 4th Plantar Layer Muscle Origin Insertion Action Innervation Plantar Plantar aspect of medial Medial sides of bases Adduct digits Interosseus Lateral plantar sides MT 3-5 prox phalanges 3-5 Flex MTP 3 (PAD) n (S2 S3) Medial (1st) and Abduct digits 2-4 Dorsal Interosseus Adjacent sides of Lateral (2-4) prox Flex MTP Lateral plantar 4 (DAB) shaftsMT's 1-5 n (S2 S3) phalanges Section 6