Foot and Ankle Anatomy PDF

XY2141. ANATOMY. FOOT AND ANKLE Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected]с.u k  LEARNING OUTCOMES ANAT.36 - Foot/Ankle ANAT.36.01 - Identify and describe the bones (and bony features) of the ankle joint an...

XY2141. ANATOMY. FOOT AND ANKLE Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected]с.u k  LEARNING OUTCOMES ANAT.36 - Foot/Ankle ANAT.36.01 - Identify and describe the bones (and bony features) of the ankle joint and foot. ANAT.36.02 - Identify and describe the major joints of the ankle and foot. Discuss the actions of the each joint. ANAT.36.03 - Summarize the compartments of the foot and discuss the muscles and their actions within each compartment. ANAT.36.04 - Review the course and distribution of the main neurovascular structures of the ankle and foot. ANAT.36.05 - Discuss the function of ligaments associated with the ankle joint and foot (joints) ANAT.36.06 - Describe the anatomy of the arches of the foot. ANAT.36.07 - Discuss the tarsal tunnel and the relationship of neurovascular structures that pass through it. ANAT.36.08 - Apply your anatomical knowledge to clinical problems associated with the ankle and foot, as discussed (e.g. Potts fracture, ankle sprains, foot amputations, plantar fasciitis).  BONES OF THE FOOT – OSSA PEDIS Bones of the foot consist of 7 tarsal bones, 5 metatarsal bones and 14 phalanges. General organisation of the metatarsals and phalanges of the foot is similar to the organisation of the metacarpals and phalanges of the hand.  TARSAL BONES (OSSA TARSI) These are short bones which together form tarsus. These are arranged in three rows: a) Proximal row consists of talus and calcaneus. b) Middle row consists of navicular. c) Distal row consists of three cuneiforms (medial, intermediate, and lateral) and cuboid.  TARSAL BONES (OSSA TARSI) 1. Talus – ankle bone 2. Calcaneus – heel bone 3. Navicular (os naviculare) 4. Medial cuneiform (os cuneiforme mediale) 5. Intermediate cuneiform (os cuneiforme intermedium) 6. Lateral cuneiform (os cuneiforme laterale) 7. Cuboid (os cuboideum).  BONES OF THE FOOT – OSSA PEDIS Mnemonic  IDENTIFICATION OF BONES IN THE SKELETON OF THE FOOT Calcaneus (heel bone) - largest and most proximal bone. Talus - second largest bone and lies above the calcaneus like a rider, hence highest bone in the skeleton of foot. Navicular - boat-shaped and lies in front of the head of talus. Cuboid - cubical in shape in front of the lateral part of calcaneum. Cuneiforms - small wedge-shaped bones and arranged from side to side in front of navicular. 360° ROTATION OF THE BONES OF THE FOOT  METATARSALS (OSSA METATARSI) Five miniature long bones, that together constitute the metatarsus. They are numbered from medial to lateral sides as first, second, third, fourth, and fifth. Each metatarsal consists of three parts: distal end (head), shaft (body), proximal end (base).  BONES OF THE FOOT – OSSA PEDIS Tarsal bones form the longitudinal and transverse arch of the foot. Longitundinal arch is divided into a medial and lateral arch. Arches of the foot protect the soft tissue of the foot and function as a spring, converting elastic energy into kinetic energy during gait.  THE FOOT (PLANTAR AND DORSAL VIEWS). A) PLANTAR VIEW. B) DORSAL VIEW. Arches are fully developed by the 3rd year of life, at which point the foot is in contact with the ground in three spots: calcaneal tuberosity, head of the 1st metatarsal bone, head of the 5th metatarsal bone.  CLINICAL CORRELATION – PES PLANUS, FLAT FEET, FALLEN ARCHES Pes planus (flat foot, or fallen arches) is a relatively common foot deformity that refers to the loss of the medial longitudinal arch of the foot, resulting in this region of the foot coming closer to the ground or making contact with the contacting the ground. Dysfunction of the arch complex is usually asymptomatic but can alter the biomechanics of the lower limbs and lumbar spine causing an increased risk of pain and injury. Etiology: congenital or acquired. Risk factors: Hypermobility of joints Weight gain (above average BMI) Muscle weakness and tightness, tendon injury Poor fitness Arthritis Repetitive high-impact activities (e.g., running, soccer) in adults with congenital pes planus Posttraumatic Secondary to disorders such as Marfan syndrome, Ehlers-Danos syndrome, and Down syndrome.  PHALANGES (OSSA DIGITORUM) – BONES OF THE TOES Phalangeal bones are miniature long bones. They are 14 in number in each foot - two for the great toe and three for each of the other four toes. I toe (great or big toe) has 2 phalanges – proximal and distal; All other toes have 3 phalanges – proximal, middle and distal.  JOINTS OF THE FOOT Joints of the foot comprise a functional unit that produces foot movements necessary for ambulation. 1. Ankle joint (articulatio talocruralis) 2. Subtalar/talocalcaneal joint (articulatio subtalaris/talocalcanea) 3. Talocalcaneonavicular joint (articulatio talocalcaneonavicularis) 4. Calcaneocuboid joint (articulatio calcaneocuboidea) 5. Cuneonavicular joint (articulatio cuneonavicularis) 6. Cuneocuboid joint (articulatio cuneocuboidea) 7. Intercuneiform joints (articulationes intercuneiformes) 8. Tarsometatarsal joints (articulationes tarsometatarsales) 9. Intermetatarsal joints (articulationes intermetatarsales) 10. Metatarsophalangeal joints (articulationes metatarsophalangeae) 11. Interphalangeal joints of foot (articulationes interphalangeae pedis)  JOINTS OF THE FOOT Functional joints: 12. Chopart’s joint – transverse tarsal joint 13. Lisfranc’s joint – tarsometatarsal and intermetatarsal joints  ANKLE JOINT (ARTICULATIO TALOCRURALIS) Type: compound joint of 3 articulating bones: talus, tibia, fibula Shape: trochlear 1. Proximal articular surface is formed by the articular facets of the: a) Lower end of tibia including its medial malleolus. b) Lateral malleolus. c) Inferior transverse tibiofibular ligament. These three together form a deep tibiofibular socket (also called “tibiofibular (ankle) mortise”). 2. Distal articular surface is formed by the: articular facets on the upper, medial, and lateral aspects of the body of the talus. ANKLE JOINT (ARTICULATIO TALOCRURALIS)  ANKLE JOINT (ARTICULATIO TALOCRURALIS) 5. Capsule is attached to the circumference of the articular surfaces, provides support 6. Collateral ligaments: 6.1 Medial/deltoid collateral ligament (ligamentum collaterale mediale / ligamentum deltoideum) – a triangular ligament composed of 4 parts: 6.1.1 Anterior tibiotalar part 6.1.2 Posterior tibiotalar part 6.1.3 Tibionavicular part 6.1.4 Tibiocalcaneal part MEDIAL / DELTOID COLLATERAL LIGAMENT  ANKLE JOINT (ARTICULATIO TALOCRURALIS) 6.2 Lateral collateral ligament (l. collaterale laterale) a complex of 3 independent ligaments 6.2.1 Anterior talofibular ligament 6.2.2 Posterior talofibular ligament 6.2.3 Calcaneofibular ligament LATERAL COLLATERAL LIGAMENT  ANKLE JOINT (ARTICULATIO TALOCRURALIS) 7. Movements: 7.1 Plantar flexion: 0–50° 7.2 Dorsiflexion: 0–20° 8. Middle position: corresponds to the anatomical position *All other joints of the foot is a part of your self-study.  POTT’S FRACTURE (FRACTURE DISLOCATION OF THE ANKLE) A common fracture–dislocation of the ankle (Pott’s fracture) occurs when the foot is forcibly everted. 1. Lateral malleolus fractures, 2. Tearing of the medial collateral ligament; 3. Posterior margin of the lower tibia shears off against the talus. Three stages are referred to as first-, second- and third-degree Pott’s fractures.  ANKLE SPRAINS Supination injury: excessive inversion of the ankle joint Typically injures the anterior talofibular ligament and other lateral ligaments (calcaneofibilar, posterior talofibular) The anterior inferior tibiofibular ligament is most commonly involved in high ankle sprains. Pronation injury: excessive eversion of the ankle joint causes a sprain of the medial deltoid ligament In supination injuries, the Anterior TaloFibular ligament Always Tears First. The most common cause of an ankle sprain is a forceful inversion of the ankle that damages the lateral ligament.  MUSCLES OF THE FOOT Muscles acting on the foot can be divided into two distinct groups: extrinsic and intrinsic muscles. Extrinsic muscles arise from the anterior, posterior, and lateral compartments of the leg. They are mainly responsible for actions such as eversion, inversion, plantarflexion, and dorsiflexion of the foot. Intrinsic muscles are located within the foot and are responsible for the fine motor actions of the foot, for example, movement of individual digits. We shall examine the anatomy of the intrinsic muscles of the foot. They can be divided into those situated on the dorsum of the foot, and those in the sole of the foot.  MUSCLES OF DORSAL FOOT There are two intrinsic muscles located within the dorsum of the foot – the extensor digitorum brevis and extensor hallucis brevis. Function: extension the toes Both are innervated by the deep fibular nerve. MUSCLES OF PLANTAR FOOT, LAYER 1 MUSCLES OF PLANTAR FOOT, LAYER 2 MUSCLES OF PLANTAR FOOT, LAYER 3 MUSCLES OF PLANTAR FOOT, LAYER 4  ARTERIAL SUPPLY TO THE FOOT Arterial supply to the foot is delivered via two arteries: Dorsalis pedis – dorsal artery of the foot (continuation of the anterior tibial artery) Posterior tibial artery.  ARTERIAL SUPPLY TO THE FOOT Dorsum of the foot Dorsalis pedis artery - continuation of the anterior tibial artery beyond the ankle joint Course Travels in the 1st intermetatarsal space, lateral to the tendon of the extensor hallucis longus Passes through the 1st dorsal interosseus muscle and enters the sole Ends by anastomosing with the lateral plantar artery and giving off the 1st dorsal metatarsal artery Dorsalis pedis artery is often aberrant or absent. Branches Tarsal arteries Arcuate artery: gives rise to the lateral 3 dorsal metatarsal arteries, from which the digital arteries arise  ARTERIAL SUPPLY TO THE FOOT Sole of the foot Branches of the posterior tibial artery Medial plantar branch: supplies the medial side of the sole Lateral plantar branch: supplies the lateral side of the sole and anastomosis with the dorsalis pedis Plantar arterial arch Formed by the anastomosis between the dorsalis pedis and lateral plantar arteries Located on the plantar aspect of the bases of the lateral 4 metatarsal bones Branches: 4 plantar metatarsal arteries  VEINS OF THE FOOT Veins of the foot Superficial veins Dorsal venous arch of the foot Lies on the dorsal aspect of the heads of the lateral four metatarsal bones Tributaries: Dorsal digital veins unite to form dorsal metatarsal veins that drain into the dorsal venous arch. Termination: continues as the medial and lateral marginal veins Marginal veins Medial marginal vein continues as the long saphenous vein Lateral marginal vein continues as the short saphenous vein  VEINS OF THE FOOT Deep veins Plantar venous arch of the foot Lies on the plantar aspect of the lateral four metatarsal bones Tributaries: Plantar digital veins unite to form metatarsal veins that drain into the deep plantar venous arch. Termination: continues as the medial and lateral plantar veins Medial and lateral plantar veins: drain into the posterior tibial vein  NERVES OF THE FOOT Foot is supplied by the tibial, deep fibular, superficial fibular, sural, and saphenous nerves: All five nerves contribute to cutaneous or general sensory innervation. Tibial nerve innervates all intrinsic muscles of the foot except for the extensor digitorum brevis, which is innervated by the deep fibular nerve. Midway between the medial malleolus and the heel, the tibial nerve bifurcates into: large medial plantar nerve, smaller lateral plantar nerve Deep fibular nerve often also contributes to the innervation of the first and second dorsal interossei.  FLEXOR RETUNACULUM Flexor retinaculum is a thick broad band of the deep fascia (2.5 cm broad) on the medial side of the ankle, behind and below the medial malleolus. It holds the long tendons, vessels, and nerves in position as they curve and pass forward from the back of the leg to the sole of the foot.  TARSAL TUNNEL/CANAL – CANALIS MALLEOLARIS Tarsal tunnel/canal is a topographical space in the medial retromalleolar space located behind the medial malleolus. Its contents are covered by the flexor retinaculum.  TARSAL TUNNEL Its contents (anterior to posterior) are: Tibialis posterior tendon Flexor digitorum longus tendon Posterior tibial artery and vein Tibial nerve Flexor hallucis longus tendon Mnemonic: Tom, Dick and a Very Nervous Harry  TARSAL TUNNEL SYNDROME Tarsal tunnel syndrome is an entrapment syndrome of the tibial nerve where it passes behind the medial malleolus through the tarsal canal (canalis malleolaris). Patients may experience altered sensation in the sensory distribution of the tibial nerve – the sole of the foot (burning pain, tingling, and numbness in the foot, which worsens with prolonged standing or walking) Motor function of the nerve can also be affected in severe disease, causing weakness and wasting of the intrinsic foot muscles.  TARSAL TUNNEL SYNDROME TREATMENT: can be conservative or surgical: Conservative: Physiotherapy, NSAIDs, corticosteroid injections Surgical: Tarsal tunnel release (cutting through the flexor retinaculum to decompress the tunnel).  PLANTAR APONEUROSIS Plantar aponeurosis is a flat band of CT that supports the arch of the sole of the foot. It runs from the calcaneal tuberosity to the base of the toes.  PLANTAR FASCIITIS Inflammation of plantar aponeurosis characterized by heel pain (worse with first steps in the morning or after period of inactivity) and tenderness. Associated with obesity, prolonged standing or jumping (eg, dancers, runners), and flat feet. Heel spurs often coexist.  AMPUTATIONS Amputation - is the surgical or traumatic severance of a body part. Indications Gangrene (e.g., due to diabetes mellitus, bacterial infection such as Clostridium perfringens, or peripheral arterial disease) Infection (e.g., osteomyelitis) Malignancy (e.g., osteosarcoma) Irreparable trauma injury (e.g., comminuted fracture of a limb) Severely burned limbs Compartment syndrome Severe contractures Congenital anomalies Severe thermal and/or electrical injury REFERENCES