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THE FOOT Lorcan Toner ltoner10@qub.ac.ukLearning Objectives ■ Identify and describe the boundaries and contents of the tarsal tunnel ■ Identify the extensor digitorum brevis and extensor hallucis brevis muscles and describe the innervation and actions of these muscles ■ Iand actions of these muscles (4 layers)ct of the foot and describe the innervationTHE TARSAL TUNNELThe Tarsal T unnel - Borders ■ Acts as a passageway, on the posteromedial aspect of ankle ■ Borders: – Floor: concave – formed by calcaneuspect of tibia, talus + – obliquely between medialm, spans malleolus + medial tubercle of calcaneus, forming the tunnel ■ The flexor retinaculum is continuous with the deep fascia of the leg and footThe Tarsal T unnel - Contents ■ From anterior to posterior: – Tibialis posterior tendon – Flexor igitorum longus tendon – Posterior tibial rtery and ein – Tibial erve – Flexor allucis longus tendon ■ Tom, ick and a Very ervous Harry ■ Tunnel divided into 4 compartments: the other 3 containing the tendonsdTarsal T unnel Syndrome ■ Entrapment and compression of the ■ Management: tibial nerve as it passes through the – Conservative: physiotherapy, tarsal tunnel NSAIDs, corticosteroid injections ■ Symptoms: – Sensory: altered sensation – Surgical: tarsal tunnel release along sensory distribution of tibial nerve – the sole of foot – Motor: (in severe cases) weakness and wasting of intrinsic foot musclesINTRINSIC MUSCLES OF THE FOOTDorsum of the Foot Extensor Digitorum Brevis Extensor Hallucis Brevis The extensor digitorum brevis muscle lies deep to the The extensor hallucis brevis muscle is medial to extensor tendon of the extensor digitorum longus digitorum longus and lateral to extensor hallucis longus ■ Attachments : ■ Attachments : – Originates from the calcaneus, the – Originates from the calcaneus, the interosseous talocalcaneal ligament and the interosseous talocalcaneal ligament and the proximal phalanx of the great toe and thes to the base of the proximal phalanx of the great long extensor tendons of toes 2-4 toe ■ Actions: ■ Actions: – extending the medial four toes at then – extending the great toe at thegus in metatarsophalangeal and interphalangeal metatarsophalangeal joint joints ■ Innervation: Deep fibular nerve ■ Innervatio: Deep fibular nerve Intrinsic muscles of dorsum of foot are both innervated by deep fibular nervePlantar Aspect of the Foot ■ 10 intrinsic muscles in sole of foot – Collectively stabilise the arches + individually control movement of digits ■ All muscles are innervated by the medial plantar nerve or the lateral plantar nerve – Both are branches of the tibial nerve ■ The muscles are organised into 4 layers which will be described from superficial to deep1 Layer • This layer is most superficial to the sole • Located immediately underneath plantar fascia • 3 muscles in this layer Abductor Hallucis Flexor Digitorum Brevis ■ The abductor hallucis muscle is located on the ■ The flexor digitorum brevis muscle is medial side of the sole, where it contributes to a located laterally to the abductor hallucis. It sits in small soft tissue bulge the centre of the sole, sandwiched between the ■ Attachments: digitorum longussis and the tendons of flexor – Originates from the medial tubercle of the ■ Attachments : plantar aponeurosis. It attaches to thehe – Originates from the medial tubercle of the medial base of the proximal phalanx of the calcaneus and the plantar aponeurosis. It great toe attaches to the middle phalanges of the lateral four digits. ■ Action: – Abducts and flexes the great toe ■ Actions: – Flexes the lateral four digits at the proximal ■ Innervatio: Medial plantar nerve interphalangeal joints. ■ Innervatio: Medial plantar nerve. st 1 Layer – cont. Abductor Digiti Minimi ■ The abductor digiti minimi muscle is located on the lateral side of the foot. It is homologous with the abductor digiti minimi of the hand ■ Attachments: – Originates from the medial and lateral tubercles of the calcaneus and the plantar aponeurosis. It attaches to the lateral base of the proximal phalanx of the 5th digit ■ Action: – Abducts and flexes the 5th digit ■ Innervatio: Lateral plantar nerve2 Layer • Contains 2 muscles • The tendons of flexor digitorum longus (FDL) and flexor hallucis longus (FHL) (extrinsic muscles) pass through this layer Quadratus Plantae ■ Lumbricals ■ There are four lumbrical muscles in the foot. They ■ The quadratus plantae muscle is located superior are each located medial to their respective tendon separated from the first layer of muscles by the of the flexor digitorum longus. lateral plantar vessels and nerve. ■ Attachments: ■ Attachments: – Originates from the tendons of flexor – Originates from the medial and lateral digitorum longus. Attaches to the extensor plantar surface of the calcaneus. It attaches hoods of the lateral four digits. to the tendons of flexor digitorum longus. ■ Action: ■ Action: – Flexes at the metatarsophalangeal joints, – Assists flexor digitorum longus in flexing the while extending the interphalangeal joints. lateral four digits. ■ Innervatio: The most medial lumbrical is ■ Innervati: Lateral plantar nerve. innervated by the medial plantar nerve. The remaining three are innervated by the lateral plantar nerve Neurovascular Structures : • Medial and lateral plantar arteries nd 2 Layer3rd Layer • Contains 3 muscles Flexor Hallucis Brevis Adductor Hallucis ■ The flexor hallucis brevis muscle is located on the ■ The adductor hallucis muscle is located laterally to medial side of the foot. It originates from two places the flexor hallucis brevis. It consists of an oblique on the sole of the foot and transverse head ■ Attachments : ■ Attachments: – Originates from the plantar surfaces of the – The oblique head originates from the bases tendon of the posterior tibialis tendon.the transverse head originates from the plantar Attaches to the base of the proximal phalanx ligaments of the metatarsophalangeal of the great toe joints. Both heads attach to the lateral base of the proximal phalanx of the great toe ■ Actions: – Flexes the proximal phalanx of the great toe ■ Action: at the metatarsophalangeal joint – Adduct the great toe. Assists in forming the transverse arch of the foot ■ Innervatio: Medial plantar nerve ■ Innervatio: Deep branch of lateral plantar nerve rd 3 Layer - cont. Flexor Digiti Minimi Brevis ■ The flexor digiti minimi brevis muscle is located on the lateral side of the foot, underneath the metatarsal of the little toe. It resembles the interossei in structure ■ Attachments: – Originates from the base of the fifth metatarsal. Attaches to the base of the proximal phalanx of the fifth digit ■ Actions: – Flexes the proximal phalanx of the fifth digit ■ Innervatio: Superficial branch of lateral plantar nerve4 Layer • Consists of dorsal and plantar interossei • Plantar interossei = unipennate, dorsal interossei = bipennate • Peroneus longus + tibialis posterior tendons travel through this layer via fibro-osseus tunnels to their insertion points Plantar Interossei Dorsal Interossei ■ There are three plantar interossei, which are ■ There are four dorsal interossei, which are located located between the metatarsals. Each arises from between the metatarsals. Each arises from two a single metatarsal metatarsals. ■ Attachments: ■ Attachments : – Originates from the medial side of – Originates from the sides of metatarsals metatarsals three to five. Attaches to the one to five. The first muscle attaches to the medial sides of the phalanges of digits three medial side of the proximal phalanx of the to five attach to the lateral sides of the proximalei ■ Action: phalanxes of digits two to four. – Adduct digits three to five and flex the ■ Actions: metatarsophalangeal joints – Abduct digits two to four and flex the ■ Innervatio: Lateral plantar nerve metatarsophalangeal joints ■ Innervatio: Lateral plantar nerve th 4 Layer – cont.Medial Plantar Nerve Entrapment ■ The medial plantar nerve can become compressed and irritated as it passes deep to theductor hallucis muscle ■ This can cause aching, numbness and paraesthesia on the medial side of the sole of the foot. The muscle can become compressed during repetitive eversionof the foot, which may occur in some sports such as gymnasticsMCQ 1: What nerve is compressed in tarsal tunnel syndrome? A. Saphenous nerve B. Superficial fibular nerve C. Deep fibular nerve D. Tibial nerveMCQ 1: What nerve is compressed in tarsal tunnel syndrome? A. Sural nerve B. Superficial fibular nerve C. Deep fibular nerve D. Tibial nerveMCQ 2: In what layer of the plantar aspect of the foot does the medial and lateral plantar arteries travel? A. Layer 1 B. Layer 2 C. Layer 3 D. Layer 4MCQ 2: In what layer of the plantar aspect of the foot does the medial and lateral plantar arteries travel? A. Layer 1 B. Layer 2 C. Layer 3 D. Layer 4THANK YOU!