Lecture 9 Anatomical Basis of Foot Movement PDF

Anatomical basis of movement of Faculty of Medicine the foot Lecture 10 By the end of this lecture the student will be able to ……. Identify important features and order of arrangement of bones of the foot. Arrange the st...

Anatomical basis of movement of Faculty of Medicine the foot Lecture 10 By the end of this lecture the student will be able to ……. Identify important features and order of arrangement of bones of the foot. Arrange the structures passing deep to the flexor and extensor retinacula. List the names of joints of the foot. Describe the structure of the ankle joint, subtalar and midtarsal joints. Discuss the important ligaments of the ankle, subtalar and midtarsal joints. State the movements permitted at these joints, the muscles producing these movements and their nerve supply. Distinguish the anatomical structures damaged in some of the common injuries of bones and joints of the foot. Bones of the foot The bones of the foot comprise the seven bones of the main part of the foot—the tarsus—together with the five bones of the forefoot—the metatarsals—and 14 bones of the toes—the phalanges.  Right foot superior view The tarsus bones, located distal to the ankle joint, comprise the: Talus 1 5 Calcaneus 2 medial, intermediate and lateral Cuboid 3 Navicular 4 Three cuneiforms (medial, intermediate and lateral). 5 The talus bone 4 Body articulates superiorly (trochlear surface) 3 Neck with the tibia and, to the sides, with the lateral malleolus and medial malleolus. Posteriorly, it presents medial and lateral tubercles Possesses a neck connecting the body to a head Trochlea 1 Head is rounded for articulation distally with the navicular bone Makes three small articulations inferiorly with the calcaneus bone. 2 Medial tubercle Lateral tubercle The calcaneus bone 1 Possesses a long body. Presents a shelf-like projection from the medial side called sustentaculum tali. 7 7 Articulates with the talus bone superiorly Calcaneus Makes an articulation at its anterior surface with the cuboid bone Receives the insertion of the tendocalcaneus (Achilles’ tendon) of superficial flexor muscles on its posterior aspect 6 Has two pronounced medial and lateral tubercles on its undersurface. Navicular bone 2 The three cuneiform bones 4 It intervenes between the Articulate at their posterior aspect with the navicular head of talus and the 3 bone cuneiform bones Articulate anteriorly with the first three metatarsals 5 Its medial side projects Are wedge-shaped so that together they help to downwards forming a maintain a transverse arch. 4 tuberosity which is felt subcutaneously 2.5 cm, in front and below the medial The metatarsal bones 5 The phalanges 6 3 2 malleolus. Are equivalent to the metacarpals of Are shorter and thicker than the hand those in the hand Comprise a base, shaft, and head Possess a base, shaft, and head The cuboid bone 3 7 Articulate anteriorly with the first row Are three in number, except in Articulates with the fourth and of phalanges. the great toe, where there are fifth metatarsals. only two. Right foot 1 inferior view  Right foot medial Ankle joint view The Medial (deltoid) ligament Synovial hinge joint, permitting dorsiflexion and plantar flexion Between upper surface (trochlear surface) of talus and lower ends and malleoli of tibia and fibula Malleoli grip the sides of the talus and restrict abduction and adduction. Its capsule is reinforced by medial (deltoid) and lateral ligaments. The Medial (deltoid) ligament is triangular. It is a very strong ligament. Its apex is attached to the medial malleolus and its lower margin as a continuous attachment from the medial tubercle of the talus along the edge of the sustentaculum tali and spring ligament to the tuberosity of the navicular bone. The Lateral ligament The Lateral ligament consists of 3 separate bands (anterior talofibular, calcaneofibular, posterior talofibular) they radiate from the lateral malleolus to the neck of talus, lateral surface of anterior talofibular calcaneous and lateral tubercle of calcaneus, respectively. It is Right foot lateral weaker than the medial one—most commonly view posterior talofibular damaged in a sprain calcaneofibular Movements of the ankle joint Dorsiflexion (foot points up) Tibialis anterior, Extensor digitorum longus, Extensor hallucis longus, Peroneus tertius Plantar flexion (foot points down) Gastrocnemius, Soleus & Plantaris. Tibialis posterior, Flexor digitorum longus & Flexor hallucis longus Muscles producing Movements of the foot at the ankle joint A- Muscles of the anterior and lateral compartments of the leg 1 1 5 2 3 4 3 2 5 4 6 6  5 1 6 1 5 2 3 3 2 4 6 5 4 5 6  3 B- Muscles of the posterior compartment of the leg 3 Two groups of muscles superficial and deep 1 2 1 4 2 4 1 3 4 4  1 1 1 2 3 2 3 4 Extensor retinacula retain extensor Superior Extensor Retinaculum tendons to dorsum of foot Superior: between anterior borders of lower tibia and fi bula Inferior Extensor Inferior: Y-shaped between Retinaculum calcaneus and medial malleolus, plantar fascia. Flexor retinaculum retains flexor tendons Runs from medial malleolus to calcaneus and plantar fascia Flexor retinaculum Arrangement of Structures deep to the superior extensor retinaculum Tom Has Very Nice Dog From medial to lateral Tibialis anterior Extensor hallucis longus Anterior tibial vessels Poopy Deep peroneal/fibular nerve Extensor digitorum longus Peroneus tertius Arrangement of Structures deep to the Flexor Tom Does Very Nice Hats retinaculum From medial to lateral Tom Drives Very Nice Honda Tibialis Posterior flexor digitorum longus Termination of posterior tibial vessels Termination of tibial nerve Flexor hallucis longus  Joints of the Foot Subtalar joint A compound joint comprising: A posterior synovial plane joint (the talocalcaneal joint) strengthened by the interosseous ligament An anterior synovial ball-and-socket joint (the talocalcaneonavicular joint); strengthened by the plantar calcaneonavicular (‘spring’) ligament calcaneonavicular The curvatures of the two articulating portions of the talus (‘spring’) ligament permit inversion and eversion. Talocalcaneonavicular calcaneonavicular joint (‘spring’) ligament Talocalcaneal joint Mid-tarsal joint A compound joint comprising: Calcaneocuboid joint (a synovial joint) strengthened by the bifurcated ligament The talonavicular articulation of the talocalcaneonavicular joint These also permit a degree of inversion and eversion Other tarsal joints—between the three cuneiform bones; cuneiform bones and the navicular bone; lateral cuneiform and cuboid bones; cuboid and navicular bones—are strengthened by interosseous, plantar and dorsal ligaments. These joints permit very little movement Tarsometatarsal joints—synovial plane Intermetatarsal joints—synovial plane Metatarsophalangeal joints—synovial condylar bifurcated ligament Interphalangeal joints—synovial hinge.  Movements of the joints of the foot Subtalar eversion Peroneus/fibularis longus and brevis superficial peroneal/fibular nerve Peroneus/fibularis tertius muscle deep peroneal/fibular nerve Subtalar inversion Tibialis anterior deep peroneal nerve Tibialis posterior tibial nerve Plantar flexion of toes Flexor hallucis longus tibial nerve and brevis medial plantar nerve Flexor digitorum longus tibial nerve and brevis medial plantar nerve Flexor digiti minimi brevis medial plantar nerve Flexor accessorius medial plantar nerve Extension (dorsiflexion) of toes Extensor hallucis longus deep peroneal nerve Extensor digitorum longus and brevis deep peroneal nerve  Muscles of the foot Dorsum of Sole of the foot the foot Dorsum of the Foot Extensor digitorum brevis The medial tendon is known as extensor hallucis brevis Insertion 4 tendons one For each of medial 4 toes Sole of the Foot The protective plantar aponeurosis extends from calcaneus to the flexor sheaths at the base of the toes plantar aponeurosis  The Muscles And Tendons Of The Sole Are Arranged Into 4 Layers From Below Upwards 1st layer 2nd layer 3rd layer 4th layer Formed of Formed of Formed of Formed of 3 muscles that 2 tendons and 3 muscles that 2 tendons and extend in the distal extend through the whole length of the 2 muscles. half of the sole. 2 muscles. sole 1st layer 3 Formed of muscles that extend through the whole length of the sole Abductor hallucis lying along the medial side of the sole. Action: abduction of the big toe. Abductor digit minimi lying along the lateral side of the sole. Action: abduction of the little toe. Flexor digitorum brevis lying in between the above mentioned 2 muscles. It is inserted by 4 tendons into the middle phalanges of the lateral 4 toes. Each tendon presents a perforation for the passage of a tendon of flexor digitorum longus ms. Action: flexion of the metatarso- phalangeal and proximal inter- phalangeal joints of the lateral 4 toes.  Abductor digit minimi Flexor digitorum brevis Abductor hallucis 2nd layer Formed of 2 tendons and 2 muscles. The 2 tendons are those of Flexor hallucis longus and Flexor digitorum longus. These tendons cross each other in the sole, the tendon of flexor digitorum longus lying superficial to that of flexor hallucis longus. The 2 muscles are  Flexor digitorum accessorius.  4 lumbricals. these muscles are related to the tendon of flexor digitorum longus. The flexor digitorum accessorius is inserted into the tendon of flexor digitorum longus. Action: it assists that tendon in flexion of the interphalangeal and metatarso -phalangeal joints of the lateral 4 toes.  2nd layer The 4 lumbrical muscles take origin from the 4 divisions of the tendon of flexor digitorum longus to be inserted into the dorsal digital expansions of extensor digitorum longus muscle. Action: they flex the metatarso -phalangeal joints and extend the interphalangeal joints of the lateral 4 toes.  Lumbricals Flexor digitorum accessorius 3rd layer Formed of 3 muscles that extend in the distal half of the sole.  Flexor hallucis brevis medially. Action: flexion of the metatarsophalangeal joint of the big toe.  Flexor digiti minimi brevis laterally. Action: it flexes the metatarosphalangeal joint of the little toe.  Adductor hallucis lies inbetween these 2 muscles. It is formed of 2 heads, an oblique head proximally, and a transverse head distally. Action: It adducts the big toe, the transverse head helps in maintaining the transverse arch of the foot. Flexor digiti minimi brevis Flexor hallucis brevis Adductor hallucis Oblique head Transverse head 4th layer Formed of 2 tendons and 2 muscles. The 2 tendons are those of  Tibialis posterior, and Peroneus longus The 2 groups of muscle are the 3 plantar and 4 dorsal interossei. Action: PAD lateral 3 toes (3,4,5) middle 3 toes (2,3,4) Peroneus longus Tibialis posterior  D D D D P P P  ALL the muscles of the sole are supplied by the LATERAL PLANTAR NERVE EXCEPT 4 MUSCLES SUPPLIED BY THE MEDIAL PLANTAR NERVE THE 4 MUSCLES SUPPLIED BY THE MEDIAL PLANTAR NERVE ARE Abductor hallucis. Flexor digitorum brevis. Flexor hallucis brevis. The 1st lumbrical.  Clinical Correlate Pott fracture: The medial (deltoid) ligament is overly stretched during severe foot eversion. The strong medial ligament does not tear, but causes fractures of the medial malleolus (transverse avulsion) and fibula (oblique at the level of the joint).  Arches of the foot The bones of the foot do not lie in a horizontal plane. Instead, they form longitudinal and transverse arches relative to the ground which absorb and distribute downward forces from the medial part of longitudinal arch body during standing and moving on different surfaces Longitudinal arch The longitudinal arch of the foot is formed between the posterior end of the calcaneus and the heads of the metatarsals. It is highest on the medial side where it forms the medial part of lateral part of longitudinal arch the longitudinal arch and lowest on the lateral side where it forms the lateral part. Transverse arch The transverse arch of the foot is formed by the 3 cuneiforms, cuboid and bases of the metatarsal bones Transverse arch Ligament and muscle support of the arches Ligaments and muscles support the arches of the foot: Ligaments that support the arches include the plantar calcaneonavicular (spring ligament), plantar calcaneocuboid (short plantar ligament), and long plantar ligaments, and the plantar aponeurosis; Muscles that provide dynamic support for the arches during walking include the tibialis anterior and posterior, and the peroneus/fibularis longus.  You have flatfeet when the arches on the inside of your feet are flattened, allowing the entire soles of your feet to touch the floor when you stand up. Some people with flatfeet A flat foot is normal in infants and toddlers, because the foot's arch hasn't yet experience foot pain, developed. Most people's arches develop throughout childhood, but some people particularly in the heel or never develop arches. This is a normal variation in foot type, and people without arch area. Pain may arches may or may not have problems. worsen with activity.  Oxford handbook of medical sciences P 310,316-317,319,322-323. References Kaplan step 1 lecture notes: p 211-213 First aid for the basic sciences p 342, 351