MSS Wk 12 L Leg & Foot PDF

MD1020 MSS Wk 12 L Musculoskeletal Anatomy of the Leg, Ankle & Foot A/Prof Kate Domett Questions to the Piazza Learning Outcomes: Lower Limb 1. 2. 3. 4. 5. 6. 7. 8. 9. Describe the osteology of the pelvis, femur, tibia, fibula and foot. Demonstrate their palpable and imaging landmarks. Demonstr...

MD1020 MSS Wk 12 L Musculoskeletal Anatomy of the Leg, Ankle & Foot A/Prof Kate Domett Questions to the Piazza Learning Outcomes: Lower Limb 1. 2. 3. 4. 5. 6. 7. 8. 9. Describe the osteology of the pelvis, femur, tibia, fibula and foot. Demonstrate their palpable and imaging landmarks. Demonstrate the origin, course and branches of the major arteries that supply the gluteal region, hip, thigh, leg, ankle and foot. Explain the functional significance of anastomoses between branches of these arteries at the knee. Demonstrate the locations at which the femoral, popliteal, posterior tibial and dorsalis pedis arterial pulses can be palpated. Demonstrate the course of the principle veins of the lower limb. Outline the origin of the lumbosacral plexus and the formation of its major branches Describe the origin, course and function of the femoral, obturator, sciatic, tibial, common fibular, sural and saphenous nerves and summarise the muscles and muscle groups that each supplies, as well as their sensory distribution. Describe the fascial compartments enclosing the major muscle groups and explain the importance of these compartments and their contents in relation to compartment syndrome. Describe the anatomical bases (nerve root or peripheral nerve) for loss of movements and reflexes at the knee and ankle resulting from spinal injuries, disc lesions and common peripheral nerve injuries. Describe the dermatomes of the lower limb that can be used to assess spinal injuries. Interpret standard diagnostic images, e.g. X-ray, MRI, CT of the lower limb to recognize major anatomical bones and bony landmarks in normal anatomy. 2 Learning Outcomes: Week 12 1. Describe the anatomy of the ankle and subtalar joints. Explain the movements of plantarflexion, dorsiflexion, inversion and eversion. Summarise the muscles responsible for these movements, their innervation and their attachments. 2. Name the contents of the tarsal tunnel. 3. Describe the factors responsible for the stability of the ankle joint, especially the lateral ligaments and explain the anatomical basis of ‘sprain’ injuries. 4. Briefly describe the arches of the foot and the bony, ligamentous and muscular factors that maintain them. 5. Explain the movements of the toes and summarise the extrinsic muscles responsible for these movements, their innervation and their attachments. 3 Bones Calcaneus Talus Cuboid Tibia Navicular Medial cuneiform Fibula Lateral cuneiform Intermediate cuneiform Metatarsals Phalanges Ankle joint •Talo-crural joint •articulation between the superior surface of the talus (trochlea) and the distal end of the tibia and fibula Ankle joint: Talo-crural joint •Hinge joint •Dorsiflexion •Plantarflexion Ankle Joint Gastrocnemius 1. COG anterior 2. Ankle in dorsiflexion Soleus (stable) 3. Contraction of triceps surae (gastrocnemius + soleus) Lateral view Ankle joint - stability • Weight of body on • Tibia and fibula held very small area together by ligaments Dorsiflexed position Plantarflexed position Superior view Posterior view Ankle joint ligaments Posterior talofibular ligament 1. Lateral Ligament •Calcaneofibular ligament •Talofibular ligaments • prevents the bones spreading apart • anterior and posterior NOTE: it is the anterior talofibular ligament that is most commonly sprained. Posterior talofibular ligament Anterior talofibular ligament Ankle joint - ligaments 2. Medial – Deltoid ligament •Four components •Don’t worry about learning individual components LL Cross section Summary Info: Leg Anterior compartment Lateral compartment Dorsiflexors Toe extensors Deep fibular nerve Subtalar evertors Superficial fibular nerve Plantarflexors Toe flexors Tibial nerve 11 Dorsiflexion (talocrural joint) •Anterior compartment muscles – Tibialis anterior –Inserts into medial cuneiform and base of MT1 Tibialis anterior – Extrinsic toe extensors can assist •Innervated by the deep fibular nerve Anterior view Plantarflexion (talocrural joint) Gastrocnemius •Posterior compartment Tibialis posterior –Triceps surae: – Gastrocnemius – Soleus Soleus –Tibialis posterior –Inserts into navicular and medial cuneiform –Extrinsic toe flexors can assist Calcaneal tendon •Innervated by the tibial nerve Posterior view (superficial) Lateral view Posterior view (deep) Dorsiflexion & Plantarflexion of the ankle joint Tibialis anterior Triceps surae Lateral view Intertarsal joints 1. Subtalar joint: 2. Transverse tarsal joint Talus and calcaneus - Talocalcaneonavicular joint (med) + calcaneocuboid joint (lat) Inversion and Eversion •Mvt of subtalar and transverse tarsal jts •Inversion • Turning the whole sole of the foot inward (medially) •Eversion • Turning the whole sole of the foot outward (laterally) Eversion •Lateral compartment muscles Fibularis brevis –Fibularis longus –Inserts into medial cuneiform and base of MT1 –Fibularis brevis –Inserts into base of MT5 (lateral) Fibularis longus •Superficial fibular nerve Fibularis longus Fibularis brevis Lateral view Inversion Combined contraction of: Tibialis anterior & Tibialis posterior Tibialis anterior Tibialis anterior: medial cuneiform and base of MT1 Medial view Tibialis posterior Tibialis posterior: navicular and medial cuneiform Anterior view Posterior view Eversion & Inversion of the subtalar joint Fibularis longus Tibialis anterior Fibularis longus and brevis Tibialis posterior Fibularis longus Tibialis anterior Tibialis posterior Anteriolateral view Posterior view Medial view Other Joints of the Foot •Tarsometatarsal •plane •Metatarsophalangeal •condyloid •Proximal interphalangeal •hinge •Distal interphalangeal •hinge Extrinsic Toe Extensors Toe extension occurs at the metatarsophalangeal joints and at the interphalangeal joints - Anterior compartment ms of leg - Deep fibular nerve Hallucis = Big Toe Extensor digitorum longus Extensor hallucis longus Anterior view Extrinsic Toe Flexors Toe flexion is occurring at the metatarsophalangeal joints and at the interphalangeal joints Flexor digitorum longus Flexor hallucis longus Hallucis = Big Toe Posterior view Flexion and Extension of the Toes Flexor hallucis longus Extensor digitorum longus and hallucis longus Lateral view Flexor digitorum longus Posterior view Tarsal tunnel (medial) structures from posterior compartment Tibialis posterior tendon Flexor Digitorum longus tendon Posterior tibial artery & veins Tibial nerve Flexor Hallucis longus tendon Tom, Dick & Harry Arches of the foot Medial longitudinal •Longitudinal •Medial •Lateral •Transverse •Maintained by bones, ligaments and muscles Lateral longitudinal Transverse Arch Support Also known as the ‘spring’ ligament – helps maintain the longitudinal arch Plantar calcaneonavicular ligament Medial View Plantar aponeurosis Dorsal View Arch Support Tibialis anterior & tibialis posterior tendons Fibularis longus tendon Plantar aponeurosis •Deep fascia of foot •DFCT •Protects plantar surface •Holds parts of foot together •Helps support longitudinal arches Plantar view LL Cross section Summary Info: Leg Anterior compartment Lateral compartment Dorsiflexors Toe extensors Deep fibular nerve Subtalar evertors Superficial fibular nerve Plantarflexors Toe flexors Tibial nerve 29