Foot and Ankle + Nerve and Arterial supply to lower limb Flashcards
What are the four compartments of the lower leg?
Anterior compartment
Posterior compartment (superficial and deep)
Lateral compartment
Divided by: Interosseous membrane, intermuscular septa, deep fascia attached to tibia.
What are the muscles of the anterior compartment, their innervation, and actions?
Tibialis Anterior: Dorsiflexion, inversion, medial arch support.
Extensor Hallucis Longus: Extends great toe, dorsiflexion.
Extensor Digitorum Longus: Extends lateral four toes, dorsiflexion.
Peroneus Tertius: Dorsiflexion, eversion.
Innervation: Deep Peroneal Nerve (L4-S1).
What is the clinical relevance of the anterior compartment?
Compartment Syndrome: Increased pressure in the compartment affects circulation.
Foot Drop: Weak dorsiflexors lead to difficulty lifting the foot during walking.
Name the muscles in the superficial posterior compartment, their innervation, and actions.
Muscles: Gastrocnemius, Soleus, Plantaris.
Innervation: Tibial Nerve (S1-S2).
Actions: Plantarflexion (all), knee flexion (Gastrocnemius, Plantaris).
What are the muscles in the deep posterior compartment, their innervation, and actions?
Popliteus: Stabilizes and unlocks knee joint.
Flexor Hallucis Longus: Flexes great toe, plantarflexion.
Flexor Digitorum Longus: Flexes lateral four toes, plantarflexion.
Tibialis Posterior: Inversion, plantarflexion, medial arch support.
Innervation: Tibial Nerve (L4-S3).
What are the muscles of the lateral compartment, their innervation, and actions?
Peroneus Longus: Eversion, plantarflexion, supports arches.
Peroneus Brevis: Eversion.
Innervation: Superficial Peroneal Nerve (L5-S2).
What are the intrinsic muscles on the dorsum of the foot?
Extensor Digitorum Brevis: Extends toes II-IV.
Innervation: Deep Peroneal Nerve (S1-S2).
What are the contents of the tarsal tunnel?
Tibialis Posterior.
Flexor Digitorum Longus.
Tibial Artery and Vein.
Tibial Nerve.
Flexor Hallucis Longus.
Mnemonic: “Tom, Dick, and Bloody Nervous Harry.”
What supports the longitudinal arch of the foot?
Ligaments: Plantar calcaneonavicular (spring ligament), long plantar ligament, short plantar ligament, plantar aponeurosis.
Muscles: Tibialis anterior/posterior, Flexor Hallucis Longus, Abductor Hallucis, Flexor Digitorum Brevis.
What supports the transverse arch of the foot?
Ligaments: Plantar calcaneonavicular ligament, plantar aponeurosis.
Muscles: Peroneus Longus.
What is the clinical relevance of the plantar aponeurosis?
Plantar Fasciopathy: Inflammation or degeneration of the plantar fascia, leading to heel pain.
What is the role of the Flexor Hallucis Longus in foot function?
Flexes the great toe.
Contributes to plantarflexion at the ankle joint.
What is the function of the Peroneus Longus muscle?
Eversion and plantarflexion of the foot.
Supports the transverse and longitudinal arches.
What are the attachments and actions of the Tibialis Posterior?
Proximal Attachment: Posterior tibia, fibula, interosseous membrane.
Distal Attachment: Navicular tuberosity, medial cuneiform.
Action: Inversion, plantarflexion, medial arch support.
What are the actions of the Popliteus muscle?
Stabilizes the knee joint.
Unlocks the knee by laterally rotating the femur on the fixed tibia.
What are the components of the lumbar plexus?
Formed by anterior rami of L1 to L3 and most of L4 (with a contribution from T12).
Main nerves:
Iliohypogastric
Ilioinguinal
Genitofemoral
Lateral cutaneous nerve of the thigh
Femoral nerve
Obturator nerve.
What are the components of the sacral plexus?
Formed by anterior rami of S1 to S4 and the lumbosacral trunk (L4-L5).
Main nerves:
Sciatic nerve
Superior gluteal nerve
Inferior gluteal nerve
Nerves to obturator internus, superior gemellus, quadratus femoris, and inferior gemellus.
Posterior femoral cutaneous nerve.
Nerve to piriformis.
What are dermatomes?
Dermatomes are areas of skin innervated by the sensory fibers of a single spinal nerve root.
Describe the femoral nerve.
Origin: Anterior rami of L2-L4.
Innervation:
Motor: Iliacus, pectineus, sartorius, quadriceps femoris.
Sensory: Anterior thigh and medial leg (via saphenous nerve).
Describe the obturator nerve.
Origin: Anterior rami of L2-L4.
Innervation:
Motor: Obturator externus, adductor longus, adductor brevis, gracilis, and part of adductor magnus.
Sensory: Medial thigh.
What is the largest nerve in the body, and what are its branches?
Sciatic nerve (L4-S3).
Branches: Common peroneal nerve, tibial nerve.
What are the functions of the sciatic nerve?
Motor: Posterior thigh, part of adductor magnus, all muscles in the leg and foot.
Sensory: Skin on lateral leg, lateral foot, sole of the foot.
Describe the tibial nerve.
Motor: Posterior leg and foot muscles, except for short head of biceps femoris.
Sensory: Skin on posterolateral leg, lateral foot, sole of the foot.
Path: Descends through popliteal fossa and posterior leg into the sole of the foot.
Describe the common peroneal nerve.
Motor: Short head of biceps femoris, anterior and lateral leg compartments, extensor digitorum brevis, first two dorsal interossei.
Sensory: Lateral leg, dorsal foot.
Branches: Deep and superficial peroneal nerves.
What does the superior gluteal nerve innervate?
Origin: L4-S1.
Innervation: Gluteus medius, gluteus minimus, tensor fascia lata.
What does the inferior gluteal nerve innervate?
Origin: L5-S2.
Innervation: Gluteus maximus.
What is the function of the sural nerve?
Sensory innervation to the lateral lower leg and foot.
Formed by branches of tibial and common peroneal nerves.
What arteries supply the lower limb?
Femoral artery: Continuation of external iliac artery.
Popliteal artery: Continuation of femoral artery, divides into anterior and posterior tibial arteries.
Posterior tibial artery: Supplies posterior leg and plantar foot.
Anterior tibial artery: Supplies anterior leg and dorsum of the foot.
Dorsalis pedis artery: Continuation of anterior tibial artery.
Where can you palpate the major lower limb arteries?
Femoral artery: In the femoral triangle, below the inguinal ligament.
Popliteal artery: Deep in the popliteal fossa, near midline.
Posterior tibial artery: Posterior to medial malleolus.
Dorsalis pedis artery: Dorsal foot, between tendons of extensor hallucis longus and extensor digitorum longus.
