Week 13 Anatomy - Knee and Lower Limb Myo/Dermatomes Flashcards
What type of joint is the knee?
Synovial hinge joint
What are the roles of ligaments in knee stability?
Lateral and medial collateral ligaments prevent lateral movement of femur on tibia
Anterior cruciate prevents tibia sliding anterior relative to the femur.
Posterior cruciate prevents tibia sliding posteriorly in relation to the femur
Describe blood supply to the knee?
Genicular anastomosis from genicular branches of the femoral, popliteal, anterior and posterior recurrent branches of the anterior tabla recurrent and circumflex fibular arteries
What is the broad sensory innervation of the knee?
Anterior = femoral nerve
Posterior = tibial nerve
Lateral = common fibular
Medial/articular surface = obturator and saphenous nerve
What is the cruciate anastomosis, and what is its function?
Four way meeting of medial and lateral circumflex femoral arteries with inferior gluteal artery superiorly and first perforating artery inferiorly, anatomically situated around the proximal femur.
Allows blood to flow from internal iliac/inferior gluteal artery into the leg if there is a blockage of the femoral artery
What are the GASP bursae of the knee, which communicate with the synovial cavity of the knee?
Gastrocnemius
Anserine
Suprapatella
Popliteus
What are the borders of the popliteal fossa?
Supero-lateral = biceps femoris
Supero-medial = Semimembranosus
Infero-lateral = lateral head gastrocnemius
Inferomedial = medial head gastrocnemius
Floor = synovial membrane of knee joint
Roof = skin + fascia
What two nerves form from the the sciatic nerve?
Tibial nerve
Common fibular nerve
(Formed when the sciatic nerve divides in posterior compartment of the thigh)
Describe contents of the popliteal fossa: (Medial to lateral)
**Serve and volley next ball
Termination of small saphenous vein
Popliteal artery and vein
Tibial nerve
Posterior cutaneous nerve of thigh and sural cutaneous nerves
Popliteal lymph nodes and lymphatic vessels
What are the muscles that make up the quadriceps group, and what are their actions?
What nerve innervates them?
Rectus femoris: AIIS to patella
Vastus lateralis: Greater trochanter to patella
Vastus intermedius: Anterior femur to patella
Vastus medius: Intertrochanteric line to patella
Act to extend knee, innervated by femoral nerve (anterior compartment of thigh)
What are the muscles of the posterior thigh, their common origin, actions, and innervation?
Semitendinosus: “T for Top”
Semimembranosus:
Biceps Femoris:
Common origin = ischial tuberosity (all except short head biceps, which originate from linea aspera femur)
Innervation = sciatic nerve (tibial division L5-S2)
Action is extension of hip, flexion of knee.
What are the muscles of the anterior compartment of the leg, and their actions?
Tibialis anterior: From lateral condyle and IOM to medial and inferior surface of medial cuneiform and base of 1st metatarsal –> dorsiflexion and inversion
Extensor digitorum longus: Lateral condyle and IOM to middles and distal phalanges of lateral 4 digits –> dorsiflexion and extension of toes
Extensor hallicus longus: middle part of anterior fibula and IOM to dorsal aspect of great toe –> dorsiflexion, extension great toe
Fibula’s tertius: Inferior third of anterior tibia and IOM to dorsum of 5th metatarsal –> dorsiflexion and eversion
What is the nerve that supplies the anterior compartment of the leg?
Deep fibular nerve
What are the muscles of the lateral compartment, actions?
Fibularis longus: Head of fibula to base of 1st metatarsal (running behind lateral malleolus) –> eversion, weak plantarflexion
Fibula’s brevis: Inferior fibular to dorsal aspect of tuberosity of 5th metatarsal –> eversion and weakness plantarflexion
What nerve innervates lateral compartment?
Superficial fibular nerve
What are the muscles of the superficial compartment of the posterior leg, actions?
Gastrocnemius: 2 heads: lateral from lateral femoral condyle, medial from popliteal aspect of femur, superior to medial epicondyle, both attaching onto calcaneal/achilles tendon –> posterior surface of calcaneus
Soleus: Posterior aspect of head of fibula, onto calcaneal/achilles tendon posterior surface of calcaneus
Plantaris: inferior end of lateral supracondylar line of femur, onto calcaneal/achilles tendon posterior surface of calcaneus
What is the major difference in function between gastrocnemius and soleus?
Gastrocnemius also functions to flex the knee as it crosses the knee joint as well
