Muscles Flashcards
Rectus Femoris
> Position: most superficial and central quadriceps muscle, anterior to femur
Origin: Straight head: AIIS
: Reflected head: Roughened area above acetabulum
Insertion: Superior base of patella via quadriceps tendon (10% of fibres go directly to patella tendon)
Actions: Extends knee
: Flexes hip
Innervation: Femoral Nerve L2-4
Vastus Medialis
> Position: Most medial quadricep, anteromedial to femur
Origin: Medial intertrochanteric line
: medial linea aspera (incl. pectineal line)
: Medial supracondylar line
Insertion: Medial border of patella via quadriceps tendon (turns 90 degrees to insert = VMO)
Action: Extends knee
: Medialises patella through VMO fibres
Innervation: Femoral Nerve L2-4
Vastus Intermedius
> Position: Deep central quadricep, anterior to femur
Origin: Upper 2/3 anterior + lateral surface of femur
Insertion: Superolateral margin of patella via quadriceps tendon
Action: Extends knee
Innervation: Femoral Nerve L2-4
Vastus Lateralis
> Position: Most lateral quadricep, anterolateral to femur
Origin: Lateral intertrochanteric line
: Lateral margin of greater trochanter
: Lateral margin of gluteal tuberosity
: Lateral lip of linea aspera
Insertion: Lateral border of patella
Action: Extends knee
Innervation: Femoral Nerve L2-4
Biceps Femoris
> Position: Lateral hamstring, posterolateral to femur
Origin: Long head: Inferomedial aspect of upper Ischial tuberosity
Short head: Lateral lip of line aspera
: Lateral supracondylar ridge
Insertion: Apex of fibula head (bifurcates round lcl)
Action: Flexes knee
: Extends hip
: Laterally rotates knee
Innervation: Sciatic Nerve L5-S2
Semimembranosus
> Position: Deep medial hamstring, posterior to femur
Origin: Superolateral impression of ischial tuberosity
Insertion: Posteromedial aspect of proximal tibia
Action: Flexes knee
: Extends hip
: Medially rotates knee
Innervation: Sciatic Nerve L5-S2
Semitendinosus
> Position: Superficial medial hamstring, posterior to femur
Origin: Inferomedial aspect of upper ischial tuberosity
Insertion: anteromedial aspect of proximal tibia (pes anserinus)
Action: Flexes knee
: Extends Hip
: Medially rotates knee
Innervation: Sciatic Nerve L5-S2
Sartorius
Position: On anterior aspect of thigh crossing from lateral hip to medial knee
Origin: ASIS
Insertion: Anteromedial portion of proximal tibia (pes anserinus)
Actions: Flexes hip
: Abducts hip
: Laterally rotates hip
: Flexes the flexed knee
: Medially rotates flexed knee
Innervation: Femoral nerve L2-3
Gracilis
> Position: Medial aspect of upper leg, medial to adductor magnus
Origin: Body of pubis
: Inferior pubic ramus
: Ramus of ischium
Insertion: Anteromedial aspect of proximal tibia (pes anserinus)
Action: Flexes the flexed knee
: Medially rotates the flexed knee
: Assists adduction of hip
: Assists flexion of the hip
: Assists medial rotation of the hip
Innervation: Obturator Nerve L3-4
Gastrocnemius
> Position: Posterior aspect of lower leg ,giving it contour
Origin: Posterior aspects of medial and lateral femoral condyles
Insertion: Posterosuperior aspect of calcaneus via calcaneal tendon
Action: Assists knee flexion
: Plantar flexes the ankle
Innervation; Tibial Nerve (S1-2)
Plantaris
> Position; Small muscle on posterior aspect of knee with long tendinous insertion to posterior heel
Origin: Lateral supracondylar line of femur
Insertion: Medial border of tendocalcaneus or posterior surface of calcaneus
Action: Assists knee flexion
: Assists plantarflexion
Innervation: Tibial Nerve L4-S1
Popliteus
> Position: Posterior aspect of lower leg just inferior to knee joint
Origin: Lateral Femoral Condyle
Insertion: Proximal aspect of posterior tibia
Action: Laterally rotates femur on fixed tibia
: Assist Medial rotation of knee (ie tibia on fixed femur)
: Assists knee flexion
Innervation: Tibial Nerve L4-S1
Tensor Fascia Latae
> Position: Anterolateral aspect of hip
Origin: ASIS and outer iliac crest
Insertion: Gerdy’s tubercle via ITB
Action: Assists hip flexion
: Assists Medial rotation of hip
: Assists Abduction of hip
: Laterally Stabilises knee via ITB
Innervation: sup gluteal nerve L4-s1
