Knee Musculature

 

 

 

                         

 

 

 

 

 

***Information and pictures were referenced from the following:

 

Moore, K.L, Dalley A.F. Clinically Oriented Anatomy 5th Edition. Lippincott Williams & Wilkins May 2005.

Verscheure, S., Smith, G. Human Anatomy Lab 1. Kendall/Hunt Publishing Company 2005.

http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/dissector/mml/. July 2, 2007.

 

 

 

 

Extensor Muscles of Knee

 

Knee extension is primarily produced by anterior muscles attached at the knee. The four main muscles which produce knee extension are together referred to as the quadratus femoris.  These muscles include: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

 

 

 

Rectus Femoris

Action Extends knee  Origin Anterior inferior iliac spine and ilium superior to acetabulum Insertion Tibial tuberosity via patella and patellar ligament  Innervation Femoral nerve

 

 Vastus Lateralis

Action Extends knee Origin Greater trochanter and lateral lip of linea aspera of femur Insertion  Tibial tuberosity via patella and patellar ligament Innervation  Femoral nerve

 

Vastus Medialis

Action Extends knee Origin Intertrochanteric line and medial lip of linea aspera of femur Insertion Tibial tuberosity via patella and patellar ligament Innervation  Femoral nerve

 

Vastus Intermedius

Action Extends knee Origin Anterior and lateral sufaces of shaft of femur Insertion Tibial tuberosity via patella and patellar ligament Innervation Femoral nerve

 

 

 

 

 

The flexor muscles of the knee are primarily made up of posterior muscles.  The main muscles which are often referred to as hamstrings are biceps femoris, semitendinosus, and semimembranosus. Other muscles that aid in knee flexion as well as internal rotation are sartorius, popliteus and gracilis.  The plantaris also  weakly assists in knee flexion.

 

Sartorius

Action Flexes knee Origin Anterior superior iliac spine and superior part of notch inferior to it  Insertion  Superior part of medial surface of tibia Innervation Femoral nerve

 

Gracilis

Action Flexes knee, Medially rotates flexed knee Origin  Body and inferior ramus of pubis Insertion  Superior part of medial surface of tibia Innervation Obturator nerve

 

Semitendinosus

Action Flexes knee, Medially rotates flexed knee Origin Ischial tuberosity  Insertion  Medial surface of superior part of tibia Innervation Tibial portion of sciatic nerve

 

Semimembranosus

Action Flexes knee Origin  Ischial tuberosity Insertion  Posterior part of medial condyle of tibia Innervation Tibial portion of sciatic nerve

 

Biceps Femoris

Action Flexes knee, Laterally rotates flexed knee Origin  Long head: ischial tuberosity Short heat: linea aspera and lateral supracondylar line of femur Insertion Lateral side of head of fibula and lateral condyle of the tibia  Innervation  Sciatic nerve

 

Gastrocnemius

Action Flexes knee Origin Lateral head: lateral aspect of lateral condyle of femur Medial Head: popliteal surface of femur, superior to medial condyle Insertion  Posterior surface of calcaneus via calcaneal tendon Innervation Tibial nerve

 

Plantaris

Action Weakly assists knee flexion Origin  Posterior surface of femur superior to the lateral condyle Insertion  Posterior surface of calcaneus via calcaneal tendon Innervation  Tibial nerve

 

Popliteus

Action Flexes knee, Medially rotates tibia Origin Lateral surface of lateral condyle of femur and lateral meniscus  Insertion  Posterior surface of tibia, superior to soleal line Innervation  Tibial nerve

 

Tensor Fascia Lata

 

 

 

 

 

Action Stabilizes the hip and knee joint using tension from the iliotibial band Origin Anterior superior iliac spine Insertion  Iliotibial band Innervation  Superior gluteal nerve

 

 

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