KNEE MYOLOGY Flashcards
Muscle compartments
Anterior- Quadriceps x4
Posterior – hamstrings x3
Others – Sartorius Gracilis Popliteus
10 total
Quadriceps
Rectus femoris
vastus medialis
vastus intermedius
vastus lateralis
Hamstrings
Semitendinosus
Semimembranosus
Biceps femoris
Rectus femoris
Shape: Spindle-shaped narrowing to thick tendon bipennate (continuous of tendon)
Origin: (2) Straight head from the anterior inferior iliac spine reflected head superior acetabulum
Insertion: Upper border of patella with some fibres passing around the patella to help form the ligamentum patellar
Direction: Inferiorly and medially
Action: Extends knee and flexes hip
Function: Getting up from a chair climbing stairs
Nerve supply: femoral nerve L2,3,4
Vastus medialis
Shape: unremarkable. Medial to rectus femoris
Origin: extensive lower medial end of the intratrochanteric line, medial aspect of the shaft of femur, media lip of linear Aspara medial supercondylar line
Insertion: tendon of rectus femoris medial border of patella anterior part of the medial tibial condyle expansions also make up the joint capsule anteromedially
Direction: upper fibres inferiorly
lower fibres horizontally and latterly VMO
Actions: extends knee
Function: getting up from a chair climbing stairs
Nerve supply: femoral nerve L2,3,4
Vastus lateralis
Shape: unremarkable. Lateral to rectus femoris broad tendon distally
Origin: extensive upper lateral end of intertrochanteric line, lower boarder of greater trochanter Lateral side of gluteal tuberosity lateral lip of linear aspera, fascia lata
Insertion: tendon of rectus femoris, base and lateral border of patella, anterior part of lateral tibial condyle, expansions also make up joint capsule anterolaterally
Direction: inferiorly and slightly anteriorly
Actions: extends knee
Function: getting up from a chair climbing stairs
Nerve supply: femoral nerve L2,3,4
Vastus intermedius
Shape: deepest component lies between VM and VL and deep to rectus femoris broad tendon distally
Origin: upper 2/3 of the anterior and lateral surfaces of femur
Insertion: blends with tendon of rectus femoris and other vastii and base of patella anterior part of lateral tibial condyle expansions also make up joint capsule anterolaterally
Direction: inferiorly and medially
Action: extends knee
Function: getting up from a chair climbing stairs
***Deep fibres form that articularis genius that prevents the synovial membrane getting trapped
Nerve supply: femoral nerve L2, 3, 4
Implications of weak quadriceps
Extension lag
Spin/slide/roll mechanism is disrupted
Poor locking
Results to instability
biceps femoris
Shape: long to head fusiform
Origin: (2)
Long head: lower medial part of ischial tuberosity blending with semitendinosus
Shorthead: lower half of lateral lip of linear aspera lateral supercondylar line
Insertion: tendon is split in 2 by the LCL before it attaches to the head of the fibula a bursa separates the tendon from the LCL
Direction: inferiorly and laterally
Actions: flexes knee extends hip laterally rotates tibia and femur
Function: walking – hip extension and deceleration at end of swinging phase
Nerve supply: sciatic nerve L5, S1, 2
Semitendinosus
Shape: fusiforn long tendon distally
Origin: lower medial part of a ischial tuberosity blending with biceps femoris
Insertion: medial surface of the medial tibial condyle behind the sartirius and Gracilis a bursa separates the tendon from the MCL
Direction: inferiorly and medially behind the medial femoral condyle
Actions: Flexes knee extends hip Medially rotates tibia and femur
Function: walking provides extension and deceleration at end of swinging phase
Nerve supply: sciatic nerve L5, S1, 2
Semimembranosus
Shape: fusiform long tendon distally deep to semitendinosus and biceps femoris
Origin: upper lateral facet on a ischial tuberosity
Insertion horizontal groove on the posterior medial surface of the medial tibial condyle and an expansion forms from here that forms the oblique popliteal ligament bursa separate the tendon from the gastrocnemius tendon
Direction: inferiorly and medially
Actions: flexes knee extend hip medially rotates tibia and femur
Function: walking provides hip extension and deceleration and of swimming fees
Nerve supply: sciatic nerve L5, S1, 2
Sartorius
Shape: Strape like thin longest muscle in body
Origin: Anterior Superior iliac spine
Insertion: upper medial shaft of tibia
Direction: inferiorly medially
Action: Flexes and laterally rotates the hip flexes the knee
Function: sitting cross-legged
Nerve supply: femoral nerve L2,3
Gracilis
Shape: long thin muscle
Origin: body and inferior ramus of pubis
Insertion: medial surface shaft of tibia between sartorius and semitendinous
Direction: inferiorly
Actions: adducts hip and flexs the knee
Function: weight transference train walking, horseriding
Nerve supply: obturator nerve L2, 3
Popliteus
Shape: triangular and deep
Origin: anterior aspect of the outer surface of lateral femoral condyle and joint capsule
Insertion: posterior surface of the tibia above the soleal
Direction: inferiorly posteriorly and medially
Action: laterally rotates femur and tibia
Function: unlocking the femur for flexion
Nerve supply: sciatic nerve L5
Transverse stability
MCL LCL
