Muscles of the Knee
Mr. Brewer
Muscles of the Knee
Quadriceps (4) –
- Vastus Medialis
- Vastus Intermediate
- Vastus Lateralis
- Rectus Femoris
Insertion/Origin:
- Distal insertion of all
quadricep muscles are
located at the tibial tuberosity
via the quadricep tendon.
- The 3 vastus quadricep
muscles attach superiorly to
the proximal portion of the
Femur WITHOUT crossing the
hip joint.
Muscles
- Vastus Muscles
- Do NOT cross the hip joint.
- Because of that, they are only responsible for
knee extension.
- VMO (Vastus Medialis Oblique) is an important
muscle to focus on rehabbing following major
knee surgery.
- Responsible for the last 15 degrees of Knee Extension,
also known as “Terminal Knee Extension”
- https://www.youtube.com/watch?v=ZscBVtoX62U
Rectus Femoris
Rectus Femoris:
- The most superficial of the
quadricep muscles
- Important to recognize when
considering treatment options.
- Responsible for not only knee
extension, like the rest of the
quadricep muscles, but also HIP
Flexion.
- This is because the Rectus Femoris
crosses the hip joint and attaches
proximally to the anterior inferior
iliac spine of the hip bone.
Muscles
- Rectus Femoris:
- The Rectus Femoris is the only Quadricep to cross
both the knee AND hip joints.
- Therefore the Rectus Femoris not only is involved
in Knee extension, but also Hip Flexion.
- Video showing hip flexion exercises and
movements, along with techniques for stretching:
- https://www.youtube.com/watch?v=eVbmiI4YSdU
Hamstring Muscles
Hamstring
Hamstring Muscles (3):
- Biceps Femoris
- Lone lateral hamstring muscle
- “Biceps” meaning 2 heads
- Distally:
- the biceps femoris does cross
the knee joint and both the
short-head and long-head
come together and attach to
the Head of the Fibula.
- Proximally:
- Long-head crosses the hip joint
and attaches to the pelvis.
- Short-head attaches to the
posterior femur along the
middle 1/3.
* Both heads are active with
knee flexion, but the long-head
assists with Hip-extension as
well.
Hamstrings
- Semitendinosus and
Semimembranosus
- Medial Hamstring muscles
- Both originate proximally
to the ischial tuberosity of
the pelvic bones.
- Both insert distally to the
medial surface of the tibia.
Hamstring Action (at the knee)
• Knee Flexion:
– All 3 of the
Hamstring muscles
have roles in Knee
Flexion.
– C1 and C2 is an
example of “bilateral
knee flexion”
– E1 and E2 are
examples of
“unilateral knee
flexion”
– F1 and F2 are
examples of
“bilateral knee
flexion” (focusing on
the eccentric
contractions of the
hamstring muscles)
Pes Anserine
The Pes Anserine is located on the
anterior, superior and medial aspect
of the tibia just below the knee joint
line.
It is the location of the insertion of 3
important muscles.
Pes Anserine is Latin for “Goose
foot”
The 3 muscles that insert at the Pes
Anserine are abbreviated SGT.
(Sartorius, Gracilis and
SemiTendinosus)
Sartorius
The “S” in SGT.
The Sartorius is the longest muscle in the
body.
The proximal insertion is the ASIS of the hip
(Anterior Inferior Iliac Spine)
It creates a movement that is a combination
of hip flexion and hip External rotation.
(Figure – 4 position)
Watch:
http://www.screenr.com/1sys
Gracilis
The “G” in SGT.
The Gracilis is primarily a HIP ADDUCTOR.
Due to the fact that the gracilis cross the
knee joint, it also plays a major roll in
assisting to stabilize the knee joint on the
medial aspect.
The proximal insertion point of the gracilis
is along the ischium of the hip bone(s).
Watch:
https://www.youtube.com/watch?v=95M
Y5Xjvtqs
SemiTendinosus
The “T” in SGT.
We discussed the
major points of the
semitendinosus
along with the
other hamstring
muscles on
previous slides.
Popliteus
The Popliteus is a very small muscle
located in the posterior aspect of the
knee.
The popliteus crosses the knee joint,
attaching to the femur laterally and
wrapping around the posterior aspect of
the leg to attach to the medial aspect of
the Tibia.
The popliteus assists in Knee Flexion.
It is said to be the muscle that “unlocks”
the knee from full extension when
initiating knee flexion.