Knee Anatomy
Bones, Ligaments and Cartilage
-Mr. Brewer
Knee Joint
• Hinge Joint
- Movements at the knee
joint are limited to
Flexion and Extension.
- The “hinge joint” is
referring to the joint
associated with the femur
and the tibia.
• Patellar Tracking
– Is how the Patella tracks in
the patellar groove when the
knee flexes and extends.
– https://www.youtube.com/
watch?v=FgBbbAjdSj4
Knee Joint Cont’d
Synovial Sac (Largest in the body):
- Filled with synovial fluid to reduce the
friction between bone and bone.
- Mainly Tibial-Femoral contact, but
also Femoral-Patellar contact as well.
Knee Capsule:
- Capsule is made up a fibrous
ligaments and tissue that enclose and
help stabilize the knee joint.
Knee Joint
- Synvisc injections are
meant to replicate
synovial fluid in
arthritic.
https://www.youtube.c
om/watch?v=Sa_NSByo-0
Knee ROM
ROM= Range of Motion
• The Knee has a typical ROM that goes from 0 degrees in full
extension to about 140-150 degrees in maximum flexion.
• Some people have hyperflexibility, and therefore, some have
“hyperextension” that goes beyond 0 degrees. (Measured in
– degrees)
Bones
• Bones:
– Tibia
– Fibula
– Patella
– Femur
Bones
• Tibia – The most weight baring bone in the lower leg.
Has a “flat” top called the tibial plateau where the
meniscus sit to help hold the femur.
• Femur – AKA the “thigh bone”. The only bone in the
thigh area. Sits on top of the Tibia distally, and the
femoral head inserts into the acetabulum of the hip at
it’s proximal end.
– Longest bone in the body
• Patella – The largest sesamoid bone in the body.
Encapsulated in the quadricep tendon, and glides over
the patellar groove of the femur during knee flexion
and extension.
Bones
Landmarks:
- Tibial Tuberosity
- Medial and Lateral
Condyles (Tibia and
Femur)
- Medial and Lateral
Epicondyles
- Head of the Femur and
Fibula
- Neck of the Femur
- Greater Trochanter
- Lesser Trochanter
- Patellar Surface
- Adductor Tubercle
- Popliteal Surface
- Intercondylar Notch
Pes Anserine
Pes Anserine:
- A term for a boney
landmark located on the
tibia.
- The attachment site for 3
muscles abbreviated SGT.
(Sartorius, Gracilis and
the SemiTendinosus)
- Literally meaning “Goose
Foot” because of the
appearance of the 3
tendons inserting.
- A bursa sac (Pes Anserine
Bursa) is located under
the insertion to act as a
friction reducer.
Ligaments
Cruciate vs. Collateral
– Cruciate - These are the most
important knee ligaments in
providing stability of the knee.
There are two cruciate ligaments,
anterior (ACL) and posterior
(PCL). They sit deep inside the
middle of the joint attaching to
the tibia and femur.
– Collateral - These knee ligaments
are found on either side of the
joint. They are responsible for
providing sideways stability by
holding the bones together.
There are two collateral
ligaments, medial and lateral.
Ligaments
Collateral Ligaments:
- Medial Collateral Ligament
(MCL):
- The medial collateral ligament is
found on the medial (inner) side of
the knee. It is a broad flat ligament
approximately 10cm long attaching to
the femur and the tibia. It resists
forces from the outside of the leg
(known as valgus forces).
- Lateral Collateral Ligament (LCL):
-
The lateral collateral ligament is found
on the outside of the knee, attaching
to the femur and the fibula. It is much
shorter than the MCL. It resists forces
from the inner side of the knee
(known as varus forces). It is less
common to injure the LCL than the
MCL.
Cruciate Ligaments
Anterior Cruciate Ligament
(ACL):
-
The anterior cruciate ligament sits
deep in the middle of the knee joint.
It attaches to the front of the tibia
and the back of the femur. It stops
the tibia sliding too far forward in
relation to the femur and is the
primary structure for propriception.
Posterior Cruciate Ligament
(PCL):
- The posterior cruciate ligament
attaches to the back of the tibia and the
front of the femur. It is shorter than the
ACL (3/5 of the length) but is twice as
strong, and is therefore not damaged as
often as the ACL. It stops the tibia
moving too far back in relation to the
femur.
Cartilage
• Menisci:
– The menisci act to disperse the weight of the body
and reduce friction during movement.
– “SHOCK Absorber”
• Medial Meniscus: *Larger of the two menisci*
– a fibrocartilage semicircular band that spans the
knee joint medially, located between the medial
condyle of the femur and the medial condyle of the
tibia.
– Semi-circular in shape
• Lateral Meniscus:
– a fibrocartilaginous band that spans the lateral side
of the interior of the knee joint.
– “C” Shaped
Meniscus
Blood Flow:
- The importance of
understanding the blood
flow of the meniscus
goes into how you will go
about treating a meniscal
injury.
- Tears to the:
- Red-Red Zone =
Repairable
- White-White Zone=
Non-repairable
Bursa Sacs
Bursa Sacs: Fluid-filled sacs located in joints,
usually where tendons insert into bones. The
“fluid” in the sacs are synovial fluid. A thick and
viscous fluid, gelatinous.
Roll of a Bursa Sac:
- These fluid-filled sacs are meant to be
positioned between tendons and bones to
reduce the friction between the two, especially
during contracting the muscles.
Bursa Sacs
Major Bursa Sacs
• Suprapatellar bursa: between the anterior surface of the
lower part of the femur and the deep surface of the
Quadriceps Femoris. It allows for movement of the
quadriceps tendon over the distal end of the femur
• Prepatellar bursa: between the patella and the skin,
results in "housemaid's knee" when inflamed. It allows
movement of the skin over the underlying patella.
• Deep infrapatellar bursa: between the upper part of the
tibia and the patellar ligament. It allows for movement of
the patellar ligament over the tibia.
• Subcutaneous infrapatellar bursa: between the patellar
ligament and skin.
• Pretibial bursa: between the tibial tuberosity and the skin.
It allows for movement of the skin over the tibial
tuberosity.
Bursa
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.
Muscles PP
Made a new Knee Muscles PP to make it easier.
Resources
1.) http://www.knee-painexplained.com/kneeligaments.html#collateral
2. Prentice, William E. Principles of Athletic
Training. (Textbook)
3.) Hoppenfiled, Stanley. Physical Examination of
the Spine and Extremeties.