Download What is the Knee Joint?

The Knee

Anatomy of the Knee on YouTube:

https://www.youtube.com/watch?v=_qJxj5sT0g

Play from RealPlayer (open)

Video is also saved on desktop if it isn’t
playing properly!
Anatomy of the Knee
Labelling Structures of the Knee
Bones: femur, tibia, patella
Muscles: quadriceps (anterior),
gastrocnemius and hamstrings (posterior)
 Ligaments:


◦ Anterior Cruciate Ligament: stops anterior
mov’t of tibia relative to the femur
◦ Posterior Cruciate Ligament: prevents posterior
mov’t of the tibia relative to the femur
◦ Medial Collateral Ligament: reinforces the joint
capsule medially
◦ Lateral Collateral Ligament: reinforces the joint
capsule laterally
Key Structures
Menisci:



The end of the femur is
covered with articulating
cartilage which rests at the
end of the tibia
There lie two thick
fibrocartilage articular
discs called the menisci
(meniscus-singular): the
lateral meniscus & medial
meniscus
They sit on the tibial
condyles and help increase
the stability of the knee
joint
Key Structures

The knee joint is
made up of the
articulation of the
femur and the tibia.
The femur however
does not come in
contact with the
fibula, but the fibula
interacts with the
tibia.
What is the Knee Joint?
 The
knee joint was first thought to
be a hinge joint because it was
believed to be responsible for only
flexion and extension
 However, the knee can rotate the leg
medially and laterally to a small
degree
 Therefore, the knee is considered to
be a modified ellipsoid joint which is
a type of synovial joint
Type of Joint

Because of the poor stability in the knee,
as well as all the structures involved in
the knee joint, discomfort and injuries are
unfortunately, quite common!
 Ligament Tears:
◦ ACL – look at Q angle
◦ PCL
◦ Unhappy Triad
 Patellofemoral Syndrome
 Patellar Tendinitis
 Osgood Schlatter
 Bursitis
KNEE INJURIES
ACL tear
 What motion of the tibia could be
responsible for this injury?
◦ Anterior movement (forward movement) of the
tibia relative to the femur

More common in sports where foot is
planted and athlete must rapidly change
directions (e.g. Soccer, football, Ultimate)
Injuries: Ligament Tears
Q-angle stands for the quadriceps angle
 The Q angle is formed by two lines drawn:

1. From the Anterior Superior Illiac Spine
(ASIS) through the centre of the patella
2. From the tibial tuberosity through the centre
of the patella

Research indicates that a Q-angle
greater than 20 increases the risk of
knee injuries
The Q-Angle
Find a friend
 Locate their ASIS,
tibial tuberosity and
the centre of their
patella
 Create two lines to
form your Q-angle
– use string or rulers
to visualize this!

Measuring Your
Q-Angle
Question:
Who are more prone to knee injuries, based on
their Q-angle - men or women?
Answer:
Generally, because a woman’s pelvis is wider,
her Q-angle will be larger than a man’s. This
predisposes her to knee ligament tears,
among other knee injuries.
An NCAA study showed that women suffered
ACL injuries four times more often in
basketball; three times more often in
gymnastics; and two-and-a-half times more
often in soccer.
Q-Angle Results
PCL tears can occur when a football or
soccer player falls on a bent knee.
 Motor vehicle accidents are another
common cause of injury to the PCL. When
the driver or passenger strikes the bent
knee just below the kneecap (patella)
against the dashboard, the force can tear
the PCL and damage other ligaments,
bones and muscles.

Posterior Cruciate Sprain
Signs and symptoms
Marked, immediate
swelling (within three
hours of the injury)
Difficulty walking after
the injury
Painful to move the
knee
Occasionally, a feeling
of instability, or the
knee "giving way“
PCL Injury
When the knee suffers a blow to the
lateral side, the medial side of the knee is
affected: the medial meniscus is torn,
the MCL is torn and the ACL is torn.
 These three traumas were coined: the
Unhappy Triad
 This injury is commonplace in football,
rugby and soccer where lateral blows to
the knee are possible

The Unhappy Triad
Medial
Gradual onset of anterior knee pain or
pain around the patella
 More common in adolescents, young
adults and females are more prone than
males
 Often aggravated by sports such as
running, volleyball and basketball
 There is quite a bit of disagreement in the
sport medicine community as to its cause

Patellofemoral Syndrome

Overuse/Overload:
◦ repeated weight bearing impact, landing from
jumps

Biomechanical Instability:
◦ flat feet (pronation) causes internal rotation of
tibia and femur which stresses the PF joint
◦ high arches puts undue stress on PF joint
◦ Q-angle?

Muscles
◦ Muscle weakness or imbalance (especially
quads: hammies)
Factors Contributing to PFS
What is patellar tendonitis?
 Patellar tendonitis, also called jumper's knee, is
inflammation in the band of tissue (the patellar
tendon) that connects the patella to the tibia.
How does it occur?
 The most common activity causing patellar
tendonitis is too much jumping. Other repeated
activities such as running, walking, or bicycling
may lead to patellar tendonitis. All of these
activities put repeated stress on the patellar
tendon, causing it to be inflamed.
Patellar Tendonitis
“Jumper’s
Knee”

Osgood-Schlatter (OS) disease is one
of the most common causes of knee
pain in the adolescent.

During periods of rapid growth, stress
from contraction of the quadriceps is
transmitted through the patellar tendon
onto a small portion of the partially
developed tibial tuberosity.

The repeated stress can cause the
tendon to pull away from the tibia,
causing pain and swelling.
Osgood-Schlatter disease
Osgood-Schlatter disease
Bursitis

“Carpet Layer’s”
knee.

This is caused by
direct trauma.
Thanks for your patience and attention
today!
 Tomorrow, and the rest of the week,
please bring materials to create a model
of a joint. See page in workbook for
material suggestions:

 Tennis balls
 Rubber bands/exercise bands
 Balloons
 Rods or dowels
 Toilet paper rolls
 Modelling clay
Tomorrow/Thursday/Friday