Knee and Meniscus Anatomy
The Knee Joint
The knee is one of the most complex and largest joints in the body. It allows you to flex and extend your knee as well as rotate it horizontally. The knee provides both strength and flexibility during leg movements, while being loose enough to allow the freedom for quick movements and changes in directions.
It is not the bones inside the knee that provides stability, instead it is the soft tissue (tendons, ligaments, muscles, menisci) that holds the femur (thigh bone), the tibia (shinbone), the fibula (the slender bone in the lower leg) and the patella (kneecap) together at the joint.
The knee cap (patella) is a bone embedded within a tendon (the largest sesamoid) that rests over a groove at the bottom of the rounded thigh bone and the top of the shinbone. It protects the bones and soft tissue in your knee joint and helps with extension for your leg.
The tendons in the knee are tough cords of tissue that connect muscle to bone and help control movement of your joint. The upper leg muscles provide your knees with mobility (extension, flexion and rotation) and strength. The quadriceps muscles located on the front of your thigh (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) straighten your legs. The hamstring muscles located on the back of your thigh (semitendinosus, semimembranosus, biceps femoris) bend your knees and the small but might popliteus muscle help the leg from locking and starts the movement of your leg.
As well as providing stability, the tendons, ligaments, articular cartilage, meniscus and other soft tissue in the joint provide cushioning and protect the bones. A type of slick, hard but flexible tissue known as articular cartilage covers the surface ends of the tibia and femur at your knee joint, allowing them to move easily against one another. It is generally 1/8 to 1/4 inch thick. A thick, stringy, egg-like fluid, called synovial fluid, found inside the knee capsule, lubricates your knee joint and, along with the meniscus and articular cartilage reduces friction.
We have tools that will help you to prevent and treat the symptoms of meniscus related injury When it comes to your injured knee, it's best to start effective long term healing right away. Our Advisers are highly trained individuals and will help find the long term healing goal that's right for YOU.
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Medial Meniscus and Lateral Meniscus
The soft tissue structure in the knee includes 2 menisci, the medial meniscus (located on the inside of the knee) and lateral meniscus (located on the outside of the knee). Menisci are crescent-shaped pads of fibrocartilage that sit on the end of the tibia bone (tibial condyles) and form a concave surface for the rounded ends of the femur bone (femoral condyles) to rest on. They cover approximately 2/3 of the tibia surface and are thicker on the outside and thinner on the inside appearing triangular in cross section. The 2 menisci fill the space between the leg bones and cushion the femur so it doesn't slide off or rub against the tibia.
The two menisci are joined together within the knee joint by the transverse ligament. The menisci also attach to leg muscles which help the menisci maintain their position during movement. The semimembranosus and quadriceps attach to both menisci. The lateral meniscus attaches to the popliteus below the knee and the femur via the posterior cruciate ligament (PCL). On the inner part of the knee, the ends of the menisci (known as the anterior and posterior horns) are attached to the tibia and joint capsule and along the exterior edge of the meniscus by the coronary ligaments. These ligaments are loose which allow the menisci to pivot freely. However, the medial meniscus does not move as freely in the joint as the lateral meniscus and as a result is torn more frequently.
The blood flow to the menisci comes from the inferior genicular artery. This artery supplies blood to the perimeniscal plexus which provides oxygen and nutrients to the synovial and capsular tissues around the menisci and within the knee joint. The coronary ligaments attached to the meniscus, transport the blood from the perimeniscal plexus (network of blood vessels) into the peripheral of the menisci. The anterior and posterior horns of the menisci also receive a good amount of blood as they are covered by a vascular synovium. The interior part of the meniscus is avascular, having NO direct blood supply.
What this means to you
The location of your meniscus injury and the amount of the damage. May help you and your doctor decide on having you face surgery to 'clip' away a piece of your meniscus or if you are using alternative therapy to heal your meniscus.
The Function of the Meniscus
The menisci play a very important role in the proper working of the knee. Essentially, they serve as cushions to decrease the stress caused by weight bearing and forces on the knees. They work like shock absorbers, supporting the load by compressing and spreading the weight evenly within the knee. Even while walking, the pressure put on the knee joints can be 2 - 4 times your own body weight; when you run these forces increase up to 6 - 8 times your body weight and are even higher when landing from a jump. By increasing the area of contact inside the joint by nearly 3 times, the menisci reduce the load significantly (dispersing between 30 and 55% of the load).
As weight is applied to the meniscus they are compressed and are forced to extend out from between the femur and tibia. However, the circular design of the menisci provides circumference tension (referred to as 'Hoop Stress') to resist this extension and provide stability as the load compresses. If the meniscus is torn at the peripheral rim, circumference tension is compromised and the meniscus loses its ability to transfer the load and the joint begins to suffer. In fact, if part of the peripheral is removed or the tear extends to the periphery, the load on the knee joint may increase by up to 350% causing stress and pain. However, if the tear remains on the interior without disrupting the periphery of the meniscus, the meniscus is still able to disperse the load without stress and pain.
The menisci also assist with the proper movement (arthrokinematic) of the femur and tibia during flexion and extension. They help stabilize the knees when in motion, reduce friction within the joint, and lubricate and protect the articular cartilage surrounding the tips of the bones from damage due to wear and tear.
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What is Fibrocartilage?
The menisci are composed of tissue called fibrocartilage which is tougher and contains more fiber than other types of cartilage in the body. The collagen fibers are woven into dense tissue that is resistant to stretching and extending in various directions. This makes fibrocartilage excellent for cushioning the knee joint that is required to move multi directionally.
The amount of blood vessels in the fibrocartilage throughout the meniscus varies. The outer one-third of the meniscus is vascular, which means there is an abundance of blood vessels to allow blood to the area. The central part of each meniscus has fewer blood vessels and the inner third does not contain any. As a result, a tear on the outer peripheral of the meniscus can heal faster than one on the inner portion. Tears in the innermost part of the meniscus may not heal completely due to the lack of blood supply.
Without proper nutrition (blood supply) the menisci may partially disintegrate resulting in less cushioning and protection within the joint. Proper blood flow ensures nutrients and oxygen reach the area and metabolic waste is removed from the fibrocartilage. When functioning properly, the knee joint naturally receives blood flow through movement and the pumping action of body weight shifting from knee to knee. Greater blood flow results in faster and more complete healing when meniscus or ligament damage occurs.
Using Blood Flow Stimulation Therapy™ (BFST®), will help with your recovery and heal your meniscus injury . BFST® increases the amount of blood that flows naturally to the tissue to nourish your tendons, improving elasticity and speeding the healing process. This increased Blood Flow Stimulation Therapy to your knee tendon(s) is greatly needed.
Ligaments are strong, elastic-like tissues that connect bone to bone and provide stability and protection to your knee joint by limiting the forward and backward movement of the shin bone. The knee has 2 collateral (parallel) ligaments and 2 cruciate (crossing) ligaments. The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) provide support to the knee by limiting the sideways motion of the joint and resisting extreme rotation in a partially flexed position. The anterior and posterior cruciate ligaments (ACL and PCL) stabilize the knee by limiting the rotation and the forward and backward movement of the joint.
The MCL is the most commonly injured of the collateral ligaments. Injury is often a result of a blow to the outer side of the knee during sports. Since the MCL is attached to the medial meniscus, damage to the medial meniscus often occurs when the MCL is injured during a hard hit to the knee. The cruciate ligaments (ACL and PCL) are strong and thick providing stability to the joint. Together they work to prevent extreme knee motions of any kind. As a result, any damage to a cruciate ligament can cause noticeable instability in the knee. An ACL injury, the most common cruciate ligament injury, occurs when the knee is locked with the foot planted and the knee is twisted quickly. Athletes required to make sudden directional changes or to slow down quickly as well as those in contact sports are at high risk for ACL tears. Minor tears may go unnoticed immediately and will appear a few hours later with pain and swelling. More serious ACL tears are accompanied by severe pain and often a popping sound. The knee may feel as though something has snapped and walking or bending the knee is usually impossible.
The medial collateral ligament (MCL) and anterior cruciate ligament (ACL) are ligaments of interest to meniscus tear sufferers because meniscus tears that occur due to force trauma are sometimes accompanied by tears to the MCL and/or ACL. When the meniscus, MCL and ACL are injured in combination it is referred to as the "unhappy triad".
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What Happens When the Meniscus is Injured?
Menisci tend to get injured during movements that forcefully twist your knee while bearing weight. As we age the tissue degenerates and becomes weaker and tear as a result of minor injuries or movements. When your meniscus is damaged and/or torn, it starts to move abnormally inside the joint. Causing the edge of the torn meniscus it to become caught between the bones of the joint (femur and tibia). Your knee then becomes swollen, painful and difficult to move. These injuries can be difficult to heal because blood supply (which helps your body heal itself) is often limited to the outside edge of the menisci.
Once you have a meniscus tear, you have an increased risk of developing knee arthritis because these shock absorbers are weakened. They slowly wear away with knee movements and are not able to protect your articular cartilage on the surface of the knee joint as much as before.
Do you really have Meniscus Injury?
A visit to your doctor can rule out these secondary conditons. It is common to suffer from two conditions at the same time.
Muscle Strain - Muscle strain are known as a 'pulled muscle', this overstretching the tissue beyond its capacity. Athletes are at more of risk of muscle strains as they use their muscles everyday. Less inactive people also are at risk as their muscles become weak and over using them can strain the tissue. This 'pull' of the muscle fibers is micro-tears and even separation from the tendon. Pain and inflammation in the muscles, you may feel more muscle weakness, swelling, bruising or even pain when move your knee.
Liagment Sprain - Sprains happen to liagments. Liagments are fiberous tissue that connect bone to bone in the knee joint such as the ACL, PCL, LCL, or MCL. To much force on the joint pulls on the bones and overstretches the liagment tissue, causing micro-tears in liagment fibers. If the sprain very tramaic the liagment may rupture under the force and surgery is required to completely recover. Anyone is at risk of for a liagment sprain, there are some that are at high risk, athletes in collision sports, football or ruby. Sometimes less impact can cause a slight sprain with the knee twisting inwards such as standing up for a chair. Pain and inflammation in the liagment affected, swelling, or even pain when move your knee.
Bursitis - Bursae (plural for bursa) are flattened fluid-filled sacs that function as cushions between your bones and muscles (deep bursae) or bones and tendons (superficial bursae). They reduce friction and allow the surface of your soft tissue to slide over bone effortlessly. When pressure or friction is too great, excess fluid can build up in the bursa sac causing inflammation. When a bursa becomes inflamed, moving the affected area becomes very painful and movement can be difficult. Any actions that put pressure on the inflamed bursa can increase irritation and cause further inflammation and pain.
Arthritis - Arthritis is a condition that can affect the tissue lining in joints (this lining is called the 'synovium'). You may suffer from rheumatoid arhtirtis (RA) which is an autoimmune disease, or osteoarthritis (OA) which is a degenerative condition from wear and tear. When experiencing arthritis in general, inflammation from arthritis causes redness, heat, pain and swelling. Symptoms start with feeling pain and stiffness in the joint, reduced joint mobility, and swelling. It's possible for arthritis to cause tendonitis, with severe swelling in the joint arhtiritis can cause weakeaning in tendon tissue resulting in a strain or rupture. Patellofemoral Arthritis causes pain in the front of your knee and can make it difficult to kneel or climb stairs. The kneecap slides up and down in a groove on the end of the thigh bone (trochlea groove). Patellofemoral arthritis occurs when the cartilage along the trochlear groove and on the underside of the patella wears down and becomes inflamed.
Cyst - A ganglion cyst or synovial cyst can occur in any joint in the body. They appear under the skin as a lump or bump (non-cancerous) and may sometimes present no other symptoms. The cyst is basically a soft sac filled with a thick, clear fluid. It's still unknown why cycts form so close to a joint or tendon.
They may or may not become painful (in a lot of cases they're harmless), will limit your activity and could possibly grow larger if you continue the activity that caused this injury in the first place. Usually cysts only become really painful if the cyst is pressing down on any nerves in the affected area. If this is the case, then you may suffer from pain, tingling, numbness or muscle weakness.
If you don't have a lot of pain then you may only need to treat the symptoms of your cyst and wait for the cyst to naturally go away on its' own. Cysts most commonly show up in the wrist, hand, ankle, feet and near other joints (ie. the back of the knee - a baker's cyst).
Synovial Plicae - Weakness in the knee as if it is unstable while walking up or down stairs or slopes. Pain with the extension of the knee, as well as may hearing a cracking noises when flexing and straightening your knee. Known as "pathological synovial plica syndrome" considered a embryonic relic. At the 12th week of life the synovial plica forms in the knee, as we grown and mature this tissue then is becomes entangled within the knee and is unable to dissolve and remains in our adulthood. Estimated that 50% of the population has the 'plicae' after birth. It is common for this condition to be over looked by doctors. (source: National Library of Medicine)
Chondromalacia patella - Causes a dull, aching pain in the front of your knee. There is damage or softening of the cartilage on the underside of the knee cap. Pain while walking up or down stairs, kneeling or squatting or after sitting for long periods of time with your knee bent.
Hoffa's syndrome or fat pad impingement - Pain, inflammation, and swelling at the front of the knee cap and along the sides of the patellar tendon. Increased pain when standing for long periods of time, squatting or using stairs and or pain when you extended you knee. Hoffa's syndrome is caused by at pad either suffers a contusion or an injury, resulting in damage and swelling. This can lead to the Hoffa's pad becoming trapped between the femur and the patella every time the leg is extended.
Patellofemoral Subluxation - Pain on the sides and around the knee cap. The kneecap slides up and down in a groove on the end of the thigh bone (trochlea groove). In some people the kneecap is pulled toward the outside of the knee and the kneecap does not slide in its groove. This condition normally affect adolescents and younger children.
At this point you're probably asking yourself...
What Should I Do?
If you think that you're suffering from meniscus injury and you're losing mobility in your knee the first thing you need to do is see your doctor. Only your doctor can give you a proper diagnosis and from this, determine a course of proper treatment.
If you suspect you have meniscus injury in your knee,
- Usually conservative treatment methods are all that's needed to treat meniscus injury. Conservative treatment options for meniscus injury typically includes rest, icing of the injury, avoiding activities that cause or worsen the pain that you're feeling and anti-inflammatory over-the-counter medication (reference: 1 and 2).
- Second, if your doctor has decided that your injury can be treated with conservative treatment options, then you'll find that many of our customers have had great success treating themselves with our powerful conservative treatment products - the knee Freezie Wrap® and Inferno Wrap®.
- Or, if surgical intervention is required, talk with your doctor about using these same products for post-surgery recovery as you'll find them to be effective for reducing post-surgery inflammation, enhancing range of motion and reducing scar tissue growth.
... and Re-injury of your knee must be avoided at all costs!
Constant re-injury (you know when it's happening, you can feel the pain) needs to be avoided at all costs. Obviously, it delays the healing process, but what's worse is that every re-injury and additional healing cycle increases the amount of scar tissue that builds up around your original meniscus injury.
No one is immune to meniscus injury, you can easily reduce your risk of further re-injury with consistent conservative treatments
Scar tissue is hard, inflexible, and tough to get rid of. The more severe your meniscus injury is, the more likely that this scar tissue will make your knee much more prone to injury again later on. The more scar tissue that develops, the more you lose the range of motion in your knee.
Continuous re-injury and build-up of scar tissue while staying active means you'll have a greater chance of winding up with on-going pain, more tearing in your tendon or a full rupture.
If you have pain and inflammation in your knee, it's very important to heal your injury quickly and completely. You must avoid the build up of scar tissue. If you don't, your meniscus injury may plague you forever. This is why it's so important to continuously use conservative treatment tools to heal any recurring tendon damage before it can build into something big. For any meniscus injury sufferer, having the right tools means all the difference.
Mild and moderate cases of meniscus injury are best treated with conservative home therapies. Severe injury to the meniscus will require surgery to bring the edges of the tear together. If you suspect that you've torn your meniscus be sure to speak with your doctor for suggested treatment.
Learn More About SUPERIOR Meniscus Treatments
Learn more about how the Knee Freezie Wrap® is designed to be the most effective cold compression wrap on the market today.
Learn more about more about how the Knee Inferno Wrap® helps with the healing process.