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.com/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-pain-explained.com/kneeligaments.html#collateral 2. Prentice, William E. Principles of Athletic Training. (Textbook) 3.) Hoppenfiled, Stanley. Physical Examination of the Spine and Extremeties.