Anatomy of the knee
You probably have some knowledge of the anatomy of the heart, lungs, digestive system. But the knee?
It is the largest joint in the skeleton. It is formed by the femur, the largest bone, and articulates with the tibia. It is a remarkable feat of evolutionary construction. Motion of the knee includes flexion to 90 degrees. It can traverse a few degrees, which facilitates running, directional change, relieves fatigue.
Tendons, tough bands of fibrous tissue, connect muscle to bone, serving to move attached body parts.They can stretch, increasing muscle strength when contracting. Ligaments, also tough fibrous tissue, connect bone to bone, maintaining stability. Both are made from collagen
The medial and lateral meniscus are shock absorbers, reducing wear and tear of the joint. They, too, are cartilagenous. Blood supply declines with age; adults have little or no circularion in the central menisci. Tears in the menisci heal very In anatomy, a meniscus (from Greek μηνίσκος meniskos, “crescent”) is a crescent-shaped fibrocartilaginous structure that, in contrast to articular disks, only partly divides a joint cavity.
Knee problems are generally caused by injury, often during contact sports. Severe sudden twisting may damage ligaments, tendons, and the ever-vulnerable menisci. Immediate treatment to limit damage and pain consists of ice pack, immobilization, and analgesic medication, aspirin or a non-steroidal such as ibuprofen. Further care may involve physical therapy, a knee brace, crutches, and even surgery, repair of tears or knee replacement.
The other main categorys of knee pathology are arthritic. Osteoarthritis is the result of aging, excessive knee activity, may be genetically linked. The knees may ‘crackle’ during a deep knee bend. Imaging shows thinning of cartilage, distortion of normal anatomy, sometimes bone fragments.
The other main disorder is rheumatoid arthritis, an auto-immune disease which may affect all body areas. Both knees are swollen, warm, and painful. Synovial fluid, a joint lubricant, becomes saturated with inflammatory material. Blood tests are positive for Rheumatoid Factor. Elevated erythrocyte sedimentation rate is a general sign of inflammation.
In sum the knee is two big bones mounted on top of each other, held in place by muscle, ligaments, tendons and continuous correction of position by the brain. Have you ever tried to make two halves of a broken broomstick into a functional whole? The knees do.
by Col. (CA) William Goldsmith M.D.