Bones in the Knee

By Tristyn Kinser, MS, ATC, LAT

What is the Knee?

The knee is a large hinge joint that allows from the bending and straightening of the lower leg. This joint allows for about 120 degrees of flexion, which helps the body with walking, jumping, running and sports. The knee is a complex joint, made up of bones, ligaments, tendons, muscles, cartilage and bursae. In this article, we will focus on the bones in the knee joint which include: the femur, patella, tibia and fibula.

The bones of the knee are supported by the tendons of the knee.

Image of the anatomy of the knee.

The Femur

The femur, most commonly referred to as the thigh bone, is the longest and strongest bone in the body. The head of the femur is ball shaped and fits into the pelvis, creating the ball-and-socket hip joint. The neck of the femur extends outward to create the greater and lesser trochanters which serve as attachment points for the glutes and other hip muscles. The body of the femur runs down the thigh to form the medial and lateral epicondyles which make up the sides of the knee.

The Tibia

The tibia, also called the shinbone, connects to the knee and ankle. It is a strong bone with a flat head that supports most of the body’s weight (about 80%). The head of the tibia is flat-shaped to allow it to form perfectly to the end of the femur so the joint will bend smoothly when walking and running. The tibia runs down the middle of leg and ends at the small bump you can feel on the inside of the ankle, which is called the medial malleolus. Shin-splints are a common injury of the tibia, caused by overworking the tissues that attach to the bone.

The Patella

The smallest bone of the knee is the patella, a small, triangular bone that glides back and forth over the femur and tibia. The primary function of the patella is to serve as the attachment point for the large thigh muscle, the quadriceps (quads). The patella tendon secures the quadriceps to the patella, which helps to bend the knee and move the lower leg. A common injury at this area is called patellar tendinitis. This condition is caused by repetitive stress, causing tiny tears in the tendon, usually from sports or exercise.

The Fibula

Lastly, the fibula is the long, skinny bone fixed along the outer portion of the lower leg, opposite the tibia. The fibula runs from the outside of the knee to the ankle, creating the large bump on the outside of the ankle, called the lateral malleolus. The primary role of the fibula is to serve as a muscle attachment. Fascinatingly, the fibula only bears about 20% of the body’s weight, leaving most of the heavy lifting to the tibia.


The knee is a hinge joint that bends and straightens the knee, allowing for all activities of daily life and playing sports. The knee is made up of 4 bones; the femur, tibia, patella and fibula and many soft tissues. Common injuries at these bones are patellar tendinitis and shin-splints which can be easily treated with physical therapy.

Pain in the knee joint may be caused by injury to the bones, muscles, tendons, ligaments, bursae or the meniscus. If you are having knee pain, JOI can help!

JOI Fracture and Injury Care

JOI Physicians are currently offering ASAP Fracture and soft tissue injury care. Make an appointment by calling (904)JOI-2000. This is a new option for patients who would like to avoid the emergency room if they have suffered a fracture or soft tissue injury. To learn more about this service, read this article about fracture and injury care.

Where is Telemedicine frequently used?

All JOI Physicians, Physical Therapists and Occupational Therapists now offer Telemedicine services for virtual visits. If you feel that it is best to stay in your own home during this time, we can still provide orthopedic Telemedicine services for you. Through the download of the free Zoom app on the your phone, tablet or laptop. Our physicians and Telehealth for Physical Therapy can evaluate you and provide the care you need.

By: Tristyn Kinser, MS, ATC, LAT

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