The fibular head is a distinct bony prominence located at the top of the fibula, which is the smaller of the two long bones in the lower leg. Its position is important for understanding its role in leg movement and stability. This article explains its location, structural characteristics, functional contributions to the knee and lower leg, and common conditions that can affect this area.
Anatomical Location and Structure
The fibular head is at the proximal end of the fibula bone. This part of the fibula is found just below the knee joint, on the outer side of the leg. It forms a joint with the tibia, the larger shin bone. Specifically, the fibular head features a flattened surface that connects with the lateral condyle of the tibia, creating the proximal tibiofibular joint.
This rounded, prominent part of the fibula is palpable on the posterolateral aspect of the knee, at approximately the same level as the tibial tuberosity. Just below the fibular head, the bone narrows to form the fibular neck. The fibular head also has a bony projection called the styloid process, located on its posterolateral aspect. While the fibula contributes minimally to weight-bearing, its head is a significant anatomical landmark.
Functional Importance
The fibular head serves as an important attachment site for muscles and ligaments, contributing to knee and lower leg stability and movement. The biceps femoris muscle, part of the hamstring group in the posterior thigh, inserts onto the fibular head. This muscle plays a role in knee flexion and external rotation of the leg when bent. Its attachment to the fibular head is important for the lateral stabilization of the knee.
Another significant attachment is the lateral collateral ligament (LCL), also known as the fibular collateral ligament. This cord-like ligament connects the lateral epicondyle of the femur (thigh bone) to the lateral aspect of the fibular head. The LCL provides stability to the knee joint, particularly against forces that push the knee inward (varus stress). The proximal tibiofibular joint, formed by the fibular head and tibia, allows for subtle movements that help reduce torsional forces from the ankle and contribute to knee stability.
Common Conditions Affecting the Fibular Head
The fibular head can be affected by conditions related to trauma or nerve compression. Fractures of the fibular head can occur due to direct blunt force impact to the knee or in conjunction with other knee injuries. An avulsion fracture, where a piece of bone is pulled away by a tendon or ligament, can also happen if the biceps femoris muscle contracts forcefully. These injuries can result in pain, swelling, and tenderness in the area.
The common peroneal nerve, a branch of the sciatic nerve, is particularly vulnerable to injury as it wraps around the fibular head and neck. Compression of this nerve at the fibular head can lead to a condition known as common peroneal neuropathy. Symptoms include weakness in ankle dorsiflexion (difficulty lifting the front of the foot) and ankle eversion (difficulty turning the sole of the foot outward), which can result in foot drop. Sensory changes like numbness or tingling on the top of the foot and outer leg may also occur. Seeking medical attention for pain, instability, or neurological symptoms in this region is important for proper diagnosis and management.