The fibula is one of the two long bones in the lower leg, situated on the outer side, parallel to the larger tibia. Its upper end, the fibular head, is a distinct, rounded bony projection. This landmark can be felt through the skin. It connects to various muscles and ligaments, contributing to the lower leg’s structural integrity.
Locating the Fibular Head
Locating the fibular head involves a simple palpation technique. Sit down and bend your knee to about a 90-degree angle, with your foot flat on the floor. Feel along the outer side of your knee, just below the joint line. You should feel a prominent, rounded bony knob, which is the fibular head.
It is positioned on the outer aspect of the knee. To confirm its location, gently rotate your foot inward and outward; you may feel surrounding soft tissues move around the stationary fibular head. You can also trace the biceps femoris tendon, a large tendon on the outside of your thigh, down to its insertion point on the fibular head.
Surrounding Structures and Attachments
The fibular head serves as an attachment site for several soft tissues that contribute to knee stability and lower leg function. The biceps femoris muscle, part of the hamstring group, inserts onto the fibular head. This muscle helps flex the knee and rotate the lower leg laterally. The lateral collateral ligament (LCL) also attaches here, originating from the lateral epicondyle of the femur and extending to the fibular head. The LCL stabilizes the outer side of the knee, resisting excessive sideways movement.
The common peroneal nerve, also known as the common fibular nerve, is in close proximity to the fibular head. This nerve, a branch of the sciatic nerve, courses around the neck of the fibula, just below the fibular head. Here, the common peroneal nerve is superficial and exposed. It then divides into superficial and deep branches, which supply sensation and control muscles for lifting the foot and toes, and outward foot movement.
Implications of its Location
The exposed position of the common peroneal nerve around the fibular head makes it vulnerable to injury. Direct trauma to the outer knee, such as a blow, can compress or damage this nerve. Fractures of the fibular head can also directly impact the nerve due to its close proximity.
Beyond acute injuries, prolonged pressure on this area can lead to nerve damage. This may occur from tight casts, habitual leg crossing, or certain surgical positions. Damage to the common peroneal nerve often results in “foot drop,” where an individual struggles to lift the front part of their foot, causing it to drag when walking. It can also lead to numbness or altered sensation on the top of the foot and outer lower leg. Understanding the fibular head’s anatomical relationships helps in recognizing potential vulnerabilities and related medical conditions.