The interosseous membrane of the leg is a fibrous sheet that spans between the tibia and fibula, serving both structural and functional roles.
Location
The membrane is positioned between the shafts of the tibia and fibula, extending from just below the tibiofibular syndesmosis down to a point proximal to the ankle joint.
Structure
- Composition: The interosseous membrane is composed of dense fibrous connective tissue. The fibers predominantly run downwards and medially from the fibula to the tibia.
- Apertures: The membrane contains several small openings which allow for the passage of blood vessels, particularly branches of the anterior tibial artery.
- Attachments: Superiorly, it attaches just below the tibiofibular syndesmosis and inferiorly it stops just above the ankle joint, leaving a gap for the passage of the perforating branch of the fibular artery.
Function
- Stability: One of the primary functions of the interosseous membrane is to provide stability to the leg by resisting forces that attempt to separate the tibia and fibula.
- Force Transmission: The membrane assists in distributing axial loads from the tibia to the fibula, especially during weight-bearing. This dispersal of force is vital in preventing fractures and ensuring effective weight distribution through the foot.
- Muscle Attachment: The membrane serves as a point of attachment for specific muscles of the leg, providing leverage and facilitating movement.
- Protection and Passage: The membrane protects interosseous blood vessels and nerves while also offering a channel for their course between the two bones.
Clinical significance
The interosseous membrane of the leg has notable clinical implications, especially in orthopedics and trauma care. Injuries or disruptions to this membrane can compromise the stability of the leg, making it susceptible to further damage. One common clinical presentation related to the interosseous membrane is the “Maisonneuve fracture.” This injury involves a fracture of the proximal fibula associated with a disrupted interosseous membrane and often an associated injury to the medial ankle structures. Such injuries demonstrate the interconnected biomechanics of the leg and ankle.
Additionally, the membrane’s role in load distribution between the tibia and fibula is vital; damage can lead to disproportionate force bearing, increasing the risk of fractures or other injuries. The apertures in the membrane for vascular passage also have clinical relevance. The anterior tibial artery, which passes through these apertures, can be compromised in the event of membrane injuries, potentially impacting blood supply to the leg. In surgical procedures involving the bones of the leg, maintaining the integrity of the interosseous membrane ensures stability and proper healing post-operatively.
