The fibula is the thinner and posteriolaterally situated of the two lower leg bones. These two bones are connected by the tibiofibular syndesmosis, which includes the interosseous membrane.
Proximal: A enlarged pointed head and small neck form the proximal part of the fibula.
Shaft: The shaft is twisted in form and triangular in cross-section. It consists of the anterior, interosseous and posterior borders, as well as medial, posterior and lateral surfaces. It is the main area for muscle attachments.
Distal: The distal part of the fibula enlarges to form the lateral malleolus inferiolaterally and form part of the ankle joint.
The fibula's role is to act as and attachment for muscles, as well as providing stability of the ankle joint. The fibula is a non-weight-bearing bone.
Proximal: The fibular head articulates with the fibular facet on the lateral tibial condyle to form the proximal tibiofibular joint.
Distal: The lateral malleolus articulates with the a) fibular notch of the tibia to form the distal tibiofibular joint and b) talus to form the superior part of the ankle joint
The fibula acts as an proximal attachment for the following muscles:
- Extensor digitorum longus: Superior 3/4 of medial border
- Extensor hallucis longus: Middle of anterior surface
- Fibularis tertius: Inferior 1/3 of anterior surface
- Fibularis longus: Fibular head and superior 2/3 of lateral surface
- Fibularis brevis: Inferior 2/3 of lateral surface
- Soleus: Fibular head (posterior) and superior 1/4 of posterior surface
- Flexor hallucis longus: Inferior 2/3 of posterior surface
- Flexor digitorum longus: Via tendon
- Tibialis posterior: Posterior surface
*Take note that above only describes fibular attachments, and that all of these muscles also has other areas of attachments not mentioned in this page.
- Fibula head: Very superficial. Palpable at the posteriolateral aspect of the knee on the level of the tibial tuberosity.
- Fibula neck: Distal to lateral part of fibula head.
- Fibula shaft: Distal 1/4 is palpable.
- Medial malleolus: Superficial prominence on lateral side of ankle.
- Moore KL, Dalley AF, Agur AMR. Clinial oriented anatomy. Philadelphia: Wolters Kluwer, 2010.