Tibia and Fibula Bones – Anatomy

Author: Scott A. Sheffield MS

Last update: Aug 31st, 2023

Introduction to the Tibia and Fibula Bones:

The tibia (os tibia) and fibula (os fibula) are the bones that support the leg. The larger tibia or shinbone is located medial to the fibula and bears most of the weight.

1. At the superior (proximal) end of the tibia, a pair of flattened condyles articulate with the rounded condyles at the distal end of the femur to form the knee joint or tibiofemoral joint.

2. The tibia and fibula articulate at two sites.

• At the knee, a superior (proximal) tibiofibular joint is formed by the lateral tibial condyle and the head of the fibula.
• At the ankle, an inferior (distal) tibiofibular joint is formed by the lower fibula and a lateral concavity (notch) on the lower tibia.

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3. A socket formed by the distal ends of the tibia and fibular articulates with the superior portion of the talus (foot tarsal bone to form the ankle (talocrural) joint.

Anterior Markings of the Tibia:

1. Lateral condyle (condylus lateralis) is a lateral expansion of the tibia’s proximal end.
   • A fibrocartilage pad or lateral meniscus covers the condyle’s flattened superior surface so it can smoothly articulate with the lateral condyle of the femur.
   • The iliotibial tract attaches to the front of the condyle and the short head of the biceps femoris attaches to the back.
2. Medial condyle (condylus medialis) is a medial expansion of the tibia’s proximal end.
   • It’s superior surface is covered by the medial condyle of the femus.
   • The posterior of the medial condyle provides attachment for the semimembranosus muscle.
3. Intercondylar eminence (eminentia intercondylaris) is an elevated area between the condyles that contains the bump-like raised medial edges of each condyle.
   • Roughened depressions located anterior and posterior to the eminence are attachment sites for the anterior and posterior cruciate ligaments and the central tips of the medial and lateral menisci.
4. Tibial tuberosity (tuberositas tibiae) is a raised, roughened area on the anterior surface of the bone, just inferior to the condyles.
   • This region, which is also called the tuberosity of the tibia, is an attachment point for the patellar ligament (= distal portion of the quadriceps tendon).
5. Tibial shaft or body (corpus tibiae) is the long, cylindrical midsection of the bone.
6. Anterior crest border or margin (margo anterior) is a anterior ridge located just under the skin (subcutaneous).
   • It extends from the tuberosity to the medial malleolus and is the most prominent along the upper two-thirds of the bone.
   • The deep fascia of the leg attaches here.

7. Interosseous border or margin (margo interosseus tibiae) is the tibia’s sharp-edged lateral margin that provides attachment for the interosseous membrane of the leg.
   • This ligament-like membrane binds the tibia and fibula.
   • It also seperates the leg into posterior and anterior compartments and is an attachment site for some of the leg muscles.
8. Medial malleolus (malleolus medialis) is a prominent downward projection at the distal end of the tibia, on the medial side.
   • It articulated with the talus bone to form the medial portion of the ankle joint.
   • The medial malleolus also serves as the proximal attachment for the deltoid (medial collateral) ligament, which binds the tibia calcaneus and talus bones of the foot.
9. Fibular notch (incisura fibularis) is an concavity at the distal end of the tibia, on the lateral side. It articulates with the fibula to form the inferior tibiofibular joint.

Anterior Markings of the Fibula:

1. Head of fibula (caput fibulae) is a small, knob-like extension from the proximal end of the fibula that articulates with the lateral condyle of the tibia.
   • The head is an attachment site for the soleus, bicep femoris (long head), fibularis (peroneus) longus, and extensor digitorum longus muscles as well as the fibular (lateral) collateral ligament.
2. Shaft of fibula or body (corpus fibulae) is the elongated midsection bone.
3. Interosseous border or margin (margo interosseus fibulae) is the sharp-edged medial margin of the fibula that serves as the attachment site for the interosseous membrane, which binds the fibula to the tibia.
4. Lateral malleolus (malleoulus lateralis) is a pyramidal-shaped, downward projection from the distal end of the fibula.
   • The lateral malleolus, which extends more inferiorly than the medial malleolus, articulates with the tibia and the talus bones of the foot to form the lateral portion of the ankle joint.
   • Several ligaments attach the lateral malleoulus to the tibia, talus, and calcaneus bones.

Posterior Markings of the Tibia and Fibula:

1. The Lateral condyle of the tibia is the lateral expansion at the proximal end of the bone.
   • Flattened superior surface (deepened by lateral meniscus cartilage) articulates with the lateral condyle of the femur.
   • The head of the fibula articulates on the facet just below the condyle.
   • The anterior aspect serves as a distal attachment point for the iliotibial tract.
2. Medial condyle of tibia is a medial expansion at the proximal end of the bone.
   • It has a flattened superior surface (deepened by medial meniscus cartilage) articulates with lateral condyle of the femur.
   • The posterior aspect serves as the distal attachment point for semimembranosus muscle.
3. Intercondylar eminence of tibia – small elevations located between the medial and lateral condyles.
   • Anterior and posterior to the eminence are roughened depressions that serve as attachment points for the anterior and posterior cruciate ligaments and for the central tips of the medial and lateral menisci.

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4. Head of fibula is a small, knob-like extension at the superior end of the bone.
   • It articulates with the lateral condyle of the tibia at the proximal tibiofibular joint.
5. Soleal line (popliteal line) of the tibia is an oblique ridge that extends along the proximal surface.
   • It marks the inferior attachment point for the popliteus muscle.
   • It serves as an attachment point for the soleus muscle.
6. Medial malleolus of tibia is the medial prominence that extends downwardly from the distal end of the bone.
   • It articulates with the talus, forming medial portion of the ankle (mortise) joint.
   • It serves as the proximal attachment for the deltoid (medial collateral) ligament of the ankle joint.

7. Lateral malleolus of fibula is the pointed distal end of the bone. It articulates with the talus, forming the lateral portion of the ankle (mortise) joint and serves as the proximal attachment for the three components of lateral (collateral) ligament of the ankle.
8. Fibular notch of the tibia is a depression on the lateral side of the distal tibia. It articulates with the distal end of the fibula.

Test yourself:

Tibia and fibula: [Show/Hide answers]

Right Leg Bones:

Anterior view [Show/Hide answers]
Posterior view [Show/Hide answers]

Interactive quizzes about the tibia and the fibula