Tibia – Bony Land Mark, Muscle Attachment, Function

Tibia is one of two bones that comprise the leg. As the weight-bearing bone, it is significantly larger and stronger than its counterpart, the fibula. The tibia forms the knee joint proximally with the femur and forms the ankle joint distally with the fibula and talus. The tibia runs medial to the fibula from just below the knee joint to the ankle joint and is connected to the fibula by the interosseous membrane.[rx]

The distal portion of the tibia is shaped like a box with a distal medial protuberance that makes up the medial malleolus.[rx] There are five surfaces that make up the distal tibia.

• The inferior surface provides a smooth articulation with the talus.
• The anterior surface is covered by extensor tendons and provides an area for ankle joint capsule attachment.
• The posterior surface has a groove for the tibialis posterior muscle.
• The lateral surface has a fibular notch which serves as an attachment for the interosseous membrane.
• The medial surface is a large bony prominence that makes up the medial malleolus.

Tibial Osteology

The Proximal Tibia

• Lateral condyle – lateral proximal aspect of the tibia that articulates with the femur
• Medial condyle – medial proximal aspect of the tibia that articulates with the femur
• Lateral tibial plateau – the superior articular surface of the lateral condyle
• Medial tibial plateau – the superior articular surface of the medial condyle

Intercondylar area

The Tibial Shaft

• Serves as the origin or insertion point of many muscles including tibialis anterior, extensor digitorum longus, soleus, tibialis posterior, flexor digitorum longus, sartorius, gracilis, quadriceps femoris, semimembranosus, semitendinosus, and popliteus muscles. [rx]

The Distal Tibia

• The distal portion of the tibia – is shaped like a box. [rx] There are five surfaces that make up the distal tibia.
  • The inferior surface provides a smooth articulation with the talus.
  • The anterior surface is covered by extensor tendons and provides an area for ankle joint capsule attachment.
  • The posterior surface has a groove for the tibialis posterior muscle.
  • The lateral surface has a fibular notch which serves as an attachment for the interosseous membrane.
  • The medial surface is a large bony prominence that makes up the medial malleolus.
• Medial malleolus – distal protrusion of the tibia which articulates with the talus

  • Groove for the tendon of tibialis posterior is located on the posterior aspect of the medial malleolus
• Fibular notch – location of the tibiofibular joint

Blood Supply and Lymphatics

• The nutrient artery and periosteal vessels supply the blood to the tibia. The nutrient artery arises from the posterior tibial artery and enters the bone posteriorly distal to the soleal line. The periosteal vessels stem from the anterior tibial artery.[rx]

Nerves

• The nerves that supply the tibia are all branches of the main nerves that supply adjacent compartments.[8] In the posterior compartment of the leg, the tibial nerve gives off branches that supply the posterior aspect of the tibia, and in the anterior compartment of the leg, the deep fibular nerve gives off branches that supply the anterior aspect of the tibia.

Muscles

Muscles demonstrating origin/insertion footprints on the tibia include [rx][rx][rx][rx][rx][rx]

• Tensor fasciae latae inserts on the lateral (Gerdy) tubercle of the tibia.
• Quadriceps femoris inserts anteriorly on the tibial tuberosity.
• Sartorius, gracilis, and semitendinosus insert anteromedially on the pes anserinus.
• Horizontal head of semimembranosus muscle inserts on the medial condyle.
• Popliteus inserts on the sole line of the posterior tibia.
• Tibialis anterior originates at the upper two-thirds of the lateral tibia.
• Extensor digitorum longus originates at the lateral condyle of the tibia.
• Soleus and flexor digitorum longus originates at the posterior aspect of the tibia on the sole line.

Muscles Inserting on the Tibia

• Tensor fasciae latae inserts on the lateral tubercle of the tibia, which is known as the Gerdy tubercle
• Quadriceps femoris inserts anteriorly on the tibial tuberosity
• Sartorius, gracilis, and semitendinosus insert anteromedially on the pes anserinus
• Horizontal head of semimembranosus muscle inserts on the medial condyle
• Popliteus inserts on the soleal line of the posterior tibia

Muscles Originating at the Tibia

• Tibialis anterior originates at the upper two-thirds of the lateral tibia
• Extensor digitorum longus originates at the lateral condyle of the tibia
• Soleus and flexor digitorum longus originates at the posterior aspect of the tibia on the seal line

Function

• As the second-largest bone in the body, the tibia’s main function in the leg is to bear weight with the medial aspect of the tibia bearing the majority of the weight load. [rx]It also serves as the origin or insertion site for 11 muscles; these allow for extension and flexion at the knee joint and dorsiflexion and plantarflexion at the ankle joint.

References