Lec 5 tibia bone

ANATOMY OF TIBIA

1. Lecture 5 TIBIA Dr. EIMAAN SUMAYYAH

2. Side determination The upper end is much larger than the lower end. The  medial  malleolus is on  medial  side. S shaped sharp border lies anteriorly.

3. Tibia Leg is the part of lower limb between knee and ankle. The osseous framework of leg is composed of two bones –tibia and fibula. The tibia is a  medial  and larger of the two bones. The bone is similar to radius bone of the upper limb.

4. UPPER END

5. Medial condyle Medial condyle is larger than the lateral condyle. Its articular surface articulates with the medial condyle of the femur. The articular surface is oval and its long axis is anteroposterior . The central part of the articular surface is slightly concave and comes in contact with the femoral condyle. The flatter peripheral part separated from the femoral condyle by the medial meniscus. The lateral margin of the articular surface is raised to cover the medial intercondylar tubercle.

6. Medial condyle On the posterior surface, the  medial  condyle has a groove. Many vascular foramina mark anterior and  medial  surfaces.

7. Lateral Condyle The  lateral  condyle overhangs more than the  medial  condyle and the articular surface is nearly circular. It articulates with  lateral  condyle of femur and in peripheral part is covered by  lateral   meniscus  [similar to  medial  condyle]. he central part is is slightly concave just like  medial  condyle and comes in contact with femoral condyle.

8. The articular surface has a raised  medial  margin which covers the  lateral   intercondylar tubercle. The posteroinferior aspect of the  lateral  condyle bears a flat, circular fibular facet and is directed downwards, backwards and laterally. This facet articulates with the fibula.. A groove marks the posterior surface of the condyle superomedial to fibular facet. The anterior aspect of the condyle bears a flattened impression.

9. Intercondylar area Intercondylar area is the roughened area on the  superior  surface, between the articular surfaces of the two condyles. The area is narrowest in its middle part. This part is elevated to from the intercondylar eminence which is flanked by the  medial  and  lateral   intercondylar tubercles.

10. Tibial Tuberosity Tibial tuberosity is a prominence located on the anterior aspect of the upper end of the tibia and forms the anterior limit of the intercondylar area. Lower down, tibial tuberosity is continuous with the anterior border of the shaft. It has an upper smooth area and a lower rough area. The epiphyseal line for the upper end of the tibia passes through the junction of these two parts.

11. Shaft of Tibia Tibial shaft is prismoid in shape and has three borders (anterior,  medial  and interosseus ), and three surfaces ( lateral ,  medial  and posterior).

12. Borders of the shaft The anterior border is sharp and S-shaped [ convex medially in the upper part and convex laterally in the lower part.] that extends from the tibial tuberosity to the anterior border of the  medial  malleolus. Anterior border is subcutaneous and forms the shin.

13. Borders of the shaft The  medial  border: It extends from the  medial  condyle, above, to the posterior border of the  medial  malleolus and is rounded. The  lateral  border is also called interosseous border and extends from the  lateral condyle [ a little below and in front of the fibular facet] to the anterior border of the fibular notch.

14. Surfaces The  lateral  surface  lies between the anterior and interosseus borders. In its upper three fourths it is concave and is directed laterally; and in its lower one fourth it is directed forwards. The  medial   surface  lies between the anterior and interosseus borders. It is subcutaneous in mostly [ upper three fourths]

15. Surfaces Between the  medial  and interosseus borders is the  posterior surface of tibia . It is widest in its upper part. A rough ridge called the soleal line crosses it here extending from the fibular facet, running downwards and medially, and terminating by joining the  medial  border at the junction of its upper and middle thirds. Above the soleal line the posterior surface is in the form of a triangular area whereas the area below the soleal line is elongated and divided into  medial  and  lateral  parts by a vertical ridge which harbors a downward directed nutrient foramen .

16. Lower End The lower end of the tibia is also expanded but lesser than upper end. It has a downward projection on the  medial  side called  medial  malleolus. It has five surfaces – The anterior surface of the lower end has an upper smooth part, and a lower rough and grooved part.

17. The  medial  surface is subcutaneous and is continuous with the  medial  surface of the  medial  malleolus. The  medial  malleolus is a short but strong process which projects downwards from the  medial  surface of the lower end of the tibia. It forms a subcutaneous prominence on the  medial  side of the ankle and serves as important anatomical landmark.

18. The lateral aspect of the lower end presents a triangular fibular notch to which the lower end of the fibula is attached. The upper part of the notch is rough. The lower part is smooth and may be covered with hyaline cartilage. The inferior surface of the lower end is articular. It articulates with the superior trochlear surface of the talus and thus takes part in forming the ankle joint. Medially the articular surface extends on to the medial malleolus. The posterior surface is traversed by a shallow groove directed obliquely downward and medialward , serving for the passage of the tendon of the flexor hallucis longus .

19. Attachments on the Tibia

20. Upper End Tibia Medial condyle The upper border – capsular ligament of the knee joint and deeper fibres of the tibial collateral ligament Groove on the posterior surface – Semimembranous Anterior surface – the  medial  patellar retinaculum

21. Lateral Condyle The iliotibial tract –on the anterior surface. The capsular ligament of the superior tibiofibular ligament – margins of the fibular facet. The origins of fibers of the extensor digitorum longus and of the peroneus longus (near the fibular facet.) The groove on the posterior surface of the lateral condyle is occupied by the tendon of the popliteus (with an intervening bursa)

22. Intercondylar Area From before backwards: The anterior horn of the medial meniscus, just in front of the medial articular surface. The anterior cruciate ligament on a smooth area just behind the previous attachment. The anterior horn of the lateral meniscus, to the front of the intercondylar eminence, and lateral to the anterior cruciate ligament. The posterior horn of the lateral meniscus, to the posterior slope of the intercondylar eminence. The posterior horn of the medial meniscus, to the depression behind the base of the medial intercondylar tubercle. The posterior cruciate ligament, to the posteriormost smooth area.

23. Tibial Tuberosity The ligmentum patellae or patellar ligament-  upper smooth part of the tibial tuberosity. Infrapatellar   bursa  separates the  lower rough area of the tuberosity from the skin.

24. Shaft Upper two thirds (or less) of the lateral surface – tibialis anterior origin Insertions of the Sartorius, the gracilis and the semitendinosus (from before backwards) Posterior to this along the medial border – tibial collateral ligament. Soleal line –The soleus muscle Fascia covering the soleus Fascia covering the popliteus Transverse fascial septum. The popliteus is inserted on the posterior surface, into the triangular area above the soleal line. The medial area (of the posterior surface) below the soleal line gives origin to the flexor digitorum profundus ; while the lateral area gives origin to the tibialis posterior.

25. Shaft The anterior border of the tibia: Deep fascia of the leg Superior extensor retinaculum The interosseus border- interosseus membrane. Fibular notch gives – interosseus tibiofibular ligament. Margins of the articular surface – The capsular ligament of the ankle joint Lower border of the medial malleolus – deltoid ligament of ankle

26. Applied Anatomy