Fibula bone Anatomy

Anatomy of fibula bone, in simple form.

1. Fibula Bone by Dr.Priyanka Kumari Junior Resident Department of Rachana Sharira FOA, IMS-BHU, Varanasi.

2. Introduction Latin clasp/pin . Lateral & smaller bone of the leg. Very thin as compared to the tibia. Homologous to the ulna. Forms a mortice of the ankle joint.

3. S ide determination Upper end/head, expanded in all directions. Lower end/lateral malleolus, expanded anteroposteriorly & flattened from side to side. Medial side of lower end bears a triangular articular facet anteriorly & deep malleolar fossa posteriorly.

4. Side determination Upper end-Head Expanded in all direction Lower end-lateral malleolus Projected downward deep malleolar fossa posteriorly. triangular articular facet anteriorly .

5. Parts of Fibula The fibula has- An upper end A shaft A lower end.

6. Parts of Fibula Upper end Shaft Low er end

7. Upper End/Head Expanded in all direction. Apex of head/ styloid process project upwards from its posterolateral aspect. Constriction below the head is neck of fibula . Superior surface bear a circular articular facet, articulates with lateral condyle of tibia.

8. Upper End/Head of Fibula Upper end Shaft Low er end Articular facet Neck Apex of head

9. S haft Shaft of fibula has three borders & three surfaces- Borders -anterior, posterior & interosseous . Surfaces -medial, lateral & posterior.

10. Anterior Borders Anterior border begins just below the ant. aspect of the head. At lower end, it divides to enclose an triangular area, which continuous with lateral surface of lateral malleolus.

11. Shaft of Fibula; Anterior Border Upper end Shaft Low er end Lateral view Anterior border

12. P osterior Borders It is rounded. Begins with line of styloid process. Below, it continuous with medial margin of the groove on back of the lateral malleolus.

13. Shaft of Fibula; Posterior border Upper end Shaft Low er end Lateral view Posterior border

14. I nterosseous Borders Interosseous /medial border, just medial to the anterior border. Terminates below at the roughened area above the talar facet of the lateral malleolus.

15. Shaft of Fibula; Medial border Upper end Shaft Low er end Medial Crest Anterior border Posterior border Medial view Medial border

16. L ateral surface b/w anterior & posterior border. Twisted backward in its lower part.

17. Shaft of Fibula; Lateral View Upper end Shaft Low er end Lateral view Anterior border Lateral surface Posterior border

18. Posterior surface Largest of the three surfaces. Lies b/w medial & posterior border. Upper 2/3 divides into two parts by a vertical ridge, medial crest.

19. Shaft of Fibula; Posterior View Upper end Shaft Low er end Posterior view Posterior surface Posterior border Medial crest

20. M edial surface b/w anterior & medial border. Upper 2/3, narrow, measuring 1mm or less.

21. Shaft of Fibula; Medial View Upper end Shaft Low er end Medial border Anterior border Posterior border Medial surface Medial view

22. L ower End AKA tip of lateral malleolus, 0.5cm lower than medial malleolus. It has four surface-Anterior, Posterior, Lateral & Medial. Medial surface bears a triangular articular facet for the talus anteriorly & malleolar fossa posteriorly.

23. Lower end of Fibula Upper end Shaft Low er end Lateral malleolus Malleolar fossa Facet for talus Medial view Lateral view

24. Articulations of Fibula Upper end- superior surface-circular facet-with the lateral condyle of tibia. L ower end- medial surface- triangular facet- with the talus bone. Joint b/w tibia & fibula at lower end- syndesmoses .

25. Articulations of Fibula

26. Attachments of Upper End 1. Fibular collateral ligament of knee joint-within the C-shaped area. 2. Capsular ligament of Sup. t ibiofibular joint-around the articular facet. 3. C-shaped insertion of biceps femoris - Apex.

27. Attachments of Upper End

28. Attachments of Shaft From medial surface- Extensor digitorum longus - upper ¼ & ant. half of middle 2/4. Extensor hallucis longus - post. half of its middle 2/4. Peroneus tertius - its lower 1/4

29. Attachments from medial surface-

30. Attachments of Shaft From posterior surface- Tibialis posterior- origin-b/w medial crest & interosseous border. Soleus ( upper ¼) & flexor hallucis longus (lower ¾)- origin- b/w interosseous & posterior border.

31. Attachments from posterior surface- Soleus Flexor h allucis longus Tibialis posterior

32. Attachments of Shaft From lateral surface- Peroneus longus - origin- upper 1/3 & post. h alf of middle 1/3. Peroneus brevis - origin-ant. half of middle 1/3 & lower 1/3.

33. Attachments from lateral surface-

34. Attachments of Shaft From anterior border- Anterior intermuscular septum. Superior extensor retinaculum- ant. margin of triangular area. Superior peroneal retinaculum- post. margin of triangular area.

35. Attachments of Shaft From medial border- Interosseous membrane. This attachment leave a gap for passage of ant. t ibial vessels. From posterior border- Posterior intermuscular septum.

36. Attachments of Lower End From triangular area- Anterior tibiofibular ligament- anteriorly. Posterior tibiofibular ligament- posteriorly. Interosseous tibiofibular ligament - in the middle.

37. Attachments of Lower End

38. Attachments of Lower End From lateral malleolus- Ant. t ibiofibular ligament- ant. Surface. Inf. transverse ligament- above to malleolar fossa. Post. t ibiofibular ligament- below to malleolar fossa. Capsule of the ankle joint- edges of articular surface. Calcaneofibular ligament- notch on the lower border.

39. Applied aspect Foot drop- due to injury of common peroneal nerve, due to rolled against the neck of fibula. Fibula is an ideal spare bone for a bone graft. Upper & lower end of fibula is palpable & subcutaneous. Pott’s fracture- the spiral fracture of lateral malleolus (in 1 st dgree ), then fracture of medial malleolus (2 nd dgree ) and then posterior margin of lower end of tibia shears off (in 3 rd dgree ), due to forcible abduction & external rotation of foot, is known as pott’s fracture.