Download TIBIA BONE

TIBIA BONE
Learning objectives:
At the end of the lecture, the student should be able to describe:
 The division of tibia bone in 3 parts
 The surfaces and borders of tibia
 The attachments of muscles on the tibia bone
 The ossification of tibia and its primary and secondary ossification
centers
Lecture outline:
Tibia:
 Prismoid in form, expanded above, where it enters into the
knee-joint, contracted in the lower third, and again enlarged but to a
lesser extent below.
 In the male, its direction is vertical, and parallel with the bone
of the opposite side , in the female it has a slightly oblique
direction downward and lateralwards, to compensate for the
greater obliquity of the femur.
 It has a body and two extremities/ ends (upper & lower).
The upper extremity:
 The upper extremity is large
 Expanded into two eminences, the medial and lateral condyles.
 The superior articular surface presents two smooth articular facets .
The medial facet :
 oval in shape
 slightly concave from side to side, and from before backward .
The lateral facet :
 nearly circular
 is concave from side to side, but slightly convex from before backward,
especially at its posterior part, where it is prolonged on to the posterior
surface for a short distance .
The central portions of these facets articulate with the condyles of the
femur, while their peripheral portions support the menisci of the knee-joint.
Intercondyloid eminence (spine of tibia):
 Located between the articular facets
 It is surmounted on either side by a prominent tubercle, on to the sides
of which the articular facets are prolonged
 In front of and behind are rough depressions for the attachment of the
anterior and posterior cruciate ligaments and the menisci.
Anterior surfaces of condyles:
 Continuous with one another
 Forms a large flattened triangular area which is broad above, and
perforated by large vascular foramina; narrow below where it ends in
tuberosity of the tibia
Tuberosity of the tibia :
 A large oblong elevation.
 Gives attachment to the ligamentum patellae
 A bursa intervenes between the deep surface of the ligament and the
part of the bone immediately above the tuberosity.
Posterior surfaces of condyles:
 Posteriorly , condyles are separated from each other by a shallow
depression, the posterior intercondyloid fossa.
 This fossa gives attachment to part of the posterior cruciate ligament
of the knee-joint.
 The medial condyle has a deep transverse groove posteriorly for the
insertion of the tendon of the Semimembranosus.
 Its medial surface is convex, rough, and prominent and gives
attachment to the tibial collateral ligament.
The lateral condyle :
 Posteriorly, it has a flat articular facet, circular in form which is
directed downward, backward, and lateralward for articulation with
the head of the fibula.
 Lateral surface is convex, rough, and prominent in front
 Has got an eminence, situated on a level with the upper border of the
tuberosity and at the junction of its anterior and lateral surfaces, for
the attachment of the iliotibial band.
 Just below this a part of the Extensor digitorum longus takes origin
and a slip from the tendon of the Biceps femoris is inserted.
Body of tibia:
Has three borders and three surfaces.
Borders :
Anterior
Medial
Interosseous
The anterior crest or border :




The most prominent of the three
Commences above at the tuberosity
Ends below at the anterior margin of the medial malleolus.
Is sinuous and prominent in the upper two-thirds of its extent, but
smooth and rounded below
 Gives attachment to the deep fascia of the leg.
Surfaces:
Lateral
Medial
Posterior
Lateral surface:
 Narrower than the medial one
 Upper two-thirds present a shallow groove for the origin of the Tibialis
anterior
 Lower third is smooth, convex, curves gradually forward to the
anterior aspect of the bone
 Is covered by the tendons of the Tibialis anterior, Extensor hallucis
longus, and Extensor digitorum longus from medial to lateral side
Posterior surface:
 Has a prominent ridge in its upper part, the popliteal line,
 This line extends obliquely downward from the back part of the
articular facet for the fibula to the medial border, at the junction of its
upper and middle thirds
Attachments:
 Marks the lower limit of the insertion of the Popliteus
 Serves for the attachment of the fascia covering this muscle
 Gives origin to part of the Soleus, Flexor digitorum longus, and
Tibialis posterior.
 The triangular area, above this line, gives insertion to the Popliteus.
 The middle third of the posterior surface is divided by a vertical ridge
into two parts; the ridge begins at the popliteal line and is well-marked
above, but indistinct below; the medial and broader portion gives
origin to the Flexor digitorum longus, the lateral and narrower to part
of the Tibialis posterior.
 The remaining part of the posterior surface is smooth and covered by
the Tibialis posterior, Flexor digitorum longus, and Flexor hallucis
longus.
 Immediately below the popliteal line is the nutrient foramen, which is
large and directed obliquely downward.
The lower extremity
 The lower extremity, much smaller than the upper, presents five
surfaces
 It is prolonged downward on its medial side as a strong process, the
medial malleolus.
Surfaces:
The inferior articular surface
 Is quadrilateral, and smooth for articulation with the talus.
 It is concave from before backward, broader in front than behind, and
traversed from before backward by a slight elevation, separating two
depressions.
 Is continuous with that on the medial malleolus.
The anterior articular surface
 Is smooth and rounded above
 Covered by the tendons of the Extensor muscles
 Lower margin presents a rough transverse depression for the
attachment of the articular capsule of the ankle-joint.
The posterior articular surface
 Is traversed by a shallow groove directed obliquely downward and
medialward,
 It is continuous with a similar groove on the posterior surface of the
talus and serving for the passage of the tendon of the Flexor hallucis
longus.
The Lateral articular surface
 Presents a triangular rough depression for the attachment of the
inferior interosseous ligament connecting it with the fibula
 The lower part of this depression is smooth, covered with cartilage in
the fresh state, and articulates with the fibula.
 The surface is bounded by two prominent borders, continuous above
with the interosseous crest
 They afford attachment to the anterior and posterior ligaments of the
lateral malleolus.
The Medial articular surface
 Is prolonged downward to form a strong pyramidal process, flattened
from without inward—the medial malleolus.
 The medial surface of this process is convex and subcutaneous
 Its lateral or articular surface is smooth and slightly concave, and
articulates with the talus
 Its anterior border is rough, for the attachment of the anterior fibers of
the deltoid ligament of the ankle-joint
 Its posterior border presents a broad groove, the malleolar sulcus,
directed obliquely downward and medialward, and occasionally
double
 This sulcus lodges the tendons of the Tibialis posterior and Flexor
digitorum longus.
 The summit of the medial malleolus is marked by a rough depression
behind, for the attachment of the deltoid ligament.
Ossification of tibia
 The tibia is ossified from three centers one for the body and one for
either extremity.
 Ossification begins in the center of the body, about the seventh week of
fetal life, and gradually extends toward the extremities.
 The center for the upper epiphysis appears before or shortly after
birth; it is flattened in form, and has a thin tongue-shaped process in
front, which forms the tuberosity;
 The center for the lower epiphysis appears in the second year.
 The lower epiphysis joins the body at about the eighteenth, and the
upper one joins about the twentieth year.
 Two additional centers occasionally exist, one for the tongue-shaped
process of the upper epiphysis, which forms the tuberosity, and one for
the medial malleolus.