osteology

Tibia

Plan

· large upper end

· smaller lower end

· vertical shaft

Upper end

· widely expanded

· tuberosity anteriorly from lower part

· epiphyseal line runs around back and dips in front to include upper tuberosity

Superior articular surface

· medial condyle concave and oval

· lateral condyle convex and circular

· lateral surface curves down over posterior surface

Spine

· separates condyle

· two ridges and central groove

· ridges called medial and lateral intercondylar tubercles

· nothing attached to them

Anterior to spine (MAL)

· large smooth area for ACL

· lateral margin of this area receives anterior horn of lateral meniscus

· smooth area anterior to this for anterior horn of medial meniscus

Posterior to spine (LMP)

· deep slit behind medial tubercle for attachment of posterior horn of medial meniscus

· posterior horn of lateral meniscus attaches behind lateral tubercle

· smooth area sloping to oblique ridge for attachment of posterior cruciate ligament

Condyles

· incline posteriorly over popliteal surface

Medial

· posterior aspect grooved for semimembranosus insertion

Lateral

· facet for head of fibula

· groove above it for popliteus tendon

· facet on anterior surface for iliotibial tract

Shaft

· triangular in cross-section

· medial, extensor (anterolateral) and flexor (posteromedial) surfaces

· anterior, interosseous (lateral) and posterior borders

Medial surface

· subcutaneous

· receives

· pes anserinus anteriorly

· MCL behind this

Anterior border

· sharp proximally

· becomes blunt below

· continous with anterior border of medial malleolus

Extensor surface

· tibialis anterior attaches to upper 2/3

· surface bare below this

· crossed by tib ant and EHL

Interosseous border

· gives attachment to interosseous membrane

Flexor surface

· soleal line runs obliquely from

· just below superior TF jt

· posterior border 1/3 of way down

· politeus arises from above soleal line

· popliteus fascia from semimembranosus attaches to soleal line

· soleus arises from soleal line and middle 1/3 of posterior border

· vertical ridge from below soleal line

· TP arises between ridge and interosseous border

· FDL arises between ridge and posterior border

· lower surface bare

· crossed by TP and FDL

Lower end

· rectangular in cross-section

Surfaces

Medial surface

· forms medial malleolus

· crossed by great saphenous vein and nerve anteriorly

· distal surface attaches deep lamina of deltoid

Anterior surface

· crossed by

· TA and EHL

· anterior tibial NV bundle

· EDL

· squatting facet

· just above articular margin

· for talus in full dorsiflexion

Lateral surface

· triangular

· attaches interosseous tbiofibular ligament

Posterior surface

· groove behind medial malleolus

· lodges tendon of TP

· tendon of FDL attaches alongside it

· belly of FHL crosses on fibular side

Distal surface

· saddle-shaped facet for talus

fibula

Plan

· quadrilateral head

· slender shaft

· flattened malleolus

Head

· oval facet for superior TF jt

· back projected up as styoid process

· ataches arcuate ligament

· LCL attached in front of process

· biceps tendon attached further forward

· groove for popliteus tendon slopes down behind articular surface

Shaft

· three surfaces

· extensor, peroneal and flexor

Peroneal surface

· lateral surface

· ridge from posterior part of lateral malleolus

· subcutaneous area anteroinferior to ridge

· PL arises from upper 2/3

· PB arises from lower 2/3

· overlap in middle 1/3

· PB in front of PL

· surface bounded by anterior and posterior peroneal ridges

Interosseous border

· inferior triangular surface for interosseous membrane

· border runs proximally from apex

Extensor surface

· extremely narrow

· between anterior peroneal ridge and interosseous border

· EDL arises from upper 3/4

· PT arises from lower 1/4

· EHL arises from middle 2/4 and adjacent IOM

Flexor surface

· between interosseous border and posterior peroneal ridge

· very wide

· medial crest

· vertical ridge on medial aspect of middle 1/3

· runs laterally into interosseous border distally

· TP arises from between interosseous border and medial crest

· medial to crest

· FHL arises from between interosseous border and posterior peroneal ridge

· lateral and inferior to crest

· soleus arises from upper 1/3

Lateral malleolus

· projects further distally than medial malleolus

Medial surface

· triangular facet for talus

· malleolar fossa behind facet

· attaches posterior tibiofibular ligament and talofibular ligament

Subcutaneous surface

· attaches anterior talofibular and calcaneofibular ligament

· posterior part has groove for PB