Cross Sectional Lower Extremity Anatomy

lower extremity function

responsible for bearing weight of upper body and accommodating demands of movement placed on this system

lower extremity consists of

hip/hip jt, femur, patella, knee/knee jt, tib/fib, ankle/ankle jt, foot (tarsal bones/metatarsals/phalanges)

hip function

provides strength to carry the weight of the body in an erect position

hip joint type/articulation of

synnvial ball and socket- wide range of motion
created by articulation of femoral head with acetabulum of pelvis

femur

longest, heaviest, and strongest bone in body
proximal end= head, neck, 2 processes (greater and lesser trochanters)

distal portion of femur broadens into ____ covered in

medial and lateral condyles covered in articular cartilage

knee jt

distal femur, proximal tibia, patella, proximal fibula

patella is

largest sesamoid bone in body with a flat, triangular shape and distal pointed apex

patella location

embedded in quadriceps tendon

tibia has

widened proximal end with two cartilage covered projections called medial and lateral condyles

superior articular surface of tibia

condyles has flattened surface called tibial plateaus that articulate with femoral condyles

intercondylar eminence

separate condyles of tibia and end in two points called medial and lateral intercondylar tubercles

attachment sites for ACL and meniscus

intercondylar tubercles and roughened areas around them

Type 1 tibial plateau fx looks like

wedge shaped fx of lateral tibial plateau w/ displacement or depression <4mm

Type 1 tibial plateau fx caused by

lateral femoral condyles being driven into articular surface of tibial plateau

Type 2 tibial plateau fx looks like

fx with compression of lateral tibial plateau (type 1 fx w/ depressed component) > 4mm

Type 3 tibial plateau fx looks like

compression fx of lateral tibial plateau in which the articular surface is depressed and driven into the lateral tibial metaphysis

Type 3 tibial plateau fx caused by

axial forces

Type 4 tibial plateau fx looks like

medial tibial plateau fx w/. asplit or depressed component

Type 4 tibial plateau fx caused by

forces combined with axial loading in a hyperflexed knee

worst prognosis tibia fx

type 4

Type 5 tibial plateau fx looks like

wedge fx of medial and lateral tibial plateau w/ an inverted Y appearance. Articular depression typically seen in lateral plateau and might be associated with a fx of the intercondylar eminence

Type 5 tibial plateau fx caused by

MVA or motorcycle accident

Type 6 tibial plateau fx looks like

bicondylar fx w/ a dislocation of the metaphysis from the diaphysis

Type 6 tibial plateau fx caused by

high energy trauma and diverse combinations of forces

tarsal bones

talus, calcaneus, navicular, cuboid, medial cuneiform, intermediat cuneiform, lateral cuneiform

talus

2nd largest tarsal bone responsible for transmitting entire weight of body to foot

what transmits entire weight of body to foot

talus

talus anatomy

head- articulates with navicular bone
neck- short and broad extends anteriorly to head
body- wedge shaped w/ upper articular surface wider in front than back (trochlea)

calcaneus shape

largest tarsal bone
elongated shape with posterior surface comprising prominence of heel

calcaneus medial surface

shelf-like process called sustentaculum tali which supports the talus

calcaneus posterior plantar surface

calcaneal tuberosity which is large and is insertion for ligaments and tendons (Achilles Tendon)

cuboid location

lateral and anterior to calcaneus

cuboid articulation

anteriorly with bases. of4th and 5th metatarsal bones

navicular articulation

posteriorly with talus and anteriorly with cuneiform bones on medial side of foot

cuneiform articulations

1st-3rd metatarsal bases

metatarsal bone shape

long and slender
each have distal head, proximal base, shaft

metatarsal articulations

heads with proximal phalanges of toes
bases with tarsal bones

1st metatarsal has

2 sesamoid bones on medial and lateral surface of metatarsal head

how many phalanges in each foot

14
3 on each toe (proximal, middle, distal)
2 on great toe (proximal, distal)

phalanges of toes compared to fingers

shorter and stoutier than finger phalanges and each have body, base, head

common studies for bad fx of lower extremity

CTA lower extremity