ESHS 120 Exam 3 Knee

knee/leg bones

femur, patella, tibia, fibula

femur

thigh bone; longest bone in the body
- femoral condyles to tibia
- trochlear groove-concavity for patella

tibia

the medial and larger bone of the lower leg (shin bone)
- 90% weight bearing
- tibial tuberosity
- Gerdy's tubercle

fibula

The lateral and smaller bone of the lower leg
- attachment for knee structures

patella

'knercap'
- sesamoid bone
- imbedded in quadriceps + patella tendons
- pully for knee extension

tibiofemoral joint (knee)
bones + joint type

femur + tibia
hinge joint (biaxial)

patellofemoral joint (kneecap)

patella posterior vertical ridge + femoral trochlear groove-concavity
arthrodial joint (gliding)

quadriceps for patellofemoral joint

- strength & endurance important for stability
- muscles prone to atrophy after injury
-therapy such as knee extension + functional weight bearing activities

knee menisci

fibrocartilage discs attached to tibial plateaus
- medial + lateral
- deepen tibial fossa
- enhance stability
medial meniscus = larger + open C
lateral meniscus = smaller + closed C

anterior cruciate ligament (ACL)

attaches to the anterior aspect of the tibial plateau to posterior femur
- restricting anterior movement of the tibia on the femur
- most common serious knee injury
- men = contact
- women = non-contact

posterior cruciate ligament (PCL)

posterior aspect of the tibial plateau to anterior femur
- restricting posterior movement of the tibia on the femur
- uncommon injury

lateral collateral ligament (LCL)

attaches to the femur and the fibula
- maintains stability of the lateral aspect of the knee joint

medial collateral ligament (MCL)

distal end of femur to proximal end of tibia
- major purpose is to prevent the knee from valgus and external rotating forces
- common injury in contact sports

synovial cavity of knee

supplies knee with synovial fluid
lies under patella and between surfaces of tibia and femur

infrapatellar fat pad

small, triangular fat pad below the patella behind the patellar ligament

knee bursae

13 located at knee joint
-absorb shock + reduce friction

knee joint
movements°

flexion: 140°
extension: 0-10° (genu recurvatum)
- as knee extends, slight external rotation
- as knee flexes, slight internal rotation

quadriceps muscles

rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
- knee extension

quadriceps functions

- concentric contraction when jumping
- eccentric contraction when deceleration
- 20-33% stronger than hamstrings

hamstring muscles

biceps femoris, semitendinosus, semimembranosus
- popliteus assist in knee internal rotation
- tensor fascia latae assist in knee external rotation
- knee flexion

knee extensors

rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

knee flexors

biceps femoris, semitendinosus, semimembranosus, sartorius, gracilis, popliteus, gastrocnemius

knee internal rotators

semitendinosus, semimembranosus, popliteus

knee external rotators

biceps femoris, tensor fascia latae

sciatic nerve

nerve extending from the base of the spine down the thigh, lower leg, and foot
- tibial: semitendinosus, semimembranosus, biceps femoris
- fibular: biceps femoris

rectus femoris

hip flexion
knee extension

vastus lateralis

knee extension

vastus intermedius

knee extension

vastus medialis

knee extension

semitendinosus

hip extension + internal rotation
knee flexion + internal rotation

semimembranosus

hip extension + internal rotation
knee flexion + internal rotation

biceps femoris

hip extension + external rotation
knee flexion + external rotation

tensor fasciae latae

hip abduction + flexion w/ internal rotation
knee external rotation

popliteal

knee flexion + internal rotation

ACL tear

- most common knee injury (athletes)
- may require surgery; dependent on severity + activity level

ACL "copers" vs. "non-copers"

the 'copers' are the ones that may not need surgery. 'non-copers' have instability and will need surgert

ACL grade I sprain

ligament is mildly damaged; slightly stretched but still able to stabilize knee joint

ACL grade II sprain

ligament stretched loose; partial tear of ligament

ACL grade III sprain

complete tear; joint unstable

ACL tear mechanism

- changing direction rapidly
- stopping suddenly
- decelerate while running
- jump landing incorrectly
- direct contact or collision

ACL tear symptoms

- pain, swelling, knee buckling
- loss ROM
- tenderness
- discomfort gait
- instability

patellar tendon rupture
partial and complete tear

tear at attachment to kneecap + bone can break off
tear from tendinitis usually occurs in middle of tendon

patellar tendon rupture causes

- injury
- falls
- jumping
- tendon weakness
- chronic patellar tendinosis

patellar dislocation

The patella becomes dislocated from the joint, most often laterally
- often in children due to abnormality of knee + looser ligaments (girls more often)
- children with cerebral palsy or down syndrome more often

patellar tendinitis (jumper's knee)

common cause of anterior knee pain (at inferior pole of patella). Running and jumping sports—an "overuse" injury
- tiny tears in tendon multiply and cause pain form inflammation + weakness

patellar tendinitis (jumper's knee) symptoms

- pain + tenderness around patellar tendon
- swelling
- pain with jumping, running, walking
- pain when bending/straightening leg
- tenderness behind lower kneecap

patellar femoral syndrome

pain in front of kneecap
- common in women and athletes
- difficult to climb stairs, kneeling, or everyday activities
- alignment of kneecap problems and overuse from athletes
- relieved from lower activity or therapeutic exercise program

patellar femoral syndrome
causes

- overuse
- patellar malalignment
- leg alignment issues
- patella alta
- muscle imbalances or weaknesses (quads)

patella atla

high riding patella or kneecap shifting too far laterally or medially

patellar femoral syndrome
symptoms

- pain beneath or around kneecap during activity
- clicking or grinding
- giving way of knee sensation
- pain after maintaining sitting position
- swelling
- tight feeling in calves and thighs

meniscus tear

A tear in the meniscus which is the cartilage that acts as a cushion for the joint

types of meniscus tears

- bucket
- flap
- radial
- degenerative

meniscus tear symptoms

- pain in knee (medial, lateral, posterior)
- swelling
- catching or locking
- inability to fully extend or bend
- limping

unhappy triad

ACL, MCL, medial meniscus

iliotibial band tendinitis

IT band irritated + swollen from rubbimg against hip or knee
- outside leg
- commonly against lateral femoral condyle
- can run against greater trochanter

ITB syndrome
causes

- not stretching, warming up, or cooling down
- overworking
- improper rest
- wearing worn-out shoes
- running uneven, tilting hip
- running downhill