Lecture 14 & 15 - The Knee Flashcards
1
Q
what actions are possible at the knee
A
flexion and extension
- > flexion/extension direction is reversed
2
Q
important structures of the femur
A
3
Q
important at the distal end of the femur
A
4
Q
important structures of the leg bones
A
5
Q
features of the tibia
A
- > medial bone in crural region
proximal features
- > has a medial and lateral condyle which are smooth surfaces for articulation with femur
- > has fibular articular facet which is an articulation site for head of fibula under lateral condyle
6
Q
tibial tuberosity
A
rough anterior projection inferior to the condyles
- > can be palpated just inferior to the patella
- > for attachment of patellar ligament
7
Q
features of fibula
A
- > long thin lateral crural bone
- > non weight bearing
- > has prox. head with flat articular facet for articulation with the tibia
- > narrow neck and slender shaft
- > distal end expands into lateral malleolus
8
Q
why do we have a fibula if it’s not weight bearing?
A
- Provides a site for muscle attachments
- It provides lateral stability to the ankle joint
- With the tibia, the fibula has an interosseous membrane (site for muscle attachment)
9
Q
what is the purpose of the patella
A
act as a pully to redirect the forces for the quad tendon
10
Q
muscles involved in knee flexion
A
- > hamstrings
- > gastrocnemius
- > sartorius
- > gracillis
11
Q
muscles involved in knee extension
A
quadriceps femoris (group of 4 muscles)
- > rectus femoris
- > vastus lateralis
- > vastus intermedius
- > vastus medialis
12
Q
what muscle “unlocks” the knee joint
A
popliteus
13
Q
OINA of popliteus
A
Origin
- > lat femoral condyle
Insertion
- > post surface of the tibial, proximal to the soleus line
Nerve
- > tibial nerve
Action
- > medially rotates the tibia relative to the femur when knee is flexed
- > unlocks the knee to allow flexion
- > helps prevent ant dislocation
14
Q
quadriceps
A
don’t forget gracillis
15
Q
OINA of rectus femoris
A
Origin
- > anterior inferior iliac spine
Insertion
tibial tuberosity (via patellar tendon)
Nerve
- > femoral
Action
- > flexes hip and extends knee
16
Q
OINA of vastus lateralis
A
Origin
- > greater trochanter and lateral lip of linea aspera
Insertion
- > tibial tuberosity via patellar tendon
Nerve
- > femoral
Action
- > extends knee
17
Q
OINA of vastus medialis
A
Origin
- > intertrochanteric line and medial lip of the linea aspera
Insertion
- > tibial tuberosity via patellar tendon
Nerve
- > femoral nerve
Action
- > extends knee
18
Q
OINA of vastus intermedius
A
Origin
- > anterior and lateral surfaces of the shaft of the femur
Insertion
- > tibial tuberosity via patellar tendon
Nerve
- > femoral nerve
Action
- > extends the knee
19
Q
OINA of sartorius
A
Origin
- > anterior superior iliac spine
Insertion
- > pes anserinus
Nerve
- > femoral
Action
- > tailors position, longest muscle in the body
- > flexes hip and knee, abducts and externally rotates hip
20
Q
OINA of the gracilis
A
Origin
- > ischiopubic ramus
Insertion
- > pes anserinus
Nerve
- > obturator
Action
- > flexes, medially rotates and adducts the hip
21
Q
OINA of the gastrocnemius
A
Origin
- > lat head: lateral aspect of the lateral condyle of the femur
- > med head: popliteal surface of the femur superior to the medial condyle
Insertion
- > post surface of the calcaneus via the calcaneal tendon (achilles)
Innervation
- > tibial nerve
Action
- > plantar flexes the ankle when the knee is extended
- > raises heel during walking
- > flexes knee
22
Q
O/I/I/A of bicep femoris
A
Origin
- > Long head: ischial tuberosity
- > Short head: linea aspera of the femur
Insertion
- > head of fibula
Nerve
- > LH fibial nerve
- > SH common fibular nerve
Action
- > both heads flex and extend the knee but only LH extends the hip
23
Q
O/I/I/A of semitendinosus
A
Origin
- > ischial tuberosity
Insertion
- > Pes anserinun (tibia)
Nerve
- > sciatic nerve (tibial)
Action
- > flex knee and extends hip
24
Q
O/I/I/A of semimembranosus
A
Origin
- > ischial tuberosity
Insertion
- > medial condyle of the tibia
Nerve
- > sciatic nerve (tibial)
Action
- > flex knee extends hip
25
knee joint characteristics
synovial hinge joint between femur, tibia and patella
- \> largest and most complex joint in the body
26
ligaments of the knee
- \> patellar lig
- \> fibular (Lateral) collateral lig
- \> tibial (medial) collateral lig
- \> ant (ACL) and post (PCL) cruciate ligs
- \> transerve lig
27
tibiofemoral joints
Menisci
- \> comprised of fibrocartilage
- \> wedge shaped with greater thickness in the periphery
- \> blood supply to the periphery but not to inner portions
* which doesn't allow for healing*
28
functions of menisci
- \> enhance stability
- \> shock absorption
- \> enhances lubrication of the joint
- \> limits movement between tibia and femur
29
injured meniscus
30
MCL
medial collateral ligament
- \> covers most medial side of knee joint
- \> protects against medial movement (imposed from a force on the lateral side
31
ligaments tears/ how do we test MCL injury
valgus stress test
32
LCL
lateral collateral ligament
- \> thinner than MCL
- \> protects agains lateral movement (imposed from a force on the medial side)
33
ACL
anterior cruciate ligament
- \> provides the primary (85%) restraint for anterior movement of the tibia
- \> tight when knee is in an extended position
34
how to test the ACL
**anterior drawer test**
- \> put fingers on patella and pull a 90deg flex knee
- \> if it pulls out then its torn
35
PCL
posterior cruciate ligament
- \> provides primary (95%) of restrained to posterior movement of the tibia on the femur
- \> taut in full knee extension
36
types of ACL injuries
non contact and contact injuries
37
why do ACL injuries occur more in females
- \> increased Q angle due to pelvis shape
38
movements of the tibiofemoral joint
Flex/Extend
- \> 130-145deg
Hyperextension
- \> 1-2deg
**Internal rotation**
**- \> 6-30deg**
**External rotation**
**- \> 45deg**
**\*through 90deg flexion, no rotation when in locked position**
39
movements of the patelofemoral joint
**Extension of the knee (resting position)**
- \> rests higher on femur between medial and lateral condyles
**Flexion at the knee**
- \> patella moves inferiorly and towards the lateral condyle of femur
40
popliteal fossa
edges defined by the…
- \> semimembranosus (sup and med)
- \> bicep femoris (sup and lat)
- \> two portions of gastrocnemius (inf and med/lat)
\*lat head of gastro and the plantaris muscle (inf and lat)
41
sciatic nerve
a bundle of 2 nerves
- \> tibial n
- \> common fibular n
* the nerve splits in the popliteal fossa*
42
vein that passes through the popliteal fossa
- \> small saphenous vein
- \> harvested to be used in some heart surguries
43
contents of the popliteal fossa
- \> tibial nerve
- \> common fibular nerve
- \> popliteal vein
- \> small saphenous vein
- \> popliteal artery
