Knee Joint Flashcards
Tuberosity vs Trocanter
What does femur use?
Trocanter is a large bony prominence
Tuberosity is a moderate
Femur uses trocanter
Bone anatomy of the knee:
Articulations
Articular cavity
Has 2 articulations:
- between the femur and tibia
-between the femur and patella (Patellofemoral joint)
The articular cavity of the knee joint includes both the patellofemoral joint and tibiofemoral joint.
**Synovial cavity is continuous between the joints
What type of joint in the Knee and what is main movement and what facilitates this movement
Hinge joint that allows for mainly flexion (140 degrees) and extension
Facilatated by a huge cartilage covered Femoral articular surface
Label the key areas on the knee joint (femur side)
Anterior and posterior
Anterior:
Adductor tubercle
Medial epicondyle
Patellar Surface
Lateral epicondyle
Posterior:
Lateral condyle
Adductor tubercle
Medical condyle
Facet for attachment of anterior cruciate ligament
Intercondylar fossa
Facet for attachment of posterior cruciate ligament
Label the key areas on the knee joint (tibia side)
Anterior and posterior
Anterior:
Tibial plateau
Tubercles of intercondylar eminence
Lateral condyle
Medial condyle
Anterior attachment of medial meniscus
Tibial tuberoscity
Shaft of tibia
Posterior:
Groove
Attachment of medial meniscus
Attachment of posterior cruciate ligament
Articualr facet for proximal head of fibula
Label the FULL knee anatomy (XRAY picture)
Lecture Slide
Patella:
Types of poles
type of bone
located
What does patella ligament attach to
Role: Protects?
Patella has an upper and lower pole
Patella is a sesamoid bone
It sits in the tendon of the quadriceps muscles
patellar ligament attaches to tibial tuberosity of tibia
Protects the quadreceps tendon
Axis of limb:
How is the weight transmitted?
Purpose of this route of transmission
Weight of body is transmitted to centre of hip joints then down leg
If leg is aligned well weight is transmitted through the knee joint and ankle joint
= “Normal alignment” of lower limb
Minimises wear on joints and energy required to stand
What are the 3 types of axis of limbs? Describe their shape
- Normal
- Varus alignment
- babies and old people, apex of the joint points out - Valgus alingment
- knees apex point in
How many major Knee ligaments and what are they
5 ligaments
- Patellar ligament /tendon
2/3. The Medial and Lateral Collateral
ligaments
4/5. Anterior and Posterior Cruciate ligaments
Tendon vs ligament
- Tendon attaches muscle to bone
- Ligament attaches bones to bones in joints
Describe the Patellar ligament/tendon
- patella is what type of bone
-attached where
The Patellar ligament is the continuation of the quadriceps mechanism (making the patella a sesamoid bone).
It is attached to the inferior margins of the patella (superiorly) and the tibial tuberosity (inferiorly).
***Clinically call it patella tendon
Describe the The Medial and Lateral Collateral
ligaments:
- Attaches where
-Where do they ‘run’ from/to
- Function
The Medial and Lateral Collateral
ligaments (MCL and LCL) attach at the sides of the knee
(Attach at femur to either side of knee)
MCL:
runs from the medial femoral epicondyle to the medial tibia plateau (posterior to the attachment of the Pes Anserinus).
* It is a broad ligament which blends with the
underlying joint capsule
LCL:
The LCL runs from the lateral femoral epicondyle to the fibula head.
It is a cord-like ligament which is discrete from the joint capsule
Function:
prevent knee going valgus or varus AND allows you to actually stand up
Anterior and Posterior Cruciate ligaments (INTRACAPSULAR)
- where do they ‘run’ to and from
-Importance?
- The Anterior and Posterior Cruciate ligaments (ACL and PCL) run from the intercondylar region of the tibia ( ‘tibial spine’) to the distal femur
- Important in stabilizing the knee in the AP plane, Stabilise knee joint so it can act as a hinge joint, Stops “sliding” of tibia back a forth
ACL:
The ACL runs from the anterior tibial spine to the lateral condyle of the femur. It prevents the tibia from sliding forward on the on the femur
(prevents the tibia sliding forward on femur)
PCL:
The PCL runs from the posterior tibial spine to the medial femoral condyle. It prevents
posterior translation of the tibia on the femur. (prevents the tibia from sliding backwards on
femur)
Are ACL and PCL inside or outside the articular cavity
Both cruciates are within the knee joint capsule but outside of the articular cavity (not within the synvoium).
ACL vs PCL location and function of BOTH (3)
- ACL - anterior tibial spine (intercondylar region of the tibia) to lateral femoral condyle
- PCL – posterior tibial spine (intercondylar region of the tibia) to medial femoral condyle
Function:
Stabilise knee joint so it can act as a hinge joint
* ACL prevents the tibia sliding forward on femur
* PCL prevents the tibia from sliding backwards
on femur
Knee Joint:
- What is joint capsule and where does it attach
- The joint capsule is the fibrous membrane that encloses the articular cavity.
- Attached where the cartilage finishes
Types of knee bursa
-location
- when does it become inflammed
Prepatellar bursa
- anterior to the patella.
* This can become inflamed with repeated
trauma e.g. kneeling for long periods of time.
Infrapatellar bursae
-superficial and deep to the patellar ligament (inferior to the patella itself)
- can also become inflamed and cause anterior knee pain
The Suprapatellar bursa
in continuity with the knee joint and sits between the quads tendon and the distal
femur.
Defining feature of prepatellar and infrapatellar bursae
The prepatellar and infrapatellar bursae dont communicate with the knee joint
Suprapatellar bursa
- coninutity or not?
- Location?
- what happens during knee joint effusion?
- Anteriorly the membrane is reinforced by
-
The Suprapatellar bursa is in continuity with the knee joint and sits between the quads tendon and the distal femur.
This is often where fluid will accumulate during a knee joint effusion
Good place to access knee joint to aspirate fluid or inject into knee
Anteriorly the membrane is reinforced by the quads tendon
and patella ligament.
Menisci:
How many?
Purpose?
There are two fibrocartilaginous menisci within the knee joint- medial and lateral
They improve/increase the articulation between the femur and the tibia as shape of
the surfaces changes throughout the full range of motion. Also act as “shock absorbers”
Where is the lateral and medial meniscus attached to?
The medial meniscus is attached to the joint capsule and MCL, making it less mobile.
The lateral meniscus is not attached to the joint capsule and hence is more mobile
Menisci
Lateral vs Medial characteristics
Medial
* Larger
* More commonly injured
* Is attached to the joint capsule and MCL, making it less mobile.
Lateral
* The lateral meniscus is not attached to the joint capsule and hence is more mobile.
Both attached to tibia medially via ligaments anterior and posterior
Label areas of menisci
Lecture Slide
Knee Dislocation:
Types
What other structures are at risk with this dislocation
- Posterior (Tibia backward) 25%
- Hyperextension
Anterior 30-50% (Tibia driven forwards)
Puts neurovascular structures at risk:
Eg: Popliteal artery and vein, Tibial and common fibular nerves
Patella Dislocation
- how to fix
-mechanism
much more common than knee dislocation easy fix just push back into place.
Mechanism:
Direct trauma or twisting on a flexed knee
Vascular supply to the knee:
Why two main sources of vascular supply?
Branches of the femoral, lateral femoral circumflex and popliteal vessels (superiorly)
anastomosing with branches of the:
-Anterior tibial
-circumflex peroneal arteries (inferiorly).
Allow some blood to get to the leg if the popliteal artery is blocked acutely or chronically.
diabetes or atherosclerosis - often get narrowing of lower limb arteries a sometimes they can occlude completely , if this happens slowly, anastomosing vessels can enlarge so that if popliteal a. becomes completely obstructed there would be enough anastomotic flow to the distal limb, if it happens suddenly eg knee dislocation, anastomotic vessels will still be quite tiny & Won’t be able to supply enough blood to distal limb for it to survive
Nerve Supply to knee
Knee joint is supplied by branches from the femoral, sciatic, and
obturator nerves, which move the joint.
Some of these nerves go to the fibrous capsule and ligaments; others
innervate this capsule and reach the synovial membrane.
Muscles Acting on the Knee:
- what spinal nerves are involved + How
when testing for knee extension what spinal nerve are u testing
Femoral nerve
Roots L2 L3 L4
Anterior compartment thigh muscles Cause Knee extension
L3 component is most important for quadriceps
L2 –iliacus. (hip flexion)
L4 –saphenous - sensation medial leg
So for motor testing knee extension is L3 level
Myotomes:
List all the assosicated movements with each spinal nerve
C5
C6
C7
C8
T1
L2 –
L3 –
L4 –
L5 –
S1 –
C5 – Elbow flexion
C6 – Wrist extension
C7 – Elbow extension
C8 – Finger flexion
T1 – Finger abduction
L2 – Hip flexion
L3 – Knee extension
L4 – Ankle dorsiflexion
L5 – Great toe extension
S1 – Ankle plantarflexion
Muscles acting on the KNEE to do movements:
Flexion
Extension
Medial/internal rotation (of leg)
Lateral/external rotation (of leg)
Flexion (Myotomes L5,S1):
- Hamstrings
- Biceps femoris
-Semimembranosus
-Semitendinosus
-(Gracilis fem) (Sartoriu fems)
-gastrocnemius
-plantaris,
-popliteus
Extension (L3/L4)
- Anterior compartment
- Quads
Medial/internal rotation (of leg)
- Semitendinosis -Semimembranosus
Lateral/external rotation (of leg)
-Biceps femoris
Pes Anserinus:
Terrible/Unhappy Triad:
The Pes Anserinus (meaning “goose’s foot”) is the insertion of the tendons of Sartorius, Gracilis and Semitendinosus onto the medial surface of the proximal tibia. These tendons can be used to reconstruct a torn ACL.
This a common injury pattern1 resulting from a lateral (valgus) force to the knee. The three structures involved are typically the medial collateral ligament, anterior cruciate ligament and medial (or lateral) meniscus
locking mechanism
There also exists a ‘locking’ mechanism so that when the knee is fully extended the muscle energy required to maintain a straight leg is reduced (e.g. when standing and walking)
