Knee Joint

Question 1

Tuberosity vs Trocanter

What does femur use?

Answer 1

Trocanter is a large bony prominence

Tuberosity is a moderate

Femur uses trocanter

Question 2

Bone anatomy of the knee:
Articulations
Articular cavity

Answer 2

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

Question 3

What type of joint in the Knee and what is main movement and what facilitates this movement

Answer 3

Hinge joint that allows for mainly flexion (140 degrees) and extension

Facilatated by a huge cartilage covered Femoral articular surface

Question 4

Label the key areas on the knee joint (femur side)

Anterior and posterior

Answer 4

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

Question 5

Label the key areas on the knee joint (tibia side)

Anterior and posterior

Answer 5

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

Question 6

Label the FULL knee anatomy (XRAY picture)

Answer 6

Lecture Slide

Question 7

Patella:
Types of poles
type of bone
located
What does patella ligament attach to
Role: Protects?

Answer 7

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

Question 8

Axis of limb:
How is the weight transmitted?

Purpose of this route of transmission

Answer 8

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

Question 9

What are the 3 types of axis of limbs? Describe their shape

Answer 9

1. Normal
2. Varus alignment
   - babies and old people, apex of the joint points out
3. Valgus alingment
   - knees apex point in

Question 10

How many major Knee ligaments and what are they

Answer 10

5 ligaments

1. Patellar ligament /tendon
   2/3. The Medial and Lateral Collateral
   ligaments
   4/5. Anterior and Posterior Cruciate ligaments

Question 11

Tendon vs ligament

Answer 11

• Tendon attaches muscle to bone
• Ligament attaches bones to bones in joints

Question 12

Describe the Patellar ligament/tendon
- patella is what type of bone
-attached where

Answer 12

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

Question 13

Describe the The Medial and Lateral Collateral
ligaments:
- Attaches where
-Where do they ‘run’ from/to
- Function

Answer 13

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

Question 14

Anterior and Posterior Cruciate ligaments (INTRACAPSULAR)

• where do they ‘run’ to and from
  -Importance?

Answer 14

• 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)

Question 15

Are ACL and PCL inside or outside the articular cavity

Answer 15

Both cruciates are within the knee joint capsule but outside of the articular cavity (not within the synvoium).

Question 16

ACL vs PCL location and function of BOTH (3)

Answer 16

• 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

Question 17

Knee Joint:
- What is joint capsule and where does it attach

Answer 17

• The joint capsule is the fibrous membrane that encloses the articular cavity.
• Attached where the cartilage finishes

Question 18

Types of knee bursa
-location
- when does it become inflammed

Answer 18

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.

Question 19

Defining feature of prepatellar and infrapatellar bursae

Answer 19

The prepatellar and infrapatellar bursae dont communicate with the knee joint

Question 20

Suprapatellar bursa
- coninutity or not?
- Location?
- what happens during knee joint effusion?
- Anteriorly the membrane is reinforced by
-

Answer 20

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.

Question 21

Menisci:
How many?
Purpose?

Answer 21

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”

Question 22

Where is the lateral and medial meniscus attached to?

Answer 22

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

Question 23

Menisci
Lateral vs Medial characteristics

Answer 23

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

Question 24

Label areas of menisci

Answer 24

Lecture Slide

Question 25

Knee Dislocation: Types What other structures are at risk with this dislocation

Answer 25

1. Posterior (Tibia backward) 25% 2. Hyperextension Anterior 30-50% (Tibia driven forwards) Puts neurovascular structures at risk: Eg: Popliteal artery and vein, Tibial and common fibular nerves

Question 26

Patella Dislocation - how to fix -mechanism

Answer 26

much more common than knee dislocation easy fix just push back into place. Mechanism: Direct trauma or twisting on a flexed knee

Question 27

Vascular supply to the knee: Why two main sources of vascular supply?

Answer 27

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

Question 28

Nerve Supply to knee

Answer 28

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.

Question 29

Muscles Acting on the Knee: - what spinal nerves are involved + How when testing for knee extension what spinal nerve are u testing

Answer 29

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

Question 30

Myotomes: List all the assosicated movements with each spinal nerve C5 C6 C7 C8 T1 L2 – L3 – L4 – L5 – S1 –

Answer 30

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

Question 31

Muscles acting on the KNEE to do movements: Flexion Extension Medial/internal rotation (of leg) Lateral/external rotation (of leg)

Answer 31

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

Question 32

Pes Anserinus: Terrible/Unhappy Triad:

Answer 32

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

Question 33

locking mechanism

Answer 33

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)