Supporting Structures

Question 1

Describe the basic structure and function of the menisci

Answer 1

Structure

• Crescent shaped fibrocartilaginous structures
• Concave superiorly & flatter inferiorly
• 2 horns: anterior and posterior
• Outer borders are thick and vascular
• Inner borders are thin and avascular

Function

• Deepen tibial articulating surfaces
• Shock absorbers
• Conform to changing femoral articular surface shape during movement.

Question 2

Describe the shape and attachments of the medial meniscus.

Answer 2

- C shaped (thinner)
Anterior horn attaches:
- Intercondylar area + ACL
- Transverse & coronary ligaments
Posterior horn attaches:
- PCl 
- Posterior horn of lateral meniscus
- Blends with capsule and MCL (makes it less mobile so more easily damage).

Question 3

Describe the shape and attachments of the lateral meniscus.

Answer 3

• more O shaped (stouter)
• no attachment to capsule or LCL
  Anterior horn attaches:
• Anterior intercondylar eminence (post to ACL)
• Transverse and coronary ligaments
  Posterior Horn attaches:
• Posterior intercondylar eminence (ant to post horn of medial meniscus)

Question 4

Describe the coronary ligaments of the knee & their function.

Answer 4

• Part of the fibrous capsule.
• 2 ligaments: lateral and medial.
• connect the inferior edges of the meniscus to the periphery of the tibial plateau
• Stabilise the menisci and limit rotation of the knee.

Question 5

Describe the capsule of the knee

Answer 5

• Thick fibrous outer layer with synovial inner layer (synovial membrane projects inwards to exclude cruciates)
  Attachments
• Posteriorly: Post femoral condyles + intercondylar fossa
  : Post tibial condyles
• Medially: Blends with gastrocnemius and soleus
  : Medial articular margins of femoral + tibial condyles
  : Blends with MCL
• Lateral: Lateral femur above popliteus
  : Lateral tibial condyle
  : Fibula head
• Anteriorly: Patella and retinaculum
  : Capsule is replace by quadriceps tendon

Question 6

Describe the oblique popliteal ligament and the ligaments of wrisberg and humphrey

Answer 6

Oblique popliteal ligament

• Expansion of the semimembranosus tendon
• Functions to reinforce the posterior capsule to prevent hyperextension

Ligaments of Wrisberg and Humphrey (meniscofemoral ligaments)

• run from post horn of lateral menisicus to lateral aspect of medial femoral condyle (splitting around the PCL)
• Stabilise the more mobile Lateral meniscus and reinforce the PCL

Question 7

Describe the attachments and function of the Anterior Cruciate Ligament

Answer 7

Attachments:
- Anterior intercondylar area of tibia
(Runs posteriorly/laterally/superiorly)
- Posterior part of intercondylar area of lateral femoral condyle

Function:
- Prevent anterior translation of the tibia

Question 8

Describe the attachments and function of the transverse ligament.

Answer 8

Attachments:
- Anterior horns of menisci

Function:
- prevents the menisci from translating forwards

Question 9

Describe the attachments and function of the Posterior Cruciate ligament

Answer 9

Attachments
- Posterior intercondylar area of tibia
(Runs anteriorly/medially/superiorly)
- Lateral surface of the medial femoral condyle

Function:
Prevent posterior translation of the tibia on fixed femur

Question 10

Describe the shape, attachments and function of the Medial Collateral ligament

Answer 10

Shape

• broad/flat ligament (~10cms long)
• fan shaped

Attachments
- Medial epicondyle of the femur
- Medial proximal shaft of tibia (above pes anserinus)
(Deep fibres blend with capsule and medial meniscus)

Function
- Limits valgus movement of tibia on fixed femur (away from midline).

Question 11

Describe the shape, attachments and function of the Lateral Collateral Ligament

Answer 11

Shape:
- Strong rounded cord

Attachments:

• Lateral epicondyle of femur
• Apex of head of femur (BF bifurcates around it)

Function:
- Limits Varus movements (tibia towards midline).