Transcript Muscles of the Knee

Myology
Myology of the
Knee
1
Distal Femur
• Anatomy:
– Medial and lateral condyles: rounded portions of distal
femur that articulate with the proximal tibia
– Medial and lateral epicondyles: blunt projections from the
sides of the condyles
– Adductor tubercle: small projection above the medial
epicondyle
– Intercondylar fossa: deep depression between condyles,
location of the cruciate ligaments
– Patellar surface: area for articulation with patella
2
Anatomical Review: Distal Femur
3
Patella
• Small triangular bone
• Sesamoid bone that develops in the tendon of the quadriceps
muscle
• Patella functions to increase the leverage of the tendon of the
quadriceps muscle, to maintain the position of the tendon when the
knee is flexed, and protect the knee joint.
• Anatomy:
– Base: broad superior end of the patella
– Apex: point inferior end of patella
– Articular surface: on posterior side of patella are two articular
facets for medial and lateral condyles of the femur
4
Anatomical Review: Patella
5
Tibia
• Known as the shin bone
• Located medially in the leg
• Anatomy:
– Medial and lateral condyles: bulging prominences on the
proximal tibia, upper surfaces are concave for articulation with
femoral condyles
– Intercondylar eminence: upward projection on articular surface
between condyles; point of ligamentous attachment
– Tibial tuberosity: projection on anterior midline surface
– Tibial crest: sharp ridge on anterior surface
– Medial malleolus: rounded downward projection of distal end
of tibia
– Fibular notch: depression on lateral tibial for articulation with
the fibula
6
Fibula
• Located parallel and lateral to tibia
• Anatomy:
– Head: rounded portion located on the proximal fibula;
articulates with the inferior portion of the lateral condyle of the
tibia
– Lateral malleolus: rounded prominence at distal end of fibula,
forms prominence on the lateral surface of ankle.
7
Anatomical Review: Tibia and Fibula
8
Articular Anatomy: Knee
Largest joint in the body; a modified hinge joint made up of 3
joints:
Intermediate patello-femoral joint: between patella and
the patellar surface of the femur
Lateral tibio-femoral joint: between lateral condyle of the
femur, lateral meniscus, and lateral condyle of the tibia
Medial tibio-femoral joint: between medial condyle of the
femur, medial meniscus, and medial condyle of the tibia
9
Soft Tissue of the knee
(See slide #12 for diagram)
Articular Capsule: composed of fibrocartilage and expansions of muscle tendons
Medial and lateral patellar Retinaculae: fused tendons of the quadriceps muscles and the TFL
that strengthen the anterior surface of the joint.
Patellar Ligament: continuation of the common tendon of the quadriceps muscle extending from
the patella to the tibial tuberosity
Medial (Tibial) collateral ligament: broad flat ligament on the medial surface of the knee joint
extending from the medial femoral condyle to the medial tibial condyle
Lateral (Fibular) collateral ligament: strong rounded ligament on the lateral surface of the knee
joint extending from the lateral femoral condyle to the lateral aspect of the fibular head.
Anterior cruciate ligament (ACL): Intracapsular ligament extending from the anterior aspect of
the tibia to the posteromedial aspect of the lateral femoral condyle. Functions to limit forward
movement of the tibia on the femur and hyperextension of the knee
Posterior cruciate ligament (PCL): Intracapsular ligament extending from the posterior aspect of
the tibia to the anterolateral aspect of the medial femoral condyle. Functions to limit backward
movement of the tibia on the femur.
10
Soft Tissue of the knee (cont..)
(See slide #12 for diagram)
Medial and Lateral Menisci: fibrocartilage discs located between the femoral and
tibial condyles. They help to compensate for the irregular shape of the bones.
Bursae:
Prepatellar bursa: located between the patella and the skin; allows free movement of the
skin over the patella
Suprapatellar bursa: located between the inferior aspect of the femur surface and the
quadriceps muscle; allows free movement of the quadriceps tendon over the femur.
Deep infrapatellar bursa: located between the patellar tendon and the tibial tuberosity.
11
12
Knee Ranges of Motion
Each student should be able to describe and
demonstrate the following movements:
1. Knee flexion
2. Knee extension
3. Knee medial
Rotation
4. Knee lateral
Rotation
Note: Rotation of the knee can only be
performed when the knee joint is in the
flexed position.
13
Palpation of the knee
Patella: Supine, with the knee extended. Locate the patella on the anterior knee and palpate
its round Surface and edges. Gently shift the patella up and down and then side to side
(remember the patella is the largest sesamoid bone in the body).
Tibial tuberosity: Seated, again locate the patella and then slide your finger three to four
inches inferiorly. You will feel a large tuberosity which serves at the attachment of the
quadriceps group.
Tibial shaft: from the tibial tuberosity continue down and palpate the shaft of the tibia. The
shaft the tibia can be palpated down to the medial malleolus.
Head of the Fibula: Seated, locate the tibial tuberosity and then move your fingers laterally
three to four inches (toward the outside of the leg). The fibular head is slightly below the
lateral tibial condyle. Note the wide tip of the fibular head.
Pes Anserine attachment site: Pes anserine is the common insertion of the sartorius,
gracilis, and semitendinosis tendons on the superior medial aspect of the knee. Have your
partner seated with the knee flexed. Locate the tibial tuberosity and slide medially one inch
and explore the flat surface of the pes anserine and any palpable tendons coming into it.
14
Palpation of the knee (cont.)
Femoral condyles: Supine with the knee fully extended. Locate the patella and shift it medially onto
the medial condyle. Palpate the edge of the lateral femoral condyle which is now exposed.
Epicondyles of the Femur: Supine, with the knee flexed. Locate the patella and then slide directly
lateral from the patella to the outside of the knee (be sure to be proximal to the head of the fibula).
This is the lateral epicondyle. Return to the patella and then slide to the medial epicondyle on the
inside of the knee
Adductor tubercle: Supine with the knee flexed. Find the medial epicondyle and slide superiorly
along the medial side of the femur. As the outline of the femur drops off into soft tissue, explore for the
small point of the tubercle.
15
Muscles that move the knee
Sartorius
Rectus Femoris
Vastus Lateralis
Vastus Medialis
Vastus Intermedius
Quadriceps
Group
Biceps Femoris
Semitendinosus
Semimembranosus
Hamstring Group
16
Sartorius
O: ASIS
I: Pes Anserine (proximal
anteromedial aspect of the
tibia
A: Hip: Flexion, lateral rotation, and
abduction of the thigh.
Knee: Flexion and medial rotation of the
leg.
Pelvis: Anteriorly tilts the pelvis
N: Femoral nerve
Pes Anserine: common insertion of
the Sartorius, Semitendinosus, and
Gracilis
17
Rectus Femoris
O: AIIS and superior brim of the
acetabulum
I: Tibial tuberosity via the patellar
ligament
A: Flexion of the femur and
extension of the knee.
**Reversed muscle action results in
anterior tilting of the pelvis
N: Femoral nerve
18
Vastus Lateralis
O: Posterior aspect of the midshaft of the femur (linea
aspera)
I: Tibial tuberosity via the
patellar ligament
A: Extension of the knee
N: Femoral nerve
19
Vastus Medialis
O: Posterior aspect of the midshaft of the femur (linea
aspera)
I: Tibial tuberosity via the
patellar ligament
A: Extension of the knee
N: Femoral nerve
20
Vastus Intermedius
O: Anterior shaft and the
linea aspera
I: Tibial tuberosity via the
patellar ligament
A: Extension of the knee
N: Femoral nerve
21
Biceps Femoris
O: Long Head: Ischial tuberosity
Short Head: Linea aspera
I: Fibular head and lateral tibial
condyle
A: Hip: Extends, laterally rotates, and
adducts (long head) the thigh
Knee: Flexion and lateral rotation
of the leg when the knee is flexed
**Reversed muscle action results in a
posterior tilt of the pelvis.
N: Sciatic nerve
22
Semitendinosus
O: Ischial tuberosity
I: Pes anserine (proximal
anteromedial aspect of the
tibia
A: Hip: Extension and medial
rotation of the thigh
Knee: Flexion and medial
rotation of the leg when the knee is
flexed.
**Reversed muscle action results in a
posterior tilt of the pelvis.
N: Sciatic nerve
23
Semimembranosus
O: Ischial tuberosity
I: Medial tibial condyle
A: Hip: Extension and medial
rotation of the thigh
Knee: Flexion and medial
rotation of the leg when the knee
is flexed.
**Reversed muscle action results in a
posterior tilt of the pelvis.
N: Sciatic nerve
24