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Questions and Answers

What is the primary function of the posterior cruciate ligament when the knee joint is extended?

Prevent posterior displacement of the femur on the tibia

Support lateral stability of the knee joint

Prevent anterior displacement of the femur on the tibia (correct)

Facilitate medial rotation of the tibia

Which muscle group assists in flexion of the knee joint?

Gluteal muscles

Adductor muscles

Quadriceps muscles

Hamstring muscles (correct)

How does the locking mechanism of the knee joint occur during standing?

By extension of the hip joint

By flexion of the knee joint

By medial rotation of the femur on the tibia (correct)

By lateral rotation of the femur on the tibia

Which ligament is located in front of the posterior cruciate ligament?

Anterior menisco-femoral ligament Signup and view all the answers

Which of the following nerves is NOT involved in the innervation of the knee joint?

Radial nerve Signup and view all the answers

What anatomical structure marks the transition between the femoral artery and the popliteal artery?

Adductor hiatus Signup and view all the answers

Which of the following structures is located above the popliteal vein?

Popliteal artery Signup and view all the answers

Which nerves arise as major branches from the sciatic nerve in the popliteal fossa?

Tibial and common fibular nerves Signup and view all the answers

What type of joint is the knee classified as?

Modified hinge joint Signup and view all the answers

What structure is NOT part of the knee joint articulation?

Fibula Signup and view all the answers

Which artery bifurcates into the anterior and posterior tibial arteries?

Popliteal artery Signup and view all the answers

Which of the following muscles is most superficial in the popliteal fossa?

Lateral head of gastrocnemius muscle Signup and view all the answers

Which anatomical feature facilitates the pull of the quadriceps femoris muscle over the knee?

Femoropatellar articulation Signup and view all the answers

What is the primary role of the menisci in the knee joint?

Stabilize the joint and absorb shock Signup and view all the answers

Which ligament extends from the medial epicondyle of the femur to the medial surface of the tibia?

Tibial collateral ligament Signup and view all the answers

What does the ligamentum patellae connect?

The patella to the tuberosity of the tibia Signup and view all the answers

How does the anterior cruciate ligament (ACL) contribute to knee function?

Prevents anterior displacement of the femur Signup and view all the answers

Which structure is responsible for lining the capsule of the knee joint?

Synovial membrane Signup and view all the answers

What is the anatomical significance of the popliteus tendon in relation to the knee joint?

It stabilizes the lateral meniscus Signup and view all the answers

Which of the following describes the fibrous capsule of the knee joint?

Reinforced by various muscles and ligaments Signup and view all the answers

Which muscle's tendon expands to form the oblique popliteal ligament?

Semimembranosus Signup and view all the answers

Study Notes

Medial Compartment of Thigh & Adductor Canal

The medial compartment of the thigh contains muscles responsible for adduction (moving towards the midline) of the thigh
The adductor canal, also known as the Hunter's canal or subsartorial canal, is a passageway within the middle third of the thigh.

Objectives

Describe the origin, insertion, nerve supply, and action of the medial thigh muscles.
Outline the boundaries of the adductor canal.
Detail the contents of the adductor canal.

Muscles of the Adductor Compartment

Obturator externus
Pectineus
Adductor longus
Adductor brevis
Adductor magnus
Gracilis

Adductor Muscles Origin

Adductor longus, adductor brevis, and gracilis originate from the pectineal line of the hip.
Adductor part of the magnus arises from the ischiopubic ramus.
Obturator externus originates from the obturator foramen.
Pectineus originates from the pectineal line of the hip bone.

Adductor Muscles Insertion

All adductor muscles (except the sciatic part of adductor magnus) are inserted into the linea aspera of the femur.
The sciatic part of adductor magnus inserts into the adductor tubercle of the femur.
Obturator externus inserts into the trochanteric fossa.
Gracilis inserts medial to the tibial tuberosity.
Pectineus inserts into the pectineal line on the femur.

Nerve Supply of Muscles

Obturator nerve: supplies most of the adductor muscles.
Femoral nerve: supplies the pectineus.
Sciatic nerve: supplies adductor magnus (sciatic portion)

Action of Muscles

All adductors adduct the hip.
Adductors (except the obturator externus) medially rotate the hip..
Obturator externus laterally rotates the hip.
Adductor magnus (sciatic part) extends the hip..

Adductor Magnus

Hamstring part: located in the posterior compartment of the thigh.
Adductor part: located in the medial compartment of the thigh.
Adductor hiatus: an opening in the distal attachment of the adductor magnus muscle, where the femoral artery and vein pass through to reach the popliteal fossa.

Adductor Canal

Intermuscular space in the middle third of the thigh
15cm in length
Starts at the apex of the femoral triangle.
Ends at the lower end of adductor magnus, (adductor hiatus)

Boundaries of Adductor Canal

Anteriorly: sartorius
Posteriorly: adductor longus and magnus
Laterally: vastus medialis

Contents of Adductor Canal

Femoral vein
Femoral artery
Saphenous nerve

Popliteal Fossa

Diamond-shaped space behind the knee joint.
Boundaries:
- Upper part of the space:
- Medially: lower end of semitendinosus and semimembranosus muscles.
- Laterally: lower end of biceps femoris muscle.
Lower part of the space:
- Medially: medial head of the gastrocnemius muscle.
- Laterally: plantaris muscle and lateral head of the gastrocnemius muscle.

Floor of Popliteal Fossa

Capsule of the knee joint.
Back of upper tibia.
Back of lower femur.
Popliteus Muscle

Roof of Popliteal Fossa

Skin
Superficial fascia
Small saphenous vein
Posterior cutaneous nerve of the thigh
Deep fascia continuous with the fascia lata of the thigh.

Popliteal Artery

Continuation of the femoral artery in the posterior compartment of the thigh
Enters popliteal fossa through the adductor hiatus.
The deepest structure in the popliteal fossa.

Popliteal Vein

Formed by the union of the anterior and posterior tibial veins.
Superficial to the popliteal artery.
Exits the popliteal fossa through the adductor hiatus, becoming the femoral vein.

Knee Joint

Synovial joint that allows flexion and extension.
Articulation point: lower end of the femur, upper end of the tibia, and patella.
The fibula is not involved.

Articular Surface of Knee Joint

Two femoro-tibial articulations (lateral and medial) between the femoral and tibial condyles.
One intermediate femoro-patellar articulation between the patella and femur (allowing quadriceps femoris to exert force).

Fibrous Capsule of Knee Joint

Superiorly: femoral condyles anteriorly and femoral condyles and intercondylar fossa posteriorly.
Inferiorly: articular margin of the tibia (except where the popliteus tendon and patellar ligament cross).
Laterally: deficient to allow popliteus tendon to exit.
Anteriorly: deficient due to patellar ligament passage.

Fibrous Capsule Reinforcement by Muscles

Anteriorly: retinacula of vasti.
Posteriorly: biceps femoris laterally and semimembranosus and semitendinosus medially.

Synovial Membrane

Lines the capsule of the knee joint.
Attaches to the peripheral margins of the patella and edges of the menisci.
Separates cruciate ligaments from the joint cavity (intracapsular, extrasynovial).

Articular Cartilages (Menisci)

Fibrocartilage in the articular surface of the tibia.
Stabilize the joint and act as shock absorbers.
Have horns attached to the intercondylar area of the tibia and are attached to the synovial membrane at their external margins.

Differences Between Medial & Lateral Menisci

Medial meniscus: semilunar shape, attached to tibial collateral ligament; frequently torn with injuries to the medial collateral ligament.
Lateral meniscus: semicircular shape, separated from the fibular collateral ligament by the popliteus tendon; less prone to tear.

Ligaments: Extrinsic Ligaments

Tibial collateral ligament extends from the medial epicondyle of the femur to the medial tibia; firmly attached to the medial meniscus.
Fibular collateral ligament runs from the lateral epicondyle of the femur to the head of the fibula; separated from the lateral meniscus by the tendon of the popliteus muscle.

Ligaments: Intrinsic Ligaments

Anterior cruciate ligament extends from the intercondylar area of the tibia superiorly, posteriorly, and laterally to attach to the posterior surface of the medial condyle of the femur. Prevents posterior displacement of femur on tibia and anterior displacement of tibia on femur.
Posterior cruciate ligament originates from the posterior part of the intercondylar area of the tibia and attaches to the anterior part of the lateral surface of the medial condyle of the femur; prevents anterior displacement of femur on tibia and posterior displacement of tibia on femur.
Oblique popliteal ligament is an expansion of the semimembranosus tendon strengthening the posterior part of the fibrous capsule.
Arcuate popliteal ligament originates from the posterior part of the head of the fibula, extends over the popliteus muscle, and attaches to the posterior surface of the capsule of the knee joint.
Transverse ligament of knee joint connects the anterior edges of the medial and lateral menisci.

Movements of the Knee Joint

Flexion: performed via biceps femoris, semitendinosus, semimembranosus, gracilis, gastrocnemius, plantaris, and popliteus.
Extension: performed by the quadriceps assisted by tensor fascia lata.

Locking/Unlocking Mechanism of Knee

Locking: medial rotation of the femur on the tibia.
Unlocking: lateral rotation of the femur on the tibia.

Blood Supply of Knee Joint

Branches from obturator, femoral, tibial, and common fibular nerves.

Nerve Supply of Knee Joint

Branches from obturator, femoral, tibial, and common fibular nerves.

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Test your knowledge on the anatomy and functions of the knee joint with our comprehensive quiz. Explore key components such as ligaments, muscles, and blood vessels involved in knee movement and stability. See how much you know about this essential joint in human anatomy.

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