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Sunday, August 22, 2010

Joints of the Lower Limb

Hip Joint
          It is synovial ball and socket variety of joint. It is formed by the articulation of head of femur with the acetabulum of hip bone. The following are the characteristics of hip joint.

  • Articular Capsule
          Superiorly it attaches to the acetabular rim(edge) and then encircle the hip joint in the form of circular fibers upto the neck of the femur.
  • Ileofemoral Ligament
          It is consist of longitudinal fibres which start from the anterior inferior iliac spine and extend upto the intertrochanteric line anteriorly and intertrochanteric crest posteriorly.
  • Pubofemoral Ligament
          It is also consist of logitudinal fibers which start from the pubic rim and converge on the intertrochanteric line anteriorly.
  • Ischiofemoral Ligament 
          Its longitudinal fibers starts from the ischium posteriorly and converge on the intertrochanteric crest of the femur.
  • Ligament of head of Femur (Ligamentus teres or Round ligament)
          It starts from the acetabular fossa superiorly and attaches to the fovea capitus inferiorly.
  • Acetabular Labrum
          The cavity of the acetabulum contains the soft cartilaginous structure called labrum which deepens the acetabular cavity thus adds the stability of hip joint.
  • Transverse Ligament
          It is consist of circular fibers which starts from acetabuar notch and attaches to the ligamentus teres and to the neclk of femur.

  • Movements
          • Flexion
             o Iliopsoas
             o Rectus femoris
             o Sartorius

           • Extension
              o Gluteus maximus
              o Hamstring muscles

           • Abduction
              o Gluteus medius 
              o Gluteus minimus

           • Adduction
              o Adductor longus
              o Adductor fibres of the adductor magnus
              o Adductor brevis

           • Lateral rotation
              o Piriformis
              o Obturator internus and externus
              o Quadratus femoris
              o Superior and inferior Gamelli

           • Medial rotation
              o Anterior fibres if gluteus medius
              o Gluteus minimus
              o Tensor fasciae lata

Knee Joint
          It is the most largest and complex joint of the body. The knee is made up of four main bones- the femur (thigh bone), the tibia (shin bone), fibula (outer shin bone) and patella (kneecap). It is made up of three compartments.
Medial Compartment: It includes medial condyles of tibia and femur along with medial meniscus.
Lateral Compartment: It includes lateral condyles of femur and tibia along with lateral meniscus.
Anterior Compartment: It includes intercondylar area of femur and posterior surface of patella.

Extra-articular Features:
  • Articular capsule
          It does'nt cover knee joint completely. It is combination of different ligaments, tendons and their fibers.
  • Medial and Lateral Patellar Retinaculae
          The tendons of the quadricep femoris form retinaculae on both sides of the patella giving strength to the knee joint.
  • Patellar Ligament
          It connects the base of patella to tibial tuberosity. It is also giving strength to the knee joint anteriorly. Infra patellar pad of fat separates the patellar ligament from the cavity of knee joint.

  • Medial Collateral Ligament
           Superiorly starts from the medial condyle of femur and attaches to the medial condyle of tibia.It give strength to knee joint from medial side.
  • Lateral Collateral Ligament
          Superiorly starts from the lateral condyle of femur and attaches to the head of fibula.
  • Oblique Popliteal Ligament 
          It is flat ligament which extends from the intercondylar fossa of femur to the head of tibia.This ligament covers knee joint from the back.
  • Arcuate Popliteal Ligament
          It starts from the lateral condyle of femur and extends to the styloid process of fibula. This ligament covers the lower back of knee joint.

Intra-articular Features:
  • Cruciate Ligaments
          They are named due to cross shaped appearance. Anterior and posterior cruciate ligaments are named due to their relation with intercondylar area of the tibia.

               Anterior Cruciate Ligament (ACL): It starts from the anterior of intercondylar area of tibia, proceeds laterally and attaches to the medial surface of lateral condyle of femur. the point of attachment is b/w lateral meniscus and posterior cruciate ligament. It restiicts hyperextention of knee joint and also prevents anterior sliding of tibia over femur.

                Posterior Cruciate Ligament (PCL): It starts posterior to the intercondylar area of tibia, proceeds medially and attaches to the lateral surface of the medial condyle of femur. It prevents posterior sliding of tibia over femur.
  • Menisci (Sing- Meniscus)
          There are two fibrocartilages discs present on the upper surface of tibial plateau.
               Medial Meniscus: It is C-shaped disc. Its anterior part lies infront of ACL while posterior part part attaches infront of Lateral meniscus . Medial meniscus is attach medially to the medial collateral ligament and it also attaches the ACL.

               Lateral Meniscus: it is almost complete circular shape. It is starts posterior to the ACL and posteriorly attaches infront of medial meniscus.

               Function of Menisci: It make superior surface of the tibia concurrent to the articular surface of femur and also help in the distribution of synovial fluid in the knee joint cavity.
  • Movements
           • Extension
             o Quadriceps Femoris

           • Flexion

              o Hamstring muscles

Ankle Joint
          The synovial hinge joint.It is formed by the articulation of lower end of tibia, the two malleoli and body of talus.
  • Articular Capsule
          Capsule is thin and allows large range of movement.
  • Ligaments
          Capsule is strengthened by ligaments

               o Medial or deltoid ligament

               o Anterior talofibular ligament

               o Calcaneofibular ligament

               o Posterior talofibular ligament

  • Movements
      • Dorsiflexion
         o Tibialis anterior
         o Extensor hallucis longus
         o Extensor digitorum longus
         o Peroneus tertius

      • Plantar flexion
         o Gastrocnemius
         o Soleus
         o Plantaris
         o Peroneus longus
         o Peroneus brevis
         o Tibialis posterior
         o Flexor digitorum longus
         o Flexor hallucis longus

Inversion and eversion take place at the tarsal joints.

Subtalar Joint
          The joint between talus and calcaneum is called as subtalar joint. Gliding and rotatory movements are possible.


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