Lower Leg 2

Anatomical Movements of the Lower Limb

  • Flexion: Decreases the joint angle. At the knee, the lower leg moves toward the posterior surface of the thigh; at the toes, it is the "scrunching" motion.

  • Extension: Increases the joint angle, such as straightening the knee or fanning the toes.

  • Dorsiflexion: Ankle flexion where the foot and toes move upwards toward the shin and face.

  • Plantar flexion: Ankle extension where the foot or toes point downward.

  • Eversion: Ankle rotation where the sole of the foot faces laterally.

  • Inversion: Ankle rotation where the sole of the foot faces medially; commonly occurs when rolling the ankle.

Quadriceps Muscles (Anterior Thigh)

  • Rectus femoris: Straight muscle running down the femur; originates on the anterior inferior iliac spine; inserts into the patella and tibial tuberosity via the quadriceps tendon and patellar ligament. Action: Hip flexion and knee extension.

  • Vastus lateralis: Large muscle on the lateral side; originates from the greater trochanter and linear aspera. Action: Knee extension.

  • Vastus medialis: Located on the medial side; originates from the linear aspera. Action: Knee extension.

  • Vastus intermedius: Situated directly beneath the rectus femoris; originates on the anterior and lateral surfaces of the femur. Action: Knee extension.

Hamstring Muscles (Posterior Thigh)

  • Biceps femoris: Positioned laterally; originates from the ischial tuberosity and linear aspera; inserts onto the lateral condyle of the tibia and the head of the fibula. Action: Hip extension and knee flexion.

  • Semitendinosus: Long muscle sitting on top of semimembranosus; originates from the ischial tuberosity; inserts into the proximal and medial surfaces of the tibia. Action: Hip extension and knee flexion.

  • Semimembranosus: Broad muscle located beneath semitendinosus; originates from the ischial tuberosity; inserts into the medial condyle of the tibia. Action: Hip extension and knee flexion.

Anterior and Lateral Compartments of the Lower Leg

  • Tibialis anterior: Located lateral to the tibia; originates on the lateral condyle of the tibia; inserts into the first metatarsal and cuneiform bone. Action: Dorsiflexion and inversion.

  • Extensor hallucis longus: Identified by the tendon running to the big toe; originates on the anterior surface of the fibula; inserts on the distal phalange of the big toe. Action: Big toe extension and ankle dorsiflexion.

  • Extensor digitorum longus: Originates on the lateral epicondyle of the tibia and anterior fibula; inserts into the middle and distal phalanges of toes 22 to 55. Action: Extension of digits and ankle dorsiflexion.

  • Fibularis longus (Peroneus longus): Located on the lateral surface; originates from the head and body of the fibula; inserts on the first metatarsal and cuneiform. Action: Plantar flexion and eversion.

Posterior Compartment of the Lower Leg

  • Gastrocnemius: Primary calf muscle; originates on the medial and lateral condyles of the femur; inserts into the calcaneus via the Achilles tendon. Action: Knee flexion and plantar flexion.

  • Soleus: Broad, flat muscle deep to the gastrocnemius; originates on the fibula head and medial tibia; inserts into the calcaneus via the Achilles tendon. Action: Plantar flexion.

  • Popliteus: Located in the popliteal fossa; originates on the lateral epicondyle of the femur; inserts into the proximal tibia. Action: Knee flexion and medial rotation of the tibia.

  • Tibialis posterior: Deepest muscle; originates on the proximal tibia and fibula; inserts into metatarsals 22 to 55, navicular bone, and all 33 cuneiforms. Action: Plantar flexion and inversion.

  • Flexor digitorum longus: Originates on the middle posterior tibia; inserts into the distal phalanges of toes 22 to 55. Action: Toe flexion and plantar flexion.

  • Flexor hallucis longus: Runs at an angle; originates on the inferior third of the fibula; inserts onto the distal phalange of the big toe. Action: Big toe flexion and plantar flexion.


Blood Vessels of the Lower Leg

  • Arteries:
      - Popliteal artery: Continuation of the femoral artery, splits into the anterior and posterior tibial arteries.
      - Fibular artery: Branches from the posterior tibial artery, travels down the leg's lateral side.

  • Veins:
      - Great saphenous vein: The longest vein, runs from the foot to the groin.
      - Lesser saphenous vein: Runs behind the knee, drains into the popliteal vein.
      - Deep veins: Anterior and posterior tibial veins merge to form the popliteal vein.