Anatomy: Legs
Muscles of Posterior Thigh
Muscle | Attachements | Nerve Supply | Actions |
Semitendinosus (Hamstring) | O:Ischial Tuberosity I: Medial surface of superior part of tibia | Tibial Nerve (Branched from Sciatic Nerve) | -Extend hip, – Flex knee, and – Medially rotated |
Semimembranosus (Hamstring) | O: Ischial tuberosity I: Posterior part of medial condyle of tibia | Tibial Nerve ( Branched from Sciatic Nerve) | Extend hip, – Flex knee, and – Medially rotated |
Biceps Femoris | O: Long Head : Ischial tuberosity, Short head: Linea aspera and lateral supracondylar line of femur I: Lateral side of head of fibula | Long Head : Tibial Nerve, Short head: Fibular Nerve | – Flexes knee and – Lateral rotation of knee – Extends hip |
Tensor Fasciae Latae | O: Anterior superior iliac spine along anterior part of iliac crest I: ITB | Superior Gluteal Nerve | – Flexes Hip |
Muscles of Anterior Thigh
Muscles | Attachements | Nerve Supply | Actions |
Rectus femoris (Quadriceps) | O: Anterior Inferior Iliac Spine I: Quadriceps tendon | Femoral Nerve | – Extends knee joint – Stabilizes hip joint |
Vastus lateralis (Quadriceps) | O: Greater Trochanter and lateral lip of linea aspera of femur I: Quadriceps tendon | Femoral Nerve | – Extends the knee joint |
Extends the knee joint (Quadriceps) | O: Intertrochanteric line and medial lip of linea aspera of femur I: Quadriceps tendon | Femoral Nerve | – Extend the knee joint |
Vastus intermedius (Quadriceps) | O: Anterior and lateral surface of femoral shaft I: Quadriceps tendon | Femoral Nerve | – Extends the knee joint |
Sartorius | O: Anterior Superior Iliac Spine I: Superior part of medial surface of tibia | Femoral Nerve | – Flexes hip – Abducts hip – Laterally rotates hip and -Flexes knee |
Medial Compartment of Thigh
Muscles | Attachement | Nerve Supply | Action |
Adductor Longus | O: Body of pubis inferior along pubic crest I: Middle third of linea aspera of the femur | Obturator nerve | – Adducts the hip |
Adductor Brevis | O: Inferior ramus of pubis I: Pectineal line and proximal part of linea aspera of the femur | Obturator Nerve | – Adducts hip |
Adductor Magnus | O: Adductor part: Inferior ramus of pubis, ramus of ischium. O: Hamstring part: Ischial Tuberosity I: Adductor tubercle | Adductor part: Obturator Nerve Hamstring part: Tibial Nerve | – Adducts hip – Flexes hip – Hamstring portion: Extends hip |
Gracillis | O: Body of inferior ramus of pubis I: Superior part of medial surface of tibia | Obturator Nerve | – Adducts hip, – Flexes knee, – Assists in medial rotation of hip |
Obturator Externus | O: Obturator foramen I: Trochanteric fossa of femur | Obturator nerve | – Laterally rotation of hip |
Anterior and Lateral Compartments of the Leg
Muscles | Attachements | Nerve Supply | Actions |
Tibialis Anterior | O: Lateral condyle and superior half of the tibia I: Medial and inferior surfaces of medial cuneiform and base of first metatarsal | Deep Fibular Nerve | – Dorsiflexes ankle – Inverts ankle – Supprots medial longitudinal arch of foot |
Extensor Hallucis Longus | O: Middle part of anterior surface of fibula I: Dorsal aspect of distal phalanx of the big toe | Deep Fibular Nerve | – Extends the big toe – Dorsiflexes ankle |
Extensor Digitorum Longus | O: Lateral condyle of tibia I: Middle and distal phalanges of lateral four digits | Deep Fibular Nerve | – Extends lateral four digits – Dorsiflexes ankle |
Fibularis Longus | O: Head and superior two thirds of lateral surface of fibula I: Base of first metatarsal and medial cuneiform | Superficial Fibular Nerve | -Everts ankle – Supports Transverse arch of the foot |
Fibularis Brevis | O: Inferior two thirds of lateral surface of fibula I: Dosral surface of tuberosity of base of 5th metatarsal | Superficial Fbular Nerve | – Evert ankle |
Posterior Compartment of Leg
Muscles | Attachements | Nerve Supply | Actions |
Tibialis Posterior | O: Interosseous membrane, posterior surface of tibia I: Tuberosity of the navicular, cuneiforms, cuboid and bases of 2nd- 4th metatarsals | Tibial Nerve | – Plantarflexes ankles, – Inverts ankle |
Gastrocnemius | O: Lateral head: Lateral aspect of lateral condyle of femur Medial Head: Popliteal surface of femur I: Achilles tendon | Tibial Nerve | – Plantarflexes ankle when knee is extended, – Flexes knee |
Soleus | O: Soleal Line of tibia I: Achilles tendon | Tibial Nerve | – Plantarflexes ankle |
Flexor Hallucis Longus | O: Inferior two thirds of posterior surface of fibula I: Base of distal phalanx of the big toe | Tibial Nerve | – Flexes big toe |
Flexor Digitorum Longus | O: Medial part of posterior surface of tibia I: Bases of distal phalanges of lateral four digits | Tibial Nerve | – Flexes lateral four digits. – Supports longitudinal arches of the foot |