Lower Limb Muscles: Origins, Insertions and Actions

Hip Muscles

Psoas Major

• Origin: Lumbar vertebrae (0.d12.5l)
• Insertion: Lesser trochanter
• Action: Hip flexion

Iliacus

• Origin: Iliac fossa
• Insertion: Lesser trochanter
• Action: Hip flexion

Gluteus Minimus

• Origin: External iliac fossa
• Insertion: Greater trochanter
• Action: Hip flexion, abduction, internal rotation

Gluteus Medius

• Origin: External iliac fossa
• Insertion: Greater trochanter
• Action: Hip flexion, abduction, extension

Gluteus Maximus

• Origin: Sacrum and coccyx, external iliac fossa (superficial plane); fascia lata and gluteal aponeurosis (deep plane)
• Insertion: Greater trochanter, gluteal tuberosity (linea aspera)
• Action: Hip extension, external rotation

Tensor Fasciae Latae

• Origin: Anterior superior iliac spine
• Insertion: Iliotibial tract (Gerdy's tubercle, tibia)
• Action: Hip flexion, abduction, internal rotation

Adductors (Pectineus, Adductor Longus, Brevis, Magnus)

• Origin: Pubis
• Insertion: Femur (linea aspera)
• Action: Hip adduction, anteversion of the pubis, internal rotation of the femur

Gracilis

• Origin: Pubis
• Insertion: Pes anserinus of the tibia
• Action: Hip adduction, knee flexion, internal rotation

Knee Ligaments

Medial Collateral Ligament

• Origin: Medial femoral condyle
• Insertion: Tibia (pes anserinus)
• Action: Primarily prevents lateral displacement of the knee outward

Lateral Collateral Ligament

• Origin: Lateral femoral condyle
• Insertion: Head of the fibula
• Action: Prevents lateral displacement of the knee inward

Anterior Cruciate Ligament

• Origin: Lateral femoral condyle
• Insertion: Anterior tibia
• Action: Prevents anterior movement of the tibia

Posterior Cruciate Ligament

• Origin: Medial femoral condyle
• Insertion: Posterior tibia
• Action: Prevents posterior movement of the tibia

Knee Extensors (Quadriceps Femoris)

Rectus Femoris

• Origin: Iliac spine
• Insertion: Patellar tendon
• Action: Knee extension

Vastus Medialis

• Origin: Intertrochanteric crest
• Insertion: Patellar tendon
• Action: Knee extension

Vastus Lateralis

• Origin: Lateral crest
• Insertion: Patellar tendon
• Action: Knee extension

Vastus Intermedius

• Origin: Femoral shaft
• Insertion: Patellar tendon
• Action: Knee extension

Knee Flexors

Sartorius

• Origin: Anterior superior iliac spine
• Insertion: Tibia (pes anserinus)
• Action: Knee flexion, external rotation, hip abduction

Biceps Femoris

• Origin: Ischium
• Insertion: Head of the fibula
• Action: Knee flexion, external rotation

Semimembranosus

• Origin: Ischium
• Insertion: Tibia
• Action: Knee flexion, internal rotation

Semitendinosus

• Origin: Ischium
• Insertion: Tibia (pes anserinus)
• Action: Knee flexion, internal rotation

Popliteus

• Origin: Lateral femoral condyle
• Insertion: Posterior surface of the tibia
• Action: Knee flexion and internal rotation (unlocks the knee)

Foot and Ankle Muscles

Tibialis Anterior

• Origin: Lateral surface of the tibia
• Insertion: First metatarsal and medial cuneiform
• Action: Dorsiflexion, supination

Extensor Hallucis Longus

• Origin: Middle or medial fibula
• Insertion: Distal phalanx of the great toe
• Action: Great toe extension, dorsiflexion

Extensor Digitorum Longus

• Origin: Upper fibula
• Insertion: Distal phalanges of toes 2 to 5
• Action: Toe extension, dorsiflexion

Peroneus Longus

• Origin: Fibula
• Insertion: First metatarsal and medial cuneiform
• Action: Eversion, plantarflexion

Peroneus Brevis

• Origin: Fibula
• Insertion: Base of the fifth metatarsal
• Action: Eversion, plantarflexion

Peroneus Tertius

• Origin: Anterior fibula
• Insertion: Fifth metatarsal
• Action: Eversion, dorsiflexion

Tibialis Posterior

• Origin: Tibia and fibula
• Insertion: Navicular (medial border)
• Action: Inversion, plantarflexion, supination

Triceps Surae (Gastrocnemius and Soleus)

• Origin: Femur (gastrocnemius); tibia and fibula (soleus)
• Insertion: Calcaneus via Achilles tendon
• Action: Plantarflexion

Hip Rotators and Deep Muscles

Piriformis

• Origin: Anterior sacrum, extending outward and downward
• Insertion: Superior greater trochanter
• Action: External rotation, abduction, flexion when acting unilaterally; internal rotation and retroversion of the femur when acting from the opposite side

Quadratus Femoris

• Origin: Lateral ischium (posterior to the obturator foramen)
• Insertion: Greater trochanter
• Action: External rotation of the femur, retroversion of the pelvis

Obturator Internus

• Origin: Internal surface of the ilium
• Insertion: Greater trochanter
• Action: External rotation, flexion, abduction

Obturator Externus

• Origin: External surface of the ilium
• Insertion: Greater trochanter
• Action: External rotation, flexion, abduction when acting unilaterally; lateral bending

Gemelli

• Origin: Greater sciatic notch
• Insertion: Greater trochanter
• Action: Satellites of the obturator internus, assisting its action

Pelvic Diaphragm

Levator Ani

• Origin: Pubis and ischial spine
• Insertion: Anococcygeal raphe and sacrum
• Action: Supports pelvic viscera, pulls the sacrum into counternutation

Ischiococcygeus

• Origin: Ischial spine
• Insertion: Sacrum
• Action: Supports pelvic viscera, pulls the sacrum into counternutation