Lower Limb Muscles

Overview – Lower Limb Muscles

The lower limb muscles play a crucial role in locomotion, posture, and dynamic stability. These muscles are compartmentalised by function and innervation and are essential to understand in clinical assessments of gait, nerve injuries, and musculoskeletal pathology. This article presents a high-yield summary of the origins, insertions, actions, and nerve supply of major lower limb muscles, from the pelvis to the foot.

Definition

Lower limb muscles refer to all skeletal muscles arising from the pelvis and extending through the thigh, leg, and foot. They are systematically organised into functional compartments and are vital for standing, walking, and running.

Muscles Originating on the Pelvis

MuscleNerve SupplyOrigin → InsertionAction
SartoriusFemoral NerveASIS → Medial aspect of proximal tibiaHip flexion, abduction, lateral rotation; weak knee flexion
IliacusFemoral NerveIliac fossa/crest, lateral sacrum → Lesser trochanter (via iliopsoas tendon)Flexes thigh (e.g., bowing motion)
Psoas MajorL1–L3 Ventral RamiLumbar vertebrae (TPs, bodies, discs) → Lesser trochanter (via iliopsoas tendon)Lateral flexion of vertebral column; postural stabiliser
lower limb muscles - Iliac Region & Anterior Thigh
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Thigh Muscles – Medial Compartment

MuscleNerve SupplyOrigin → InsertionAction
GracilisObturator NerveInferior pubic ramus → Medial tibia (below condyle)Adducts, flexes, medially rotates thigh; flexes knee
PectineusFemoral NervePubic crest → Posterior femur (between LT & linea aspera)Adducts, flexes, medially rotates thigh
Adductor BrevisObturator NerveInferior pubic ramus → Linea aspera (above longus)Adducts, medially rotates thigh
Adductor LongusObturator (anterior)Pubis near symphysis → Linea asperaAdducts, flexes, medially rotates thigh
Adductor MagnusObturator & SciaticIschial & pubic rami + ischial tuberosity → Linea aspera & adductor tubercleAnt: adducts, flexes, medially rotates; Post: extends thigh
lower limb muscles - Thigh Medial & Posterior
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Thigh Muscles – Anterior Compartment

MuscleNerve SupplyOrigin → InsertionAction
Tensor Fasciae LataeSup. Gluteal NerveASIS → Iliotibial tractFlexes, abducts, medially rotates thigh
Rectus FemorisFemoral NerveAIIS & acetabular rim → Patella & tibial tuberosityFlexes thigh, extends knee
Vastus LateralisFemoral NerveGreater trochanter → Patella & tibial tuberosityExtends and stabilises knee
Vastus MedialisFemoral NerveLinea aspera & intertrochanteric line → PatellaExtends knee; inferior fibres stabilize patella
Vastus IntermediusFemoral NerveAnterior/lateral femoral shaft → PatellaExtends knee

Note: The iliotibial tract is a thickened band of fascia lata extending from the iliac crest to the lateral knee.

lower limb muscles - thigh muscles
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Gluteal Muscles

MuscleNerve SupplyOrigin → InsertionAction
Gluteus MaximusInferior GlutealIlium, sacrum, coccyx → Gluteal tuberosity & iliotibial tractExtends, laterally rotates, abducts thigh
Gluteus MediusSuperior GlutealIlium (between ant/post gluteal lines) → Greater trochanterAbducts, medially rotates thigh; stabilises pelvis during gait
Gluteus MinimusSuperior GlutealIlium (between ant/inf gluteal lines) → Greater trochanterAbducts, medially rotates thigh; stabilises pelvis during gait
lower limb muscles - Gluteal region
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Lateral Rotators of the Hip

MuscleNerve SupplyOrigin → InsertionAction
PiriformisS1, S2, L5Anterior sacrum → Superior greater trochanterLateral rotation, adduction; stabilises hip
Gemellus SuperiorL5, S1Ischial spine → Greater trochanterSame as above
Obturator InternusL5, S1Obturator membrane (inner) → Greater trochanterSame as above
Gemellus InferiorL5, S1Ischial tuberosity → Greater trochanterSame as above
Obturator ExternusObturator NerveObturator membrane (outer) → Trochanteric fossaSame as above
Quadratus FemorisL5, S1Ischial tuberosity → Trochanteric crest of femurLateral rotation; stabilises hip

Thigh Muscles – Posterior Compartment

MuscleNerve SupplyOrigin → InsertionAction
Biceps FemorisLong: Sciatic-Tibial
Short: Common Fibular		Ischial tuberosity (long), linea aspera (short) → Head of fibula & lat. tibial condyleExtends thigh; flexes/laterally rotates flexed knee
SemitendinosusSciatic-Tibial NerveIschial tuberosity → Medial tibial shaftExtends thigh; flexes/medially rotates knee
SemimembranosusSciatic-Tibial NerveIschial tuberosity → Medial tibial condyleSame as above
lower limb muscles - Thigh Muscles - Posterior Compartment
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Anterior Compartment of Leg

MuscleNerve SupplyAction
Tibialis AnteriorDeep FibularDorsiflexion
Extensor Hallucis LongusDeep FibularExtension of great toe
Extensor Digitorum LongusDeep FibularExtension of digits 2–5
Fibularis TertiusDeep FibularDorsiflexion

Lateral Compartment of Leg

MuscleAction
Fibularis LongusEversion, plantarflexion
Fibularis BrevisEversion, plantarflexion

Posterior Compartment of Leg

MuscleAction
Gastrocnemius (med & lat)Plantarflexion, knee flexion
SoleusPlantarflexion
PlantarisWeak plantarflexion
Tibialis PosteriorPlantarflexion, arch support
Flexor Digitorum LongusFlexes digits 2–5
Flexor Hallucis LongusFlexes great toe
lower limb muscles - lower leg
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Intrinsic Muscles of the Foot

Plantar Aspect

Layer 1:

  • Abductor Hallucis
  • Flexor Digitorum Brevis
  • Abductor Digiti Minimi

Layer 2:

  • Quadratus Plantae
  • Lumbricals
  • Flexor Hallucis Brevis
  • Flexor Digiti Minimi Brevis

Layer 3:

  • Adductor Hallucis (Oblique & Transverse Heads)

Layer 4:

  • Plantar Interossei – Adduct toes

Dorsal Aspect

Layer 1:

  • Extensor Hallucis Brevis
  • Extensor Digitorum Brevis

Layer 2:

  • Dorsal Interossei – Abduct toes
Intrinsic Muscles of the Foot
OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Key Anatomical Regions

Femoral Triangle

Boundaries:

  • Superior: Inguinal Ligament
  • Lateral: Sartorius
  • Medial: Adductor Longus

Corners:

  • Inferior: Sartorius meets Adductor Longus
  • Superior: Sartorius meets Inguinal Ligament
  • Medial: Adductor Longus meets Pectineus

Contents *(Remember: NAVEL)*:

  • Femoral Nerve
  • Femoral Artery
  • Femoral Vein
  • Empty space
  • Inguinal Lymphatics
Femoral Triangle

Popliteal Fossa

  • Diamond-shaped region behind the knee
  • Boundaries:
    • Superomedial: Semimembranosus & Semitendinosus
    • Superolateral: Biceps femoris
    • Inferomedial/lateral: Gastrocnemius (medial & lateral heads)

Contents:

Popliteal Fossa
https://www.physio-pedia.com/Popliteal_Fossa

Malleolar Structures

Medial Malleolus:

Mnemonic: Tom, Dick, And Nervous Harry

Medial Malleolus
Y. Yang, M. L. Du, Y. S. Fu, W. Liu, Q. Xu, X. Chen, Y. J. Hao, Z. Liu & M. J. Gao, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0>, via Wikimedia Commons

Lateral Malleolus:

  • Fibularis Longus
  • Fibularis Brevis
Structures Passing Lateral Malleolus
Henry Vandyke Carter, Public domain, via Wikimedia Commons

Summary – Lower Limb Muscles

The lower limb muscles are organised anatomically and functionally to allow complex and powerful movements. From pelvic stabilisation to precise toe control, these muscles play essential roles in gait, posture, and athletic performance. Familiarity with their origins, insertions, and actions is crucial for clinical practice. For a broader context, see our Musculoskeletal Overview page.

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