Overview
The lower limb contains powerful muscles that maintain posture, allow locomotion, and control complex movements such as running and jumping. For exams and clinical practice, you must know the key facts: origin, insertion, nerve supply, and main action of each muscle group.
This summary focuses on the gluteal region, thigh, leg, and foot. Use it together with the detailed regional articles on lower limb musculature for deeper study and clinical correlations such as gait analysis and nerve injuries.
Gluteal Region
The gluteal region muscles stabilize the pelvis during weightbearing and control hip extension, abduction, and rotation.
Gluteal Muscles Summary
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Gluteus Maximus | Ilium posterior to posterior gluteal line; sacrum; coccyx; sacrotuberous ligament | Iliotibial tract; gluteal tuberosity of femur | Inferior gluteal nerve (L5, S1, S2) | Powerful hip extension; lateral rotation; assists rising from sitting |
| Gluteus Medius | External surface of ilium between anterior and posterior gluteal lines | Greater trochanter (lateral surface) | Superior gluteal nerve (L4, L5, S1) | Hip abduction; medial rotation; pelvic stabilization in single-leg stance |
| Gluteus Minimus | External ilium between anterior and inferior gluteal lines | Greater trochanter (anterior surface) | Superior gluteal nerve (L4, L5, S1) | Hip abduction; medial rotation; assists gluteus medius |
| Tensor Fasciae Latae | Anterior superior iliac spine (ASIS) and anterior iliac crest | Iliotibial tract to lateral condyle of tibia | Superior gluteal nerve (L4, L5) | Stabilizes knee via IT tract; assists hip flexion and abduction |
| Piriformis | Anterior surface of sacrum | Greater trochanter (superior border) | Nerve to piriformis (S1, S2) | Lateral rotation of extended hip; abduction of flexed hip |
| Obturator Internus | Internal surface of obturator membrane and surrounding bone | Medial surface of greater trochanter | Nerve to obturator internus (L5, S1) | Lateral rotation of extended hip |
| Superior Gemellus | Ischial spine | Tendon of obturator internus | Nerve to obturator internus (L5, S1) | Lateral rotation of extended hip |
| Inferior Gemellus | Ischial tuberosity | Tendon of obturator internus | Nerve to quadratus femoris (L5, S1) | Lateral rotation of extended hip |
| Quadratus Femoris | Lateral border of ischial tuberosity | Intertrochanteric crest of femur | Nerve to quadratus femoris (L5, S1) | Lateral rotation and weak adduction of hip |
For full regional detail, see gluteal region muscles.
Thigh — Anterior Compartment
Anterior thigh muscles mainly flex the hip and extend the knee. They are critical for walking, running, and getting up from a seated position.
Quadriceps and Hip Flexors
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Iliacus | Iliac fossa and crest | Lesser trochanter via common iliopsoas tendon | Femoral nerve (L2, L3) | Powerful hip flexion |
| Psoas Major | Bodies and transverse processes of T12–L5 vertebrae | Lesser trochanter | Anterior rami of L1–L3 | Hip flexion; trunk flexion when femur is fixed |
| Sartorius | ASIS | Medial surface of proximal tibia (pes anserinus) | Femoral nerve (L2, L3) | Flexes, abducts, and laterally rotates hip; flexes knee |
| Rectus Femoris | Anterior inferior iliac spine (AIIS) and acetabular rim | Tibial tuberosity via patellar ligament | Femoral nerve (L2–L4) | Knee extension; assists hip flexion |
| Vastus Lateralis | Greater trochanter and lateral lip of linea aspera | Tibial tuberosity via quadriceps tendon and patellar ligament | Femoral nerve (L2–L4) | Knee extension |
| Vastus Medialis | Intertrochanteric line and medial lip of linea aspera | Tibial tuberosity via quadriceps tendon and patellar ligament | Femoral nerve (L2–L4) | Knee extension; medial stabilization of patella |
| Vastus Intermedius | Anterolateral shaft of femur | Tibial tuberosity via quadriceps tendon and patellar ligament | Femoral nerve (L2–L4) | Knee extension |
See anterior thigh muscles for detailed attachments and clinical notes.
Thigh — Medial Compartment
The medial thigh contains the adductor group, which pulls the limb toward the midline and stabilizes the pelvis during gait.
Adductor Group
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Adductor Longus | Body of pubis | Middle third of linea aspera | Obturator nerve (L2–L4) | Hip adduction |
| Adductor Brevis | Body and inferior ramus of pubis | Proximal linea aspera | Obturator nerve (L2–L4) | Hip adduction; minor flexion |
| Adductor Magnus (Adductor Part) | Inferior ramus of pubis and ramus of ischium | Linea aspera and medial supracondylar line | Obturator nerve (L2–L4) | Powerful hip adduction |
| Adductor Magnus (Hamstring Part) | Ischial tuberosity | Adductor tubercle of femur | Tibial division of sciatic nerve (L4) | Hip extension |
| Gracilis | Body and inferior ramus of pubis | Pes anserinus on medial tibia | Obturator nerve (L2, L3) | Hip adduction; assists knee flexion and medial rotation |
| Obturator Externus | External surface of obturator membrane and adjacent bone | Trochanteric fossa of femur | Obturator nerve (L3, L4) | Lateral rotation of hip; stabilizes head of femur in acetabulum |
For layer-by-layer organization, refer to medial thigh muscles.
Thigh — Posterior Compartment
Posterior thigh muscles (hamstrings) extend the hip and flex the knee. They are commonly injured in sports and affected in sciatic nerve lesions.
Hamstring Group
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Biceps Femoris (Long Head) | Ischial tuberosity | Head of fibula | Tibial division of sciatic nerve (L5–S2) | Hip extension; knee flexion; lateral rotation of flexed knee |
| Biceps Femoris (Short Head) | Linea aspera and lateral supracondylar line | Head of fibula | Common fibular division of sciatic nerve (L5–S2) | Knee flexion; lateral rotation of flexed knee |
| Semitendinosus | Ischial tuberosity | Pes anserinus on medial tibia | Tibial division of sciatic nerve (L5–S2) | Hip extension; knee flexion; medial rotation of flexed knee |
| Semimembranosus | Ischial tuberosity | Posterior medial condyle of tibia | Tibial division of sciatic nerve (L5–S2) | Hip extension; knee flexion; assists medial rotation |
See posterior thigh (hamstring) muscles for expanded notes and clinical correlations.
Leg — Anterior Compartment
These muscles dorsiflex the ankle and extend the toes, essential for foot clearance during the swing phase of gait.
Dorsiflexors
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Tibialis Anterior | Lateral condyle and superior half of lateral tibia; interosseous membrane | Medial cuneiform and base of first metatarsal | Deep fibular (peroneal) nerve (L4, L5) | Dorsiflexion and inversion of foot; supports medial longitudinal arch |
| Extensor Hallucis Longus | Middle anterior fibula; interosseous membrane | Distal phalanx of great toe | Deep fibular nerve (L5, S1) | Extends great toe; assists dorsiflexion |
| Extensor Digitorum Longus | Lateral condyle of tibia; superior three-quarters of anterior fibula | Middle and distal phalanges of lateral four toes | Deep fibular nerve (L5, S1) | Extends toes 2–5; dorsiflexes foot |
| Fibularis (Peroneus) Tertius | Inferior anterior fibula and interosseous membrane | Dorsum of base of 5th metatarsal | Deep fibular nerve (L5, S1) | Dorsiflexion and weak eversion |
Review detailed attachments under anterior leg muscles.
Leg — Lateral Compartment
Lateral compartment muscles evert the foot and assist with plantarflexion, helping to stabilize the ankle.
Evertors
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Fibularis (Peroneus) Longus | Head and superior two-thirds of lateral fibula | Base of first metatarsal and medial cuneiform (plantar surface) | Superficial fibular nerve (L5–S2) | Eversion of foot; weak plantarflexion; supports transverse arch |
| Fibularis (Peroneus) Brevis | Inferior two-thirds of lateral fibula | Tuberosity of base of 5th metatarsal | Superficial fibular nerve (L5–S2) | Eversion of foot; weak plantarflexion |
See lateral (peroneal) muscles for cross-sectional relationships and clinical notes.
Leg — Posterior Compartment (Superficial)
Superficial posterior leg muscles are the main plantarflexors of the ankle, crucial for push-off in gait.
Plantarflexors
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Gastrocnemius | Lateral and medial condyles of femur | Posterior calcaneus via calcaneal (Achilles) tendon | Tibial nerve (S1, S2) | Plantarflexion when knee extended; knee flexion |
| Soleus | Posterior fibular head; soleal line of tibia | Posterior calcaneus via calcaneal tendon | Tibial nerve (S1, S2) | Powerful plantarflexion; postural muscle during standing |
| Plantaris | Lateral supracondylar line of femur | Posterior calcaneus (often with Achilles tendon) | Tibial nerve (S1, S2) | Weak plantarflexion; weak knee flexion |
Leg — Posterior Compartment (Deep)
Deep posterior muscles flex the toes, invert the foot, and support the arches.
Deep Flexors
| Muscle | Origin | Insertion | Nerve Supply | Main Action |
|---|---|---|---|---|
| Tibialis Posterior | Posterior tibia and fibula; interosseous membrane | Navicular tuberosity; cuneiforms; bases of 2nd–4th metatarsals | Tibial nerve (L4, L5) | Inversion and plantarflexion; supports medial arch |
| Flexor Digitorum Longus | Posterior tibia | Bases of distal phalanges of toes 2–5 | Tibial nerve (S2, S3) | Flexes lateral four toes; supports longitudinal arches |
| Flexor Hallucis Longus | Inferior posterior fibula; interosseous membrane | Base of distal phalanx of great toe | Tibial nerve (S2, S3) | Flexes great toe; important in push-off phase of gait |
| Popliteus | Lateral condyle of femur and lateral meniscus | Posterior tibia superior to soleal line | Tibial nerve (L4–S1) | Unlocks knee by laterally rotating femur on fixed tibia |
Intrinsic Muscles of the Foot
Intrinsic foot muscles fine-tune movements of the toes and support the arches. For exams, it is sufficient to remember their layer arrangement, innervation, and key functions.
Plantar Layers (Summary)
| Layer | Main Muscles | Innervation (Key) |
|---|---|---|
| First Layer | Abductor hallucis; Flexor digitorum brevis; Abductor digiti minimi | Medial and lateral plantar nerves |
| Second Layer | Quadratus plantae; Lumbricals (1–4) | Medial plantar (1st lumbrical); lateral plantar (2nd–4th) |
| Third Layer | Flexor hallucis brevis; Adductor hallucis; Flexor digiti minimi brevis | Medial and lateral plantar nerves |
| Fourth Layer | Dorsal and plantar interossei | Lateral plantar nerve |
For layer-by-layer origin, insertion, and actions, use intrinsic muscles of the sole and intrinsic muscles of the dorsum.
Exam Strategy
To master lower limb muscles, group them by compartment, then learn origin, insertion, nerve supply, and action for each. Combine this table with nerve and vascular summaries to rapidly integrate anatomy with gait and common injury patterns.