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Structure

Muscles of the lower limb

Not medically reviewed · Content last updated · 2 min read ·

This is the date the draft was written, not a medical review date.

The lower limb muscles are arranged in fascial compartments of the gluteal region, thigh, leg and foot, each with a typical nerve supply and action. They are powerful and adapted to posture, gait and propulsion.

Terminologia Anatomica (Latin): Musculi membri inferioris · Open in the 3D atlas

Location

Gluteal region: gluteus maximus, medius, minimus, piriformis. Thigh: anterior (quadriceps, sartorius), medial (adductors) and posterior (hamstrings) compartments. Leg: anterior (dorsiflexors), lateral (evertors) and posterior (plantarflexors) compartments.

Structure

Quadriceps (rectus femoris, vastus lateralis, medialis, intermedius) extends the knee; hamstrings (biceps femoris, semitendinosus, semimembranosus) extend the hip and flex the knee; adductor group (longus, brevis, magnus, gracilis, pectineus) adducts the thigh; calf muscles (gastrocnemius, soleus, plantaris) insert through the Achilles tendon.

Blood supply

Gluteal muscles: superior and inferior gluteal arteries. Thigh: femoral artery and its profunda femoris branch (perforators to the posterior compartment), obturator artery for adductors. Leg: anterior tibial (anterior compartment), fibular (lateral), posterior tibial (posterior). Foot: dorsalis pedis and plantar arteries.

Innervation

Femoral nerve (L2-L4): anterior thigh and knee extension. Obturator nerve (L2-L4): medial thigh adductors. Superior gluteal (L4-S1): gluteus medius, minimus, tensor fasciae latae; inferior gluteal (L5-S2): gluteus maximus. Sciatic nerve (tibial division for hamstrings and posterior leg; common fibular for anterior and lateral leg).

Function

Gluteus maximus extends the hip (stairs, rising from sitting); gluteus medius and minimus stabilise the pelvis in gait; quadriceps extends the knee; hamstrings extend the hip and flex the knee; the calf muscles plantarflex for push-off; the anterior compartment dorsiflexes and clears the foot in swing phase.

Clinical correlations

Femoral nerve injury weakens knee extension; sciatic nerve injury (for example after posterior hip dislocation or misplaced gluteal injection) affects the hamstrings and all muscles below the knee; common fibular nerve injury causes foot drop with a high-stepping gait; superior gluteal nerve injury causes a Trendelenburg gait. Hamstring strains, quadriceps contusion, Achilles rupture and compartment syndrome of the leg are common.

Common exam points

  • Femoral nerve: anterior thigh (quadriceps, sartorius); obturator nerve: adductors; sciatic nerve: hamstrings and everything below the knee.
  • Gluteus medius and minimus (superior gluteal nerve) prevent pelvic drop: Trendelenburg sign.
  • Gluteal injections are given in the upper outer quadrant to avoid the sciatic nerve.
  • Common fibular nerve: dorsiflexion and eversion, foot drop; tibial nerve: plantarflexion and inversion.
  • Compartment syndrome: pain out of proportion, pain on passive stretch; anterior compartment of the leg most often affected.

References

  1. Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. Elsevier — Tier 3 (textbook)
  2. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. Wolters Kluwer, 8th edition (2018) — Tier 3 (textbook)
  3. Netter FH. Atlas of Human Anatomy. Elsevier — Tier 3 (textbook)

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