Lower Limb Muscles


Lower Limb Muscles



  • Sacrotuberous Ligament
    • Extends from the ischial tuberosity to the posterior iliac spines, lower sacrum, and coccyx.
    • Converts, with the sacrospinous ligament, the lesser sciatic notch into the lesser sciaticforamen.
  • Sacrospinous Ligament
    • Extends from the ischial spine to the lower sacrum and coccyx.
    • Converts the greater sciatic notch into the greater sciatic foramen.
  • SciaticForamina
    • Greater Sciatic Foramen
      • Provides a pathway for the
        • piriformis muscle
        • superior and inferior gluteal vessels and nerves
        • internalpudendal vessels
        • pudendal nerve
        • sciatic nerve
        • posterior femoral cutaneous nerve
        • nerves to the obturatorinternus and quadratusfemoris muscles.
    • Lesser Sciatic Foramen
      • Provides a pathway for the
        • tendon of the obturatorinternus
        • thenerve to the obturatorinternus
        • internalpudendal vessels and pudendal nerve.
    • Structures that Pass through both the Greater and the Lesser Sciatic Foramina
      • pudendal nerve
      • internalpudendal vessels,
      • nerve to the obturatorinternus.
  • Iliotibial Tract
    • Is a thick lateral portion of the fascia lata.
    • Provides insertion for the gluteus maximus and tensor fasciae latae muscles.
    • Helps form the fibrous capsule of the knee joint
    • important in maintaining postureand locomotion.
  • FasciaLata
    • Is a membranous, deep fascia covering muscles of the thigh
    • It forms the lateral and medial intermuscular septaby its inward extension to the femur.
    • Is attached to the pubic symphysis, pubic crest, pubic rami, ischial tuberosity, inguinal and sacrotuberous ligaments, and the sacrum and coccyx.


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Muscles of the anterior and medial thigh

    • Femoral Triangle
    1. Isbounded by the
      1. inguinal ligament superiorly
      2. sartorius muscle laterally
      3. adductorlongus muscle medially.
    2. flooris formed by
      1. iliopsoas
      2. pectineus
      3. adductorlongus muscles
    3. roofis formed by the
      1. fascialata
      2. cribriform fascia.
    4. Contains the femoral nerve, artery, vein, and lymphatics (in the canal).
      1. NAVY – structures from lateral to medial (nerve, artery, vein, yahoo!!!).
    5. The pulsation of the femoral artery may be felt just inferior to the midpoint of the inguinal ligament.
    • Femoral Ring
    1. Is the abdominal opening of the femoral canal.
    2. Is bounded by the
      1. inguinal ligament anteriorly
      2. femoral vein laterally
      3. lacunar ligament medially
      4. pectineal ligament posteriorly.
    • FemoralCanal
      • Lies medial to the femoral vein in the femoral sheath.
      • Contains fat, areolar connective tissue, and lymph nodes and vessels.
      • Transmits lymphaticsfrom the lower limb and perineum to the peritoneal cavity.
      • Is a potential weak area and a site of femoral herniation
      • Femoral hernia occurs most frequently inwomen because of the greater width of the superior pubic ramus of the female pelvis.

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      1. Femoral Sheath
        1. Is formed by a prolongation of the transversalisand iliac fasciae in the thigh.
        2. Contains the
          1. femoral artery and vein
          2. femoral branch of the genitofemoral nerve
          3. femoral canal.
        3. The femoral nerve lies outside the femoral sheath, lateral to the femoral artery.
        4. Reaches the level of the proximal end of the saphenous opening with its distal end.
      2. AdductorCanal
        1. Begins at the apex of the femoral triangle and ends at the adductor hiatus
        2. Lies between the adductor magnus and longus muscles and the vastusmedialis muscle
        3. covered by the sartorius muscle and fascia.
        4. Contains the
          1. femoral vessels
          2. saphenous nerve
          3. nerve to the vastusmedialis
          4. descendinggenicular artery.
      3. Adductor Hiatus (Hiatus Tendineus)
        1. Is the aperture in the tendon of insertion of the adductor magnus.
        2. Allows the passage of the femoral vessels into the popliteal fossa.
      4. Saphenous Opening (Saphenous Hiatus) or Fossa Ovalis
        1. Is an oval gap in the fascia lata below the inguinal ligament
        2. covered by the cribriform fascia, which is a part of the superficial fascia of the thigh.
        3. Provides a pathway for the greater saphenous vein.

      Anterior and lateral muscles of the leg

        • Popliteal Fossa
        1. Is bounded
          1. superomedially by the semitendinosus and semimembranosus muscles, superolaterally by the biceps muscle
          2. inferolaterally by the lateral head of the gastrocnemius and plantaris muscles
          3. inferomedially by the medial head of the gastrocnemius muscle.
        2. Has a floor that is composed of the
          1. Femur
          2. oblique popliteal ligament
          3. popliteus muscle.
        3. Contains
          1. popliteal vessels
          2. commonperoneal and tibial nerves
          3. small saphenous vein.
        • PesAnserinus
          • Is the combined tendinous expansions of the sartorius, gracilis, and semitendinosus muscles
          • Occur at the medial border of the tuberosity of the tibia
          • It may be used for surgical repair of the anterior cruciate ligament of the knee joint.

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          Muscles of the foot

          1. Superior Extensor Retinaculum
            1. Is a broad band of deep fascia
            2. extends between the tibia and fibula, above the ankle.
          2. Inferior Extensor Retinaculum
            1. Is a Y-shaped band of deep fascia
            2. forms a loop for the tendons of the extensor digitorumlongus and the peroneus tertius
            3. divides into an
              1. upper band, which attaches to the medial malleolus
              2. lower band, which attaches to the deep fascia of the foot and the plantar aponeurosis.


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          • FlexorRetinaculum
            • Is a deep fascial band
            • passes between the medial malleolus and the medial surface of the calcaneus
            • forms the tarsal tunnel with tarsal bones for the tibial nerve, posterior tibial vessels, and flexor tendons.
            • Holds three tendons and blood vessels and a nerve in place deep to it (from anterior to posterior) Tom, Dick ANdHarry
              • tibialis posterior
              • flexordigitorumlongus
              • posteriortibialartery and vein
              • tibialnerve,
              • flexorhallucislongus
            • Provides a pathway for the tibial nerve and posterior tibial artery beneath it.
          • Tendo Calcaneus (Achilles Tendon)
            • Is the tendon of insertion of the triceps surae(gastrocnemius and soleus) into the tuberosity of the calcaneus.
          • PlantarAponeurosis
            • Is a thick fascia investing the plantar muscles.
            • Radiates from the calcaneal tuberosity (tuber calcanei) toward the toes
            • Providesattachment to the short flexor muscles of the toes.
          • Arches of the Foot
            • Medial Longitudinal Arch
              • Is formed and maintained by the interlocking of the talus, calcaneus, navicular, cunei- form, and three medial metatarsal bones.
              • Has, as its keystone, the head of the talus, which is located at the summit between the sustentaculumtali and the navicular bone.
              • Is supported by the spring ligament and the tendon of the flexor hallucislongus.
            • Lateral Longitudinal Arch
              •  Is formed by the calcaneus, the cuboid bone, and the lateral two metatarsal bones. The keystone is the cuboid bone.
              • Is supported by the peroneus longus tendon and the long and short plantar liga- ments.
              • Supports the body in the erect position
              • acts as a spring in locomotion
            • Transverse Arch
              • Proximal (metatarsal) arch
                • Is formed by the navicular bone, the three cuneiform bones, the cuboid bone, and the bases of the five metatarsal bones of the foot.
                • Is supported by the tendon of the peroneus longus.
              • Distal arch
                • Is formed by the heads of five metatarsal bones.
                • Is maintained by the transverse head of the adductor hallucis.
          • Ligaments
            • Long Plantar (Plantar Calcaneocuboid) Ligament
              • forms a canal for the tendon of the peroneus longus.
              • Supports the lateral side of the longitudinal arch of the foot.
            • Short Plantar (Plantar Calcaneocuboid) Ligament
            • Spring (Plantar Calcaneonavicular) Ligament
              • Passes from the sustentaculumtali of the calcaneus to the navicular bone.
              • Supports the head of the talusand the medial longitudinal arch.
              • Is called the spring ligament because it contains considerable numbers of elastic fibersto give elasticity to the arch and spring to the foot.
              • Is supported by the tendon of the tibialis posterior.


          • Summary of muscle actions of the lower limb
            • Movements at the Hip Joint (Ball-and-Socket Joint)
              • Flexion—iliopsoas, tensor fasciae latae, rectus femoris, adductors, sartorius, pectineus, gracilis
              • Extension—hamstrings, gluteus maximus, adductor magnus
              • Adduction—adductor magnus, adductor longus, adductor brevis, pectineus, gracilisAbduction—gluteus medius, gluteus minimus
              • Medial rotation—tensor fasciae latae, gluteus medius, gluteus minimus
              • Lateral rotation—obturatorinternus, obturatorexternus, gemelli, piriformis, quadratusfemoris, gluteus maximus
            • Movements at the Knee Joint (Hinge Joint)
              • Flexion—hamstrings, gracilis, sartorius, gastrocnemius, popliteus Extension—quadriceps femoris
              • Medial rotation—semitendinosus, semimembranosus, popliteus Lateral rotation—biceps femoris
              • Movements at the Ankle Joint (Hinge Joint)
              • Dorsiflexion—anterior tibialis, extensor digitorumlongus, extensor hallucislongus, peroneus tertius
              • Plantar flexion—triceps surae, plantaris, posterior tibialis, peroneus longus and brevis, flexor digitorumlongus, flexor hallucislongus (when the knee is fully flexed)
            • Movements at the Intertarsal Joint (Talocalcaneal, Transverse Tarsal Joint)
              • Inversion—tibialis posterior, tibialis anterior, triceps surae, extensor hallucislongus
              • Eversion—peroneus longus, brevis, and tertius, extensor digitorumlongus
            • Movements at the Metatarsophalangeal Joint (Ellipsoid Joint)
              • Flexion—lumbricals, interossei, flexor hallucisbrevis, flexor digitiminimibrevis
              • Extension—extensor digitorumlongus and brevis, extensor hallucislongus
            • Movements at the Interphalangeal Joint (Hinge Joint)
              • Flexion—flexor digitorumlongus and brevis, flexor hallucislongus
              • Extension—extensor digitorumlongus and brevis, extensor hallucislongus



            • Summary of muscle innervations of the lower limb
              • Muscles of the Gluteal Region
                • Gluteus maximus (inferior gluteal nerve)
                • Gluteus medius (superior gluteal nerve)
                • Gluteus minimus (superior gluteal nerve)
                • Tensor fasciae latae (superior gluteal nerve)
                • Piriformis (nerve to piriformis)
                • Obturatorinternus (nerve to obturatorinternus)
                • Superior gemellus (nerve to obturatorinternus)
                • Inferior gemellus (nerve to quadratusfemoris)
                • Quadratusfemoris (nerve to quadratusfemoris)
              • Muscles of the thigh
                • Muscles of the Anterior Compartment: Femoral Nerve
                  • Sartorius,
                  • quadricepsfemoris
                  • rectusfemoris, vastusmedialis, vastusintermedius, vastuslateralis
                • Muscles of the Medial Compartment: Obturator Nerve
                  • Adductor longus
                  • adductorbrevis,
                  • adductormagnus (obturator and tibial nerves) (MCQ)
                  • gracilis, obturatorexternus
                  • pectineus (femoral and obturator nerves) (MCQ)
                • Muscles of the Posterior Compartment: Tibial Part of Sciatic Nerve
                  • Semitendinosus; semimembranosus; biceps femoris, long head
                  • bicepsfemoris, short head (common peroneal part of sciatic nerve) (MCQ)
                  • adductormagnus (tibial part of sciatic and obturator nerve) (MCQ)
              • Muscles of the leg
                • Muscles of the Anterior Compartment: Deep Peroneal Nerve
                  • Tibialis anterior, extensor digitorumlongus
                  • extensorhallucislongus, peroneus tertius
                • Muscles of the Lateral Compartment: Superficial Peroneal Nerve
                  • Peroneus longus, peroneus brevis
                • Muscles of the Posterior Compartment: Tibial Nerve
                  • Superficial layer—gastrocnemius, soleus, plantaris
                  • Deep layer—popliteus, tibialis posterior, flexor digitorumlongus, flexor hallucislongus
              • Muscles of the foot
                • Muscles of the Anterior Compartment (Dorsum): Deep Peroneal Nerve
                  • Extensor digitorumbrevis, extensor hallucisbrevis
                • Muscles of the Plantar Compartment (Sole): Medial and Lateral Plantar Nerves
                  • Medial plantar nerve
                    • Flexor digitorumbrevis
                    • abductorhalluces
                    • flexorhallucisbrevis
                    • firstlumbrical
                  • lateral plantar nerve
                    • Quadratusplantae
                    • abductordigitiminimi
                    • lateral three lumbricals
                    • adductorhallucis, flexor digitiminimibrevis
                    • plantarinterossei, dorsal interossei
                • Surgical Anatomy
                  • Gluteal gait (gluteus medius limp)
                  • waddling gait
                  • characterized by the pelvis falling (or drooping) toward the unaffected side when the opposite leg is raised at each step
                  • It results from paralysis of the gluteus medius muscle, which normally functions to stabilize the pelvis when the opposite foot is off the ground.
                • gluteal region —  intramuscular injection of medications
                  • Injection should always be made in the superior lateral quadrant of the gluteal region
                  • to avoid injury to the underlying sciatic nerve and other neurovascular structures in the medial and inferior quadrants.
                • Piriformis syndrome
                  • piriformis muscle irritates andplaces pressure on the sciatic nerve causes
                    • pain in the buttocks
                    • referring pain along the course of the sciatic nerve (“sciatica,”)
                • Positive Trendelenburg’s sign
                  • seen in a
                    • fracture of the femoral neck
                    • dislocated hip joint (head of femur)
                  • weakness and paralysis of the gluteus medius and minimus muscle
                  • causesinability to abduct the hip
                  • If the right gluteus medius and minimus muscles are paralyzed, the unsupported left side (sound side) of the pelvis falls (sags) instead of rising; normally the pelvis rises.
                • Hamstring injury or strains (pulled or torn hamstrings)
                  • common in personswho are involved in running, jumping, and quick-start sports.
                  • origin of the hamstrings from the ischial tuberosity may be avulsed
                  • result in rupture of blood vessels.
                • Avulsion of the ischial tuberosity
                  • result from forcible flexion of the hip with the knee extended
                  • tearing of hamstring fibers is very painful.
                • Femoral hernia
                  • more common in women than in men
                  • passes through the femoral ring and canal
                  • lieslateral and inferior to the pubic tubercle and deep and inferior to the inguinal ligament;
                  • its sac is formed by the parietal peritoneum.
                  • Strangulation of a femoral hernia may occur because of the sharp, stiff boundaries of the femoral ring
                • Groin injury or pulled groin
                  • strain, stretching, or tearing of the origin of theflexor and adductor of the thigh
                  • often occurs in sports that require quick starts such as a 100-meter dash and football.
                • Gracilis
                  • a relatively weak member of the adductor group of muscles
                  • surgeons often transplant this muscle or part of it, with nerve and blood vessels, to replace a damaged muscle in the hand.
                • Anterior tibial compartment syndrome
                  • characterized by ischemic necrosis of themuscles of the anterior compartment of the leg.
                  • occurs presumably as a result of compression of arteries (anterior tibial artery and its branches) by swollen muscles following excessive exertion
                  • It is accompanied by extreme tenderness and pain on the anterolateral aspect of the leg.
                • Knee-jerk (patellar) reflex
                  • tests the L2–L4 spinal (femoral) nerves
                • Ankle-jerk (Achilles)
                  • its reflex center in the L5–S1 or S1–S2 segments of the spinal cord.
                • Tarsal tunnel syndrome
                  • compression ofthe tibial nerve or its medial and lateral plantar branches in the tarsal tunnel
                  • pain, numbness, and tingling sensations on the ankle, heel, and sole of the foot.
                  • It may be caused by repetitive stress with activities, flat feet, or excess weight.
                • Avulsion or rupture of the Achilles tendon
                  • disables the triceps surae (gastrocnemius and soleus) muscles;
                  • patient is unable to plantar flex the foot
                • Forced eversion of the foot avulses the medial malleolus or ruptures the deltoid ligament,
                • Forced inversion avulses the lateral malleolus or tears the lateral collateral (anterior and posterior talofibular and calcaneofibular) ligament.
                • Ankle sprain (inversion injury) results from
                  • caused by forced inversion of the foot
                  • caused by
                    • rupture of calcaneofibular and talofibular ligaments
                    • fracture of the lateral malleolus
                • Flat foot (pesplanus or talipesplanus)
                  • condition of disappearance or collapse of the medial longitudinal arch
                  • occurwith eversion and abduction of the forefoot
                  • causes greater wear on the inner border of the soles and heels of shoes than on the outer border.
                  • It causes pain as a result of
                    • stretching of the plantar muscles
                    • straining of the spring ligament and the long and short plantar ligaments.
                • Pescavus
                  • exaggerated height of themedial longitudinal arch of the foot.
                • Clubfoot (talipesequinovarus)
                  • foot is plantarflexed, inverted, and adducted
                  • causesdeformity in which the
                    • footis plantarflexed (equinus) or dorsiflexed (calcaneus)
                    • heel is turned laterally (valgus) or medially (varus),
                    • heel is elevated and turned laterally (equinovalgus) or medially (equinovarus)
                    • anterior part of the foot (forefoot) is elevated and the heel is turned laterally (calcaneovalgus) or medially (calcaneovarus).

                  Muscles of the Leg – Part 1 – Posterior Compartment – Anatomy
                  Lower Limb Muscles
                  Anatomical dissection # 25: Muscles, vessels & nerves of the hip & tight.
                  Muscles of the lower extremities
                  Muscles and Nerves of Lower Limb