Lower Limb Muscle Anatomy

PSOAS MAJOR

• PA (Proximal Attachment): Side of T12-L5 vertebrae and discs between them; TP (Transverse Processes) of all lumbar vertebrae
• DA (Distal Attachment): Lesser trochanter of femur
• N (Nerve): Ventral rami of L1-L3
• A (Action): Hip flexion

ILIACUS

• PA: Iliac crest, iliac fossa, ala of sacrum, and anterior sacroiliac ligament
• DA: Lesser trochanter of femur
• N: Femoral nerve
• A: Hip flexion

RECTUS FEMORIS

• PA: AIIS (Anterior Inferior Iliac Spine) and ilium superior to the acetabulum
• DA: Base of patella and tibial tuberosity via the patellar ligament
• N: Femoral nerve
• A: Knee extension, hip flexion

VASTUS LATERALIS

• PA: Greater trochanter and lateral lip of linea aspera of femur
• DA: Base of patella and tibial tuberosity via the patellar ligament
• N: Femoral nerve
• A: Knee extension

VASTUS MEDIALIS

• PA: Intertrochanteric line and medial lip of linea aspera
• DA: Base of patella and tibial tuberosity via the patellar ligament
• N: Femoral nerve
• A: Knee extension

VASTUS INTERMEDIALIS

• PA: Anterior and lateral surfaces of body of femur
• DA: Base of patella and tibial tuberosity via the patellar ligament
• N: Femoral nerve
• A: Knee extension

TENSOR FASCIA LATAE

• PA: ASIS (Anterior Superior Iliac Spine) and anterior part of external lip of iliac crest
• DA: Lateral condyle of tibia via IT (Iliotibial) tract (Gerdy’s tubercle)
• N: Superior gluteal nerve
• A: Hip abduction, internal rotation, and flexion; helps keep knee extended; steadies trunk on thigh

SARTORIUS

• PA: ASIS (Anterior Superior Iliac Spine)
• DA: Superior part of medial tibia (Pes Anserine)
• N: Femoral nerve
• A: Hip flexion, abduction, external rotation, knee flexion

PECTINEUS

• PA: Pectin pubis, superior ramus of pubis
• DA: Pectineal line of femur
• N: Femoral nerve
• A: Hip flexion and adduction

ADDUCTOR LONGUS

• PA: Body of pubis inferior to pubic crest
• DA: Middle third of linea aspera
• N: Obturator nerve
• A: Hip adduction

ADDUCTOR MAGNUS

• Hamstring Portion
  • PA: Ischial tuberosity
  • DA: Adductor tubercle of femur
  • N: Tibial portion of sciatic nerve
  • A: Hip extension
• Adductor Portion
  • PA: Inferior ramus of pubis, ramus of ischium
  • DA: Gluteal tuberosity, linea aspera, medial supracondylar line
  • N: Obturator nerve
  • A: Hip adduction and flexion

GRACILIS

• PA: Body and inferior ramus of pubis
• DA: Superior part of medial tibia (Pes Anserine)
• N: Obturator nerve
• A: Hip flexion, adduction, and internal rotation; knee flexion

SEMITENDINOSUS

• PA: Ischial tuberosity
• DA: Superior part of medial tibia (Pes Anserine)
• N: Tibial portion of sciatic nerve
• A: Hip extension, knee flexion

SEMIMEMBRANOSUS

• PA: Ischial tuberosity
• DA: Medial condyle of tibia
• N: Tibial portion of sciatic nerve
• A: Hip extension, knee flexion

BICEPS FEMORIS

• Short Head
  • PA: Linea aspera of the femur
  • DA: Medial condyle of tibia
  • N: Common fibular portion of sciatic nerve
  • A: Hip extension, knee flexion
• Long Head
  • PA: Ischial tuberosity
  • DA: Head of fibula, lateral condyle of tibia
  • N: Tibial portion of sciatic nerve
  • A: Hip extension, knee flexion, knee lateral rotation (when knee is flexed)

GLUTEUS MAXIMUS

• PA: Ilium posterior to posterior gluteal line, sacrum, coccyx, and sacrotuberous ligament
• DA: Iliotibial tract, some fibers insert on gluteal tuberosity
• N: Inferior gluteal nerve
• A: Hip extension, abduction, and external rotation

GLUTEUS MEDIUS

• PA: Gluteal surface of ilium
• DA: Greater trochanter of femur
• N: Superior gluteal nerve
• A: Hip abduction, internal rotation, stabilize pelvis in unilateral standing

GLUTEUS MINIMUS

• PA: Gluteal surface of ilium between anterior and inferior gluteal lines
• DA: Greater trochanter of femur
• N: Superior gluteal nerve
• A: Hip abduction, internal rotation, stabilize pelvis in unilateral standing

PIRIFORMIS

• PA: Anterior surface of sacrum and sacrotuberous ligament
• DA: Superior border of greater trochanter of femur
• N: Branches of ventral rami S1-S2
• A: Hip abduction, external rotation, steadies femoral head in acetabulum

SUPERIOR GEMELLUS

• PA: Ischial spine
• DA: Trochanteric fossa
• N: Nerve to obturator internus
• A: Hip lateral rotation

INFERIOR GEMELLUS

• PA: Ischial tuberosity
• DA: Trochanteric fossa
• N: Nerve to quadratus femoris
• A: Hip lateral rotation

OBTURATOR INTERNUS

• PA: Pelvic surface of obturator membrane and surrounding bones
• DA: Trochanteric fossa
• N: Nerve to obturator internus
• A: Hip lateral rotation, hip abduction when hip is flexed

OBTURATOR EXTERNUS

• PA: Obturator foramen and membrane
• DA: Trochanteric fossa
• N: Obturator nerve
• A: Hip adduction and external rotation

QUADRATUS FEMORIS

• PA: Lateral border of ischial tuberosity
• DA: Quadrate tubercle and intertrochanteric crest of femur
• N: Nerve to quadratus femoris
• A: Hip adduction and lateral rotation

TIBIALIS ANTERIOR

• O (Origin): Lateral condyle and superior half of the lateral tibia and interosseus membrane
• I (Insertion): Medial cuneiform and base of 1st metatarsal
• N: Deep fibular
• A: Foot inversion and ankle dorsiflexion

EXTENSOR DIGITORUM LONGUS

• O: Lateral condyle of the tibia, upper anterior surface of the fibula, and the interosseus membrane
• I: Middle and distal phalanges of toes 2-5
• N: Deep fibular nerve
• A: Extends the proximal phalanges of the lateral 4 toes, ankle dorsiflexion

EXTENSOR HALLUCIS LONGUS

• O: Middle portion of the anterior fibula and the interosseus membrane
• I: Dorsal aspect of the base of the distal phalanx of the big toe
• N: Deep fibular nerve
• A: Big toe extension, assists in ankle dorsiflexion, weak foot inversion

PERONEUS TERTIUS

• O: Inferior 1/3 of fibula and interosseus membrane
• I: Dorsum of base of 5th metatarsal
• N: Deep fibular nerve
• A: Foot eversion and ankle dorsiflexion

PERONEUS LONGUS

• O: Head and upper 2/3 of the lateral fibula
• I: Plantar surface of the medial cuneiform and 1st metatarsal
• N: Superficial fibular nerve
• A: Foot eversion and ankle plantar flexion

PERONEUS BREVIS

• O: Distal 2/3 of the lateral fibula
• I: Lateral side of the base of the 5th metatarsal
• N: Superficial fibular nerve
• A: Foot eversion and weak ankle plantar flexion

GASTROCNEMIUS

• O: Medial and lateral condyles of the femur
• I: Calcaneus via the tendinous raphe and calcaneal tendon
• N: Tibial nerve
• A: Knee flexion, ankle plantar flexion, raises heel during walking

SOLEUS

• O: Head and proximal 1/3 of the fibula, the soleal line, and the medial border of the tibia
• I: Calcaneus via the tendinous raphe and calcaneal tendon
• N: Tibial nerve
• A: Ankle plantar flexion

PLANTARIS

• O: Lateral supracondylar line of the femur and oblique popliteal ligament
• I: Calcaneus
• N: Tibial nerve
• A: Weakly assists in ankle plantar flexion and knee flexion

POPLITEUS

• O: Lateral condyle of the femur and lateral meniscus
• I: Posterior surface of the tibia, superior to the soleal line
• N: Tibial nerve
• A: Knee flexion and medial rotation, rotates the femur laterally on the tibia to “unlock” the knee joint

TIBIALIS POSTERIOR

• O: Posterior interosseus membrane, posterior tibia inferior to soleal line, and posterior fibula
• I: Tuberosity of the navicular bone, plantar surfaces of the cuboid and cuneiform bones, and the bases of the 2nd, 3rd, and 4th metatarsals
• N: Tibial nerve
• A: Foot inversion and ankle plantar flexion

FLEXOR DIGITORUM LONGUS

• O: Middle portion of the posterior tibia
• I: Bases of the distal phalanges of the 4 lateral toes
• N: Tibial nerve
• A: Flexes the 4 lateral digits

FLEXOR HALLUCIS LONGUS

• O: Inferior 2/3 of the posterior fibula and from the inferior portion of the interosseus membrane
• I: Base of the distal phalanx of the big toe
• N: Tibial nerve
• A: Flexes the distal phalanx of the big toe, ankle plantarflexion, helps propel the foot during walking or running