agonist muscle

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agonist muscle

Controlled movements involve two opposing muscles: the agonist muscle produces the main action, while the antagonist muscle produces the opposite action to a lesser degree. The balance between agonist and antagonist muscles allows precise control of the final action.
Synonym: antagonist muscle See: PNF Stretching Techniques
See also: muscle
agonist muscle prime mover (see agonist)
  • antagonist muscle muscles or muscle groups which neutralize action of another muscle or muscle group (see antagonist; muscle contraction)

  • cardiac muscle; myocardium striated heart muscle

  • involuntary muscle smooth muscle, not under voluntary control

  • muscles of sole of foot see Table 1, and see named individual muscles

  • muscle stretch reflex see reflex, deep tendon

  • prime mover muscle see agonist

  • skeletal muscle voluntary muscle attached at one or both ends to bone, crossing a joint or joints, and formed of elongated, multinuclear, transversely striated contractile fibres

  • smooth muscle muscle tissue under involuntary (autonomic) control, e.g. vascular smooth muscle

  • striated muscle skeletal and cardiac muscle; constituent fibres show cross-striations

  • voluntary muscle skeletal muscle, i.e. muscle tissue that contracts in response to a decision to move or in response to reflex action (contrast with muscle, involuntary)

Table 1: Structures of the sole of the foot (superficial to deep) (see also Table J2)
LayerStructure
0Plantar aponeurosis (plantar fascia)
IMuscles: abductor hallucis; flexor digitorum brevis; abductor digiti minimi
Nerves: plantar digital nerves
Vessels: plantar digital vessels
IINerves: lateral plantar nerve; medial plantar nerve
Vessels: superficial branches of the medial and lateral plantar arteries
IIITendons: tibialis posterior; flexor hallucis longus; flexor digitorum longus
Muscles: flexor accessories (quadratus plantae); lumbrical muscles
IVMuscles: flexor hallucis brevis; adductor hallucis; flexor digiti minimi brevis
VNerves: lateral plantar artery (deep branches)
Vessels: lateral plantar artery (deep branches)
VILigaments: deep plantar ligaments
Tendons: peroneus longus; tibialis posterior
Muscles: interossei
Vessels: perforating branches of the plantar metatarsal arteries
Table 2: Movements occurring about the joints of the lower limb and foot
Movement about jointMuscle causing the movementNerve supply to muscle
Hip flexionIliacus
Psoas major
Rectus femoris
Sartorius
Tensor fasciae lata
Pectineus
Adductor longus
Adductor brevis
Ventral rami of L1 and L2
Ventral rami of L1 and L2
Femoral
Femoral
Superior gluteal
Femoral
Obturator
Obturator
Hip extensionGluteus maximus
Semimembranosus
Semitendinosus
Biceps femoris, long head
Adductor magnus, ischial part
Inferior gluteal
Tibial part of sciatic nerve
Tibial part of sciatic nerve
Tibial part of sciatic nerve
Tibial part of sciatic nerve
Hip adductionAdductor longus
Adductor brevis
Adductor magnus
Gracilis
Pectineus
Quadratus femoris
Obturator
Obturator
Obturator
Obturator
Femoral
Ventral rami of L4, L5 and S1
Hip abductionGluteus medius
Gluteus minimus
Tensor fasciae lata
Piriformis
Obturator internus, in flexion
Superior gluteal
Superior gluteal
Superior gluteal
Ventral rami of L5 and SI
Ventral rami of L5 and S1
Medial rotation of leg at hipTensor fasciae lata
Gluteus minimus
Anterior fibres of gluteus maximus
Adductors longus, brevis and magnus
Iliopsoas
Superior gluteal
Superior gluteal
Superior gluteal
Superior gluteal
Ventral rami L1 and L2
Lateral rotation of leg at hipSartorius
Gluteus maximus
Obturator internus
Gemelli
Obturator externus
Quadratus femoris
Piriformis, in flexion
Femoral
Inferior gluteal
Ventral rami of L5, S1 and S2
Ventral rami of L5, S1 and S2
Obturator
Ventral rami of L4, L5 and S1 Ventral rami of L5, S1 and S2
Knee flexionSemimembranosus
Semitendinosus
Biceps femoris, long head
Biceps femoris, short head
Gracilis
Sartorius
Popliteus
Gastrocnemius
Sciatic (tibial)
Sciatic (tibial)
Sciatic (tibial)
Common peroneal
Obturator
Femoral
Tibial
Tibial
Knee extensionVastus medialis
Vastus lateralis
Vastus intermedius
Rectus femoris
Gluteus maximus
Tensor fasciae lata
Femoral
Femoral
Femoral
Femoral
Inferior gluteal
Superior gluteal
Lateral rotation of leg = medial rotation of thigh in knee flexionBiceps femoris, long head
Biceps femoris, short head
Gluteus maximus
Tensor fasciae lata
Tibial
Common peroneal
Inferior gluteal
Superior gluteal
Medial rotation of leg with knee flexedPopliteusTibial
Medial rotation of leg with knee extendedSemimembranosus
Semitendinosus
Gracilis
Sartorius
Sciatic (tibial)
Sciatic (tibial)
Obturator
Femoral
Ankle plantarflexionGastrocnemius
Soleus
Plantaris
Tibialis posterior
Flexor hallucis longus
Flexor digitorum longus
Peroneus longus
Peroneus brevis
Tibial
Tibial
Tibial
Tibial
Tibial
Tibial
Superficial peroneal
Superficial peroneal
Ankle dorsiflexionTibialis anterior
Extensor hallucis longus
Extensor digitorum longus
Peroneus tertius
Deep peroneal
Deep peroneal
Deep peroneal
Deep peroneal
Subtalar and midtarsal inversionTibialis anterior
Extensor hallucis longus
Tibialis posterior
Deep peroneal
Deep peroneal
Tibial
Subtalar and midtarsal eversionPeroneus longus
Peroneus brevis
Extensor digitorum longus
Peroneus tertius
Superficial peroneal
Superficial peroneal
Deep peroneal
Deep peroneal
1 Toe plantarflexion (MTPJ; IPJ)Flexor hallucis longus
Flexor hallucis brevis
Tibial
Medial plantar
2-5 Toes plantarflexion (MTPJs; IPJs)Flexor digitorum longus
Flexor accessorius (quadratus plantae)
Flexor digitorum brevis
Lumbricals
Interossei
Tibial
Lateral plantar
Medial plantar
Medial plantar, toe 2; lateral plantar toes 3-5
Lateral plantar
1 Toe dorsiflexionExtensor hallucis longus
Extensor hallucis brevis
Deep peroneal
Deep peroneal
2-5 Toes dorsiflexion
2-4 Toes dorsiflexion
Extensor digitorum longus
Extensor digitorum brevis
Deep peroneal
Deep peroneal
Toe abduction (away from midline of foot = adduction toward midline of body)
Toe 1
Toes 2-4
Toe 5
Abductor hallucis
Dorsal interossei
Abductor digit minimi
Medial plantar
Lateral plantar
Lateral plantar
Toe adduction (toward the midline of foot = abduction away from midline of body)
Toe 1
Toes 2-5
Adductor hallucis*
Plantar interossei
Lateral plantar
Lateral plantar

Note: Primary action of muscles is printed in normal type; muscles that give some contribution to this action are printed in italics .

The nerve supply to the lower limb (lower leg and foot) is derived from the sciatic and femoral nerves. Dysfunction or compromise of either of these nerves causes marked motor, sensory and autonomic effects in the lower leg and foot.

MTPJ, metatarsophalangeal joint; IPJ, interphalangeal joint.