Hip flexors

In human anatomy, the hip flexors are a group of skeletal muscles that act to flex the femur (thigh bone) onto the lumbo-pelvic complex, i.e., pull the knee upward.

The hip flexors are (in descending order of importance to the action of flexing the hip joint):^[1]

• Collectively known as the iliopsoas or inner hip muscles:
  • Psoas major
  • Psoas minor
  • Iliacus muscle

• Anterior compartment of thigh
  • Rectus femoris (part of the quadriceps muscle group)
  • Sartorius

• One of the gluteal muscles:
  • Tensor fasciae latae

• Medial compartment of thigh
  • Pectineus
  • Adductor longus
  • Adductor brevis
  • Gracilis

Without the iliopsoas muscles, flexion in sitting position is not possible across the horizontal plane.^[1]

Contents 1 Other actions 2 Notes 3 References 4 See also

Other actions

Muscles that act as hip flexors frequently perform other actions. Due to this, they can be strengthened with movements besides those involving hip flexion, and stretched with movements that do not involve hip extension (or hyper extension). Awareness of these actions allows trainers to modify flexion/extension movements/stretches to modify the work done and emphasize different hip flexor muscles Examples include:

• Knee extensor: rectus femoris
• Knee flexor: gracilis, sartorius

• Hip abductor: sartorius, tensor fasciae latae
• Hip adductor: adductor brevis/longus, gracilis, pectineus

• Hip lateral rotator: adductor longus, psoas, sartorius
• Hip medial rotator: pectineus

• Spine lateral flexor and anti-rotator: psoas
• Spine flexor: psoas (both sides)

Notes

References

• Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol 1: Locomotor system (5th ed.). Thieme. ISBN 3-13-533305-1.  (ISBN for the Americas 1-58890-159-9.)
• "Iliopsoas". http://www.exrx.net/Muscles/Iliopsoas.html. Retrieved 1 September 2010. 

See also

• Hip extensors, the antagonist muscles to the hip flexors

List of muscles of lower limbs (TA A04.7, GA 4.465) ILIAC Region / ILIOPSOAS psoas major/psoas minor · iliacus BUTTOCKS gluteals: (maximus, medius, minimus) · tensor fasciae latae lateral rotator group: quadratus femoris · inferior gemellus · obturator internus · superior gemellus · piriformis THIGH / compartments Anterior sartorius · quadriceps (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) · articularis genu Posterior/hamstring biceps femoris · semitendinosus · semimembranosus Medial pectineus · obturator externus · gracilis · adductor (longus, brevis, magnus, minimus) Fascia Femoral sheath (Femoral canal) · Femoral ring Adductor canal · Adductor hiatus fascia lata (Iliotibial tract, Lateral intermuscular septum of thigh, Medial intermuscular septum of thigh, Fascia cribrosa/Saphenous opening) · Muscular lacuna LEG/ Crus/ compartments Anterior tibialis anterior · extensor hallucis longus · extensor digitorum longus · fibularis tertius Posterior superficial · triceps surae (gastrocnemius, soleus, accessory soleus, Achilles tendon) · plantaris deep · tarsal tunnel (flexor hallucis longus, flexor digitorum longus, tibialis posterior) · popliteus Lateral fibularis muscles (longus, brevis) Fascia Pes anserinus crural fascia (Anterior crural intermuscular septum, Posterior crural intermuscular septum, Transverse intermuscular septum) FOOT Dorsal extensor hallucis brevis · extensor digitorum brevis Plantar 1st layer (abductor hallucis, flexor digitorum brevis, abductor digiti minimi) · 2nd layer (quadratus plantae, lumbrical muscle) · 3rd layer (flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis) · 4th layer (dorsal interossei, plantar interossei) Fascia Plantar fascia retinacula (Fibular, Inferior extensor, Superior extensor, Flexor) M: MUS, DF+DRCT anat (h/n, u, t/d, a/p, l)/phys/devp/hist noco(m, s, c)/cong(d)/tumr, sysi/epon, injr proc, drug (M1A/3)