In human anatomy

Human anatomy

Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...

, the hip flexors are a group of skeletal muscle

Skeletal muscle

Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...

s that act to flex

Flexion

In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...

 the femur

Femur

The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

 (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):

• Collectively known as the iliopsoas
  Iliopsoas
  -External links:*...
  
   or inner hip muscles:
  • Psoas major
    Psoas major muscle
    -External links: - "Posterior Abdominal Wall: Muscles of the Posterior Abdominal Wall"* *...
    
    
  • Psoas minor
    Psoas minor muscle
    The psoas minor is a long, slender skeletal muscle which, when present, is located in front of the psoas major muscle. This muscle does not exist in about half the human population.-Course:...
    
    
  • Iliacus muscle
    Iliacus muscle
    The iliacus is a flat, triangular muscle which fills the iliac fossa.- Course :The iliacus arises from the iliac fossa on the interior side of the hip bone, and also from the region of the anterior inferior iliac spine...
    
    

• Anterior compartment of thigh
  Anterior compartment of thigh
  The anterior fascial compartment of thigh contains the knee extensors and hip flexors.It contains the following five muscles:* sartorius...
  
  
  • Rectus femoris
    Rectus femoris muscle
    The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius , and the vastus lateralis...
    
     (part of the quadriceps muscle
    Quadriceps muscle
    The quadriceps femoris , also called simply the quadriceps, quadriceps extensor, quads, is a large muscle group that includes the four prevailing muscles on the front of the thigh...
    
     group)
  • Sartorius
    Sartorius muscle
    The Sartorius muscle – the longest muscle in the human body – is a long thin muscle that runs down the length of the thigh. Its upper portion forms the lateral border of the femoral triangle.-Origin and insertion:...
    
    

• One of the gluteal muscles
  Gluteal muscles
  The gluteal muscles are the three muscles that make up the buttocks: the gluteus maximus muscle, gluteus medius muscle and gluteus minimus muscle.-The gluteal muscles:...
  
  :
  • Tensor fasciae latae
    Tensor fasciae latae
    The tensor fasciae latae or tensor fasciæ latæ is a muscle of the thigh. The English name for this muscle is the muscle that stretches the band on the side...
    
    

• Medial compartment of thigh
  Medial compartment of thigh
  The medial fascial compartment of thigh contains the hip adductors.The obturator nerve is the primary nerve supplying this compartment.The muscles in the compartment are:* gracilis* adductors** adductor longus** adductor brevis** adductor magnus...
  
  
  • Pectineus
    Pectineus muscle
    The pectineus muscle is a flat, quadrangular muscle, situated at the anterior part of the upper and medial aspect of the thigh....
    
    
  • Adductor longus
    Adductor longus muscle
    In the human body, the adductor longus is a skeletal muscle located in the thigh. One of the adductor muscles of the hip, its main function is to adduct the thigh and it is innervated by the obturator nerve...
    
    
  • Adductor brevis
    Adductor brevis muscle
    The adductor brevis is a muscle in the thigh situated immediately behind the pectineus and adductor longus.-Origin and insertion:It is somewhat triangular in form, and arises by a narrow origin from the outer surfaces of the superior and inferior rami of the pubis, between the gracilis and...
    
    
  • Gracilis
    Gracilis muscle
    The gracilis is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.-Origin and insertion:...
    
    

Without the iliopsoas muscles, flexion in sitting

Sitting

Sitting is a rest position supported by the buttocks or thighs where the torso is more or less upright.- Sitting on the floor :The most common way of sitting on the floor involves bending the knees...

 position is not possible across the horizontal plane

Horizontal plane

In geometry, physics, astronomy, geography, and related sciences, a plane is said to be horizontal at a given point if it is perpendicular to the gradient of the gravity field at that point— in other words, if apparent gravity makes a plumb bob hang perpendicular to the plane at that point.In...

.

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
  Knee flexor
  The knee flexors are a group of muscles which cross the posterior of the knee joint whose contraction induces flexion of the joint. They include, but are not limited to:*The hamstrings :**biceps femoris...
  
  : 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)

See also

• Hip extensors
  Hip extensors
  In human anatomy, the hip extensors are a group of skeletal muscles that act to extend the femur from the lumbo-pelvic complex, i.e., pull the knee down and backward....
  
  , the antagonist muscles to the hip flexors