Hip Flexor Muscles

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Primary

• Iliopsoas¹
• Sartorius¹
• Tensor fasciae latae¹
• Rectus femoris¹
• Adductor longus (when in hip Extension)¹
• Pectineus (When in hip extension)¹

Secondary

• Adductor brevis¹
• Gracilis¹
• Gluteus minimus (anterior fibers)¹
• Gluteus medius (anterior fibers)¹

Primary

Table 1: Primary Flexors of the Hip

Muscle	Origin	Insertion	Innervation	Action
Adductor Longus	Superior pubis ramus Anterior side of Pubic Symphysis	Linea aspera	Obturator n. L2 - L4	Hip: Adduction, Flexion, Extension Pelvis: Frontal plane stabilization, Sagittal plane stabilization
Iliacus	Iliac Fossa	Lesser Trochanter	Femoral n. L2 - L3	Hip: Flexion, ER L/S (UNIL contraction on fixed femur): I/L spine sidebend L/S (BIL contraction): Raises trunk from supine position
Pectineus	Pecten pubis	Pectineal line Proximal linea aspera	Femoral n. Obturator n. L2 - L3	Hip: ER, Adduction, *slight* Flexion Pelvis: Frontal plane stabilization, Sagittal plane stabilization
Psoas Major	T12-L4 and associated IV discs L1-L5 TP	Lesser Trochanter	Lumbar Plexus Direct Br. L1 - L3	Hip: Flexion, ER L/S (unilateral contraction with femur fixed): I/L spine sidebend L/S (bilateral contraction): Raises trunk from supine position
Rectus femoris	AIIS Acetabular roof	Tibial tuberosity via Patellar ligament	Femoral n. L2 - L4	Hip: Flexion Knee: Extension
Tensor Fascia Latae	ASIS	IT Band	Superior gluteal n. L4 - S1	Tenses fascia latae Hip: Abduction, Flexion, IR

Secondary

Table 2: Secondary Flexors of the Hip

Muscle	Origin	Insertion	Innervation	Action
Adductor brevis	Inferior pubic ramus	Linea aspera	Obturator n. L2 - L3	Hip: Adduction, Flexion, Extension Pelvis: Frontal stabilization, Sagittal stabilization
Gluteus Minimus	Ilium gluteal surface (inferior to gluteus medius origin)	Greater trochanter (anterolateral surface)	Superior gluteal n. L4 - S1	Entire mm.: Abduction, Frontal stabilization Anterior fibers: Flexion, IR Posterior fibers: Extension, ER (when <60° HF), IR (when &gt60° HF)
Gracilis	Inferior pubic ramus	Pes anserine	Obturator n. L2 - L3	Hip: Adduction, Flexion Knee: Flexion, IR

Functional subgroups

To produce pure hip flexion, without deviations in the transverse or frontal plane, these two groups must work together:

Flexion + Abduction + IR

These hip flexors perfoms flexion, abduction, and IR²

• Gluteus minimus
• Glute Med
• TFL
• Gracilis

Flexion + ADD + ER

These hip flexors perfoms flexion, adduction, and IR²

• Iliopsoas
• Pectineus
• Adductor longus

Manual muscle tests

Hip flexors act as synergists during:

• Unilateral SCM MMT³

Stretches

• 3D hip flexor stretch

References

1.

Neumann DA, Kelly ER, Kiefer CL, Martens K, Grosz CM. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.

2.

Jones B. B Project Foundations. b Project; 2025.

3.

Weinstock D. NeuroKinetic Therapy: An Innovative Approach to Manual Muscle Testing. North Atlantic Books; 2010.