Human Anatomy — all lessons
Foundations of Anatomy
Anatomical terminology, planes, axes and movement directionsThe Skeletal System
Skeletal system: structure and functionsBone structure, remodelling and adaptation to loadingJoints and the Muscular System
Joint types and classificationJoint mechanics: arthrokinematics and stabilityThe muscular system: organisation and major muscle groupsMuscle architecture: pennation, length and cross-sectional areaMuscle fibre typesRegional Functional Anatomy
Spine and postureThe shoulder complexThe hip complexThe knee complexThe ankle and foot complexCore and pelvic stabilityElbow and wrist functional anatomyCervical and thoracic spine functional anatomyThe hip complex
The acetabulofemoral joint, its stabilising ligaments and labrum, the major hip muscle groups, and how hip anatomy shapes squatting, hinging, running and single-leg control.
Learning objectives
- Describe the bony and soft-tissue structures of the hip
- Identify the main hip muscles by action
- Explain how individual hip morphology influences squat depth and stance
- Relate hip abductor function to single-leg control
Before this lesson
Why this matters
The hip produces much of the power in sprinting, jumping and lifting, and controls the pelvis in every single-leg activity. Its anatomy also varies a lot between people — which is why one “correct” squat stance does not exist.
Fundamental concepts
The hip (acetabulofemoral) joint is a ball-and-socket joint between the femoral head and the acetabulum of the pelvis, deepened by the fibrocartilaginous labrum. A thick capsule is reinforced by three ligaments: iliofemoral (strongest; limits extension), pubofemoral (limits abduction and extension) and ischiofemoral (limits internal rotation and extension) [neumann2017].
Muscles by action
| Action | Main muscles |
|---|---|
| Flexion | Iliopsoas, rectus femoris, sartorius, tensor fasciae latae |
| Extension | Gluteus maximus, hamstrings, adductor magnus (posterior part) |
| Abduction | Gluteus medius, gluteus minimus, TFL |
| Adduction | Adductor longus, brevis, magnus; gracilis; pectineus |
| External rotation | Deep six rotators (piriformis etc.), gluteus maximus |
| Internal rotation | Anterior gluteus medius/minimus, TFL (weaker overall) |
Many hip muscles change action with hip position — for example, piriformis is an external rotator near neutral but contributes to internal rotation when the hip is deeply flexed [neumann2010].
Single-leg control
In single-leg stance, body weight tends to drop the pelvis on the unsupported side. The stance-side abductors (gluteus medius and minimus) prevent this. Weakness or poor control produces a pelvic drop (Trendelenburg pattern), often seen in running, stair descent and step-downs.
Individual anatomy
Acetabular depth and orientation, femoral neck-shaft angle and femoral torsion (anteversion) vary widely. These differences influence comfortable squat depth, stance width and toe angle. Pinching at the front of the hip at depth may reflect bony contact rather than “tight muscles” in some people.
Practical application
Common mistakes and misconceptions
Case study
A client reports pinching at the front of the hip below parallel. Toe-out of 20° and a slightly wider stance remove the symptom while maintaining depth. The trainer records the change and monitors; persistent symptoms would prompt referral to rule out structural hip pathology.
Further learning: video lessons
Video links are only marked “verified” after a human has watched them. Unverified entries open a YouTube search for that channel and topic rather than a guessed link.
Hip joint anatomy
Kenhub
You will understand: bones, ligaments and muscle groups of the hip
Why: Labelled 3D anatomy.
Hip anatomy and squat depth — individual differences
Squat University (Dr Aaron Horschig)
You will understand: why squat stance varies with hip structure
Why: Physiotherapist applying anatomy to lifting.
Knowledge check
Knowledge check · 0/5
1. The strongest ligament of the hip, resisting extension, is the…
2. A Trendelenburg sign (pelvis dropping on the unsupported side in single-leg stance) suggests weakness of…
3. The primary hip flexor is…
4. Why might two clients need different squat stance widths?
5. The acetabular labrum…
Short-answer & application questions
- Explain the role of the hip abductors during running.
- Why might adductor magnus be considered an important hip extensor in a deep squat?
- Describe how you would individualise squat stance for a client with pinching at the front of the hip at depth.
Key takeaways
- The hip is a deep ball-and-socket joint, stabilised by the labrum, a strong capsule and the iliofemoral, pubofemoral and ischiofemoral ligaments.
- Gluteus maximus is the main hip extensor; gluteus medius and minimus stabilise the pelvis in single-leg stance.
- Hip socket orientation and femoral neck angles vary widely, so optimal squat stance and depth vary between people.
- Many hip muscles change their action depending on hip position.
Connected topics
The knee complex
anatomyCore and pelvic stability
corrective exerciseHip
strength conditioningCompound lifts: squat, deadlift and bench variations
functional trainingFundamental movement patterns: push, pull, squat, hinge
References
- Neumann DA (2010). Kinesiology of the hip: a focus on muscular actions. Journal of Orthopaedic & Sports Physical Therapy, 40(2):82–94. doi:10.2519/jospt.2010.3025 Narrative review check pending
- Neumann DA (2017). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation (3rd ed.). Elsevier. Textbook check pending
Educational content only — not medical advice. Consult a qualified clinician for diagnosis or treatment.