Articular Surfaces
- Femoral head (convex): Approximately two-thirds of a sphere. Covered with hyaline cartilage that is thickest superolaterally (the weight-bearing surface). The fovea capitis (a small pit on the medial femoral head) is the attachment of the ligamentum teres and is devoid of cartilage.
- Acetabulum (concave): A deep, cup-shaped socket formed by the fusion of the ilium, ischium, and pubis. The articular surface (lunate surface) is a C-shaped rim of hyaline cartilage — the central acetabular fossa is non-articular and filled with fat and the ligamentum teres. The deep socket covers approximately 170° of the femoral head (compared to the glenoid's 75° coverage of the humeral head).
- Acetabular labrum: A fibrocartilaginous ring that deepens the acetabulum by approximately 10%, creating a negative intra-articular pressure ("suction cup" seal) that significantly enhances stability. Labral tears are increasingly recognized as a source of hip pain, particularly in young active adults with femoroacetabular impingement (FAI).
Movements and ROM
| Movement |
Normal ROM |
Plane |
Muscles Producing |
| Flexion |
120–135° |
Sagittal |
anatomy/muscles/psoas-major, anatomy/muscles/iliacus, anatomy/muscles/rectus-femoris, anatomy/muscles/sartorius, anatomy/muscles/tensor-fasciae-latae |
| Extension |
10–30° |
Sagittal |
anatomy/muscles/gluteus-maximus, anatomy/muscles/hamstrings (long head of biceps, semimembranosus, semitendinosus) |
| Abduction |
40–50° |
Frontal |
anatomy/muscles/gluteus-medius, anatomy/muscles/gluteus-minimus, anatomy/muscles/tensor-fasciae-latae |
| Adduction |
25–30° |
Frontal |
anatomy/muscles/adductor-longus, anatomy/muscles/adductor-brevis, anatomy/muscles/adductor-magnus, anatomy/muscles/gracilis, anatomy/muscles/pectineus |
| Internal rotation |
30–40° |
Transverse |
anatomy/muscles/gluteus-medius (anterior fibers), anatomy/muscles/gluteus-minimus (anterior fibers), anatomy/muscles/tensor-fasciae-latae, anatomy/muscles/adductor-longus, anatomy/muscles/adductor-brevis |
| External rotation |
40–60° |
Transverse |
anatomy/muscles/piriformis, anatomy/muscles/obturator-internus, anatomy/muscles/obturator-externus, anatomy/muscles/gemellus-superior, anatomy/muscles/gemellus-inferior, anatomy/muscles/quadratus-femoris, anatomy/muscles/gluteus-maximus |
Capsular Pattern
IR > Flexion > Abduction (ER relatively preserved)
Internal rotation is the most limited movement in hip capsular pathology (OA, capsulitis). This is because the anterior capsule and iliofemoral ligament — the strongest structures — tighten first. Flexion loss follows, then abduction. External rotation is typically the least affected early on.
Resting Position
- 30° flexion, 30° abduction, slight external rotation
- Maximum capsular volume; used for joint mobilization and joint play assessment
Close-Packed Position
- Full extension, internal rotation, abduction
- Maximum bony congruence, capsule and ligaments at maximum tension
End-Feels
| Movement |
Normal End-Feel |
Type |
| Flexion |
Tissue approximation (soft) |
Anterior thigh meets abdomen. In lean individuals, capsular (firm). |
| Extension |
Capsular (firm) |
Iliofemoral ligament and anterior capsule — the strongest ligamentous check in the body |
| Abduction |
Capsular (firm) |
Pubofemoral ligament, adductor muscles, inferior capsule |
| Adduction |
Tissue approximation / capsular |
Thigh contacts opposite thigh (tissue approximation) or capsular (firm) from superior capsule |
| Internal rotation |
Capsular (firm) |
Ischiofemoral ligament, posterior capsule, external rotators |
| External rotation |
Capsular (firm) |
Iliofemoral ligament (lateral band), pubofemoral ligament, anterior capsule |
Ligaments
Iliofemoral Ligament (Y-Ligament of Bigelow)
- Attachments: AIIS and superior acetabular rim → intertrochanteric line of the femur (two bands form an inverted Y)
- Function: The strongest ligament in the body. Resists hyperextension, external rotation, and adduction. Prevents the trunk from falling backward during standing (allows standing with minimal muscular effort). The superior band resists ER; the inferior band resists adduction.
- Clinical significance: This ligament is the primary restraint that tightens in hip OA, producing the capsular pattern (IR most limited because the iliofemoral ligament tightens first in IR).
Pubofemoral Ligament
- Attachments: Superior pubic ramus and obturator crest → intertrochanteric line (inferior to the iliofemoral ligament)
- Function: Resists excessive abduction and extension. Works with the inferior band of the iliofemoral ligament to prevent hyperextension.
Ischiofemoral Ligament
- Attachments: Ischial portion of the acetabulum → greater trochanter (posterior neck)
- Function: Resists excessive internal rotation and adduction (in flexion). The weakest of the three hip capsular ligaments — this is why the posterior capsule is the most vulnerable to dislocation (posterior hip dislocation from dashboard injury).
Ligamentum Teres (Ligament of the Head of the Femur)
- Attachments: Acetabular notch and transverse acetabular ligament → fovea capitis of the femoral head
- Function: Carries a small artery (artery of the ligamentum teres, branch of the obturator artery) that provides limited blood supply to the femoral head. The ligament's mechanical contribution to stability is minimal in adults. The artery is significant in children (where it is a major femoral head blood supply) and becomes insignificant in adults (the medial and lateral circumflex femoral arteries dominate).
Mobilization Techniques
Hands-on instruction is required. The descriptions below provide clinical reference detail for understanding and supervised practice. They are not a substitute for instructor-led technique training. Correct hand placement, force dosage, and tissue response interpretation require hands-on coaching and feedback.
Convex-Concave Rule at the Hip Joint
The femoral head is
convex articulating with the
concave acetabulum. When mobilizing the convex femur on the fixed pelvis, the glide is in the
opposite direction to the restricted movement (same rule as the GH joint).
| Restricted Movement |
Glide Direction |
Reasoning |
| Flexion |
Posterior glide |
Convex on concave → opposite direction |
| Extension |
Anterior glide |
Convex on concave → opposite direction |
| Abduction |
Inferior (lateral) glide |
Convex on concave → opposite direction |
| Internal rotation |
Posterior glide |
Convex on concave → opposite direction |
| External rotation |
Anterior glide |
Convex on concave → opposite direction |
General Contraindications
- Absolute: Acute fracture (femoral neck fracture, acetabular fracture), hip dislocation, active joint infection (septic arthritis), malignancy, avascular necrosis (AVN — aggressive mobilization of a compromised femoral head risks collapse), acute inflammatory arthritis (RA flare)
- Relative: Total hip replacement (follow surgeon protocol — typically 90° flexion precautions, no IR or adduction past midline for 6–12 weeks), osteoporosis (Grade I–II only), significant OA with bony end-feel (do not force into bony blocks), labral tear (gentle grades, avoid provocation position of flexion + IR + adduction)
Inferior (Caudal) Hip Glide (Long-Axis Distraction)
Purpose: General capsular stretch and pain modulation. Distracts the femoral head from the acetabulum, decompressing articular surfaces. The most commonly used hip mobilization — appropriate as a first technique for any hip capsular restriction.
Patient position:
- Supine on the treatment table
- Hip positioned at approximately 30° flexion, 30° abduction, slight ER (resting position)
- A mobilization belt around the clinician's hips and the patient's proximal femur can provide mechanical advantage
Hand placement:
- Stabilizing hand: The patient's pelvis is stabilized by body weight and table contact. A belt around the pelvis and table can provide additional stabilization.
- Mobilizing hand: Both hands grip the distal femur and proximal tibia (or a belt around the proximal femur). Force directed distally (toward the feet) along the long axis of the femur — pulling the femoral head away from the acetabulum.
Technique execution:
- Apply a sustained or oscillatory traction force directed inferiorly along the femoral shaft
- Grade I–II: Gentle traction for pain modulation — appropriate for acute OA flare
- Grade III: Sustained traction at end-range for capsular stretch
- Duration: 30–60 seconds per set, 3–5 sets. Reassess hip ROM between sets.
Indications:
- Hip OA with capsular restriction
- General hip stiffness following the capsular pattern (IR > flexion > abduction)
- Post-immobilization or post-surgical stiffness (when cleared)
- As a preparatory technique before directional glides
Technique notes:
- A mobilization belt provides significant mechanical advantage — the hip joint is deep and surrounded by powerful muscles; manual traction alone may be insufficient.
- Reassessment: Re-test IR and flexion PROM. Improvement confirms capsular involvement.
Posterior Hip Glide
Purpose: Restores flexion and internal rotation. Stretches the anterior capsule and iliofemoral ligament — the structures responsible for the hip capsular pattern.
Patient position:
- Supine on the treatment table
- Hip flexed to approximately 90° (or to the point of restriction), knee flexed
- The hip is positioned in the resting position or at the current end-range of flexion
Hand placement:
- Stabilizing hand: Placed on the anterior pelvis (ASIS) to prevent the pelvis from lifting off the table
- Mobilizing hand: Both hands on the anterior proximal femur (just distal to the inguinal crease). Force directed posteriorly (toward the table).
Technique execution:
- Apply an oscillatory force directed posteriorly through the proximal femur
- Grade I–II: Gentle oscillations for pain modulation
- Grade III–IV: Oscillations into the posterior end-range resistance. The anterior capsule and iliofemoral ligament provide a strong, firm barrier.
- Duration: 30–60 seconds per set, 3–5 sets
Indications:
- Decreased flexion with capsular end-feel (the defining hip OA restriction)
- Decreased IR with capsular end-feel (the earliest hip OA finding)
- Joint play assessment reveals decreased posterior glide
Technique notes:
- Common error: Compressing the femoral nerve and femoral artery against the proximal femur. Place hands distal to the inguinal crease, over the proximal femoral shaft, not the inguinal region.
- Common error: Allowing the pelvis to rock posteriorly — the pelvis must remain stabilized.
- Integration: Perform after psoas, rectus femoris, and hip adductor release.
- Reassessment: Re-test hip flexion and IR PROM. Improvement confirms anterior capsular involvement.
Muscles Crossing This Joint
Hip Flexors
Hip Extensors
- anatomy/muscles/gluteus-maximus — the most powerful hip extensor; essential for stair climbing, rising from seated, and running
- anatomy/muscles/hamstrings — biceps femoris (long head), semimembranosus, semitendinosus
Hip Abductors
Hip Adductors
Deep External Rotators ("Deep Six")
Conditions Affecting This Joint
- conditions/osteoarthritis — the most common hip condition; follows the capsular pattern (IR > flexion > abduction); groin pain worsened by weight bearing; eventually requires hip replacement
- Femoroacetabular impingement (FAI) — cam type (bony bump on femoral head-neck junction) or pincer type (acetabular overcoverage); produces hip and groin pain with flexion + IR + adduction; associated with labral tears
- Labral tear — fibrocartilaginous labral damage; catching, clicking, groin pain; FADIR test positive (flexion + adduction + internal rotation reproduces pain)
- Avascular necrosis (AVN) — loss of blood supply to the femoral head; risk factors include corticosteroid use, alcohol abuse, sickle cell disease, hip fracture
- Hip fracture (femoral neck, intertrochanteric) — common in elderly osteoporotic patients after a fall; shortened and externally rotated limb position; absolute contraindication to mobilization
- Greater trochanteric pain syndrome — lateral hip pain at the greater trochanter; involves gluteus medius/minimus tendinopathy and trochanteric bursitis
Clinical Notes
- IR loss is the earliest sign of hip OA. Assess internal rotation first in any hip assessment. Loss of IR with a capsular end-feel in a patient over 50 with groin pain is hip OA until proven otherwise. The capsular pattern (IR > flexion > abduction) then confirms the diagnosis.
- Groin pain means hip; lateral pain means trochanteric; posterior pain means SI or lumbar. This is a simplification but a useful starting framework. True hip joint pain is felt in the groin and may radiate to the anterior thigh and knee (via the obturator nerve). Lateral hip pain typically indicates gluteus medius/minimus tendinopathy or trochanteric bursitis. Posterior buttock pain is more likely SI joint or lumbar referred.
- The iliofemoral ligament is the strongest ligament in the body. It resists hyperextension so effectively that humans can stand upright with minimal muscular effort. In hip OA, contracture of the iliofemoral ligament and anterior capsule is the primary cause of the capsular pattern — this is why posterior glide mobilization targeting the anterior capsule is the priority technique.
- Trendelenburg sign and gluteus medius. During single-leg stance, the gluteus medius on the stance side contracts to prevent the pelvis from dropping on the swing side. Weakness produces Trendelenburg gait (the pelvis drops on the unsupported side). Gluteus medius weakness is both a consequence and a perpetuator of hip pathology.
Key Takeaways
- Capsular pattern IR > flexion > abduction — IR loss is the earliest sign of hip OA; always assess IR first.
- Convex femoral head on concave acetabulum means glide is opposite to the restricted movement — same rule as the GH joint.
- The iliofemoral ligament is the strongest ligament in the body — its contracture drives the hip capsular pattern; posterior glide targets it directly.
- True hip joint pain is felt in the groin, not laterally (trochanteric) or posteriorly (SI/lumbar) — this localization guides differential diagnosis.
