Functional Anatomy of the Pelvis and Hip

Functional Anatomy of the Pelvis

  • Stability and Function of Pelvis

    • Acts as a mechanical link between upper and lower body
    • Supports weight due to its flat bones (ilium)
    • Provides attachment for 28 muscles
    • Protects internal organs

  • Bones of the Pelvis

    • Sacrum: Composed of five fused bones
    • Ilium: Large flat bone forming the upper portion of the pelvis
    • Ischium: Known as the sit bones
    • Pubis: Forms the front of the pelvis
    • Coccyx: Four fused vertebrae at the bottom

  • Motions of the Pelvis

    • Sacral Motions:
    • Flexion (Mutate): Anterior sacrum tilting forward relative to ilium
    • Extension (Counternutation): Posterior sacrum tilting backward
    • Rotational movements also occur:(Right & Left rotation of the sacrum).

  • Spinal Interactions:

    • Spine extension causes sacral flexion
    • Spine flexion causes sacral extension

  • Pelvic Tilts:

    • Sagittal Plane:
    • Anterior tilt: pelvis tilts forward
    • Posterior tilt: pelvis tilts backward
    • Frontal Plane:
    • Left lateral tilt: left side of pelvis rises
    • Right lateral tilt: right side of pelvis rises
    • Transverse Plane:
    • Right rotation: pelvis rotates to the right
    • Left rotation: pelvis rotates to the left

  • Injury Discussion:

    • Osteitis Pubis:
    • Inflammation at the symphysis pubis joint
    • Common in male soccer players
    • Prevalence: 10-18% of all athletes' osteitis pubis cases

Functional Anatomy of the Hip

  • Strength and Mobility:

    • Hip joint complex: stable yet mobile for movements
    • Head of femur is 70% covered by acetabulum, enhancing stability

  • Functions of the Hip Joint:

    • Transfers lower body loads to upper body
    • Supports spine and trunk
    • Facilitates movement (walking, running, crawling)

  • Key Motions at the Hip:

    • Sagittal Plane:
    • Flexion: lifting femur toward pelvis
    • Extension: moving femur backward
    • Frontal Plane:
    • ABduction: moving away from midline
    • ADduction: moving towards midline
    • Transverse Plane:
    • Internal rotation: femur rotates inward
    • External rotation: femur rotates outward

  • Risks:

    • Increased chance of hip fracture in elderly post-fall
    • Risk of death from hip fracture increases 5-8 fold within three months post-fall

Anatomy of Hip and Pelvic Bones

  • Bone Structures:
    • The pelvis consists of ilium, ischium, pubis, sacrum, and coccyx
    • Ilium forms the upper flat portion, ischium is the sit bone, pubis is the front part, sacrum is five fused vertebrae, coccyx is the fused vertebrae at the bottom
    • Iliac Crest: Top curved edge of the ilium
    • Greater & Lesser Trochanters: Bony prominences on femur for muscle attachment

Joints of the Pelvis and Hip

  • Pelvic Joints:

    • Sacroiliac joints (two) connecting sacrum and ilium
    • Symphysis pubis joint joining right and left pubis
    • Sacrococcygeal joint between sacrum and coccyx (immovable)

  • Hip Joint:

    • Ball and socket joint between head of femur and acetabulum
    • Provides stability with 70% surface area coverage of femur by pelvis
    • Permits motion: flexion, extension, ABduction, ADduction, internal and external rotation

  • Hypermobility Considerations:

    • May develop in athletes leading to dysplasia or impingement

Hip Muscles

  • Gluteus Muscles:

    • Gluteus Maximus: Powerful hip extender; assists in external rotation
    • Gluteus Medius: Hip ABductor; assists in internal rotation and external rotation
    • Gluteus Minimus: Internal rotator and ABductor

  • Hamstring Muscles:

    • Cross both hip and knee; important for hip extension
    • Bicep Femoris: External rotation
    • Semimembranosus & Semitendinosus: Internal rotation contributor

  • Anticipated Injuries:

    • Common hamstring strain due to crossing both joints, usually occurs when knee extends during sprinting

  • Anterior Hip Muscles:

    • Psoas Major: Hip flexor and contributes to pelvic tilt
    • Iliacus: Assists psoas in flexion and rotations
    • Rectus Femoris: Part of quadriceps, assists hip flexion

Adductor Muscles & Tensor Fascia Lata

  • Adductor Group (inside thigh):

    • Adductor Brevis: Shortest, helps in adduction and external rotation
    • Adductor Longus: Assists in hip flexion and adduction
    • Adductor Magnus: Largest, aids in both adduction and hip extension
    • Gracilis: Contributes to adduction, internal rotation, and flexion

  • Tensor Fascia Lata:

    • ABduction and assists with internal rotation; connects to the ITB

Pelvic Floor Muscles

  • Importance of Pelvic Floor Health:

    • Supports abdominal viscera, aids in continence, assists in breathing
    • Forms the core canister: diaphragm and pelvic floor

  • Muscle Groups:

    • Levator Ani: Group of muscles including iliococcygeus, pubococcygeus, and puborectalis for pelvic stability
    • Piriformis & Obturator Internus: Help with lateral rotation of the femur and contribute to pelvic stability

Pelvic Floor Dysfunction

  • Types of Dysfunction:

    • Underactive (relaxation issues): leads to incontinence, pelvic organ prolapse
    • Overactive (constant contraction): may lead to pelvic pain and sexual dysfunction

  • Prevalence: More common in athletes, particularly high-impact sports; often underreported

  • Management Strategies:

    • Modify activities causing issues; pelvic floor muscle training; consult specialists

  • Key Recommendations:

    • Educate on pelvic health, denormalize incontinence, recognize risk factors, and facilitate referrals to specialists.