Hip Joint Flashcards
Sacroiliac joint (SI)
- Designed for force transmission and weight-bearing
- Articulating bony surfaces are irregular
- Limited motion
Sacroiliac joint (SI) is located between
- L-shaped auricular surface of ilium and sacrum (S1-3)
Irregular articulating bony surfaces of sacroiliac joint
- Increase friction and congruency
Limited motion of sacroiliac joint
- 2 degrees of rotation
- 2mm of translation
2 parts of sacroiliac joint
- Anterior planar (synovial joint)
- Posterior syndesmosis (fibrous joint)
Anterior planar (synovial joint)
- Auricular surfaces
- Sacral surface covered by hyaline cartilage
- Ilium surface covered by fibrocartilage
Ligaments of the sacroiliac joint
- Anterior (ventral) sacroiliac
- Interosseous sacroiliac
- Poster (dorsal) sacroiliac
- Iliolumbar
- Sacrotuberous
- Sacrospinous
Anterior (ventral) sacroiliac ligament
- Thickening of anterior joint capsule
Interosseous sacroiliac ligament
- Connect tuberosities of sacrum/ilium
- Posterior/superior to joint
Posterior (dorsal) sacroiliac
- Overlies interosseous ligament posteriorly
- Connects intermediate/lateral crest of sacrum of S1,2 to PSIS and internal lip of iliac crest
Long posterior (dorsal) sacroiliac ligament
- S3,4 to PSIS
Iliolumbar ligament
- L4,5 to iliac crest, sacral ala and anterior sacroiliac ligament
- Primarily supports lumbosacral joint (L5/S1)
- Also supports SI joint
Sacrotuberous ligament
- Broad attachment to PSIS, posterior sacroiliac ligaments, dorsolateral sacrum and coccyx
- Attaches to ischial tuberosity
Glut max, piriformis, biceps femoris, semitendinosus muscles attach
Sacrospinous ligaments
- Attaches from ischial spine to lateral margin of sacrum/coccyx
- Anterior to sacrotuberous ligament
Ligaments that resist nutation
- Sacrotuberous
- Sacrospinous
- Anterior and interosseous SI
Nutation
- Anterior/inferior motion of sacral base
- Posterior/superior motion of coccyx
- There is concurrent superior rotation of pelvis (weight-bearing)
Counternutation
- The opposite motion of nutation
Ligaments resisting counternutation
- Long posterior (dorsal) sacroiliac ligament
Blood supply to SI joint
- Superior gluteal
- Iliolumbar
- Lateral sacral
Innervation of the SI joint (variable among individuals)
- Primarily dorsal rami L4-S3(4)
- Vental rami L5-S2
- Superior gluteal nerve
Pubic symphysis
- Articular surfaces of pubis are covered by hyaline cartilage
- Fibrocartilage disc connects the 2 pubic bones (symphysis joint)
Pubic symphysis joint functional classification
- Amphiarthrosis joint
Superior pubic ligament
- Attaches to pubic bones superiorly
- Extend out to pubic tubercles
Inferior pubic ligaments
- Also called arcuate pubic ligament
- Extends out to inferior pubic rami
Hip joint
- Ball and socket (spheroid)
- Synovial joint (diarthrosis)
Hip joint movements
- Triplanar motion
- Flex/ext/ab/add/int & ext rot/circumduction
Hip movement from the anatomical position
- Adduction is more limited than abduction
- Lateral rotation is stronger than medial rotation
Hip joint articulates between
- Femoral head and acetabulum (lunate surface)
Hip joint socket
- Stable
- More than ½ of femoral head fits into “socket”
- Anterior femoral head has less coverage of acetabulum
Acetabular fossa (cotyloid fossa) filled with
- Fat
- Ligament of the head of the femur
Acetabular labrum
- Fibrocartilage attached to acetabular rim
Acetabular labrum function
- Deepens socket
- Shock absorber
- Decrease stress between
- Helps create negative pressure (sealing function)
- Distributes compressive loads
Joint capsule attaches proximally to
- Rim of acetabulum
- Transverse acetabular ligament
Joint capsule attaches distally to
- Intertrochanteric line anteriorly
- Extends to mid neck posteriorly (doesn’t attach firmly to bone)
- Lateral half of neck is extracapsular posteriorly
Muscles that attach to the hip capsule
- Gluteus minimus
- Iliocapsularis
- Indirect head of rectus femoris
- Obturator externus
- Conjoint tendon of hip
Conjoint tendon of hip
- Obturator internus
- Superior and inferior gemelli
- Also known as the triceps coxae
Synovium
- Lines capsule and all structures within the capsule except for articular cartilage
Ligaments of the hip joint
- Extracapsular (extrinsic)
- Iliofemoral
- Pubofemoral
- Ischiofemoral
Extracapsular (extrinsic) ligaments
- Reinforce joint capsule
- Spiraling shaped fibers “screw” head into acetabulum
- All resist hip extension and anterior translation of femoral head
Iliofemoral (Y-ligament, ligament of Bigelow)
- Strongest ligament in the hip
- Splits into 2 bands
Iliofemoral (Y-ligament, ligament of Bigelow) proximal attachment
- AIIS
- Iliac portion of acetabular rim
Iliofemoral (Y-ligament, ligament of Bigelow) two bands
- Upper (lateral) band
- Lower (medial) band
Upper (lateral) band of iliofemoral ligament
- Attaches to superior intertrochanteric line
- Resists extension and external rotation
Lower (medial) band of iliofemoral ligament
- Attaches to inferior intertrochanteric line
- Resists extension and external rotation
Pubofemoral ligament
- Attaches to pubic part of acetabular rim/obturator crest
- Blends with joint capsule/iliofemoral ligament
- Resists extension and abduction/external rotation
Ischiofemoral ligament
- Ischial part of acetabular rim to capsule around femoral neck
- Resists extension and internal rotation
Zona orbicularis
- Circular fibers from the capsular ligaments for a collar around the neck
- Not directly attached to bone
- “Locking ring”
Zona orbicularis function
- Aids in holding femoral head into acetabulum
- Resists distraction
Intracapsular ligaments
- Ligament of head of the femur
- Transverse acetabular ligament
Ligament of head of the femur other names
- Ligamentum teres femoris
- Round ligament of the femur
- Ligamentum capitis femoris
- Foveal ligament
Intracapsular ligament
- Located at the acetabular fossa
Ligamentum capitis femoris
- Secondary stabilization function of normal hip
- More important stabilizer in pathological hip
Ligamentum capitis femoris is a conduit for
- Artery to head of the femur and nerves
- Functions in proprioception
Ligamentum capitis femoris attaches
- Margin of acetabular notch/transverse acetabular ligament
- Fovea capitis on the femur
Transverse acetabular ligament
- Attaches to edges of acetabular notch
- Creates foramen for vessel passage
Iliocapsularis origin
- Anterior inferior iliac spine
- Anterior hip capsule
Iliocapsularis insertion
- Below lesser trochanter
- Sometimes iliopfemoral ligament and/or intertrochanteric line
Iliocapsularis innervation
- Femoral nerve
Iliocapsularis function
- Raise the capsule with hip flexion
- Stabilize the hip
Iliocapsularis becomes hypertophied with
- Dysplastic hips (insufficient acetabular coverage)
Trochanteric bursa
- Between gluteus maximus muscle and lateral aspect of greater trochanter
- Associated with “hip bursitis”
Hip bursitis
- Point tenderness
- Lateral thigh/gluteal pain
- Pain with ext rotation and extension
Ischial bursa
- Between glut max and ischial tuberosity
- Prolonged sitting in a position that puts increased pressure on ischial tuberosity
Gluteofemoral bursa
- Between glut max (IT band) and vastus lateralis
Gluteus medius bursa
- Between gluteus medius and superior greater trochanter
- These are not the only ones
Blood supply to the hip joint
- Trochanteric anastomosis
- Primarily from retinacular arteries from the ascending branches of medial and lateral femoral circumflex arteries
- Medial femoral circumflex is major supplier in the adult
Medial femoral circumflex as the major supplier in the adult
- High risk of avascular necrosis with femoral neck fracture
Hip joint blood supply in the child
- Obturator is major supplier
- (Artery to the head of the femur)
Artery to the head of the femur
- Branch of acetabular artery (from posterior branch of obturator or MFC)
- Important in younger children (< 3)
- Not a major supplier in the adult
Nerve supply to hip joint
- Posterior division of femoral
- Sciatic
- Superior gluteal
- Anterior branch of obturator nerve
- Accessory obturator nerve can innervate if present
- Nerve to quadratus femoris
Avascular necrosis of femoral head
- Interruption of blood supply to the femoral head resulting in ischemia
- Osteocyte death and necrosis of the tissue (superolateral femoral head)
- Can lead to femoral head collapse
Traumatic causes of avascular necrosis of femoral head
- Trauma resulting in hip dislocation/subluxation or femoral neck fracture
Non-traumatic causes of vascular necrosis of femoral head
- Excessive corticosteroid and alcohol use most common
- Hematological disease
- Many others
Imaging modalities for detecting avascular necrosis of the femoral head
- Plain radiographs
- MRI is most sensitive and specific
Thigh/hip flexors
- Flexors
- Iliacus and psoas major (iliopsoas)
- Rectus femoris
- Sartorius
- Tensor fascia latae
- Pectineus
- Adductor longus
- Adductor brevis
- Adductor magnus
Thigh/hip extensors
- Extensors
- Gluteus maximus
- Biceps femoris long head
- Semitendinosus
- Semimembranosus
- Adductor magnus, hamstring part
Thigh/hip abductors
- Abductors
- Gluteus medius
- Gluteus minimus
- Tensor fascia latae
- Piriformis
- Sartorius
Thigh/hip lateral (external) rotators
- Gluteus maximus
- Piriformis
- Obturator internus
- Superior gemellus
- Inferior gemellus
- Quadratus femoris
- Obturator externus
- Sartorius
- Gluteus medius and minimus
Thigh/hip medial (internal) rotators
- Medial (internal) rotators
- Tensor fascia latae
- Gluteus medius
- Gluteus minimus
- Pectineus
Thigh/hip adductors
- Adductors
- Pectineus
- Adductor longus
- Adductor brevis
- Adductor magnus
- Gracilis
- Quadratus femoris
- Obturator externus