The Hip Flashcards
What type of joint is the hip joint?
Multiaxial ball and socket joint.
What bones form the hip joint?
Proximal femur and the innominate bone (ilium, ischium, pubis).
What provides hip joint stability?
Tough capsule, strong ligaments, deep acetabulum, and muscular support.
How does the femoral head fit into the acetabulum?
Snugly, allowing both mobility and stability.
How much body weight is loaded on the hip when standing?
About 2/3 of body weight.
How much load is on the hip during walking?
Between 1.5–5.5 times body weight.
How much load is on the hip when standing on one leg?
2–2.5x body weight.
What is the hip load when walking upstairs?
~3x body weight.
What is the load during running?
> 4.5x body weight.
What is the strongest ligament of the hip?
Iliofemoral ligament (limits extension).
What ligament is anterior and limits excessive abduction/extension?
Pubofemoral ligament.
What is the weakest ligament of the hip?
Ischiofemoral ligament (posterior).
What arteries supply the femoral head?
Retinacular arteries (branches of medial circumflex femoral artery).
What can result from tearing the retinacular arteries?
Avascular necrosis of the femoral head.
What does external rotation and limb shortening suggest?
Posterior dislocation or neck of femur fracture due to iliopsoas action.
Iliopsoas (Iliacus + Psoas major) movement?
hip flexion
Rectus femoris movement?
hip flexion
Sartorius movement?
hip flexion, external rotation
Pectineus movement?
adduction, slight flexion
Adductors (Brevis, Longus, Magnus) movement?
adduction
Gracilis movement?
adduction
Obturator externus movement?
lateral rotation
Tensor fascia lata movement?
abduction, internal rotation
Vastus medialis/lateralis movement?
knee extension
What nerve innervates gluteus maximus?
Inferior gluteal nerve (L5–S2).
What is the main function of gluteus maximus?
Hip extension.
Where does gluteus maximus insert?
Gluteal tuberosity and iliotibial tract.
Which muscles abduct the hip?
Gluteus medius, gluteus minimus, tensor fascia lata.
What nerve supplies the abductors of the hip?
Superior gluteal nerve (L4–S1).
What is a Trendelenburg gait?
Hip drop on the contralateral side due to weak abductors or superior gluteal nerve lesion.
: Name the 6 lateral rotators of the hip.
Piriformis, obturator internus, obturator externus, superior gemellus, inferior gemellus, quadratus femoris.
What nerve group innervates these muscles?
Small branches from the sacral plexus.
Why is the piriformis clinically important?
The sciatic nerve runs near or through it; tightness or variation can compress the sciatic nerve (piriformis syndrome).
What are the posterior thigh muscles?
Biceps femoris, semitendinosus, semimembranosus, and hamstring part of adductor magnus.
What nerve supplies most hamstrings?
Tibial nerve (sciatic nerve branch).
What innervates the short head of biceps femoris?
Common fibular nerve.
Main function of hamstrings?
Hip extension, knee flexion, eccentric control in running.
Most common type of hip dislocation?
Posterior dislocation (e.g., dashboard injury in car accident).
Clinical signs of posterior dislocation?
Adducted, internally rotated, shortened limb.
Clinical signs of anterior dislocation?
Abducted, externally rotated limb.
What spinal roots are responsible for hip flexion?
L2–L3
What are the main muscles involved in hip flexion?
Iliopsoas, rectus femoris, sartorius, pectineus
What nerves innervate the hip flexors?
Femoral nerve and lumbar plexus
What spinal roots are responsible for hip extension?
L4–L5
What are the main muscles involved in hip extension?
Gluteus maximus, hamstrings
What nerves innervate the hip extensors?
Inferior gluteal nerve and tibial nerve
What spinal roots are responsible for hip abduction?
L4–L5
What are the main muscles involved in hip abduction?
Gluteus medius, gluteus minimus, tensor fascia latae
What nerve innervates the hip abductors?
Superior gluteal nerve
What spinal roots are responsible for hip adduction?
L2–L3
What are the main muscles involved in hip adduction?
Adductor longus, adductor brevis, adductor magnus, gracilis, pectineus
What nerve innervates the hip adductors?
Obturator nerve
(Note: part of adductor magnus = sciatic nerve, pectineus = femoral nerve)
