M:Gluteal region and hip joint Flashcards
What is the name for the 2 hip bones which together with the sacrum form the pelvic girdle?
Innominate bones
What does each innominate bone articulate with?
The sacrum posteriorly at the sacroiliac joint
With the other innominate bone at the pubic symphysis
Which 3 bones is each innominate bone derived from during development?
The ilium, ischium and pubic
At which point are the ilium, ischium and pubic bone fused?
the acetabulum
What are the 3 main differences between a male and female pelvis?
1) Male has a heart shaped inlet, female has a circular pelvic inlet, as female has broader alae and a less distinct sacral promontory
2) Angle formed between 2 arms of pubic arch are smaller in a male (50-60 degrees) than in a female (80-85 degrees)
3) Ischial spines project more medially in a male
What is the pubic symphysis?
A secondary cartilaginous joint between the 2 pubic bones
What covers the articular surfaces of the pubic bones at the pubic symphysis?
Hyaline cartilage
What joins the 2 pubic bone articular surfaces at the pubic symphysis?
A fibrocartilaginous disc
What are the 3 functions of the pelvis?
1) Transfer of weight from the upper axial skeleton to the lower parts of the skeleton, especially during movement
2) Provides attachment for a number of muscles and ligaments used in movement
3) Contains and protects the abdominopelvic and pelvic viscera
How is the pelvic girdle strengthened?
By ligaments attaching the sacrum to the ischium of the innominate bone
What are the attachments of the sacrotuberous ligament?
From the sacrum to the ischial tuberosity
What are the attachments of the sacrospinous ligament?
From the sacrum to the ischial spine
What 2 foramen do the sacrotuberous and sacrospinour ligaments form?
Sacrospinous - greater sciatic foramen
Both - lesser sciatic foramen
What 2 structures form the hip joint?
The acetabulum of the innominate bone and the head of the femur
What type of joint is the hip joint?
Ball and socket
What are the 7 possible movements of the hip joint?
1) Flexion 120 degrees
2) Extension 30 degrees
3) Abduction 45 degrees
4) Adduction 25 degrees
5) Internal rotation 45 degrees
6) External rotation 45 degrees
7) Circumduction
What 5 things stabilise the hip joint?
1) Good congruency
2) Acetabular notch bridged by transverse acetabular ligament to improve congruency
3) Has a labrum
4) Fibrous articular capsule - encircles rim of acetabulum then attaches to neck of femur
5) Ligaments - capsular thickenings that form a spiral around the hip
What are the attachments of gluteus maximus?
Proximal - fascia over gluteus medius, external ileum behind posterior gluteal line, dorsal sacrum, coccyx and external surface of sacrotuberous ligament
Distal - Posterior iliotibial tract, gluteal tuberosity of femur
What are the actions of gluteus maximus?
Powerful extensor of the hip (used when resisting gravity eg. standing up), laterally rotates and abducts thigh
What is the innervation of gluteus maximus?
Inferior gluteal nerve L5,S1,S2
What are the attachments of gluteus medius?
Proximal - external surface of ilium between anterior and posterior gluteal lines
Distal - Greater trochanter (elongate facet on lateral surface)
What are the actions of gluteus medius?
Abducts femur at the hip joint
Medially rotates thigh
Stabilises legs during walking
What is the innervation of gluteus medius?
Superior gluteal nerve L4,L5,S1
What are the attachments of gluteus minimus?
Proximal - external surface of ilium between inferior and anterior gluteal lines
Distal - Greater trochanter (linear facet on anterolateral aspect)
What are the actions of gluteus minimus?
Abducts femur at the hip joint
Medially rotates thigh
Stabilises legs during working
What is the innervation of gluteus minimus?
Superior gluteal nerve L4,L5,S1
Describe the iliotibial tract
Fascia lata is thickened laterally into a longitudinal band called the iliotibial tract which descends along the lateral margin of the limb from the tuberculum of the iliac crest to a bony attachment just below knee
What is the fascia lata?
Outer layer of deep fascia in the lower limb which forms a thick ‘stocking like’ membrane, which covers the limb and lies beneath the superficial fascia. This fascia is particularly thick in the thigh and gluteal region and is termed the fascia lata
What is the function of the iliotibial tract? 3
1) Provides attachment for tensor fascia lata and gluteus maximus muscles
2) The iliotibial tract and its associated muscles hold the leg in extension once other muscles have extended the leg at the knee joint
3) Stabilize the hip joint by preventing lateral displacement of proximal femur away from the acetabulum
Which 2 muscles are the chief abductors of the hip joint?
1) Gluteus medius
2) Gluteus minimus
How do gluteus medius and minimise stabilize the lower limbs when walking?
when standing on the right leg, right gluteus medius and minimus contract and prevent the pelvis sagging on the left
What are the attachments of the piriformis muscle?
Proximal - anterior sacrum
Distal - medial side of superior border of greater trochanter of femur
How does piriformis exit the pelvis to reach the gluteal region?
Passes laterally and inferiorly through the greater sciatic foramen to get out of the pelvis
Where does the sciatic nerve emerge in the gluteal region?
Lower border of piriformis
Where is a safe area to perform intramuscular injections in the gluteal region?
Upper, outer quadrant of either gluteal region
Which 3 vessels/nerves pass through the greater sciatic foramen superior to piriformis?
1) Superior gluteal nerve
2) Superior gluteal artery and veins
Which 10 vessels/nerves pass through the greater sciatic foramen inferior to the piriformis muscle?
1) Pudendal nerve
2) Internal pudendal artery and vein
3) Inferior gluteal nerve
4) Inferior gluteal artery and vein
5) Sciatic nerve
6) Posterior cutaneous nerve of thigh
7) Nerve to quadratus femoris
8) Nerve to obturator internus
Which structures pass through the lesser sciatic foramen?
1) Pudendal nerve, artery and vein (to enter perineum)
2) Tendon of obturator internus
What are the attachments of obtruator internus?
Proximal - anterolateral wall of true pelvis, deep surface of obturator membrane and surrounding bone
Distal - medial side of greater trochanter of femur
What 4 muscles are found in very close proximity to the sciatic nerve?
1) Obturator internus
2) Superior and inferior gemelli
3) Quadratus femoris
What are the attachments of superior gemellus?
Proximal - external surface of ischial spine
Distal - along length of superior surface of tendon of obturator internus and into medial greater trochanter of femur with it
What are the attachments of inferior gemellus?
Proximal - upper aspect of ischial tuberosity
Distal - along inferior length of tendon of obturator internus and into medial greater trochanter of femur with it
What is the common distal attachment of piriformis, obturator internus and the gemelli?
Medial side of greater trochanter of the femur
What are the 2 common actions of the piriformis, obturator internus and the gemelli?
1) Laterally rotates extended femur at the hip joint
2) Abducts flexed femur at the hip joint
What are the attachments of quadratus femoris?
Proximal - lateral aspect of ischium (just anterior to ischial tuberosity)
Distal - Quadrate tubercle on the intertrochanteric crest of the femur
