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)
