Applied Anatomy of Gluteal Region and Bony Pelvis Flashcards
3 bones forming hip bone
- Ilium
- Ischium
- Pubis
3 joints of pelvis
- Sacrococcygeal joint
- Pubic symphysis
- Sacroiliac joint
Organs contained and protected by pelvis
- Distal ureters
- Bladder
- Rectum
- Prostate (M)
- Uterus (F)
- Ovaries (F)
Key landmarks of pelvic region
- Pubic tubercle
- Pubic symphysis
- Ischial tuberosity
- Greater trochanter
- ASIS
- Iliac crest
- PSIS
- Natal cleft
- Gluteal fold
- Inguinal ligament
- Midpoint of inguinal ligament
- Midinguinal point
- Supracristal plane
How many vertebrae form the sacrum?
5 (S1-5)
What is the sacral promontory?
Vertebral body of S1 being very prominent anteriorly
What are the ala of the sacrum?
Lateral expansions coming from S1
What is the sacral canal?
Tube-shaped structure on posterior aspect of sacrum
What passes through the sacral canal?
- Filum terminale
- Cauda equina
How many vertebrae form the coccyx?
4
What is sacralisation of L5?
- Where L5 fuses with the sacrum
- Means sacrum has 6 bones
What is lumbarisation of S1?
- Where S1 doesn’t fuse in the sacrum
- Means sacrum has 4 bones
Male vs female pelvic inlets
- M = more heart-shaped, narrower
- F = more circular, wider
Male vs female pubis
- M = narrower - narrower subpubic angle
- F = wider - wider subpubic angle
Boundaries of pelvic inlet (posterior to anterior)
- Promontory
- Margin of ala
- Arcuate line
- Pecten pubis
- Pubic crest
What is the linea terminalis?
Pubic crest, pecten pubis and arcuate line collectively
Ligaments of the pelvis
- Sacroiliac ligaments
> Anterior
> Posterior
> Interosseus - Sacrospinous ligament
- Sacrotuberous ligament
- Sacrococcygeal ligament
- Pubic ligaments
> Superior
> Inferior
Boundaries of pelvic outlet (anterior to posterior)
- Pubic symphysis
- Ischiopubic rami
- Ischial tuberosity
- Sacrotuberous ligament
- Coccyx
Components of the pelvic diaphragm
- Levator ani
- Ischiococcygeus
What is levator ani made of?
- Pubovaginalis
- Pubococcygeus
- Puborectalis
- Iliococcygeus
Structures that pass through pelvic diaphragm
- Ureter
- Cervix
- Anal canal
What is the iliotibial tract and where does it run from and to?
- Thick band of fascia lata
- From iliac crest to lateral condyle of tibia
Which muscles insert into the iliotibial tract?
- Tensor fascia lata
- Gluteus maximus
Functions of iliotibial tract
- Help steady pelvis on thigh
- Keep knee extended in erect position
Origin, insertion, action and innervation of gluteus maximus
- O = external surface of ilium behind posterior gluteal line, back of sacrum + coccyx, sacrotuberous ligament
- Ins = gluteal tuberosity of femur (deeper 1/4), iliotibial tract (rest)
- A = hip extensor, knee extensor
- Inn = inferior gluteal nerve (L5-S2)
Origin, insertion, action and innervation of gluteus medius and minimus
- O = gluteal surface of ilium
- Ins = greater trochanter
- A = hip abduction, stabilising + maintaining balance of pelvis during walking
- Inn = superior gluteal nerve (L4-S1)
What is Trendelenburg sign?
Patient is unable to stabilise hip when standing on one leg
What causes Trendelenburg sign?
- Weak or paralysed hip abductors
- Affected side cannot stabilise pelvis when standing on affected side’s leg
- Unaffected side of pelvis drops
What is Trendelenburg’s gait?
- Person is seen lurching toward weakened side when normal sided foot is raised
- When normal foot sided foot is raised, there is a tilt towards unsupported side, so person leans towards weakened side to compensate
6 lateral rotators of the hip
- Piriformis
- Obturator internus
- Obturator externus
- Quadratus femoris
- Superior gemellus
- Inferior gemellus
What passes through the greater sciatic foramen above piriformis?
- Superior gluteal vessels
- Superior gluteal nerve
What passes through the greater sciatic foramen below piriformis?
- PIN PINS:
> Pudendal nerve
> Internal pudendal vessels
> Nerve to obturator internus
> Posterior cutaneous nerve of thigh
> Inferior gluteal vessels + nerve
> Nerve to quadratus femoris
> Sciatic nerve
What passes through the lesser sciatic foramen?
- PINT:
> Pudendal nerve
> Internal pudendal vessels
> Nerve to obturator internus
> Tendon of obturator internus
