What is the shape of the sacrum and which direction does the base go?
Large triangle shaped bone with the base directed upward.
What is the sacrum wedged between?
The innominate bones on each side.
The sacrum is formed by the fusion of _ sacral vertebrae after aproximately __ years of age.
5 sacral vertebrae after approx. 20 years of age
What does the base of the sacrum articulate with?
5th lumbar vertebrae
What does the apex of the sacrum articulate with?
What does the sacral canal contain?
Cauda equina and spinal meninges
Describe the pelvic surface of the sacrum and the direction it faces.
Smooth concave surface facing anteriorly and inferiorly
How many pairs of pelvic sacral foramen are present and what is their purpose?
4 pairs which serve as passage for nerves
How many raised lines does the pelvic surface of the sacrum have? Which direction do they run?
4 raised transverse lines
Describe the dorsal surface of the sacrum
Roughened convex shaped surface
What type of facets are present on the dorsal surface of the sacrum? What do they articulate with?
Superior articular facets which articulate with the inferior articular facets of the 5th lumbar vertebrae.
How many pairs of dorsal sacral foramen are present and what is their purpose?
4 pairs which serve as passage for nerves
Median sacral crest is a midline ridge comprised of fused ____
2 intermediate sacral crests on the ___ side of the dorsal foramen formed by the fused ___ and ___ processes.
2 intermediate sacral crests on the MEDIAL side of the dorsal foramen formed by the fused SUPERIOR and INFERIOR articular processes.
2 lateral sacral crests on the ____ side of the dorsal foramen formed by the fused ___ processes.
2 lateral sacral crests on the LATERAL side of the dorsal foramen formed by the fused TRANSVERSE processes.
What does the articular surface of the sacrum articulate with?
What does the rough and pitted area on the lateral surface of the sacrum provide attachment for?
The sacroiliac ligament
What is the shape of the coccyx and what direction does it point?
Triangular in shape, directed inferiorly.
How many vertebrae does the coccyx consist of? What type
4 vestigial, rudimentary, undeveloped vertebrae
Describe the dorsal and pelvic surface of the coccyx.
Dorsal surface is roughened, pelvis surface is smooth.
What 3 components compose the innominate bone?
Ilium, ischium and pubis
What fraction of the hip bone is comprised of the ilium?
What fraction of the acetabulum is comprised from the ilium?
what direction does the gluteal surface point?
posterior and lateral
what is the gluteal surface inferior and superior to?
inferior to iliac crest, superior to acetabulum
How many ridges does the glutel surface have?
What are there directions?
3 - posterior, anterior, inferior
Which is the shortest most pronounced gluteal line?
posterior gluteal line
what two points does the posterior gluteal line run between?
iliac crest 4cm anterior to the PSIS running downward to the PIIS
what is the longest, arc shaped gluteal line?
anterior gluteal line
what two points does the anterior gluteal line run between?
tubercle of the crest 5cm posterior to ASIS to the middle of the upper margin of the greater sciatic notch
what two points does the inferior gluteal line run between?
starts from the AIIS above and arches posterior and inferior to the lower border of the greater sciatic notch
which direction does the iliac fossa point
anterior and medial
what bony landmark provides origin for iliacus?
The iliac fossa
What seperates the iliac fossa and the sacropelvic surface?
a ridge called the medial border
Describe the auricular surface
ear shaped smooth surface, irregular and covered by hyaline cartilage
what does the scaropelvic surface articulate with and what does this articulation form?
articulates with the sacrum to form the sacroiliac joint
what two points does the iliac crest run between?
ASIS to PSIS
What is the superior border of the ilium called?
where is the tubercle of the iliac crest found?
5cm posterior to the ASIS on the superior side of the crest
What does the ASIS provide attachment for?
Origin of sartorius and superior attachment of inguinal ligament
What is on either end of the greater sciatic notch (boney landmarks)
Ischial Spine (Inferiorly)
what converts the sciatic notch into a foramen?
sacrotuberous and sacrospinous ligaments
what is another name for the arcuate line?
what does the arcuate line provide seperation between?
divides bone into that part that bounds the abdomen and that part that bounds the pelvis
what is the bump that marks the union of the ilium and the pubis called?
what is the anterior portion of the innominate called?
where is the pubis in relation to the acetabulum?
anterior and inferior
the pubis consists of a ___ and two ___
a BODY and two RAMI
the pubis comes from both sides to meet in front to form the ___
what muscles does the pubis provide origin for?
what part of the innominate is the ischium?
inferior, posterior part
what shape is the ischium?
the ischium consists of a ___ and one __
body and one ramus
what is the lowest part of the innominate?
what obscures the ischial tuberosity when the hip is extended?
what muscles originate from the ischial tuberosity
what ligament attaches to the ischial tubersoity?
Where is the ischial spine located?
small projection on the posterior border between the GSN and LSN
what is the ischial spine superior/inferior to?
superior to the lesser sciatic notch and inferior to the greater sciatic notch
what does the Ischial spine provide attachment for?
which aspect of the innominate is the acetabulum found?
what directions does the acetabulum face?
lateral inferior and anterior
what is the shape of the articular surface of the acetabulum? Which aspect is widest?
articular surface is horseshoe shaped and widest superiorly
What forms the acetabulum? (_/5)
-pubis forms the anterior and inferior 1/5
-ischium forms the posterior and inferior 2/5
-ilium forms the remaining 2/5