Osteology Of The Sacrum, Coccyx, Ribs, And Sternum Flashcards
Which joint links the sacrum to the pelvic girdle?
Sacroiliac joint
How many segments make up the sacrum?
5 fused segments
What is the purpose of the sacrum?
Specialized wedge-shaped structure is designed to transfer weight of the body through the pelvis to the lower extremity.
What kind of curvature do we see in the sacrum?
Kyphosis (primary) - concave anteriorly
What is the sacral promontory?
“Ridge-like prominence” found on the most anterior upper aspect of the body of S1
Which two parts make up the base of the sacrum?
Body of S1 and the ala
What are the transverse lines?
Lines of fusion of S1-S5
Where are the sacral foramina?
The anterior and posterior sides of the sacrum
What is the purpose of the anterior sacral foramina?
Allow ventral rami to exit (similar to IVF)
What is the purpose of the posterior sacral foramina?
Allow the dorsal rami to exit (like the IVF)
Describe the location of the intermediate sacral crest.
Just lateral to the median sacral crest, medial to the posterior sacral foramina
What is the intermediate sacral crest reminiscent of?
Z joints, fused.
What is the sacral hiatus?
Opening at the base of the sacrum, allowing for exit of the paired S5 and coccygeal nerves
Where do the sacral nerves exit?
S1-4, through the sacral foramina.
S5, through the sacral hiatus
What are the sacral cornu?
“Horns” guarding the sacral hiatus
Which sacral structure is most like the inferior articular processes?
Sacral cornu of S5
Where is the median sacral crest?
Directly in the middle of the sacrum, “mid-sagittal”
What is the median sacral crest reminiscent of?
SPs, fused.
What is the sacrum’s equivalent of the vertebral foramen?
Sacral canal
Which structure is housed by the sacral canal?
Cauda equina
Name the two parts of the pars lateralis.
Sacral tuberosity
Auricular surface
Describe the position of the lateral sacral crest.
Lateral to the sacral foramina, medial to the pars lateralis (serving as a border)
What is the sacral tuberosity?
Part of the pars lateralis, surface for ligament attachment
What is the function of the auricular surface?
Articular part, facet for articulation with the ilium.