Osteology Of The Sacrum, Coccyx, Ribs, And Sternum

Question 1

Which joint links the sacrum to the pelvic girdle?

Answer 1

Sacroiliac joint

Question 2

How many segments make up the sacrum?

Answer 2

5 fused segments

Question 3

What is the purpose of the sacrum?

Answer 3

Specialized wedge-shaped structure is designed to transfer weight of the body through the pelvis to the lower extremity.

Question 4

What kind of curvature do we see in the sacrum?

Answer 4

Kyphosis (primary) - concave anteriorly

Question 5

What is the sacral promontory?

Answer 5

“Ridge-like prominence” found on the most anterior upper aspect of the body of S1

Question 6

Which two parts make up the base of the sacrum?

Answer 6

Body of S1 and the ala

Question 7

What are the transverse lines?

Answer 7

Lines of fusion of S1-S5

Question 8

Where are the sacral foramina?

Answer 8

The anterior and posterior sides of the sacrum

Question 9

What is the purpose of the anterior sacral foramina?

Answer 9

Allow ventral rami to exit (similar to IVF)

Question 10

What is the purpose of the posterior sacral foramina?

Answer 10

Allow the dorsal rami to exit (like the IVF)

Question 11

Describe the location of the intermediate sacral crest.

Answer 11

Just lateral to the median sacral crest, medial to the posterior sacral foramina

Question 12

What is the intermediate sacral crest reminiscent of?

Answer 12

Z joints, fused.

Question 13

What is the sacral hiatus?

Answer 13

Opening at the base of the sacrum, allowing for exit of the paired S5 and coccygeal nerves

Question 14

Where do the sacral nerves exit?

Answer 14

S1-4, through the sacral foramina.

S5, through the sacral hiatus

Question 15

What are the sacral cornu?

Answer 15

“Horns” guarding the sacral hiatus

Question 16

Which sacral structure is most like the inferior articular processes?

Answer 16

Sacral cornu of S5

Question 17

Where is the median sacral crest?

Answer 17

Directly in the middle of the sacrum, “mid-sagittal”

Question 18

What is the median sacral crest reminiscent of?

Answer 18

SPs, fused.

Question 19

What is the sacrum’s equivalent of the vertebral foramen?

Answer 19

Sacral canal

Question 20

Which structure is housed by the sacral canal?

Answer 20

Cauda equina

Question 21

Name the two parts of the pars lateralis.

Answer 21

Sacral tuberosity

Auricular surface

Question 22

Describe the position of the lateral sacral crest.

Answer 22

Lateral to the sacral foramina, medial to the pars lateralis (serving as a border)

Question 23

What is the sacral tuberosity?

Answer 23

Part of the pars lateralis, surface for ligament attachment

Question 24

What is the function of the auricular surface?

Answer 24

Articular part, facet for articulation with the ilium.

Question 25

Describe the shape and size of the auricular part.

Answer 25

Spans S1-3 segments. Ear-shaped and concave. Oriented lateral and slightly posterior

Question 26

What is lumbarization?

Answer 26

Congenital condition where S1 does not completely fuse to S2. Many clinical symptoms. IVD present, more likely to develop pathologies. Effects 2% of people

Question 27

How many parts make up the coccyx?

Answer 27

3-5 fused segments,

Question 28

Describe the position of the coccyx, relative to the sacrum.

Answer 28

Inferior to the apex of the sacrum

Question 29

Does the coccyx have intervertebral discs?

Answer 29

Generally, no. They are rudimentary at best.

Question 30

What is the coccyx?

Answer 30

Likely remnants of a tail. Currently nothing but a site for muscle attachment

Question 31

T/F The coccyx lacks features of a typical vertebrae.

Answer 31

True. No vertebral arch or canal, TP, SP, articular processes, or intervertebral foramina.

Question 32

Name the three parts of the sternum, and describe their relative location.

Answer 32

Manubrium, the most superior part. Body, inferior to the sternum and superior to the xiphoid process Xiphoid process, most inferior part

Question 33

How many segments make up the sternum? What is the other name for these segments?

Answer 33

6 fused “sternebrae”

Question 34

What is the joint between the first and second segments of the sternum?

Answer 34

Manubriosternal joint

Question 35

There are two notches on the manubrium: give names and relative position.

Answer 35

Suprasternal (Jugular) Notch - on superior aspect of the manubrium, between the clavicular notches Clavicular notch - on superiolateral aspect of the manubrium, on either side of the jugular notch. Serves as an articulation point for the clavicle.

Question 36

Describe the costal articulations of the manubrium.

Answer 36

Full facet for articulation with the rib 1 costal cartilage Demifacet for partial articulation with the rib 2 costal cartilage

Question 37

What are the other names for the manubriosternal joint?

Answer 37

Sternal angle, angle of Louis

Question 38

Describe the features of the body of the sternum.

Answer 38

4 fused segments | Facets for articulation with costal cartilages of ribs 2-7

Question 39

Name the joint between the two most inferior aspects of the sternum.

Answer 39

Xiphisternal joint

Question 40

T/F The xiphoid process may be bifid.

Answer 40

True

Question 41

Is the xiphoid process bone or cartilage?

Answer 41

Typically bone. May exist as cartilage in some.

Question 42

Are there costal articulations on the xiphoid process?

Answer 42

Sometimes, it can articulate with the costal cartilage of rib 7.

Question 43

What are the three types of ribs? Which are which?

Answer 43

``` True Ribs (R1-7 False Ribs (R8-12) Floating Ribs (R11-12)r ```

Question 44

T/F The bony elements of the ribs directly articulate with the vertebra.

Answer 44

True.

Question 45

T/F The bony elements of the rib directly articulate with the sternum.

Answer 45

False - costal cartilages articulate

Question 46

What is the rib-vertebrae articulation rule?

Answer 46

Tn & Tn-1 AKA - vertebrae on the same level and one level above.

Question 47

Where would we find the costal groove on a typical rib?

Answer 47

Inferior surface, sharp ridge.

Question 48

The costal groove houses which structures?

Answer 48

Intercostal nn, aa, vv.

Question 49

Which end of the rib articulates with the T vertebrae?

Answer 49

The head.

Question 50

Which end of the rib articulates with the costal cartilages?

Answer 50

Distal end

Question 51

How many articulating parts does a typical rib have?

Answer 51

3 - superior articular facet and inferior articular facet for T vertebrae, on head - articular facet for TP of vertebrae, on neck

Question 52

Which ribs do we consider to be atypical?

Answer 52

R1, 10, 11 ,12

Question 53

What is/ are the atypical feature(s) of R1?

Answer 53

One articular surface on head (T1 only) Two grooves for vascular use Curved

Question 54

There are two grooves on rib 1... What are they called and what are they for?

Answer 54

Anterior groove, houses subclavian v. | Posterior groove, houses subclavian a.

Question 55

What is/ are the atypical feature(s) of R10?

Answer 55

Only one articular surface on head (T10 only) **Typically. May articulate T9-10 in some.

Question 56

What is/ are the atypical feature(s) of R11?

Answer 56

One articular surface on the head (T11 only) Short, mostly straight No neck or tubercle No facet for TP articulation

Question 57

What is/ are the atypical feature(s) of R12?

Answer 57

One articular surface on the head (T12 only) Short, mostly straight No neck or tubercle No facet for TP articulation

Question 58

T/F The rib will usually fracture at the point of impact.

Answer 58

False - will fracture at its weakest point.

Question 59

What is a supernumerary rib?

Answer 59

Rare cervical or lumbar ribs!

Question 60

What are the problems with cervical supernumerary ribs?

Answer 60

Can compress neurovasculature - subclavian a. - brachial plexus

Question 61

What are the problems with lumbar supernumerary ribs?

Answer 61

Usually asymptomatic