Sternum, Ribs and Hyoid

Question 1

head

Answer 1

posterior or vertebral end, angled anteromedially; articulates with lateral thoracic vertebral body/centrum

Question 2

shaft (body)

Answer 2

flattened internal-externally (on all but first and second ribs) and curved (half heart-shaped)

Question 3

sternal end

Answer 3

anteromedial; slightly flared and typically cupped (for costocartilage) in all ribs except for eleventh and twelfth ribs; angled anteromedially and slightly inferiorly

Question 4

inferior border

Answer 4

sharp or crest-like

Question 5

Superior Border

Answer 5

smooth and rounded

Question 6

Facets on Rib Heads:

First and tenth–twelfth ribs

Second–ninth ribs

interarticular crest

Answer 6

one facet on each head (articulates solely on one thoracic vertebral body)

two facets (one superior and one inferior) on each head divided by a crest (each rib articulates with two thoracic vertebral bodies)

crest dividing articular facets on heads of second–ninth ribs

Question 7

First–Tenth Ribs:

neck

tubercle:

           1) articular facet of tubercle
           2) non-articular portion

angle

costal groove

Answer 7

tapered shaft posterolateral to head and anteromedial to tubercle(s)

–on medial aspect of tubercle; for articulation with the costal facets of the transverse processes(T1–T10vertebrae)
–on lateral aspect of tubercle (for ligamentous attachment)* the two portions of the tubercle sometimes appear to be two distinct tubercles (one articular and one non-articular)

coincident with (or just lateral to)tubercles; area of sharp anterior curvature of the shaft, often marked by an area of roughened bone on the external surface (muscle attachment)

(absent on first rib) –inferior internal shaft; for intercostal arteries, veins, and nerves

Question 8

The First Rib–most distinct rib; short, thick shaft that is flattened superoinferiorly instead of internal-externally

groove for subclavian artery and brachial plexus

groove for subclavian vein

scalene tubercle

Answer 8

–superior midshaft, closer to head of rib (i.e., more posterior than groove for subclavian vein); broad and shallow

–superior shaft, near sternal end; broad and shallow

–superior midshaft, along internal edge; between the two subclavian grooves(for attachment of the anterior scalene muscle)

Question 9

The Second Rib–also quite distinct with a short and obliquely flattened shaft

tuberosity for the serratus anterior m.

Answer 9

superolateral (or external) midshaft

Question 10

manubrium

Answer 10

superior; broad and flat

Question 11

jugular (suprasternal) notch

Answer 11

superior manubrium

Question 12

clavicular notch

Answer 12

superolateral manubrium; saddle type of synovial joint and only bony articulation between the upper limb and the axial skeleton

Question 13

costal notch/facet 1

Answer 13

lateral manubrium

Question 14

costal notch/demifacet 2

Answer 14

half on inferior manubrium and half on superior sternal corpus

Question 15

sternal corpus(body) or gladiolus

Answer 15

thin and flat; slightly concave on posterior surface and convex on anterior surface

Question 16

sternal angle

Answer 16

between manubrium and sternal body (often unfused until old age)

Question 17

costal notches/facets 3–7

Answer 17

lateral sternal body/corpus (facet for rib 7 may be a demifacet: half on inferior sternal body and half on superior xiphoid process)

Question 18

xiphoid (xyphoid) process

Answer 18

inferior to sternal body, often remains cartilaginous

Question 19

greater horn/cornu

Answer 19

posterolateral

Question 20

lesser horn/cornu

Answer 20

anterolateral