Ribs- anatomy & biomechanics

When the spine flexes, how do the ribs rotate?

the ribs torsion externally on one side, internally on the other.

Relationship between ribs & transverse process:

think of the rib as an extension of the transverse process- so that vertebral rotation causes the corresponding rib pair at that level to rotate.

Where is the axis for respiratory motion?

(of the typical ribs) runs along a line drawn through the costovertebral and costotransverse joints.

What are 3 articulations of the typical ribs to the spine?

1) costovertebral 2) costotransverse 3) anterior articulation (with the sternum)

Which ribs are considered typical?

3-9

Motions happen at ribs 1-10?

Both bucket handle and pump motions happen at these ribs.

Ex: what does rib 5 articulate with? (2)

Inferior demifacet to T4 Superior demifacet to T5

What is caliper motion? Where does it occur?

Opens laterally upon inhalation and closes on exhalation occurs at ribs 11 and 12

3 motions of the rib cage:

Pump handle - AP motion Bucket handle - lateral motion Caliper

What muscle attatches to the lower margin of T12?

Quadratus Lumborum

What makes up the costovertebral joint? (4)

Rib head Two vertebrae One intervertebral disc Demifacets *vertebral body above and vertebrae at that same level

What are the 2 atypical ribs? Why is rib 1 atypical? Why is rib 2 atypical?

Ribs 1 and 2 Rib 1 has no angle- it has an articulation ith T1 only. It is a synovial joint with the sternum. Rib 2 has an articularion with T1 and T2- and two synovial joints with the sternum.

What are the other 3 atypical ribs?

Ribs 10,11,12

Why are 11 and 12 especially different?

Ribs 11 and 12 have no costrochondral joint (no articulation with the sternum). They are floating ribs.

In this same example, what do you feel on the right and left ribs when palpating?

Right 5th rib externally rotates and you feel the superior border of the rib more prominent posteriorly. Left 5th rib internally rotates and you feel the inferior border of the rib sharp posteriorly.

How do ribs 10,11,12 articulate with the t-spine?

T10, T11, T12 articulate with the ribs by unifacets (demifacets).

Where does the superior costotransverse ligament attatch?

Transverse process of the 4th vertebrae to the 5th rib. Couples the motion of the rib and vertebrae.

Ex: thoracic rotation to the right T4 on T5 T4 vertebral body rotates...? T4 vertebral body translates...? Right 5th rib...? Left 5th rib????

Vertebral body rotates right T4 vertebrae translates left Right 5th rib externally rotates Left 5th rib internally rotates

What is the anterior articulation?

by a costochondral articulation to the sternm either directly or by a costal arch.

Where does bucket handle motion occur? What kind of motion is it

lower rib cage lateral movement in the coronal plane

What is the rib angle? What muscle attatches here?

most posterior aspect of the rib- attatchment of the iliocostalis muscle.

When the spine extends, how do the ribs rotate? (2)

rotate backward (external torsion) facets slide down and back

When the spine flexes, how do the ribs rotate? (2)

rotate forward (internal torsion) facets slide up and open

Where does pump handle motion occur? What kind of motion is it (what plane)?

upper rib cage up and down movement in the sagittal plane