Anatomy and Positioning of theBony Thorax, Sternum and Ribs

ribs attach between vertebral bodies via demifacets

2nd - 9th

Floating ribs

False ribs 11 and 12 Anterior ends do NOT articulate with sternum or costal cartilage of rib above

Neck of Rib

"Skinny" portion of the rib; lateral to head; located between head and tubercle

Sternoclavicular

(between sternum and clavicle) Diarthroidal gliding

Costal groove of Rib

On inner surface of body inferiorly; "protection" for nerves, veins, and arteries

AP RibsBelow Diaphragm positioning

Place bottom of cassette 1" below iliac crests CR perpendicular to midpoint of cassette Expose on expiration Ninth to twelfth ribs visualized

AP Oblique RibsBelow Diaphragm

Place bottom of cassette at iliac crests CR perpendicular to midpoint of cassette Make exposure on suspended deep expiration

AP Oblique RibsAbove Diaphragm

Place top of cassette 1.5" - 2" above shoulder CR perpendicular to midpoint of cassette Make exposure on suspended deep inspiration

Tubercle of Rib

Projection lateral and posteroinferior to neck; articulates with vertebra's transverse process; forms costotransverse joint

Sternal extremity is on which end of the rib

is on anterior end of rib. Attached anteriorly to sternum via costal cartilage (not directly attached to sternum)

Ribs

12 pair Flat bones, curving anteriorly & inferiorly Connect sternum to thoracic vertebrae (around and down)

RAO Sternum Positioning

15°- 20° RAO (separates sternum from spine) CR to center of sternum (1" to left of midline and midway between jugular notch and xiphoid process) Trauma alternative: 15°-20° cross angle, grid crosswise

ribs attach directly to a single vertebral body via one facet

1st and 10th - 12th

where do the ribs become shorter again

7th rib

Where are the Ribs the widest

8th and 9th ribs

What does the sternum articulate with

Articulates with ribs (facets) and clavicle (top)

Head of Rib

At posteromedial end; articulates with demifacets of adjacent vertebral bodies to form costovertebral joint

Sternocostal joint -

Connect costal cartilages to sternum

Costovertebral joint -

Between rib and vertebra occurring between the head and facet of the vertebral body; ONLY ONE VERTEBRA ARTICULATES WITH RIBS 1, 11, AND 12.

Costotransverse joint -

Between rib tubercle and facet on anterior surface of transverse process

Costochondral Joints

Between sternal end of rib and costal cartilage No motion (synarthroidal) Ten of these, with no anterior attachment to ribs 11 and 12

Costochondral joint -

Between sternal end of rib and costal cartilage (no movement)

AP Above Diaphragm positioning

CR 3" - 4" below jugular notch Place top of cassette 1.5" - 2" above the shoulder CR perpendicular to midpoint of cassette Make exposure on suspended deep inspiration

Costal cartilage -

Cartilage at rib's MEDIAL end

only connection to shoulder girdle from bony thorax; connects to sternum above first rib

Clavicle

Ribs 1 - 10 Articulations

Costotransverse and costochondral joints

All ribs (12) Articulation

Costovertebral joints

STERNOCOSTAL JOINTS:

First sternocostal joint has no motion (synarthroidal) Second - seventh have their own cartilage and are diarthroidal (gliding)

Rib Oblique above / below diaphragm

For anterior obliques, side of interest will be AWAY from IR For posterior obliques, side of interest will be closest to IR

Ribs 6 - 10 -articulation

Interchondral joints

LPO / RAO Ribs

Left axillary ribs Right vertebral ribs

Sternum has three components:

Manubrium (approx. 2") Body (gladiolus) Xiphoid process or xiphoid tip (the "end"; begins as cartilage and ossifies in the 40s)

Angle of the Rib

Most posterior portion; lateral to tubercle

True ribs

Rib pairs 1 - 7 Attach directly to sternum via costal cartilage

False ribs

Ribs 8 - 12 - Ribs 8 - 10 articulate via costal cartilages with 7th rib's costal cartilage; ribs 11 and 12 are not connected anteriorly

RPO / LAO Ribs

Right axillary ribs Left vertebral ribs

PA Oblique SC Joints positioning

Rotate 10° -15° with side of interest down Center joint of interest to midline of table CR perpendicular to level of jugular notch Center film to CR Expose on suspended expiration Obtain both sides for comparison

AP Oblique Ribs positioning

Rotate patient to 45° RPO or LPO with affected side down Raise the arm on the side down to remove scapula

joints are above first rib

SC (sternoclavicular)

Body of the Rib

Shaft of rib; the longest part

Intercostal space -

Space between ribs

RAO SternumEvaluation Criteria

Sternal ends of clavicles and entire sternum included Sternum separated from vertebral column Sternum superimposed on heart

Lateral SternumEvaluation Criteria

Sternal ends of clavicles superimposed Sternum separated from ribs and shoulders

Ribs 1 - 7 articulation

Sternocostal joints

Bony Thorax Comprised of:

Sternum anteriorly Thoracic vertebrae posteriorly Twelve pairs of ribs

Lateral Sternum positioning

Top of cassette 1.5" above jugular notch CR perpendicular to center of film 72" SID Expose on suspended deep inspiration

PA Sternoclavicular Joints

True PA CR perpendicular to T2 - T3 (3" distal to vertebra prominens)

INTERCHONDRAL JOINTS:

between the cartilages of ribs 8 - 10 and the 7th. They are diarthroidal/gliding joints and involved in the breathing process.

Functions of the Bony Thorax

expand and contract during breathing

First ribs are

short and broad

A source of red bone marrow found in

sternum