Sternal angle vertebral level: the T4-T5 disk space
Key takeaways
- The sternal angle is at the T4-T5 disk space on an average adult.
- It lies about 5 cm (2 in) below the jugular notch.
- The second costal cartilage attaches at this level.
- The jugular notch is at T2-T3. Bontrager's puts the xiphoid tip at T9-T10, and Merrill's text says T10.
- T7, the usual chest centering level, is not the sternal angle.
The sternal angle lies at the level of the T4-T5 intervertebral disk space on an average adult. Bontrager’s and Merrill’s both give this level.
What is the sternal angle?
It’s the palpable ridge where the manubrium meets the body of the sternum. It’s also called the angle of Louis or the manubriosternal joint. To find it, feel for the jugular notch at the top of the sternum, then move down about 5 cm (2 in).
The second costal cartilage attaches to the sternum at this level. That makes the angle a handy way to find the second rib: feel the ridge, then move outward along the rib.
What other landmarks should you learn with it?
| Landmark | Level on an average adult |
|---|---|
| Jugular notch | T2-T3 |
| Sternal angle | T4-T5 disk space |
| Xiphoid tip | T9-T10 in Bontrager’s and in a Merrill’s figure; T10 in Merrill’s text |
| T7 | About 8 to 10 cm (3 to 4 in) below the jugular notch |
The carina is close to the sternal angle, but sources word it differently. Merrill’s places the end of the trachea at the T4-T5 interspace, and Bontrager’s places the carina at about T5. Learn the wording your program uses.
How does it help with centering?
The sternal angle isn’t where you center a chest, but it can help you find T7.
- PA chest: center to T7, about 18 to 20 cm (7 to 8 in) below the vertebra prominens. See the PA chest page. The beam enters from the back, so you measure from a back landmark.
- AP chest: the jugular notch is the landmark, with T7 about 8 to 10 cm (3 to 4 in) below it.
- AP thoracic spine: Bontrager’s also places T7 about 3 to 5 cm (1 to 2 in) below the sternal angle.
Does ARRT test this?
ARRT® doesn’t say. Its outlines list topographic landmarks under positioning, and the sternum under Thorax, but they contain no table of vertebral levels. Knowing the landmarks helps you center correctly, whichever questions you see.
To go further, read our bony thorax chapter, the lateral sternum page and the Procedures guide. Then test yourself with the thorax and abdomen questions.
Frequently asked questions
At what vertebral level is the sternal angle?
The T4-T5 intervertebral disk space on an average adult. Bontrager's and Merrill's agree.
What rib attaches at the sternal angle?
The second rib. Its costal cartilage attaches to the sternum at this level, so you can find the second rib by feeling the angle and moving outward.
Is the sternal angle the centering point for a PA chest?
No. A PA chest centers to T7, about 18 to 20 cm (7 to 8 in) below the vertebra prominens. An AP chest centers about 8 to 10 cm (3 to 4 in) below the jugular notch.
Is the carina at the sternal angle?
Close to it. Merrill's places the end of the trachea at the T4-T5 interspace, and Bontrager's places the carina at about T5.
Sources
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