Clinical anatomy of the thoracic cage Part 1

Hello there people, today I am going to share about the anatomy of the human ribs of its clinical significance which I think will be beneficial to those who aspire to be a surgeon or just anyone who’s curious about our body structures and the way they articulate with one another in a perfectly synergistic manner.

typical rib

So what you’re looking at above here is a posterior view of  a “typical” rib which consists of a head with 2 concave facets, a neck and a tubercle. The 2 top and bottom articular facets are arranged in such a manner to connect with the adjacent vertebra and the vertebra above its respective spinal level. The rib curves from superior to inferior from behind to the front before it attaches to the edge of the sternum.

1st rib.png

What’s interesting is that not all of our ribs resemble one another, take for example the first rib. It is said to be the shortest and the curvaceous of all ribs. Just at the middle portion of this rib, there’s a tubercle set for the insertion of the anterior scalene muscle. The significance of this muscle is that it acts as a partition that seperates the subclavian vein from the subclavian artery and the brachial plexus. This is where the local anaesthetic agent is being injected before surgery. Both of these vessels sit on top of the dented region(groove) infront and behind the anterior scalene tubercle.  

By the way, the fact the subclavian vein lies just above and behind the clavicle makes it a hallmark for setting a central venous line for total parenteral nutrition, checking of CVP or to carry out a fluid challenge.

Regarding rib fractures, it is important to take note that it rarely happens to children due to the high elasticity of the ribs. Therefore it should raise an alarm of child abuse if a physician came across such situation should he take a thorough history and mechanism of the fractures.

For adults, it is commonly due to trauma or motor-vehicle accidents. The first two ribs are well protected by the clavicle and the last two ribs are unattached, hence they are less prone to fractures.

When more than one rib fracture occurs, the phenomenon known as “flail chest” and “paradoxical respiratory movement” may be seen clinically.  This is when air is sucked into the thoracic cavity during inspiration, shifting the mediastinum with each respiratory movement due to the difference between the intrathoracic pressure and air pressure, vice versa for expiration.

X2604-F-14.png

This is an emergency situation and warrants immediately medical intervention to prevent shock from taking place. This is managed by inserting a chest drain with underwater seal, followed by endotracheal intubation or tracheostomy (whichever applies) combined with a positive pressure ventilation.

To be continued..Part 2

Thank you for reading and stay tuned.

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