Dr Suresh Mukerji | Retropharyngeal Space Explained | CT Anatomy & Deep Neck Spaces #mastersseries

Duration: 4:25 717 transcript words EN summary

Video summary

The retropharyngeal space is anatomically defined as the region located directly behind the pharynx, bounded by three distinct fascial layers: the visceral fascia anteriorly, the alar fascia posterior to it, and the prevertebral fascia forming the deepest posterior boundary. While a general understanding often simplifies this area merely as the space behind the pharynx, a more precise anatomical distinction is crucial for specialists in head and neck medicine. In this refined view, the true retropharyngeal space lies between the visceral and alar fasciae and contains the retropharyngeal lymph nodes, whereas the deeper compartment situated between the alar fascia and the prevertebral fascia constitutes the danger space. Clinical significance arises from the presence of specific structures within these spaces, such as the retropharyngeal carotid artery, which can be mistaken for a pathological mass during procedures like tonsillectomy in young children. Furthermore, pathologies in this region often manifest as enlarged or abnormal lymph nodes; however, differentiation is key between metastatic nodes and infectious processes. A critical distinction exists between a true retropharyngeal space abscess, characterized by fluid collection within the fascial plane, and septic adenitis, where pus is contained specifically within an infected lymph node. The management of these conditions varies significantly based on airway stability, with stable cases involving septic adenitis potentially treated with antibiotics alone, while true abscesses often require surgical drainage. The anatomical continuity of the retropharyngeal space extends from the skull base down to the mediastinum, terminating around the T2 to T6 vertebral levels, which allows infections to spread vertically along this path. This connection is particularly dangerous because an abscess in the neck can extend inferiorly into the superior mediastinum, a complication that was highlighted by a case where inadequate drainage failed to address the full extent of the infection. Consequently, when managing retropharyngeal abscesses, it is imperative to ensure that drains are placed not only in the neck but also extended down into the mediastinum and anteriorly to prevent recurrent fevers caused by the continued spread of pus into these contiguous spaces.

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[music] So remember the fairings has a nasal fairings, it has a oral fairings and a hypoparrenx. So basically what do you call the space that's located behind the fairings? Well that space behind the fairings is going to be the retrofaringial space. It's literally that simple. So this fascia layer right here is going to be the visceral fashcia. This dashed line right here is what we refer to as the AAR fashcia and this dotted line right here is called the prevertebral fashion. And we'll come back to this in a couple slides. Now if today is Saturday, if tomorrow on Sunday, if you're not a headneck or neuroraiologist and you just remember the space behind the fairings in the retrofaringal space, I'm really really happy. But on the other hand, if you're a neuroraiologist or love head and neck, then what I want you to try to remember is that the actual space between the visceral fashcia and this aar fashcia is the true retrofaringal space which contains retrofarangal lymph nodes. And then this space that's located between the aar fashcia and the prevertebral fashcia. Well, this is located in the danger space. So the the aar fashcia actually subdivides this into two spaces. But again, if you're just if a general radiologist and you have to look at everything, just remember that the space behind the fairings is the retrofarangal space. So this is just an example of a patient that had trauma. This is the normal airway and this is air dissecting along the retrofaringal space. Here's an example which I showed early in a different case. This is a retrofaringal corateed artery. Important to mention this. This was a case years ago where the surgeon wanted to do a tonslectomy on a 2-year-old. He saw a pulsating mass. He was worried about a retrofaringal corateed artery. In fact, there it was. So when he did his tonslectomy, he was especially careful to stay away from that posterior ferangeal wall. And this is an example of a metastatic retrofarangial lymph node. So I did mention this in the last lecture but I did want to emphasize the specific space it's in and and emphasize the fact that there is a medial and a lateral group of retrofaring lymph nodes and here we can see the lateral retrofarangial lymph node which corresponds to this metastatic lymph node which we see here. Now this is an example of again an abnormality involving a lymph node but in this case it's low attenuation and it's separative and this patient has a fever. So when you see something like this this is not a true retrofarangal space absess rather this is what we refer to as separative adinitis. So this is actually pus that's located in a retrofarangal lymph node. If we see this and the patient has a stable airway, these patients can be treated with antibiotic therapy. They do not have to go to the operating room. On the other hand, this is the classical example of a retrofaringal space abscess. So here we see fluid extending into the retrofarangal space. The retrofaringal space is contiguous from the skull base and it goes all the way down into the mediainum and it ends at around T2 to T6. The danger space extends from the skull base and goes all the way through the crew of the diaphragm and is continuous with the retroparinium. The reason why I mentioned this specific anatomy is that when we see abscesses involving the retrofarangal space, they can extend all the way down as I mentioned before into the superior media. This patient had a large abscess and the surgeons in this case just put the drains in into the superior portion of the neck. They failed to take the drains all the way down to the base of the neck and in the mediainum and also anterly. And as a result about 2 days later this space patient spike fevers again. So this is just one of those examples about applied anatomy. So anytime that you're looking at abscesses involved in the retrofarangal space make sure you always look in the superior medastinum to make sure that there's no continued spread of pus into that area. >> [music]