Regions of the back and buttocks

Hello everyone! It's Megan from Kenhub here, and in today's tutorial, we'll be discussing the descriptive terms used to describe the regions of the back and buttocks. You may be wondering why we divide the body into so many regions. Well, each broad portion of the body such as the head and the neck, the upper limbs, the lower limbs and of course the back and buttocks are divided into regions to help clinicians in the identification of injuries or pathologies to underlying bones, organs or muscles. The body is divided into many, many regions and because of this we're going to cover the regions of the body across five different tutorials. But as you know our focus for today will be the regions of the back and buttocks or the area you can see contained within the blue rectangle on your screen. So we're going to start with the regions of the back and then we'll move on to the regions of the buttocks working in a roughly superior to inferior direction.

The first region that we're going to see is the deltoid region. This region is demarcated by the outline of the deltoid muscle which is the muscle that forms the rounded fleshy part of the upper arm that we see at the top of the shoulder. The next region that we can see is the suprascapular region and as the name suggests, this region is situated superior to the scapula.

Okay, so we've just looked at the suprascapular region and just below it we can see this region highlighted in green which is the scapular region. This region encompasses the area that overlies the scapular bone and is where we can find the muscles of the rotator cuff and other structures that are related to the scapula. Medial to the scapular region, we can see this region here which is the interscapular region. This region lies within an area roughly spanning the first 8 thoracic vertebrae.

Speaking of the vertebrae, the next region we'll look at seen here highlighted in green is the vertebral region of the back. This region is basically the central region of the back that corresponds to the underlying thoracic and lumbar regions of the spine. Next, we see this region here highlighted in green which is the posterior lateral pectoral region. This region also has an anterior aspect which we'll talk about in our tutorial on the regions of the thorax and abdomen but for now let's focus on the posterior part.

So the posterior lateral pectoral region has two medial boundaries. The first of which is formed by the scapular region and the second of which is formed by the infrascapular region. This region also has a superolateral boundary which is formed by the axillary region of the upper limb.

Situated below the scapular and interscapular regions and lateral to the vertebral region, we can see the infrascapular region. This region encompasses an area of the back that's situated inferior to the scapula and we can see that the posterior lateral pectoral region is situated at its superolateral boundary.

The next region that we're going to look at is the inferior lumbar triangle. This region has three boundaries that are formed by three different structures. Its medial boundary is formed by the latissimus dorsi which we can now see roughly drawn on top of our image, its inferior boundary is formed by the iliac crest, and lastly its lateral boundary is formed by the external oblique. So if we have a closer look at this roughly drawn on muscles and bones we can see how the structures nicely define this region.

The inferior lumbar triangle is also known as Petit's triangle and is an anatomical space through which lumbar hernias can occur. Situated just above the buttocks and at the base of the spine is this region we can see here which is called the sacral region. This region essentially consists of the area that overlies the sacrum.

So now that we've covered the regions of the back, let's move on to the regions of the buttocks starting with the gluteal region. This region encompasses the area that is more commonly referred to as the buttocks. The gluteal region extends from the iliac crest to the gluteal fold and is considered to be a transitional region between the trunk and the lower limbs. It contains three gluteal muscles and if we remove the skin we can take a look at these muscles.

The first of which is the gluteus maximus which is the largest of the gluteal muscles then we have the gluteus medius which is deep to it. Lastly, we have the gluteus minimus which we can see just poking out from underneath the gluteus medius. In addition, this region also contains the piriformis muscle, the obturator internus muscle, the superior and inferior gemelli and part of the quadratus femoris muscle. The sacrotuberous and sacrospinous ligaments are found in this region along with the upper part of the femur and various vessels and nerves also emerge from this region to enter the lower limb.

Finally, we'll discuss the anal region which we can see here highlighted in green. This region is situated deep to the intergluteal cleft and comprises the anus and the surrounding skin.

So before we bring our tutorial to a close, let's quickly summarize what we've talked about today. So first we focused on the regions of the back which included the deltoid region which is the area overlying the deltoid muscle, the suprascapular region which is found superior to the scapula and the scapular region which overlies the scapular bone. Medial to the scapular region we had the interscapular region followed by the vertebral region which corresponds to the underlying thoracic and lumbar regions of the spine. Then we had the posterior lateral pectoral region which also has an anterior part, the infrascapular region which is located inferior to the scapula, the inferior lumbar triangle which is vulnerable to herniation and the sacral region which overlies the sacrum.

We then moved on to the regions of the buttocks where we looked at the gluteal region which contains the gluteal muscles and the anal region which comprises the anus and the surrounding skin.

So that brings us to the end of our tutorial on the regions of the back and buttocks. I hope you found it useful and thanks for watching.

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