Hello everyone! It’s Megan from Kenhub here, and welcome to our tutorial about the descriptive terms used for the regions of the upper limb. So before we begin, let me first give you a quick overview of what we’re going to discuss today.
Now the body is divided into regions in order to allow for clear and precise communication regarding the location of structures, injuries or pathologies. The regions into which the body is divided are a reflection of both their functional complexity and their importance. We’re going to cover the regions of the body across five different tutorials but today we’re focusing on the regions of the upper limb. We use our arms or the upper limbs every day and in almost every task that we carry out that comprise of an anterior surface and a posterior surface. In this tutorial, we’ll discuss the regions into which the anterior and posterior surfaces of the upper limb are divided including the shoulder region.
We’ll begin with the anterior surface of the upper limb starting with the infraclavicular fossa which is an indentation located just inferior to the clavicle. This small depression is situated between the deltoid muscle and the pectoralis major muscle. Next on our list, we have the clavipectoral triangle which we can see here highlighted in green. This region is also referred as the deltopectoral triangle as it's bordered by the deltoid muscle and pectoralis major muscle as well as the clavicle. This small triangle contains the cephalic vein and the deltopectoral fascia – a deep investing layer of the deltoid and pectoralis major muscles. This triangle may be used to access the subclavian vein and the subclavian artery which lie deep to it.
Another region of the upper limb is the anterior deltoid region which of course is the part of the deltoid region that’s situated anteriorly. The deltoid muscle as you may know is a triangular-shaped muscle located at the uppermost part of the arm and the shoulder. This muscle is what forms the rounded part of the shoulder. So the deltoid region is basically the region of the shoulder demarcated by the outline of the deltoid muscle.
The next region of the upper limb we’re going to talk about is the axillary region better known as the armpit. This region is situated underneath the shoulder joint at the junction of the upper limb and the thorax. The contents of this region include the axillary artery and vein, the brachial plexus, the axillary lymph nodes and the tendons of the biceps brachii and coracobrachialis muscle which pass through this region to attach to the coracoid process of the scapula.
The anterior border of the axillary region is formed by the pectoralis major, the pectoralis minor and the subclavius muscles. Its posterior border is formed by the subscapularis muscle, teres major and latissimus dorsi. Medially, it’s bordered by the serratus anterior muscle, the ribs and the intercostal muscles. The lateral boundary of the axillary region is formed by the intertubercular groove of the humerus. Its apex which is also known as the axillary inlet is formed by the lateral border of the first rib, the superior border of the scapula and the posterior border of the clavicle.
The region of the upper limb we can now see highlighted in green is the anterior arm. It extends from the deltoid region which is situated superiorly and borders the anterior cubital region inferiorly. This region contains the flexor muscles of the arm. The brachial artery and vein as well as the musculocutaneous nerve and the radial nerve also pass through this region.
Situated between the anterior arm region and the anterior forearm region of the upper limb is this area here – the anterior cubital region. This region is location of the anterior cubital fossa and it’s the anterior region of the elbow. Among the structures located in this region are the tendon of the biceps brachii muscle, the median nerve, the radial nerve and the brachial artery which bifurcates at the apex of the anterior cubital fossa into the radial artery and the ulnar artery.
Located just below the anterior cubital region is the anterior forearm region. This region may also sometimes be referred to as the anterior antebrachial region. It encompasses the anterior part of the forearm and as such comprises the muscles of the anterior compartment of the forearm as well as the ulnar and radial vessels, the median nerve and the ulnar nerve.
Moving further down the upper limb we see the anterior carpal region. This region is the region of the forearm that corresponds to the underlying carpal bones of the hand and is basically the anterior part of the wrist. It's in this region of the forearm that the flexor retinaculum which stretches between two carpal eminences to form the carpal tunnel is found. The structures found in this region correspond to those that pass through the carpal tunnel.
The final region of the anterior aspect of the upper limb that we’ll look at is palm of the hand. Seen here highlighted in green, this region contains the thenar and hypothenar muscles of the hand as well as the vessels and nerves of the hand and the underlying metacarpal bones.
Now moving on to the posterior surface of the upper limb, the first region we see here is the posterior deltoid region which is basically the posterior aspect of the deltoid region that we saw earlier on in this tutorial. Next we can see the scapular region which is the region that overlies the scapular bone. This region seen here highlighted in green is the location of the muscles of the rotator cuff among other structures related to the scapula. Inferior to the posterior deltoid region, we can see the posterior region of the arm highlighted in green. This is the region that corresponds to the back of the arm. It’s also known as the posterior brachial region and it overlies the muscles of the posterior compartment of the arm.
We’ve already seen the anterior cubital region so the posterior cubital region is a region of the arm that corresponds to the back of the elbow. This region is also known as the olecranon region and is situated between the posterior arm region and the posterior forearm region. So the next region we’re going to look at is the posterior forearm region which is situated just inferior to the posterior cubital region. This region corresponds to the posterior compartment of the forearm and as such comprises the extensor muscles of the forearm and the radial nerve which innervates these muscles.
Next we see the posterior carpal region which corresponds to the posterior part of the wrist. The extensor retinaculum and the tendons of the extensor muscles of the wrist can be found in this region. Finally, the region we can see here highlighted in green is the dorsum of the hand or the back of the hand. The anatomical snuffbox which is also known as the radial fossa is found on the dorsum of the hand. This triangular-shaped depression on the dorsum of the hand is best seen when the thumb is abducted. The contents of the dorsum of the hand include the extensors of the hand, the radial artery, a branch of the radial nerve, the cephalic vein and the dorsal venous network of the hand.
Before we conclude our tutorial, let’s quickly summarize what we’ve learned today. We started with the regions of the anterior surface of the upper limb namely the infraclavicular fossa which is located inferior to the clavicle; the clavipectoral triangle which is bordered by the clavicle, the deltoid and the pectoralis major; and the anterior deltoid region which is demarcated by the outline of the deltoid muscle.
We also looked at the axillary region or commonly known as the armpit followed by the anterior arm which contains the flexor muscles of the arm. Inferior to the anterior arm, we saw the anterior cubital region otherwise known as the anterior region of the elbow then we had the anterior forearm which contains the muscles of the anterior compartment of the forearm. Linking the forearm and the hand is the anterior carpal region or the anterior aspect of the wrist. Finally, we saw the palm of the hand.
Once we talked about the regions of the anterior surface of the upper limb, we moved on to the posterior surface of the upper limb. First we had the posterior deltoid region which is essentially the posterior aspect of the deltoid muscle. Next we saw the scapular region where we can find the rotator cuff muscles followed by the posterior arm region which contains the muscles of the posterior compartment of the arm. Inferior to the posterior arm, we saw the posterior cubital region also known as the olecranon region then we had the posterior forearm which contains the extensor muscles of the forearm followed by the posterior carpal region and the posterior aspect of the wrist. Lastly, we looked at the dorsum of the hand.
So that brings us to the end of our tutorial on the regions of the upper limb. I hope you enjoyed it and thank you for listening.
Now that you just completed this video tutorial, then it’s time for you to continue your learning experience by testing and also applying your knowledge. There are three ways you can do so here at Kenhub. The first one is by clicking on our “start training” button, the second one is by browsing through our related articles library, and the third one is by checking out our atlas.
Now, good luck everyone, and I will see you next time.