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Functions and anatomy of the adductor longus muscle shown with 3D model animation.
Hello everyone! This is Joao from Kenhub, and on this tutorial, we will be looking at the anatomy and functions of the adductor longus muscle which is the muscle that you can see now isolated on the screen. Now, let's get straight into it. Before we look at the functions and movements of the adductor longus muscle, let's first look at its anatomy.
As you can see in the image, it is a triangular or fan-shaped muscle which extends from the anterior aspect of your pelvis to then the posterior aspect of your thigh bone or femur. The adductor longus muscle is one of the adductor muscles of the thigh, also known as the hip adductors. These muscles which are six in total are all located along the medial thigh tucked in behind muscles of the anterior compartment.
The adductor muscles of the thigh are arranged into three layers. Our muscle of interest – the adductor longus muscle – along with the neighboring pectineus muscle are the most anterior of this group.
As you know, all muscles are innervated by a certain nerve and the adductor longus is, of course, no different. Like most of the adductor muscles, the adductor longus muscle is innervated by the anterior division of the obturator nerve which originates from the lumbar plexus specifically the anterior rami of the second through fourth lumbar nerves which are seen here highlighted in green on the image.
Let's take a moment now to look more specifically at the attachment sites of the adductor longus muscle. Zooming in at the origin, we see that the muscle originates from the anterior aspect of the body of the pubis just inferior to the pubic tubercle. This attachment is particularly prone to overload during exercise and often is a cause of sports-related groin injury or strain.
The adductor longus muscle continues posterolaterally from its origin into a large broad belly before inserting into the middle third of the linea aspera which is the rough longitudinal ridge which runs along the posterior surface of the femur.
The medial border of the adductor longus muscle also forms the medial boundary of the femoral triangle which gives the passage to several major neurovascular structures of this area namely the femoral artery, vein, and nerve.
Now, we're ready to move on to the functions of the adductor longus muscle. We're going to look at three main actions which this muscle is involved in. The first function is no surprise and, as its name suggests, the adductor longus muscle is primarily involved in adduction of the thigh at the hip joint – meaning it acts on the hip joint to move the thigh medially or towards the midline of your body as you can now see on the screen.
The adductor longus muscle also works in unison with the anterior muscles of the thigh to produce flexion of the thigh lifting the lower limb forward or anteriorly bringing it to the front of your body. The third function which the adductor longus muscle also supports is outward or external rotation of the thigh. This is when you rotate your thigh laterally or away from the midline.
Functionally, the adductor longus is perhaps most commonly used during crossing of one's legs at the knee or ankle or when kicking a football with the medial side of your foot. It also plays a role in stabilizing the pelvis both during standing and walking.
So let's quickly summarize what we have learned today about the adductor longus muscle. We learned that the adductor longus muscle is part of the adductor group of the muscles of the medial thigh. It originates from the body of the pubis and inserts into the linea aspera on the posterior aspect of the femur bone. These attachments mean the adductor longus muscle works only on the hip joint and we saw that it performs three main functions on this joint. These were, of course, adduction of the thigh which causes the lower limb to move medially towards the midline. We also saw then flexion of the thigh which causes the lower limb to move anteriorly or in front of the body. And, finally, we looked at external rotation of the thigh which is when the muscle rotates the thigh laterally or away from the midline.
And that's it for the function of the adductor longus muscle. Thanks for using Kenhub today and I hope you enjoyed our tutorial. I will see you on the next one.