Hello, this is Ryo. Today, I am going to talk about anatomy of gluteus maximus. Its attachment, function, innervation, blood supply, and relationship to other tissues. Let’s see its origin and insertion. You know, gluteus maximus is maximus. Very big muscle. attachment, especially origin, is very wide. As you see, it is very wide here. Gluteus maximus is considered the biggest muscle in the body. It makes sense its attachment is wide. Let’s check origin first. The first origin is PSIS. Which is the most posterior part of pelvis. Then it continues to iliac crest. And it also attaches to sacrum. Especially upper part of sacrum. It is rather superior part, rather than side. And also coccyx As you see from iliac crest to all the way to coccyx. Not only that. If you look closer You see ligament running here. This ligament is called sacrotuberous ligament. Sacrotuberous ligament runs from ischial tuberosity to sacrum. Gluteus maximus has attachment to the ligament. Let’s look closer. Glutes runs like this. The muscle deep to maximus is gluteus medius. Gluteus maximus covers medius, thus maximus attaches to fascia of medius. Oh I see, guteus maximus has attachment to ligament and muscle, not only bony structure. If you consider gluteus maximus attaches to other muscle, Let’s think gluteus maximus is not separated structure, because it attaches to medius. That means gluteus maximus and medius one continuous structure. Glutes as one unit. Again, it attaches to glutesus medius fascia. Actually, it has more connection, which is erector spinae fascia which is associate with many muscles. You see connection here? Again, it attaches to ligament and fascia of erectors. Gluteus maximus has tons of origin as you see. Such as bone, ligament, and fascia. Then let’s look at insertion. maximus runs like this and you see insertion? It’s here. Usually, muscle attaches to bone, but this part of glutes attaches to fascia again. This fascia is called ilio-tibial band How does this app say about atachment? Oh yeah, it says ilio-tibial band. It attaches to ilio-tibial band, and at deeper part it attaches to gluteal tuberosity. Superficial part=fascia, deep part=bone. As you have seen, its attachments are very unique. I have talked its origin and insertion, so let’s talk about its function. Maximus, it is THE extensor muscle of hip. Especially, when hip is flexed position like this. let’s pretend gluteus maximus is here. Then it can extend leg very strongly. Such as jumping or like squat. When yo squat, you need to fire glutes a lot. Because you need to fire glutes to extend hip joint. The difference in between glutes and hamstrings. Ham is also hip extensor. Hamstrings work when knee is extended. It extends hip like this. On the other hand, hip and knee need to be much more flexed to stimulate glutes. Glutes work when you jump or squat. Hamstring work when you run. It is like you need to use glutes for vertical movement. As you see direction or its fiber, from gluteal tuberosity to sacrum. If muscle contracts toward this vector, it makes lateral rotation of hip joint little bit. But the most important function is hip extension. [email protected] extension is the key of gluteus maximus. Then let’s check its innervation. It is innervated by inferior gluteal nerve. Where is inferior gluteal? It’s here. Inferior gluteal nerve is from L5 – S2 It is from 3 nerve roots, then innervates gluteus maximus. By the way, there is a nerve called superior gluteal nerve. superior gluteal nerve innervates TFL, gluteus medius and minimus. medius and minimus is innervated by superior gluteal nerve. gluteus maximus is by inferior gluteal nerve. You need to be clear these muscle have different nerve supply. maximus=inferior gluteal. Very important to remember. We have looked nerve supply, so let’s look at blood supply. As you have seen, gluteus maximus is very big muscle. running like this. That means it is supplied by 2 arteris. One is inferior gluteal artery. There is inferior gluteal nerve, of course there is inferior gluteal artery. As I said before, nerve supply is different in gluteal muscles. Like there are inferior/superior gluteal nerve. Now I am showing inferior gluteal artery. There is inferior gluteal artery, then? This is called superior gluteal artery. Gluteus maximus is supplied blood by these two arteries. inferior/superior gluteal artery. These are two arteries supply blood to gluteus maximus. nerve supply=inferior. blood supply=inferior and superior. Remember, artery is 2. This is innervation and blood supply. Next up. Let’s look relationship with other tissues. I said this in Latissimus dorsi video. But let’s recall. Left gluteus maximus’ direction is like this. right side is opposite. runs like diagonally. Latissimus dorsi’s direction is opposite. like crossing. Other side is same thing. Opposite side glutes and lat much their direction of fibers. Glutes control leg movement, Lat controls shoulder movement. This opposite side movement is crucial for athletic movement. Such as jumping or running, they have contralateral movement. left side glutes and right lat, right glutes and left lat. This contralateral connection is crucial for performance. Again, gluteus maximus and latissimus dorsi cross here. It is called thoracolumbar fascia. crossing happens at thoracolumbar fascia. This is very important relationship. I will explain another connection. This is glutes. It attaches ilio-tibial band as I said. ilio-tibial band runs inferiorly toward knee joint. you see there is connection from front? glutes is from this direction and there is something from front. This muscle is called tensor fascia lata (TFL) TFL is very famous for tensing femoral fascia. That is why it is called Tensor Fascia Lata. In general, cause of tight ilio-tibial band is TFL, many people think. TFL pulls up tissue, then it affects to ilio-tibial band. Actually, gluteus maximus connects to ilio-tibial band as well. Because its insertion is ilio-tibial band. TFL attaches to ilio-tibial band. Gluteus maximus attaches to ilio-tibial band. That means conection among these 3 tissue makes like Y shape. See, it is for gluteus maximus Then this is for TFL Again you see Y shape connection. That means TFL can affect gluteus maximus via ilio-tibial band. vise versa. If you think like functionally, it is hard to connect front part and back part. Because they act opposite. Guteus maximus=hip extensor. TFL=hip flexor. If you think about pelvic movement, TFL=anterior tilt. Gluteus maximus=posterior tilt. Completely opposite. But via ilio-tibial band, there is connection. Completely opposite function, completely opposite location. They meed in middle, at ilio-tibial band. I think it is cool connection, Also gluteus maximus covers medius. That means it connects to gluteus medius fascia. And it also has connection to TFL, via ilio-tibial band. TFL in in front, gluteus medius in middle, gluteus maximus in back That means they are all connected from bacl to all the way to front. And it is so important. When you look at hip joint you find local restriction somewhere in hip. Then you treat or train what you find. Like treat maximus, because it is tight. Or train medius because it is weak. It is ok to look body individually, But if you think about all the connection around hip You want to treat or train whole part of hip joint. Then you can see hip joint in different perspective. I explained connection to latissimus dorsi first, Then I explained TFL to gluteus maximus which is via ilio-tibial band, As I said before, it also connects to fascia of erector. It can go superior as well. Glutes is so so important muscle When you jump or running, especially. because it is strong hip extensor. Also it fires when you squat and dead lift. It has very important function, But it has so important connection as well. to hip joint, to upper part of body, to upper soine. to sacrum. If you go deeper, you can reach ligament called sacotuberous ligament, This can affect tension around pelvic gurdle. If you chase multiple connection, you find gluteus maximus is interesting muscle. This is it. Thank you for watching.