Obturator Nerve Anatomy, Function & Diagram | Body Maps Your message has been sent. OK We're sorry, an error occurred. We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later. Close Obturator nerve The obturator nerve begins at the medial border of the psoas major muscle. It travels through the obturator foramen (an opening in the pelvic bone) before entering the thigh, where it branches into two parts, an anterior branch and posterior branch. The obturator nerve is part of the group of nerves called the anterior lumbar plexus. The nerve provides sensory perception to the skin on the medial side of the thigh. It also provides motor function to the hip and knee joints and the abductor muscles and gracilis. The obturator nerve can be damaged through injury to the nerve itself or to surrounding muscle tissue. This type of injury can occur during household or car accidents and it can also happen accidentally during abdominal surgery. A damaged obturator nerve can cause pain, numbness, and weakness of the thigh. Mild damage to the obturator nerve can be treated with physical therapy. More severe cases may require surgery.

The nerve has the ability to regenerate itself at a rate of about one inch per month. Video: Gluteal muscles | Kenhub Gluteal muscles Show transcript Hello, everyone! This is Joao from Kenhub, and welcome to another tutorial where, this time, I'm going to be talking about the gluteal muscles that we’re going to be looking at right now on your screen. And these are muscles that you find on your buttocks region. And on this tutorial, I will help you learn and understand the anatomy and functions of the gluteal muscles. Now, before we move forward, I want to just describe a little bit of what you’re seeing here on your image. We’re looking at the posterior or dorsal view of the bony pelvis, right here. And you can see the group of muscles that we’re going to be discussing on this tutorial, right about here. And these are the right gluteal muscles. You would, of course, have the same here on the left side. And you can see a little bit of the femur here projected here inferiorly on the image here. Now, keep in mind that now I'm going to be adding another set of muscles known as the posterior thigh muscles.

So you can also see, if I zoom out, you can then see the gluteal muscles in context with other muscles of the lower limb. Now, on this tutorial, I want to add that the gluteal muscles are important because they’re essential for different functions including extension and also abduction of the hip joint. And therefore, they’re quite useful for different things, including walking, standing on one leg, or just walking the stairs. Now, the gluteal muscle group contains four muscles and these are the gluteus maximus, the gluteus medius, the gluteus minimus, and the tensor fasciae latae. Underneath the gluteal muscles, we’re going to find another layer known as the posterior hip musculature that we’re going to be discussing on this tutorial, and you can see now on the image on the right side. And these include the piriformis muscle, the internal and external obturator muscles, the superior and inferior gemelli, and the quadratus femoris. Now, let’s start with the very first muscle here on our list, seen here highlighted in green. This is, yes, the greatest of all gluteal muscles.

For that reason, we had to call it the gluteus maximus. Now, the gluteus maximus shapes the superficial gluteal surface and is the strongest extensor and also the external rotator of the hip joint. Now, in terms of origin points, we need to remember a few, including the sacrum which will serve as an origin point. And you can see here that the gluteus maximus is arising from the dorsal part of the sacrum. The ilium will also serve as an origin point, specifically the gluteal fossa. A ligament will also serve as an origin point known as the sacrotuberous ligament. And we can also consider the thoracolumbar fascia as an origin point for this muscle. Now, let’s take a look at the insertion points for the gluteus maximus. And for the caudal fibers, they will insert at the gluteal tuberosity of the femur. While the cranial fibers go over into insert on what is known to be as the iliotibial fascia, iliotibial tract on the fascia lata.

You can see a piece here of the gluteal muscle that will be connecting to the iliotibial tract. Now, keep in mind that the iliotibial tract is a strong fibrous bend on the outside of the thigh inserting at the lateral condyle of the tibia. Let’s take a look now at the functions of the gluteus maximus. And this includes the most important ones which are the extension of the thigh, as you can see here, and also external rotation of the hip joint, as you can see with the arrows, and also, we need to include that this muscle is going to help on stabilizing the hip joint. Important to add here that the contractions of the cranial fibers will abduct, and the caudal fibers, when they contract, they will adduct the femur. The explanation for this opposite or this opposite movement of the cranial and also caudal fibers is that the cranial fibers are positioned above the rotational pivot point of the joint. Thus, a contraction causes abduction. And the caudal fibers run below the rotational axis, so then, will cause adduction. We’ve learned almost everything about the gluteus maximus, but there is still the innervation missing.

And here we find the nerve highlighted in green that is going to be innervating the gluteus maximus. This is known as the inferior gluteal nerve, and you have here, also, the Latin terminology. And coming out… or this nerve will come out of the sacral plexus. Now, let’s continue on to the next muscle on our list. This is known as the gluteus medius. And this is positioned one layer underneath the gluteus maximus. In terms of origin point for the gluteus medius is going to be the iliac wing or the gluteal fossa. The gluteus… The gluteus medius muscle originates between the anterior and also the posterior gluteal lines of the ilium. Let’s look at the insertion point that you can clearly see on this image here on the right side. The insertion point for the gluteus medius is going to be the greater trochanter of the femur right about here as you can see. This is the insertion point for this muscle. Now, let’s look into the functions of this muscle.

And this… The main ones that you need to remember and write down on your notes are going to be abduction and also internal rotation of the hip joint. And keep in mind that the anterior part of the anterior fibers of this muscle is going to be causing the internal rotation, while the posterior part or the posterior fibers will be causing extension and external rotation. And also write this down that this is one of the most powerful muscle for abduction and also internal rotation of the hip joint. Moving on to the small ones, the small gluteal muscle: the gluteus minimus. And the gluteus minimus is found also one or underneath the gluteus medius. And if I show you here the… or add the gluteus medius to the image, you can now see the gluteus minimus just underneath it. In terms of origin point, we’re going to see that this muscle is going to be coming from the iliac wing or the gluteal fossa. And the gluteus minimus originates a short bit below the gluteus medius between the gluteal lines of the ilium.

In terms of insertion point, we’re going to see the same insertion point as we’ve seen on the medius, and this is going to be the greater trochanter of the femur. Now, let’s take a quick look at the functions of the gluteus minimus. The first one is also like we’ve seen on the medius. It’s going to be abduction and also internal rotation of the hip joint. Now, in this case as well, we’re going to see that the interior part or the anterior fibers are going to be responsible for internal rotation, while the posterior fibers are going to be responsible for extension and external rotation. Altogether, the medius and the minimus are going to play a major or an important role in stabilizing the pelvis. Before we move on to other muscles, I want to make here a clinical point related to the medius and the minimus, and to do so, I'm showing here the image of the highlighted medius and the shy minimus just hiding beneath it.

Now, what I want to show here with this image is that in order to understand the function of how these muscles are able to stabilize your pelvis, imagine you’re standing on your right leg like you see on the picture. If these small muscles, these gluteal muscles, the medius and the minimus, wouldn’t be there, your pelvis would then be dropped to the left. The muscles hold it towards the right femur and thus erecting the pelvis. If in any case the muscle or its innervation is damaged, what is going to happen, people will have their pelvis dropped down to the healthy side, this is what we call the Trendelenburg sign, or you can also call it the Trendelenburg position. Next muscle on our list is this one seen here, highlighted in green, known as the tensor fascia latae. This is a thin muscle that lies above all hip muscles and can be easily palpated at the side of the hip, especially in athletes. Origin point, we’re going to look at two. The first one is known as the iliac crest, and the other one is going to be the anterior superior iliac spine, which you can also see here on this image.

Now, it is time for us to move on to the insertion point of the tensor fascia latae, and I mentioned one point because that’s all you need to remember. And this muscle is going to be inserting on this bend here, as you can see, this long bend. This is known as the iliotibial tract. Now, the iliotibial tract is a longitudinal fibrous reinforcement of the fascia lata. Now, well, you may ask what is the fascia lata—is basically a deep fascia surrounding the entire thigh musculature. It is time for us to move on to the functions associated to the tensor fascia latae. Now, the main task of this muscle is to sustain tension of this bend that we just talked about, the iliotibial tract. As the femoral shaft meets the pelvis, there is going to be an angle pressure from above, which imposes high bending strain to the femur. Both of the hip abductors and the tensor fascia latae counteract the pressure on the opposite side and helps stabilize the bone. This is what we call the tension bending effect.

In addition, there are other functions that we need to include here on this list, and these are the abduction, flexion, and also internal rotation of the hip joint. Now, I covered three muscles, but I did not explain their innervation, but now you’re seeing it highlighted in green. This nerve is responsible for the innervation of the three muscles that we just covered. So the gluteus medius, the gluteus minimus, as well as the tensor fascia latae are all innervated by the superior gluteal nerve which comes out of the sacral plexus. And as I mentioned earlier, the second part of this tutorial includes the posterior hip musculature. Now, the posterior hip musculature comprises a group of muscles that extend from the pelvic bone to the femur. During their course, they cross the hip joint dorsally. And you can clearly see here on this image the group of muscles that we just talked about going all the way from the pelvis to the femur. Before we talk about them in a little bit more detail, I just want to start off with the posterior hip musculature in terms of their innervation.

And this is going… the innervation is going to be supplied by the direct branches of the sacral plexus with the exception of one muscle of that list, which is the external obturator nerve, which we’re going to look its innervation later on this tutorial. So remember that all posterior hip musculature or muscles are going to be supplied by direct branches of the sacral plexus. On to the first one on our list, the piriformis muscle. And about the origin of this muscle, this is going to come from the ventral side of the sacral bone also known as the pelvic surface of the sacrum. And as you can see here, this muscle is originating from the front of this or the ventral side of this bone here known as the sacrum. In terms of insertion point, the muscle runs to then the greater trochanter of the femur as you can see, also, here. Let’s take a look at the different functions of the piriformis. Now, the piriformis muscle is an external rotator of the hip joint. Another functions related to the muscle include abduction, as you can see here also with the arrows, and slight extension.

The next muscle on our list is going to be these two muscles here, this pair that is known as the internal obturator, seen here on the left side, and the external obturator muscle, seen on the right side. And you can clearly see why we named it internal obturator and external obturator, because as you can see here on the external obturator, it’s found a bit more ventrally while the internal one is found a bit more dorsally. Now let’s take a closer look at these two muscles. And what you need to know about the internal and external obturator muscles in terms of origin point is that they have a sim… the same one, and that one would be the obturator membrane and its bony margin. Now, in terms of insertion point, you also need to remember that both of them are going to extend and go all the way to, then, insert at the trochanteric fossa on the femur. Now, if you remember from previous slides, I mentioned that all the muscles from the posterior hip, they’re going to be supplied by direct branches of the sacral plexus, but there was an exception.

And this exception is going to be supplied by the nerve that you see here, highlighted in green, which is known as the obturator nerve. Now, if you also remember correctly, the exception is one of the muscles that we’ve been talking about, which is the external obturator muscle. Now, let’s talk about the different functions associated to the internal and external obturator muscles. Now, in terms of functions, these muscles work as external rotators of the hip joint, as you can see here with these arrows. Now, in addition, the external obturator muscle has or produces adduction or has an adduction role in the hip movement. And the internal obturator is going to have slight extension. The next set of muscles is also a pair known as the gemelli. Now, as you can see, you have them highlighted in green on both these images. On your left side, you find the superior gemellus muscle. And on the right side, you find the inferior one. Now, let’s talk about their origin points for both the gemelli. Now, the origin points are the ischial spine. The superior gemellus muscle originates from the ischial spine as you can see here.

This is going to serve as the origin point for this muscle. Now, the inferior one is going to come from the tuberosity of the ischium as you can see here coming all the way from the superior portion of the tuberosity of the ischium. And then they both go and insert into the trochanteric fossa, the trochanteric fossa on the femur. And you can clearly see on both of these images that they’re inserting very close to one another. Now, it is time for us to move on to the functions of the gemelli. And what we see here is that the superior gemelli muscles are going to serve as external rotators of the hip joint, and other functions that these muscles are going to have include adduction and also extension of the hip. Moving on to the last muscle here on our tutorial, the quadratus femoris, and the quadratus femoris originates at the tuberosity of the ischium as you can clearly see here from this image that this muscle is originating from the tuberosity of this bone.

Now, in terms of insertion points, this muscle is going to cross the border and go all the way to the intertrochanteric crest, as you can see here on the femur. And this area is known as intertrochanteric crest because it exists as an area between the greater trochanter and also the lesser trochanter as you can see here on these images. Moving on to, then, the functions associated to the quadratus femoris. And what you need to know is that the quadratus femoris muscle is an external rotator of the hip as well as an adductor of the hip joint. Continue your learning Dissector Answers - Hip & Posterior Thigh & Leg lateral border of ischial tuberosity quadrate line below intertrochanter crest laterally rotates thigh nerve to quadratus femoris 2. Identify the sacral plexus, its general plan, and its major branches in the hip and posterior thigh regions.

(W&B 559-561, N499A , N499B , TG3-25A , TG3-25B , TG3-28 , TG3-29 ) Images from "Anatomy of the Human Body" by Henry Gray are provided by: The sacral plexus proper includes contributions from L4 through part of S4. The contributions from L4 and L5 fuses to form the lumbosacral trunk, because it crosses the pelvic brim to join the sacral ventral primary rami. (Also shown here is the coccygeal plexus, which includes the rest of S4, S5, and the coccygeal nerve.) All of the contributing nerves, except S4, divide into anterior (shown yellow above) and posterior (shown yellow with black shading above) branches, but we will not dwell on the anterior/posterior division scheme. Focus instead on spinal cord segments contributing to various nerves.

sciatic nerve: actually two separate nerves that are usually fused together (though in some cases they are not) - the tibial nerve, from anterior branches of L4 through S3, and the common fibular (peroneal) nerve, from the posterior branches of L4 through S2. The sciatic nerve runs under the piriformis muscle, emerging at its inferior border. It travels through the greater sciatic foramen, and on into the thigh. The sciatic nerve provides motor innervation to the flexors of the knee (posterior thigh muscles) and all of the muscles in the leg and the foot. superior gluteal nerve: from posterior branches of L4 through S1. Travels through the greater sciatic foramen superior to the piriformis muscle, and moves laterally between the gluteus medius muscle and the gluteus minimus muscle. Provides motor innervation to gluteus medius muscle, gluteus minimus muscle, and tensor fascia lata muscle. inferior gluteal nerve: from the posterior branches of L5 through S2.

Travels through the greater sciatic foramen inferior to the piriformis muscle, and travels for a short distance deep to the gluteus maximus muscle but superficial to the sciatic nerve. It provides the sole motor innervation of the gluteus maximus muscle. nerve to quadratus femoris muscle: from the anterior branches of L4 through S1. Travels through the greater sciatic foramen inferior to the piriformis muscle. Provides motor innervation to quadratus femoris and inferior gemellus muscles. nerve to obturator internus muscle: from the anterior branches of L5 through S2. Travels through the greater sciatic foramen inferior to the piriformis muscle, but then loops back around to reenter the pelvis through the lesser sciatic foramen. Provides motor innervation to the obturator internus and superior gemellus muscles. posterior femoral cutaneous nerve: from the anterior branches of S2 and S3 and the posterior branches of S1 and S2. Travels through the greater sciatic foramen inferior to the piriformis muscle, and lies alongside the sciatic nerve.

It provides sensory innervation to the skin of the back of the thigh in addition to the skin of the lower and lateral buttocks (through gluteal branches) and the perineum (via perineal branches). pudendal nerve: from the anterior branches of S2 through S4. Travels through the greater sciatic foramen inferior to the piriformis muscle, but then loops back around to enter the perineum through the lesser sciatic foramen, entering the pudendal canal. Provides motor innervation to the muscles of the perineum, and is the primary sensory innervation to the genitalia. (Latin, pudere = to be ashamed) perforating cutaneous nerve: from the posterior branches of S2 and S3. Pierces the sacrotuberal ligament to provide sensory innervation to the skin of the medial part of the fold of the buttock. nerve to piriformis muscle: from posterior branches of S1 and S2. Provides motor innervation to the piriformis muscle. nerves to coccygeus and levator ani muscles: from anterior branches of S3 and S4. Provide motor innervation to coccygeus and levator ani muscles.

pelvic splanchnic nerves: from the anterior branches of S2 through S4. Travel to the inferior hypogastric plexus (see below). perineal branch of the fourth sacral nerve: from the anterior branch of S4. Descends through the coccygeus muscle and runs anteriorly to the external sphincter ani muscle. Provides motor innervation to this muscle and sensory innervation to the overlying skin. 3. Describe the muscular anatomy of the posterior thigh, its muscles, their nerve supply, and their actions in locomotion. (W&B 595-597, N492 , N495 , N502 , N540 , TG3-29 ) The posterior thigh contains the hamstring muscles - the semitendinosus, semimembranosus, and biceps femoris muscles. They all arise on the ischial tuberosity and cross the knee to insert. The short head of the biceps femoris muscle is not a hamstring muscle, since it arises from the back of the femur, its innervation is different than the rest. See the table below.

Muscle extends thigh, flexes leg tibial nerve Note: There is also a hamstring portion of the adductor magnus muscle which inserts on the adductor tubercle and is innervated by the tibial nerve. 4. Predict the functional loss and cutaneous areas affected by a given nerve injury to the hip or posterior thigh region; or conversely, given a functional and/or cutaneous loss, be able to predict which nerve or nerves are involved and the probable level of the injury. Example #1: If the superior gluteal nerve (L4, L5, and S1) is injured, the muscles affected are the gluteus medius, gluteus minimus, and tensor fasciae latae. These muscles stabilize the pelvis when we walk, preventing our hips from dropping as we lift a foot off the ground to propel forward. The pelvis drops on the opposite side of the nerve injury.

In other words, the right gluteus medius and gluteus minimus support the pelvis in such a way that when the left foot is lifted off the ground, the left pelvis remains level with the right pelvis, but when the right gluteal muscles are injured, the left side of the pelvis will drop when the left foot is lifted off the ground. Example #2: damage to the femoral nerve (L2, L3, and L4) impairs actions of sartorius, iliopsoas, and quadriceps muscles. This will result in weak or absent flexion of the thigh and extension of the knee. Example #3: damage to the inferior gluteal nerve (L5, S1, and S2) impairs the gluteus maximus muscle. This will result in weak or absent extension of the thigh. Example #4: damage to the sciatic nerve (L4 through S3) will impair the action of the hamstrings. This will result in weak or absent extension of the thigh and/or flexion of the knee. Furthermore, the leg and foot will lose innervation, resulting in foot drop.

Example #5: damage to the obturator nerve (L2, L3, and L4) will impair the action of the adductors and obturator externus muscle. This will result in weak or absent adduction and medial rotation of the thigh. (OTE: The obturator externus muscle is a lateral rotator, but there are other muscles that do that, so it would not be missed). The Femur - The Muscles and Fasciae of the Thigh - The Veins of the Lower Extremity, Abdomen, and Pelvis - The Arteries of the Lower Extremity - Surface Anatomy of the Lower Extremity - Surface Markings of the Lower Extremity Questions and Answers: 1. Note that both gluteus maximus and tensor fasciae latae insert via the iliotibial tract of the fascia lata. Where does the iliotibial tract attach? ( TG3-57 ) Superiorly, the iliotibial tract attaches to the iliac tubercle. Inferiorly, it attaches to the lateral condyle of the tibia. 2.

Locate the superior gluteal artery and nerve coursing deep to the gluteus medius muscle. What are their sources? The superior gluteal artery originates from the posterior division of the internal iliac artery. The superior gluteal nerve is from the sacral plexus (L4-S1). It passes through the greater sciatic foramen above the piriformis muscle, then passes between the gluteus medius and minimus muscles to innervate them and the tensor fascia latae muscle. ( TG3-25 , TG6-17 ) 3. What is the innervation and blood supply to the gluteus maximus muscle? The inferior gluteal nerve innervates gluteus maximus, while the superior and inferior gluteal arteries supply it with blood. ( TG3-26 ) 4. Locate the piriformis muscle and trace it to its insertion. Through what foramen does it exit the pelvis? The piriformis muscle exits the pelvis via the greater sciatic foramen. ( TG6-22A , TG6-22C ) 5. Through what foramen does obturator internus muscle pass?

The obturator internus muscle exits the pelvis via the lesser sciatic foramen. ( TG6-23 ) 6. What major action do the gemelli muscles, obturator internus muscle, and the quadratus femoris muscles have in common? They are all lateral rotators of the femur. 7. Is there a perforating cutaneous nerve and artery associated with the sacrotuberal ligament? A perforating cutaneous neurovascular bundle usually passes through the sacrotuberal ligament to reach the inferomedial portion of the buttock. 8. What structures do the greater and lesser sciatic foramina transmit? Greater Sciatic Foramen transmits: tendon of the obturator internus m. nerve to the obturator internus** internal pudendal vessels and pudendal nerve** **pass through both the greater and lesser sciatic foramen ( TG3-26 ) 9. Do you find a branch from the tibial division of the sciatic nerve to adductor magnus; and one from the common fibular division to the short head of biceps? 10. The popliteal fascia is part of what fascia?

The popliteal fascia is continuous with fascia lata above, and crural fascia below. ( TG3-03 ) 11. Where exactly is the popliteal fossa located in the lower extremity? See #7 above. ( TG3-31 ) 12. Do you find lymph nodes in the popliteal fossa? A few popliteal nodes lie embedded in the fat there. They receive lymph following the lesser saphenous vein. ( TG3-70 ) Nerves of the Leg and Foot | Interactive Anatomy Guide Home > Nervous System > Nerves of the Leg and Foot Nerves of the Leg and Foot The nerves of the leg and foot serve to propel the body through the actions of the legs, feet, and toes while maintaining balance, both while the body is moving and when it is at rest. Sensory nerves are of course present throughout the lower extremities; however, with the exception of the bottom of the foot, they play a lesser role here than in the upper extremities. Primarily, this section of the peripheral nervous system sends and receives signals regarding locomotion and balance of the body....

Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Full Nerves of the Leg and Foot Description [Continued from above] . . . The motor regions of the brain and spinal cord control most of the nerve impulses that stimulate muscles in this region. However, many reflex pathways are also active in the legs and foot. The nerve signals in these reflexes come from stretch receptors located in the joints, ligaments, tendons, and even the muscles themselves. Reflexes help to maintain proper muscle tone, balance, and responsiveness of the legs and feet to stimuli such as stepping on a sharp object. The nerves of the leg and foot arise from spinal nerves connected to the spinal cord in the lower back and pelvis. As these nerves descend toward the thighs, they form two networks of crossed nerves known as the lumbar plexus and sacral plexus.

The lumbar plexus forms in the lower back from the merger of spinal nerves L1 through L4 while the sacral plexus forms in the pelvic region from spinal nerves L4, L5, and S1 through S4. The femoral, saphenous, obturator, and lateral femoral cutaneous nerves all extend from the lumbar plexus into the muscles and skin of the thigh and leg. Each of these major nerves further divides into many smaller nerve branches to stimulate individual muscles and sense touch, pain, warmth, and cold in the skin. The branches of the femoral nerve serve the quadriceps muscles and skin of the anterior and medial thigh, while its largest branch, the saphenous nerve, extends to the skin of the medial leg and foot. The obturator nerve connects to the adductor muscles and skin in the groin, while the lateral femoral cutaneous nerve connects to the skin on the anterior, posterior, and medial regions of the thigh. One of the body's largest and longest nerves is the sciatic nerve.

It descends from the sacral plexus through the buttocks and into the thighs to supply nerve impulses to and from the muscles and skin in the hip joints and thighs, the lower legs, feet and most of the skin below the knee. Along its route through the legs, the sciatic nerve splits into the tibial and common fibular (peroneal) nerves, which in turn split into many smaller nerves in the legs and feet. The nerves of the foot help move the body and keep balance both while it's moving and at rest. All of these nerves extend as branches of nerves in the leg that pass through the ankle and into the foot. The sural nerve branches from the tibial and common fibular nerves and is responsible for feeling on the outside of the foot and the small toe. The medial and lateral plantar nerves are the two largest nerves in the bottom of the foot. Working together, the plantar nerves command the many small muscles of the feet and toes to create the constant, subtle shifting of the feet that keeps us from falling down.

At the same time, these nerves deliver messages to the brain that bring information about the angles and position of joints, the length and tension of muscles, or even the speed of movements so that through the interaction of the nervous system with the muscles of the lower extremities, balance may be maintained. Prepared by Tim Taylor, Anatomy and Physiology Instructor Chapter 38: The perineal region and external genitalia Chapter 38: The perineal region and external genitalia Perineal region (fig. 38-1 ) The perineal region is that part of the trunk below the pelvic diaphragm. It is diamond shaped and has the same boundaries as the pelvic outlet. It is divided into an anterior, urogenital triangle and a posterior, anal triangle. The term "perineum" in obstetrics and gynecology is generally limited to the area between the anal and vaginal orifices. The tendinous center, or perineal body, is a median, fibromuscular mass between the urogenital and anal triangles. Several muscles and fasciae are anchored to it, including the levator ani and the external anal sphincter. The perineal body may be damaged during parturition.

To avoid injury, the opening for the passage of the fetal head may be enlarged by incising the posterior wall of the vagina and the nearby part of the perineum (episiotomy). Urogenital region (fig. 38-1 A, C, and F) The male urogenital region is pierced by the urethra, whereas the female urogenital region is pierced by the vagina as well as the urethra and also contains the female external genitalia. In the male, the region (fig. 38-2 ) consists of (1) skin, (2) superficial perineal fascia (which consists of fatty and membranous layers of the subcutaneous tissue), (3) deep perineal fascia, (4) the superficial perineal space (which contains the root of the penis and the superficial perineal muscles), (5) inferior fascia of the urogenital diaphragm, (6) the deep perineal space (which contains the urogenital diaphragm, membranous urethra, and bulbourethral glands), and (7) superior fascia of the urogenital diaphragm (recently disputed).

In the female, the urogenital region comprises the seven components listed above for the male, but the superficial perineal space transmits the distal vagina and contains the greater vestibular glands. Superficial Perineal Muscles (figs. 38-1 D and 38-2 ). Three muscles are found bilaterally. In the male, the bulbospongiosus arises from the perineal body and the fibrous raphe on the bulb of the penis and is inserted into the superior aspect of the corpus spongiosum. It aids in expelling urine or semen. The ischiocavernosus arises from the ischial ramus and is inserted on the crus penis. It helps to maintain erection by compressing the veins in the crus. The superficial transverse perineal muscle arises from the ischial ramus and is inserted into the perineal body. All three superficial muscles are supplied by the pudendal nerve. In the female, the bulbospongiosus is separated from the contralateral muscle by the vagina. It arises from the perineal body, passes around the vagina, and is inserted into the clitoris.

The ischiocavernosus is inserted on the crus clitoridis (see fig. 38-1 C). Deep Perineal Muscles (figs. 38-1 F and 38-2 ). The urogenital diaphragm, which is pierced by the urethra, consists of two muscles bilaterally: the deep transverse perineal and the sphincter urethrae. The deep transverse perineal muscle arises from the ischial ramus and is inserted into the perineal body, which it supports. In the male, the sphincter urethrae, which may be fused with the deep transverse perineal muscle, arises from the inferior pubic ramus and passes medially to meet the muscle of the opposite side and surround the membranous urethra. * It constricts the membranous urethra and is said to expel the last drops of urine. Both of the deep muscles are supplied by the pudendal nerve (through the dorsal nerve of the penis). In the female, the urogenital diaphragm is pierced by the vagina as well as the urethra.

The sphincter urethrae is inserted mostly on the lateral wall of the vagina. The sphincters of the two sides do not surround the urethra and hence, despite their name, do not act as a sphincter urethrae (see fig. 38-1 E). Anal region (see fig. 38-1 A) The anal triangle is the posterior part of the perineal region, and it contains the external anal sphincter muscle. The subcutaneous tissue ascends on each side of the anus as the ischioanal pad of fat, which fills the ischioanal (ischiorectal) fossa. The ischioanal fossa is the space between the skin of the anal region that marks its inferior extent and the pelvic diaphragm on the superior side. It is sometimes the site of an abscess, which may communicate with the rectum or anal canal. The ischioanal fossa, triangular in coronal sections (figs.

38-2 and 38-3 ), is situated between (1) the obturator internus muscle and its fascia laterally and (2) the pelvic diaphragm and its inferior fascia, as well as the external anal sphincter, medially. The pudendal canal, which contains the internal pudendal vessels and pudendal nerve, is a fascial compartment on the lateral wall of the ischioanal fossa (fig. 38-3 ). External genitalia The male external genitalia are the penis and scrotum. The penis. The penis (see figs. 34-1 and 38-4 ), or male organ of copulation, becomes erect and enlarged as a result of engorgement with blood. The penis is attached to the linea alba and pubic symphysis by fundiform and suspensory ligaments. It consists of a root and a body. The root, or attached portion, is situated in the perineum, is covered by the bulbospongiosus, and consists of three masses of erectile tissue: a bulb and two crura.

The bulb is pierced by the urethra, which continues anteriorward in it, and it is covered by the bulbospongiosus muscles. At its anterior extent, the bulb becomes the corpus spongiosum. Each crus of the penis is attached to the corresponding ischial ramus and is covered by the ischiocavernosus muscles (see fig. 38-2 ). The two crura meet and turn inferiorward as the corpora cavernosa. The body of the penis is the free portion covered by skin. The surface that is continuous with that of the anterior abdominal wall is termed the dorsum of the penis. The other, or urethral, surface is characterized by a median raphe continuous with that of the scrotum. The body of the organ contains the corpus spongiosum and the paired corpora cavernosa. Erectile tissues The corpus spongiosum contains the urethra and ends in an expansion, the glans. The glans penis is limited circumferentially by a neck, adjacent to which is a rim known as the corona. Preputial glands, which secrete smegma, are present on the neck and corona.

The external urethral orifice is a median slit near the tip of the glans. The prepuce, or foreskin, is a double layer of skin that extends from the neck to cover the glans. A median fold, the frenulum of the prepuce, is present near the urethral opening. The corpora cavernosa, which constitute the bulk of the body of the penis, form the dorsum and sides of the organ. They end in blunt projections covered by the glans. Vasculature and innervation. The penis is supplied by branches (the artery of the bulb and the dorsal and deep arteries of the penis) of the internal pudendal artery. The penis is innervated by branches of the pudendal, perineal, ilio-inguinal, and cavernous nerves. The cavernous nerves (from the prostatic plexus) contain parasympathetic fibers that cause vasodilatation in the erectile tissue. The flow of blood into the cavernous spaces causes distension of the corpora cavernosa and the corpus spongiosum. Venous return is limited by pressure on the veins that drain the corpora.

At the end of ejaculation, sympathetic vasoconstriction of the arteries allows blood to enter the veins. The scrotum. The scrotum (see fig. 34-1 ) is a cutaneous pouch that contains the testes and epididymides. The left half of the scrotum is usually at a slightly more inferior level than the right. A median raphe indicates the subdivision of the scrotum by a septum into right and left compartments. Smooth muscle, the dartos, is firmly attached to the overlying skin. Loose connective tissue underlying the dartos allows free movement. Female external genitalia The female external genitalia (fig. 38-5 ), known as the pudendum or vulva, are the mons pubis, labia majora and minora, vestibule of the vagina, bulb of the vestibule, vestibular glands, and clitoris. The mons pubis is a fatty eminence in front of the pubic symphysis. Two elongated folds, the labia majora (labium majus in the singular), pass posteriorward from the mons.

They are usually united in anteriorly (by an anterior commissure) but not posteriorly, although the forward projection of the perineal body may give the appearance of a posterior commissure. The round ligaments of the uterus end in the deep surface of the labia majora. Developmentally, the labia majora are homologus with the scrotum of the male. The labia minora and vestibule. The labia minora (labium minus in the singular) are two cutaneous folds situated between the labia majora and on either side of the vaginal opening. In their anterior extent, they unite anterior to the glans clitoris to form a prepuce, and posterior to it to form a frenulum. The labia minora join the labia majora in their posterior extent and may be united by a transverse fold known as the frenulum of the labia, or fourchette. The vestibule of the vagina is the space between the labia minora. It has the openings of the urethra, vagina, and ducts of the greater vestibular glands. The external urethral orifice is posterior to the clitoris.

The vaginal orifice, immediately posterior to the urethral orifice, varies with the condition of the hymen. The bulb of the vestibule consists of two elongated, erectile masses covered by the bulbospongiosus muscles. The masses are united anteriorly at the glans. The bulb of the vestibule is homologous with the bulb of the penis and the adjoining part of the corpus spongiosum (see fig. 38-4 ). The two greater vestibular glands are situated posterior to the bulb of the vestibule. The duct of each gland opens into the vestibule between the vaginal orifice and the labia minora. The greater vestibular glands are homologus to the bulbo-urethral glands of the male (see fig. 38-4 ). The clitoris. The clitoris, which is homologous with the penis, consists of erectile tissue but is not traversed by the urethra. It is posterior to the anterior commissure and partly hidden by the labia minora. Each crus clitoridis (see fig. 38-4 ) is attached to the corresponding ischial ramus and is covered by the ischiocavernosus.

The two crura meet and turn downward as the corpora cavernosa. The corpora constitute the body of the clitoris and end as the glans clitoridis (see fig. 38-4 ), which consists of erectile tissue and is highly sensitive. The clitoris is attached to the pubic symphysis by a suspensory ligament. The blood supply and innervation of the female external genitalia are similar to those of the corresponding structures in the male. Questions 38-1 What is the perineum? 38-1 The term perineum in obstetrics and gynecology is generally limited to the area between the anal and vaginal orifices. Anatomically, the perineal region is that part of the trunk below the pelvic diaphragm. It underlies the outlet of the pelvis (see fig. 38-1 A). 38-2 What is the perineal body? 38-2 The perineal body (see fig. 38-1 B), or tendinous center of the perineum, is a median, fibromuscular node situated at the convergence of several muscles, including the levator ani and the exteal anal sphincter.

The perineal body may be injured during parturition. 38-3 What is the urogenital diaphragm? 38-3 The urogenital diaphragm, which is pierced by the urethra and the vagina, includes the deep transverse perineal and the sphincter urethrae muscles bilaterally (see fig. 38-1 F). However, the sphincter urethrae is not horizontal, and "the concept of a urogenital diaphragm is not borne out" (T. M. Oelrich, Am. J. Anat., 158:229, 1980). 38-4 What is the ischioanal fossa? 38-4 The ischioanal fossa (see fig. 38-2 ) is the fat-filled space between the obturator internus laterally (overlying the ischium) and the external anal sphincter and pelvic diaphragm medially (overlying the anal canal and rectum; hence the name ischioanal).

The base of the fossa is the skin of the anal region, which allows surgical access to the fossa, e.g., to drain an ischiorectal abscess. Anorectal abscesses may be found 1) in the region of the subcutaneous part of the external sphincter (perianal abscess), (2) in the ischioanal fossa (ischiorectal abscess), (3) beneath the mucosa of the upper part of the anal canal (submucous abscess), and (4) above the pelvic diaphragm (supralevator abscess). Anorectal abscesses are important because they may give rise to a fistula-in-ano, i.e., an open passage between the anal canal or rectum and the perianal skin. 38-5 What is excision of the prepuce termed? 38-5 The prepuce is a double layer of skin that covers the glans (see fig. 38-4 ), and its excision is termed circumcision (L., cutting around). 38-6 What is the pudendum? 38-6 The pudendum consists of the external genitalia.

The term female pudendum is more or less synonymous with vulva. Figure legends Figure 38-1 A, Boundaries and subdivisions of the perineal region, inferior view. H, Fasciae of the male perineal region. The superficial fascia has been removed at the right. C, Muscles of the superficial perineal space in the female after removal of the superficial and deep perineal fasciae. D, Similar view in the male. E, Muscles of the deep perineal space in the female. The inferior fascia of the urogenital diaphragm has been removed at the right. F, Similar view in the male. Figure 38-2 Fasciae of the male pelvis and urogenital region, as seen in a coronal section through the prostatic part of the urethra. Figure 38-3 The ischioanal fossae and pelvic diaphragm. Figure 38-4 The male and female external genitalia. M., membranous urethra. Figure 38-5 The female external genitalia. * The usual account has been disputed. According to T. M. Oelrich (Am. J.

Anat., 158:229-246, 1980). (1) "there is no distinct superior fascia of the so-called urogenital diaphragm." (2) the sphincter urethrae is not horizontal ("the concept of a urogenital diaphragm is not borne out"), and (3) the sphincter urethrae (at least developmentally) is part of a continuous sheet that extends from the bladder to the perineal membrane and that lies within the pelvic cavity. Jump to: Hip adductors - Anatomy, Function and Pathology | Kenhub Hip adductors Contents Anatomy and supply The adductors of the hip are part of the inner hip musculature and range from the lower pelvic bone to the femur and knee region . Thereby it lies in between the extensor and flexor group of the thigh muscles. The hip adductors shape the surface anatomy of the medial thigh. The innervation is mainly supplied by the obturator nerve which arises from the lumbar plexus and reaches the adductors through the obturator canal; two muscles have a double innervation.

The hip adductors are as follows: Pectineus muscle: runs from the superior pubic ramus to the pectineal line and linea aspera of the femur. It is additionally innervated by the femoral nerve . Adductor magnus muscle: is one of the biggest muscles of the human body. It originates at the inferior pubic ramus, the ischial ramus and the ischial tuberosity and inserts both at the linea aspera (“fleshy insertion”) and the medial epicondyle (“tendinous insertion”). The superficial part of the adductor magnus is supplied by the tibial nerve . Adductor longus muscle: has its origin at the superior pubic ramus and the pubic symphysis and insertion at the linea aspera. Distally it forms an aponeurosis extending to the vastus medialis muscle (vastoadductorial membrane). Adductor brevis muscle: originates at the inferior pubic ramus and inserts at the linea aspera. Adductor minimus muscle: describes the inconstant cranial separation of the adductor magnus which is found in many people.

It extends from the inferior pubic ramus to the linea aspera. Gracilis muscle: runs from the inferior border of the pubic symphysis to the medial surface of the tibia, where it inserts as the superficial pes anserinus. Its tendon is easy to palpate in the inguinal region – together with the tendon of the adductor longus muscle. Both the femoral artery and vein as well as the saphenous nerve proceed within a groove between the adductor magnus, adductor longus and vastus medialis muscles. This so-called adductor canal (Hunter’s canal) is ventrally covered by the vastoadductorial membrane. Distally it ends between the “fleshy” and “tendinous” insertion of the adductor magnus and leads to the popliteal fossa. Recommended video: Hip adductors Overview of the anatomy of the adductors of the hip. Function As the name suggests the main function of the hip adductors is the adduction of the hip joint .

Furthermore it supports the outward rotation (pectineus, adductor minimus, brevis and magnus), inward rotation (tendinous insertion of the adductor magnus), flexion (all) and extension (tendinous insertion of the adductor magnus). Being the only two joint adductor the gracilis muscle moves the knee joint as well where its contraction causes a flexion and inward rotation. The hip adductors are particularly used when crossing one’s legs. Overall they play an important role in balancing the pelvis during standing and walking. Pathology The adductor muscle tear (groin strain) ranks among the most common sport injuries (e.g. playing soccer, doing the splits, slipping on ice etc.) and affects favorably the origin tendon at the pubic region. It is caused by a disproportional strain of the muscles, often in combination with a poor warm-up and a lack of stretching. Hereby even ruptures and hemorrhages may occur. Symptoms include pain extending to the inguinal and knee region when stretching and straining the muscles. A malposition of the sacroiliac joint can restrict the function of the hip adductors in the long run as well and should be addressed clinically.

The above mentioned orthopedic pathologies are to be distinguished from the neurogenic adductor spasm. This is a common symptom in spastic diplegia (Little’s disease). Due to the spasticity in the hip adductors the affected children walk – if at all – with adducted, flexed and inward rotated legs (scissor gait). Get me the rest of this article for free Create your account and you’ll be able to see the rest of this article, plus videos and a quiz to help you memorize the information, all for free. You’ll also get access to articles, videos, and quizzes about dozens of other anatomy systems. References: M. Schünke/E. Schulte/U. Schumacher: Prometheus – LernAtlas der Anatomie – Allgemeine Anatomie und Bewegungssystem, 2.Auflage, Thieme Verlag (2007), S.474-475 W. Graumann/D.Sasse: CompactLehrbuch der gesamten Anatomie – Band 2 – Bewegungsapparat, Schattauer Verlag (2003), S.140-145 J.

W. Rohen: Topographische Anatomie, 10.Auflage, Schattauer Verlag (2008), S.152-157 J. Weineck: Sportanatomie, 16.Auflage, Spitta Verlag (2003), S.158-159 C. Mayer/W. Siems: 100 Krankheitsbilder in der Physiotherapie, Springer Verlag (2011), S.8 F. Niethard/J. Pfeil/P. Biberthaler: Duale Reihe – Orthopädie und Unfallchirurgie, 6.Auflage, Thieme Verlag (2009), S.252-255 Author:

Question: In which part of the human body would you find the obturator muscles?
Answer: Pelvis