Introduction

Today you will learn about the neurovasculature of the lower extremity. You will explore the nerves, arteries, and veins of the gluteal region, thigh, leg, and foot. Keep in mind that all structures are not visible on all tissue or other tools, and that is okay. By the end of the lab today, you should have identified all of the structures on the list using multiple modalities. Over the next two labs, you will learn about the muscles, and you will make the connection between these nerves and vessels and the muscles they innervate or supply.

In this lab, we will mention the general area innervated and supplied by these nerves and vessels. In future labs, we will study this more in-depth. You should reference the muscle tables posted on Canvas to see the specific muscles innervated by each nerve.

Lab Activity 1: Lower Extremity Donor Tissue-Arteries and Nerves

Like the previous units, you should use nearby structures as a reference when identifying neurovascular structures of the lower extremity. By following a nerve or artery to a specific muscle, you can determine which artery or nerve it is.

The lower extremity tissue will be positioned with either the anterior side or posterior side up. Please do not rotate them. You will view the anterior structures on two of the extremities and posterior structures on the other two extremities. You can also view the structures on Donors A and B.

Posterior Neurovasculature of the Lower Extremity

Anterior, Lateral, and Medial Neurovasculature of the Lower Extremity

Lab Activity 2: Visible Body Digital Atlas-Neurovasculature of the Lower Extremity

We will use the Visible Body Digital Atlas to explore the neurovasculature provided in the Terms to Know. While you are viewing the neurovasculature, use the muscle tables to make connections between the nerves and the muscles that they innervate.

Arteries of the Lower Extremity

Click on the Regions tab, and then choose 10. Hip. In the side Systems toolbar, uncheck the lymphatic, nervous, muscular, and venous systems. You will be left with the bones and arteries of this region. Zoom in on the region of the hip and pelvis. From the anterior view, click on and observe the common iliac artery. This artery originates on each side as the aorta ends and splits in the lower abdominal region. Rotate the image, and observe that the common iliac artery divides into the internal and external iliac arteries.

First, explore the internal iliac artery and its branches. While this artery also supplies the perineum and other pelvic structures, we will focus on the branches that supply muscles of the lower extremity. Click on the superior gluteal artery, a superior branch that runs posteriorly to the gluteal region. With this artery highlighted, rotate the image to a posterior view and observe its path. From the posterior view, click on the internal iliac artery again. Follow this artery inferiorly, and, as it divides, click on the more lateral artery, the inferior gluteal artery. While you still have the inferior gluteal artery highlighted, click on the radius blast (bullseye) three times. Observe how the ligaments of the pelvis form the greater sciatic foramen in the region of the greater sciatic notch of the pelvis, and notice how these arteries both travel through the greater sciatic foramen. The piriformis muscle has also been added to this image. You can now see that the superior gluteal artery leaves the greater sciatic foramen superior to the piriformis muscle, while the inferior gluteal artery leaves the greater sciatic foramen inferior to the piriformis muscle. The superior gluteal artery supplies the gluteus maximus, gluteus medius, gluteus minimus, and tensor fasciae latae muscles, while the inferior gluteal artery supplies the gluteus maximus, two lateral rotators, and the superior parts of the hamstring muscles.

Return to the anterior view, where you started this section, and remove the lymphatic, nervous, muscular, and venous systems. Now click on the obturator artery, which branches from the internal iliac artery just inferior to the superior gluteal artery and runs anterolaterally along the ilium. Observe how this artery runs through the obturator foramen of the pelvis. With this artery highlighted, rotate the image to view it from different angles. It supplies the thigh adductors, the proximal part of the hamstrings, and one lateral rotator muscle. The obturator artery gives off an anterior and a posterior branch, though you are not responsible for identifying these branches. However, you should know that the posterior branch of the obturator artery gives off the acetabular branch or the artery to the femoral head. Though it is not visible on the iPads, you should know that this artery travels through the ligamentum teres and helps to supply the femoral head.

Zoom out to view the full hip and thigh. Just distal to the common iliac artery, now click on the external iliac artery. Branches of this artery supply the rest of the lower extremity. Notice that the external iliac artery ends as it passes behind the inguinal ligament. Distal to the inguinal ligament, this vessel becomes the femoral artery. Zoom in to take a closer look at the branches of the femoral artery. Observe the deep femoral artery running posteriorly. The deep femoral artery gives off two branches that supply the hip joint: The medial and lateral circumflex femoral arteries. They form an anastomosis to supply the hip region and the head and neck of the femur. Rotate the image to observe how this artery wraps around the proximal femur.

Observe the femoral artery from a medial view and notice that it moves posteriorly as it descends in the medial thigh. Also, notice that the femoral artery ends just superior to the knee joint. At this joint, the artery becomes known as the popliteal artery. This artery will be best viewed posteriorly.

The popliteal artery ends just inferior to the knee joint as it splits to form the anterior tibial and posterior tibial arteries.

Rotate the image to an anterior view, click on the anterior tibial artery, and observe that it passes through the interosseous membrane. It descends on its anterior aspect, supplying the anterior compartment of the leg. As it crosses the talocrural joint, it becomes the dorsal pedis artery.

The posterior tibial artery supplies both the deep and superficial posterior compartments. Soon after branching off the popliteal artery, it gives off the fibular artery, which travels just posterior to the interosseus membrane. The fibular artery supplies the lateral compartment of the leg.

Look at the plantar aspect of the foot. Observe the posterior tibial artery running around the medial malleolus and then dividing into the medial and lateral plantar arteries (you will need to hide the plantar fascia to see this). Also, observe the plantar arch and digital arteries.

Veins of the Lower Extremity

Click on the Regions tab, and then choose 10. Hip. In the side Systems toolbar, uncheck the lymphatic system, nervous system, and muscular system. You will be left with the bones, arteries, and veins of this region. Zoom in on the region of the hip and pelvis. First, observe the two main superficial veins of the leg, the great saphenous vein, and the small saphenous vein. The small saphenous vein drains the lateral foot and leg and drains into the popliteal vein. The great saphenous vein drains the rest of the lower limb and drains into the femoral vein near the hip.

The deep veins of the lower extremity travel with the artery of the same name. Notice how the anterior tibial vein travels with the anterior tibial artery, and the posterior tibial vein travels with the posterior tibial artery. Furthermore, the fibular vein travels on the posterolateral aspect of the interosseous membrane with the fibular artery. The fibular vein drains the lateral leg and ankle and drains into the posterior tibial vein. The anterior and posterior tibial veins drain the anterior and posterior compartments of the leg, respectively, and unite to form the popliteal vein.

Moving superiorly, observe the popliteal vein and notice that it ends just superior to the knee. At this point, it becomes the femoral vein. In addition to the great saphenous vein, the deep femoral vein also drains into the proximal portion of the femoral vein. Similar to the femoral artery, the femoral vein becomes the external iliac vein as it passes deep to the inguinal ligament.

Nerves of the Lower Extremity

Click on the Regions tab, then 10. Hip. In the side Systems toolbar, uncheck the lymphatic system, muscular system, and the vascular systems. You will be left with the bones and nerves of this region. Zoom in on the region of the hip and pelvis from a posterior view. Now use the Anatomy Search icon and type in piriformis. Add the piriformis as well as the gluteus minimus. Similar to the arteries of the same name, observe that the superior gluteal nerve leaves the greater sciatic foramen superior to the piriformis, while the inferior gluteal nerve leaves the greater sciatic foramen inferior to the piriformis. The superior gluteal nerve innervates the gluteus medius, gluteus minimus, and tensor fasciae latae muscles, while the inferior gluteal nerve innervates the gluteus maximus only.

Move to an anterior view. Click on the femoral nerve, and observe its branches traveling to the muscles of the anterior thigh. Now rotate to a posterior view. Observe a nerve running through the obturator foramen. This is the obturator nerve, and it innervates the muscles of the medial thigh (except the hamstring portion of the adductor magnus).

In this view, you can also observe the sciatic nerve exiting through the greater sciatic foramen inferior to the piriformis. As you move inferiorly, you will observe that the tibial and common fibular nerves comprising the sciatic nerve separate from each other in the superior popliteal fossa.

Observe the tibial nerve traveling through the posterior leg and branching into the lateral and medial plantar nerves (you will need to hide the plantar fascia to see this). Also, observe the common fibular (peroneal) nerve running rather superficially, wrapping around the head of the fibula. Then it splits into the superficial and deep fibular (peroneal) nerves. Notice that the deep fibular (peroneal) nerve travels just anterior to the interosseous membrane. This nerve innervates the muscles of the anterior compartment of the leg and the dorsal aspect of the foot. The superficial fibular (peroneal) nerve innervates the muscles of the lateral compartment of the leg.