- Identify the parts of the hip bones, femur, patella, and tibia that are associated with the anterior and medial thigh.
- Identify the femoral triangle, its boundaries, and contents, including the structures passing through the subinguinal space.
- Identify the adductor canal and its contents.
- Identify the muscles, nerves, and vessels in the anterior compartment of the thigh.
- Identify the muscles, nerves, and vessels in the medial compartment of the thigh.
- Identify the bony and ligamentous features of the hip joint.
Osteology Relevant to This Session
Sacrum
Review These Parts of the Pelvic Skeleton
■Iliac crest
■Anterior superior and anterior inferior iliac spines
■Superior ramus and inferior ramus of pubis
■Body of pubis (where the pubic rami meet—the left and right pubic bodies are joined by the pubic symphysis)
■Pubic tubercle
■Obturator foramen
■Ischiopubic ramus
■Ischial tuberosity
Femur
Femur
■Head
■Fovea capitis (the ligament of the head of the femur attaches here)
■Neck
■Shaft
■Greater trochanter (insertion for gluteus minimus and medius)
■Lesser trochanter (insertion for iliopsoas)
■Intertrochanteric line (anterior—connecting the trochanters) and Intertrochanteric crest (posterior—connecting the trochanters)
■Trochanteric fossa
■Linea aspera: A vertical ridge on the posterior femoral shaft where many muscles attach (origin of vastus lateralis and medialis; insertion of adductor longus, brevis, and magnus)
■Medial and lateral condyles (articulate with the condyles of the tibia)
■Medial and lateral epicondyles
■Adductor tubercle: On medial condyle—the hamstrings part of the adductor magnus attaches here
■Intercondylar fossa (notch): The cruciate ligaments occupy this space and attach on the inner surfaces of the condyles
■Patellar surface
■Popliteal surface
Patella
■A sesamoid bone contained within the quadriceps tendon.
Question
What’s a sesamoid bone?
■Identify the base and apex of the patella.
Proximal Tibia
■Tibial tuberosity (attachment site for the patellar ligament)
■Anterolateral tubercle of tibia (Gerdy’s tubercle) – the distal attachment site of the iliotibial tract
■Medial and lateral condyles (articulate with the condyles of the femur)
■Tibial plateau (the menisci and cruciate ligaments of the knee attach here)
■Anterior border of tibia (“shin”)
Before cutting, see if you can locate and palpate the following:
■Anterior superior iliac spine and pubic tubercle—these are attachment sites for the inguinal ligament
■Surface projection of the femoral artery, vein, and nerve (visualize these by identifying the mid-inguinal point midway between the two bony landmarks listed above)
■Patella
■Patellar ligament—attaches distally to tibial tuberosity
■Medial and lateral condyles of femur
■Medial and lateral condyles of tibia
Note
There will be superficial and deep sides to your dissections. It’s not important to select these up front—you can do this as you work—but do pay attention to the directions for the deep work later in these instructions.
Anterior Compartment of the Thigh
Both sides: Perform the following tasks on both of the limbs.
Make a vertical incision in the skin of the anterior thigh and proximal leg from the mid-inguinal point superiorly to the tibial tuberosity (just below the patella) inferiorly.
Make a transverse incision in the skin over the proximal tibia through the tibial tuberosity.
Reflect the two flaps of skin—one medially and one laterally—to expose the superficial fascia.
DON’T REMOVE TOO MUCH OF THE SUPERFICIAL FASCIA WITH THE SKIN FLAPS.
Don’t cut too deep when you reflect the lateral skin flap because you might damage the IT band.
Don’t take too much superficial fascia with the medial skin flap because you might damage the great saphenous vein.
There may be lots of adipose here—the superficial fascia in the anterior thigh is continuous with the Camper’s fascia (superficial layer of superficial fascia) of the abdominal wall.
Both sides: Identify and clean superficial vessels and nerves.
Veins of the leg
Use scissors and forceps to probe the superficial fascia along the medial thigh to locate the great saphenous vein (Figure 7).
Best bet
Locate and clean the great saphenous vein in the superficial fascia on the medial side of the knee and then follow it upwards along the medial thigh.
Clean the vein from inferior to superior and note in the upper thigh (just below the inguinal ligament) that the vein is joined by several large tributaries, including the external pudendal veins (these receive blood from the external genitalia).
The great saphenous vein is a tributary of the femoral vein. These veins join just below the inguinal ligament. See Figures 7 and 8.
Clean the superficial fascia from the anterior thigh—noting any cutaneous nerves. These are anterior cutaneous branches of the femoral nerve. See Figure 8.
Locate the lateral cutaneous nerve of the thigh piercing the inguinal ligament several centimeters medial to the ASIS. See Figure 8.
After the superficial fascia is removed, you will see the tough and dense deep fascia of the thigh = the fascia lata. This fits the thigh like a tight stocking.
There is a hole in the fascia lata called the saphenous opening just inferior to the inguinal ligament. The great saphenous vein passes through this hole to drain into the femoral vein.
Identify a few superficial inguinal lymph nodes in the superficial fascia, scattered around the saphenous opening and inguinal ligament. See Figure 9.
Clinical correlation
The superficial inguinal nodes receive lymph from the entire lower limb, most of the perineum, and the superficial tissues of the abdominal wall and back, below the level of the umbilicus. That’s a lot of territory!!
Deep inguinal nodes are deep to the fascia lata, in or near the femoral canal (remember this potential space?). You won’t see these yet.
The femoral nerve, artery, and vein are deep to the fascia lata in the upper thigh.
Both sides: Clean and identify the deep fascia (fascia lata).
Alert
The fascia lata along the lateral thigh is thick and is known as the iliotibial tract (also called the IT band). Remove the deep fascia from the anterior thigh, but LEAVE THE FASCIA LATA along the lateral thigh.
Identify the tensor fascia latae muscle originating from lateral margin of the iliac crest. It inserts into the IT tract.
The IT tract crosses the knee joint and attaches to Gerdy’s tubercle (anterolateral tubercle of tibia) on the lateral condyle of the proximal tibia.
Use scissors to remove the fascia lata just below the inguinal ligament. The area deep to the inguinal ligament is the subinguinal space = it connects the abdominopelvic cavity to the upper thigh.
Review!
The neurovascular structures in the subinguinal space—from lateral to medial—can be remembered with a simple mnemonic: NAVEL = what does this mean?
Question
How could you identify the location of the femoral artery on the surface of the proximal thigh? Why is this important to know?
Question
What is the clinical relevance of the femoral canal (the “empty space” in the NAVEL mnemonic)?
The iliopsoas muscle also passes through the subinguinal space, lateral to the femoral vessels. See Figures 11 and 12.
Both sides: Clean the femoral triangle.
Femoral triangle
Identify and clean the deep fascia from the sartorius and adductor longus muscles. Together with the inguinal ligament, they define the femoral triangle (inverted triangle: broad above, tapered below).
Clean and separate the femoral vessels and the femoral nerve within the triangle. Any nodes you find medial to the femoral vein are deep inguinal nodes.
Identify and clean the muscles in the floor of the triangle: the iliopsoas and pectineus.
Question
The iliopsoas is a compound muscle formed by the fusion of two muscles. Which muscles? Identify the origins and innervations of the two muscles that make up the iliopsoas. Where does the iliopsoas insert? What is its function?
Identify these femoral nerve branches within the femoral triangle:
■Motor branches to the quadriceps, sartorius, and pectineus
■Anterior cutaneous branches to the skin of the anterior thigh. These will be stumps since the skin has been removed.
■The terminal branch of the femoral nerve is the saphenous nerve—it leaves the apex of the femoral triangle to enter the adductor canal.
Note
The saphenous nerve has no function in the thigh. It is an important sensory nerve below, supplying the medial side of the knee, leg, and foot.
Chalk Talk
Sketch the boundaries of the femoral triangle.
Vessels in the Anterior Thigh
One side: Preserve veins.
Other side: Remove veins.
Arteries in the Anterior Thigh
On one side, remove the veins to get a better look—keep the veins on one side of the dissection.
Clean and identify these branches of the femoral artery within the femoral triangle. You will be able to follow them easier on the side where the veins have been removed.
■Deep artery of the thigh (Profunda femoris artery). The largest branch of the femoral artery and the chief source of blood to the thigh. It usually arises from the lateral or posterior side of the femoral artery in the femoral triangle.
■Lateral and medial circumflex femoral arteries. These usually arise from the deep artery of the thigh, but may branch from the femoral artery.
■The lateral circumflex femoral arises from the lateral side of the deep artery of the thigh and circles around the anterior side of the proximal femur. The medial circumflex femoral arises from the medial side of the deep artery and circles behind the proximal femur. As the names suggest, the circumflex femoral arteries form an anastomosis around the proximal femur. See Figure 15.
Clinical correlation
Clinicians often use different terminology when describing the femoral artery in the thigh. The proximal part between the inguinal ligament and the origin of the deep artery of the thigh is referred to as the “common femoral artery.” The part of the femoral artery distal to the origin of the deep artery of the thigh is referred to as the “superficial femoral artery."
Clinical correlation
The medial circumflex femoral artery is important since it is the chief blood supply to the head and neck of the femur. Why is this clinically important (think hip fractures)?
Expose the adductor canal.
Do this on ONE SIDE.
This will be the DEEP SIDE of your dissection .
Clean the sartorius muscle and then transect it just above the apex of the femoral triangle.
Reflect the inferior part of the cut muscle to expose the adductor canal (Hunter’s canal). See Figure 16. It connects superiorly to the apex of the femoral triangle and inferiorly it opens into the popliteal fossa via the adductor hiatus (a gap in the adductor magnus muscle). The adductor canal thus connects the anterior thigh to the popliteal fossa (posterior to the knee). Distal to the adductor hiatus, the femoral vessels change their names to the popliteal artery and vein—same vessels, different names.
Adductor canal contents:
■Femoral artery and vein
■Saphenous nerve (from the femoral nerve): The saphenous nerve enters the proximal part of the adductor canal but does not leave the canal distally (through the adductor hiatus). It becomes superficial at the medial knee, passing distally along the medial side of the leg in the superficial fascia with the great saphenous vein.
Clinical correlation
A blow to the inner knee compresses the saphenous nerve against the superficial bones here. That hurts! This is the “funny bone” of the lower limb!
Both sides: Identify and clearn the quadriceps femoris.
Deep side (same side as the transected sartorius): Cut through the rectus femoris muscle.
Anterior compartment of the thigh
Clean the fascia from the quadriceps femoris.
Question
What are the four muscles that make up the quadriceps femoris?
On the deep side (same side as transected Sartorius), cut the rectus femoris near its midpoint in the anterior thigh. Reflect the superior part of the muscle.
Note
The rectus femoris has two proximal attachments (origins) on the hip bone. One is from the anterior inferior iliac spine. The other is from ilium, just above the acetabulum.
Identify the three vastus muscles: medialis, lateralis, and intermedius.
These muscles along with the rectus femoris join distally and attach to the superior border (base) of the patella via the quadriceps tendon.
Note
Note that part of the vastus medialis continues several centimeters below the quadriceps tendon, attaching to the medial side of the patella. This lower part of the vastus medialis produces a noticeable bulge on the surface and is often referred to as the vastus medialis obliquus (VMO). It is thought to be important for maintaining normal patellar tracking = preventing lateral pull on the patella (due to the “Q angle”—see Anterior and Medial Compartments of the Thigh in the Gross Anatomy textbook). See Figure 18.
Distal to the patella, observe the patellar ligament attaching to the tibial tuberosity.
Both sides: Dissect the medial (adductor) compartment of the thigh.
Nerves and muscles of the medial compartment of the thigh
Clean and separate via blunt dissection the adductor longus, adductor brevis, adductor magnus, pectineus, and gracilis muscles. See Figure 19.
Question
The obturator nerve supplies all these muscles EXCEPT the pectineus. Which nerve innervates the pectineus? Can you locate the obturator nerve above in the pelvic cavity? Which spinal nerves give rise to the obturator nerve? How does the obturator nerve leave the pelvic cavity and enter the thigh?
Deep side (same side where you transected the sartorius and rectus femoris): Cut the adductor longus just below its proximal attachment to the pubic bone and reflect it inferiorly.
Identify the adductor brevis muscle (the “baby” of the adductor group). The obturator nerve splits around the adductor brevis. The anterior branch of the obturator nerve passes in front of the adductor brevis.
Cut the adductor brevis muscle just below its proximal attachment. Reflect it inferiorly and find the posterior branch of the obturator nerve behind the adductor brevis.
Now you can observe the grandeur of the huge adductor magnus muscle. They don’t call it “magnus” for nothing!
Recall that the adductor magnus has two parts: Adductor part and hamstrings parts. See if you can identify each. These two parts of the adductor magnus have different functions and different innervations.
■The adductor part has the same functions and innervation as the other “adductor” muscles.
■The hamstrings part has the same function (at the hip joint) and same innervation as the hamstrings.
■The adductor hiatus is between the two parts of the adductor magnus. Recall that it is the distal opening of the adductor canal. See Figure 19.
Hip Joint
(Use the model—and view a prosection if available.)
Hip joint
On a model, identify the extracapsular ligaments of the hip joint: iliofemoral (“Y” ligament of Bigelow), pubofemoral, and ischiofemoral.
Question
Of these, which is the strongest?
■Examine the open hip joint. Identify the femoral head, acetabulum, and acetabular labrum.
Note
Both the head and neck of the femur are within the articular capsule of the hip joint (they are intracapsular).
Checklist, Lab #16
Review and make sure you have identified each of the structures below.
Bones
See the lists above, in the Osteology section of the Dissection Guide
Muscles and fascia
Know attachments, actions, and innervations of muscles. If we are learning specific bony landmarks (greater and lesser trochanters, adductor tubercle of femur, for example), you should know the muscles that attach to them. If muscles have broad, somewhat ill-defined origins (like the adductor muscles from the pubic bones)—know the attachment in broad terms (proximal attachments of adductors are to pubic bones—that’s broad!).
Quadriceps femoris muscle: Rectus femoris, vastus medialis, vastus intermedius, vastus lateralis
Quadriceps tendon and Patellar ligament
Sartorius
Iliopsoas
Pectineus
Adductor muscles: longus, brevis, and magnus
Gracilis
Tensor fasciae latae (we will see this again in the next lab)
Fascia lata = the deep fascia of the thigh
Iliotibial tract (band) = the lateral, thickened part of the fascia lata
Know the contents and arrangement of structures within the subinguinal space (NAVEL)
Boundaries and contents of femoral triangle
Proximal and distal openings and contents of adductor (Hunter’s) canal
Nerves
Femoral nerve with anterior cutaneous nerves of thigh
Saphenous nerve
Obturator nerve with anterior and posterior branches
Lateral cutaneous nerve of the thigh
Vessels and Nodes
Femoral artery and vein
Superficial inguinal lymph nodes
Deep artery of thigh (profunda femoris artery)
Medial and lateral circumflex femoral arteries
Great saphenous vein
Hip Joint: Models and prosection (if available)
Head of femur and acetabulum of hip bone
Iliofemoral ligament (see this on a model)
Acetabular labrum
