Lateral view of the rabbit's right leg; craniad is to the top of the photo; caudad is to the bottom of the photo.

Medial view of the rabbit's right leg; the gracilis muscle is reflected medially; craniad is to the top of the photo.

For comparison, see thigh dissections of a bat, a cat, a ferret, a fox, and a tree shrew.

Part I: Non-muscular structures

The sciatic nerve innervates the muscles found in the posterior region of the thigh. After its origin from the seventh lumbar and first sacral nerve, this nerve travels through the greater sciatic notch and behind the piriformis to reach the posterior muscles of the thigh. The femoral nerve splits into two portions and innervates the muscles located in the anterior and medial regions of the thigh. After its origin from the fifth and sixth lumbar nerve, it passes between psoas major and iliaus and under the inguinal ligament where it then divides into two portions and travels to the anterior and medial muscles of the thigh.

Part II: Superficial muscles of the hip and thigh

The developmental origin of each muscle is given in parentheses beside its name.

In O. cuniculus, biceps femoris has two heads with two different origins. In this mammal adductor femoris is divided into adductor magnus and adductor brevis. Concerning the question about the developmental origin of pectineus, I think that its placement and origin should take precedence over its innervation. Therefore, I think that the developmental origin of pectineus is ventral. By the femoral nerve splitting into two main portions and then traveling to innervate the muscles of the thigh, it is conceivable that it may travel and innervate muscles that are not in its assigned compartment.

Dissection notes:

Starting with the medial thigh muscles- After removing the more loose fitting skin that covers the medial surface of the thigh and the easy-to-remove fascia covering the muscles, one reveals the superficial musculature of the medial side of the thigh. The most superficial of the muscles are sartorius and gracilis. Observe how sartorius and gracilis fuse before their insertion. You can also see more anterior to sartorius the most anterior muscle tensor fascia lata, rectus femoris and vastus medialis. Cutting sartorius and gracilis from their insertion and reflecting them back, you reveal more superficial musculature. These muscles include pectineus being the most anterior, adductor femoris, semimembranosus, and semitendinosus. You can then push aside vastus medialis with a probe and see vastus intermedius. [See Figure 2]

Now turning the rabbit over to identify the dorsal and lateral thigh musculature -The skin and fascia has to be removed using careful cutting and skinning. The fascia around the thigh muscles is extremely thick and tough. It snugly fits around each muscle separating it from the surrounding muscles. It is extremely difficult to remove the fascia from each muscle without tearing away some of the muscle. However, with much careful work it can be done. Once you have removed as much fascia as you can, the superficial layer of musculature will be uncovered. These muscles include tensor fascia lata, gluteus superficialis, coccygeofemoralis (triangular shaped abductor muscle), biceps femoralis (triangular shaped), and semitendinosus. [See Figure 1]. [Biceps femoralis has a little indentation in it (because of the two separate heads) that makes it look like it may be two different muscles. This may led to identifying one of the heads of biceps femoralis as coccygeofemoralis. However, the fascia around the two heads does not completely separate the two heads from each other like it completely separates the first head of biceps femoris from coccygeofemoralis.] Once these muscles have been revealed and identified, one can began to look for the deeper layer of musculature. This can be accomplished by making an incision through gluteus superficialis close to its insertion tendon and reflecting it back. One then reveals gluteus medius and other muscles of the deepest layer (further discussed in Part III). By cutting coccygeofemoralis from its origin and biceps femoralis from its insertion and then reflecting the muscles back reveals more muscle from the deeper layer which include (from anterior to posterior): vastus lateralis, adductor femoris (adductor magnus and adductor brevis), semimembranosus, and semitendinosus.

Other notes:

Observe the shape and relative size of gracilis in the rabbit (flat, extremely wide, and short) and compare it to the shape and relative size of gracilis in humans (extremely thin and long).

Part III: Deep hip flexors (see also deep hip and tail)

Dissection notes:

The deepest musculature of the thigh can be revealed from the reflection of gluteus superficialis and coccygeofemoralis from the dorsal side of the rabbit. One can then see where gluteus superficialis inserts onto the femur. If you move inferior to this insertion, one can then see the insertions of the deep layer of thigh musculature onto the trochanteric fossa of the femur. These muscles include obturator internus, gemellus inferior, obturator externus, and quadratus femoris. [See Figure 3].

Other notes:

Gemellus superior is discussed in more detail in deep hip and tail.

References:

- Information in Part I is from Craigie.

- Others that are not marked : Information about origins and insertions of muscles was provided by Craigie. Information about actions of the muscles was provided by Agur & Lee.

Links:

to Comparative Mammalian Anatomy

to mammalian thigh dissections