Sunday, January 8, 2012

Muscles of Thigh

Muscles of Thigh:
After the skinning process, the skin is then pulled back exposing the underlying muscle of the thigh, leg and shank. Use your blunt probe to rip through the remaining connective tissue as well as fat to expose more of the individual muscles underneath. Make sure not to rip the muscles by only ripping through layers you are able to see your probe through.

Tensor fasciae latae: This muscle arises from the iliac crest of the thigh and is located above the gluteus medius toward the back of the big. In order to find this muscle, you must expose the lateral surface of the thigh using the process given above. After, look to see where the separations of the muscles are by locating the weakest point to break through using your blunt probe. Push down on the area to make things underneath easier to see and look for a dark extended line in between two pink muscles which is an opening that will allow you to cut through the connective tissues and isolate the muscle.

Vastus lateralis: This muscle is best seen on the lateral surface after the biceps femoris and tensor fasciae latae muscles have been cut and reflected. It originates on the lateral surface of the femur. To find the muscle you must separate it from the rectus femoris which is the first muscle on the thigh beside the tensor fasciae latae and gluteus medius. Find the point of separation at the bottom of the tensor fasciae latae from before and follow through with the blunt probe clearing away the fat and connective tissue. This will separate the bottom half of the rectus femoris and top of the vastus lateralis thus leading to the isolation of both of them.
Lateral View of Rectus femoris:
Medial view of Rectus femoris:
Rectus femoris: This is the first muscle in the thigh that is thick and located on the anterior medial side. It originates from the ilium. In order to locate and isolate the muscle, all you have to do is follow the steps above in the process of isolating the vastus lateralis. Find the point of separation following that of the tensor fasciae latae and continue with the blunt probe clearing away the fat and connective tissue until the muscle is exposed.
Biceps femoris: This is a very large and thick muscle which covers most of the lateral surface of the thigh. It lies posterior to the tensor fasciae latae and below the gluteus maximus. To locate and isolate this muscle, you must first locate the bottom half of the gluteus maximus which will also be the top half of your muscle. To do so, you again look for the opening or separation point by following the darkened line in between the muscles and ripping through it with your blunt probe. Once you have done so, the top of the muscle will be exposed and you will be able to identify the angle it lies in. From there, locate the bottom half of the muscle which will be towards the butt of the pig and once again find the opening to separate and isolate the muscle.

Gluteus Medius: This is a thick and narrow muscle located right below the tensor fasciae latae and lies deep in the gluteus maximus. It originates from the lumbodorsal and gluteal fascia and inserts in the greater trochanter of the femur. Because the top half of the muscle has already been separated from the tensor fascia latae, you now only have to separate the bottom half. In order to isolate this muscle, you must once again locate the opening between the neighboring muscle below and tare through it using your probe separating it from the other and therefore exposing the muscle.

Semitendinosus: This muscle along with the next may be seen superficially on both lateral and medial sides but their major parts are hidden. The semitendinosus on the other hand bisects the biceps femoris and reflects its ends. To isolate it, you only have to locate the bottom half of it since the top is already separated from the biceps femoris. The bottom of it can be found closer to the anus of the pig almost on the medial side where you will find the separation point between its neighboring muscle to cut through. You might need to hold the area with some tweezers so that it does not move too much while separating and isolating as well.

Semimembranosus: This is another large muscle of the thigh which lies posterior and medial to the semitendinosus. You are also able to see this muscle on the medial surface of the thigh. To isolate it, use your probe to remove connective at the opening of the previous separation from the semitendinosus and continue along until it comes out from the other end exposing the other point of separation and isolating the muscle.
Two broad, thin superficial muscles which are visible in the anterioventral thigh area are:
Sartorius: This muscle occupies the anterior half of the thigh and is a flattened band about a half inch wide. You can find it in between its neighboring muscles which are the adductor magnus which is anterior to the semimembranosus and the vastus medialis which is on the opposite side of the vastus lateralis. Look for the separation point in that area by poking around with your probe, clearing away connective tissue, until you find a spot it is able to break through that is not muscle and then cutting through it.
Gracilis: This is the second medial superficial thigh muscle which is also broad and thin. It covers the posterior position of the medial thigh. This muscle can be exposed in the beginning of the dissection when skinning the thigh area. Once the skin is removed, you will notice a muscle which attaches from a point just anterior to the external gentalia up to the shank. Remove the fat and connective tissue surrounding it with a probe to isolate the muscle and see it more clearly.
Vastus medialis: This is a small mass of muscle sticking closely to the rectus femoris. It originates from the head of the femur. To find the muscle, take a look at the lateral side where the vastus lateralis separates from the rectus femoris and use the probe to cut through connective tissue and a little bit of the muscles until you get to the other side. Once the separation point is exposed on the medial side, follow it until the muscles are separated.
Adductor magnus: This is a triangular muscle which lies anterior to the semimembranosus. To find the first separation point, follow that of the semimembranosus all the way down breaking through any connective tissue and fat until you see the edge of the muscle. From the top of it, use the probe to find the other separation point which creates a triangular shape and follow through until you have exposed the muscle.

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