Hindlimb Skeletal Muscle Extraction: A Procedure to Excise Hindlimb Skeletal Muscles from Murine Model

To begin, prep a euthanized mouse in the supine position. Clamp one of its feet to extend the limb vertically. Gently hold the skin of the lower limb.

Next, surgically remove the skin and fascia, the layer of loose connective tissue just underneath the skin, exposing the underlying muscle bellies of the lower limb.

Identify the gastrocnemius muscle - a large, superficial two-headed muscle - on the posterior lower limb. It originates from the lateral and medial condyles of the posterior femur and attaches to the calcaneus - heel bone - via the calcaneal tendon.

Hold the distal end of the muscle and pull the muscle belly towards its origin. Excise the gastrocnemius calcaneal tendon followed by the muscle at the origin closest to the femur. 

Now, locate the tibialis anterior muscle. The muscle originates from the anterolateral surface of the tibia and attaches to the medial cuneiform bone via the distal tendon.

Detach the tibialis muscle belly from the underlying connective tissue. Cut the distal tendon and the muscle at the origin closest to the tibia.

Finally, transfer the excised muscles into cryotubes. Store the tubes at low temperatures until further downstream analysis.