Cat Muscles – Sartorius, Gracilis, and Semitendinosus

The sartorius muscle is the longest muscle in the human body, extending from the hip to the inside of the thigh.  On the cat, this muscle is much more compact, and covers the thigh and knee joint as a superficial muscle.   It is shown on the photo below marked with a green pin.

The gracilis muscle is also a superficial muscle located below the sartorius.

The semitendinosis muscle on humans is commonly called the hamstring.  On the cat, find this muscle by probing behind the knee joint.


Green pin = sartorius
Yellow pin (top) = gracilis
Yellow pin (lower) = gastrocnemius
Black pin = tibialis anterior
Pink pin = semitendinosis