Cremaster muscle

In the stallion, the cremaster muscle is a thin band of skeletal muscle fibres that originates from the abdominal wall/inguinal region and descends into the inguinal canal along the spermatic cord to insert on or next to the testicle and its coverings. It functions primarily to retract the testicle toward the inguinal region and thus plays a role in testicular thermoregulation and positioning.

Origin: the internal abdominal oblique muscle and associated aponeuroses in the region of the inguinal (external) ring/arcade.

Insertion: lateral/dorsal surface of the testicle or its tunica vaginalis.

Action: elevate or retract the testicle when it contracts, pulling it toward the inguinal region.

Nerve: genitofemoral nerve