Ventral intertransverse muscles of tail [of coccyx]

Origin: Third caudal vertebra.

Insertion: Ventral surface of each caudal vertebra.

Action: Lateral flexion of the tail.

Nerve: Branches of the plexus caudalis ventralis.

Variation:

In equids, the ventral intertransverse muscles of tail are much weaker and shorter than their dorsal counterparts. However, the muscles remain distinct until the last vertebrae, where they become intersegmental. They originate from the ventral part of the last sacral transverse process and from the transverse processes of the first coccygeal vertebrae. The successive tendons insert on the ventral surface of the transverse processes, and then on the rough areas that replace them.