The posterior intertransverse muscles are small muscles, best developed in cervical and lumbar regions, where they can be divided into medial and lateral slips.  

In the thoracic region, anterior and posterior intertransverse muscles blend and pass between adjacent transverse processes from T10 to L1.  In the cervical region, the lateral slips pass between adjacent costal lamellae and the medial slips between adjacent transverse processes from C1/C2 to C7/T1.  In the lumbar region, the lateral slips pass between the transverse process of the vertebra below and the transverse process and accessory process of the vertebra above, while the medial slips pass between the accessory process of one vertebra and the mamillary process of the next from L1 to L5.