Musculus sacrocaudalis dorsalis medialis
The sacrocaudalis muscles are the primary muscles controlling the equine tail. The sacrocaudalis dorsalis lateralis elevates and laterally deviates the tail. The sacrocaudalis dorsalis medialis elevates the tail dorsally (lifts it straight up). The sacrocaudalis ventralis lateralis depresses the tail and assists in lateral movement. The sacrocaudalis ventralis medialis depresses the tail ventrally (pulls it down). They originate from the sacral and caudal vertebrae and insert on the corresponding caudal vertebrae. All are innervated by the caudal (coccygeal) spinal nerves.
Origin: Spinous processes of sacral and caudal vertebrae
Insertion: Dorsal caudal vertebrae
Action: Elevates the tail dorsally
Innervation: Caudal (coccygeal) spinal nerves
Isolated injury is uncommon. Tail tone and movement are assessed in neurologic examinations. Trauma to the tail or sacrocaudal region can affect these muscles and associated nerves. Relevant in evaluations of cauda equina or sacral nerve dysfunction.
## Overview Loss of tail tone, so the tail feels heavy and limp when lifted and cannot be clamped against the perineum, is an important early indicator of neurologic disease affecting the sacral spin
Persistent abnormal tail carriage, weakness, or asymmetry after trauma should be evaluated. Protect the tail from injury during transport and handling.
## Overview Loss of tail tone, so the tail feels heavy and limp when lifted and cannot be clamped against the perineum, is an important early indicator of neurologic disease affecting the sacral spinal cord or cauda equina. It may be an early sign of equine herpesvirus-1 myeloencephalopathy, equine protozoal myeloencephalitis, or polyneuritis equi. ## What It Indicates Sacral spinal cord or nerve-root dysfunction. ## Diagnosis Neurologic examination including tail and anal tone, plus further testing for specific diseases. ## Treatment Directed at the underlying neurologic disease. ## Recovery and Prognosis Depends on the cause. Early recognition improves management. ## Prevention Vaccination and biosecurity for equine herpesvirus-1 where applicable. Signs include: reduced tail tone (heavy and limp when lifted); inability to clamp the tail; may be early sign of equine herpesvirus-1 myeloencephalopathy, equine protozoal myeloencephalitis, or polyneuritis equi
Isolated injury is uncommon. Tail tone and movement are assessed in neurologic examinations. Trauma to the tail or sacrocaudal region can affect these muscles and associated nerves. Relevant in evaluations of cauda equina or sacral nerve dysfunction.
Persistent abnormal tail carriage, weakness, or asymmetry after trauma should be evaluated. Protect the tail from injury during transport and handling.
See the Sacrocaudalis Dorsalis Medialis on our interactive 3D horse model. Open 3D Model