## Overview C1-C2 rotational restriction is reduced axial rotation at the atlantoaxial joint between the first and second cervical vertebrae. This joint accounts for the majority of the horse’s ability to rotate the head (“shake the head no”). Restriction may result from muscle spasm, osteoarthritis, previous trauma, or true mechanical limitation. It commonly contributes to resistance to lateral bending, asymmetric gaits, or performance issues under saddle. ## Causes Muscle hypertonicity in the poll region, osteoarthritis of the atlantoaxial facets, compensatory guarding from lower cervical or forelimb pain, and prior subluxation or ligament injury are typical. Congenital malformations are uncommon but can produce fixed restriction. ## Diagnosis Motion palpation reveals asymmetry or reduced rotational range. Clinical correlation with head carriage and ridden evaluation is essential. Radiographs or advanced imaging assess for osteoarthritis or malalignment when neurologic signs or trauma history are present. ## Treatment Manual therapies, anti-inflammatory medication, and targeted joint treatment when osteoarthritis is confirmed form the main approach. Rehabilitation exercises restore mobility. Structural instability is rare but may require surgical stabilization. ## Recovery and Prognosis Most functional restrictions improve with appropriate therapy. Advanced degenerative change or true instability carries a more guarded outlook for high-level work. ## Prevention Balanced training, attention to dental and bit issues, and early treatment of neck discomfort help maintain normal motion.
resistance to lateral head movement; asymmetric neck posture; reduced performance in lateral work; pain on palpation of the atlas-axis region
## Overview C1-C2 rotational restriction is reduced axial rotation at the atlantoaxial joint between the first and second cervical vertebrae. This joint accounts for the majority of the horse’s ability to rotate the head (“shake the head no”). Restriction may result from muscle spasm, osteoarthritis, previous trauma, or true mechanical limitation. It commonly contributes to resistance to lateral bending, asymmetric gaits, or performance issues under saddle. ## Causes Muscle hypertonicity in the poll region, osteoarthritis of the atlantoaxial facets, compensatory guarding from lower cervical or forelimb pain, and prior subluxation or ligament injury are typical. Congenital malformations are uncommon but can produce fixed restriction. ## Diagnosis Motion palpation reveals asymmetry or reduced rotational range. Clinical correlation with head carriage and ridden evaluation is essential. Radiographs or advanced imaging assess for osteoarthritis or malalignment when neurologic signs or trauma history are present. ## Treatment Manual therapies, anti-inflammatory medication, and targeted joint treatment when osteoarthritis is confirmed form the main approach. Rehabilitation exercises restore mobility. Structural instability is rare but may require surgical stabilization. ## Recovery and Prognosis Most functional restrictions improve with appropriate therapy. Advanced degenerative change or true instability carries a more guarded outlook for high-level work. ## Prevention Balanced training, attention to dental and bit issues, and early treatment of neck discomfort help maintain normal motion.
resistance to lateral head movement; asymmetric neck posture; reduced performance in lateral work; pain on palpation of the atlas-axis region