From the Research
The triceps muscle is primarily innervated by the C7 nerve root of the cervical spine, with some contribution from C6 and C8, as confirmed by the most recent study 1. The radial nerve, which carries these cervical nerve fibers, is the specific peripheral nerve responsible for supplying the triceps. This innervation pattern explains why clinicians test the triceps reflex to assess C7 function during neurological examinations. When examining a patient with suspected cervical radiculopathy or spinal cord injury, weakness in the triceps muscle or diminished triceps reflex typically indicates pathology at the C7 level. Understanding this innervation is important for accurate neurological assessment, as well as for planning surgical approaches to the cervical spine that might affect these nerve roots. Some key points to consider include:
- The C7 nerve root contributes consistently to the lateral pectoral nerve, the thoracodorsal nerve, and long head of the triceps branch of the radial nerve, as shown in a study 2.
- The triceps muscle's function of elbow extension is critical for many daily activities, making proper assessment of its innervation essential in neurological evaluations.
- Other studies have also confirmed the primary innervation of the triceps muscle by the C7 nerve root, with some variations in the specific branches of the radial nerve involved 3, 4, 5. However, the most recent and highest quality study 1 provides the most reliable evidence for the innervation of the triceps muscle.