POST. BR. OF SPINAL CORD
- The posterior branches are thinner & shorter than the ant. branches
- Innervate the muscles of the back & neck and provide sensory innervation for the skin for the neck, back & butt.
- 1 Suboccipital nerve (nervus suboccipitalis) – the posterior branch of C1
- – a purely motor nerve for the suboccipital muscles and the semispinalis capitis
- 2 Greater occipital nerve (nervus occipitalis major)
- – the posterior branch of C2
- – a purely somatosensory nerve for the skin posterior to the interauricular line (a line joining the auricles in the frontal plane)
- 3 Third occipital nerve (nervus occipitalis tertius)
- – the posterior branch of C3
- – a purely somatosensory nerve innervating a narrow area of the skin medial to the greater occipital nerve
- 4 Superior clunial nerves (nervi clunium superiores)
- – the posterior branches of L1 to L3
- – provides somatosensory innervation of the superior gluteal region
- 5 Middle clunial nerves (nervi clunium medii)
- – the posterior branches of S1 to S3
- – provides somatosensory innervation of part of the gluteal region
Anterior branches:
- – are longer and thicker branches than the posterior branches
- – provide both motor and sensory innervation of the limbs and the hypaxial part of the trunk
- – provide motor innervation of the muscles of the anterior abdomen, thorax and neck (except for the suprahyoid muscles)
- – provide sensory innervation of the skin on the anterior aspect of the abdomen and thorax
- 1 Cervical plexus (plexus cervicalis) – C1 to C4
- 2 Brachial plexus (plexus brachialis) – C4 to T1
- 3 Thoracic nerves (nervi thoracici) – T1 to T12
- 4 Lumbar plexus (plexus lumbalis) – T12 to L4
- 5 Sacral plexus (plexus sacralis) – L4 and L5 and S1 to S4
- 6 Coccygeal plexus (plexus coccygeus) – S5 and Co