Semispinalis Capitis O, I, A
Origin: Articular processes of vertebrae C4-C7, transverse processes of vertebrae T1-T6
Insertion: Between superior and inferior nuchal lines of occipital bone
Actions: Extension of the head and cervical spine
Innervation: Descending branches of greater occipital nerve (C2) and spinal nerve C3
Blood Supply: Descending branches of the occipital artery
Primary Actions of the Semispinalis Capitis
1. Extension of the head and cervical spine when acting bilaterally
Agonists:
- Longissimus capitis
- Spinalis capitis
- Splenius capitis
- Sternocleidomastoid (posterior fibers)
Antagonists:
- Longus capitis
- Sternocleidomastoid (anterior fibers)
2. Contralateral rotation of the head and cervical spine when acting unilaterally
Agonists:
- Trapezius (upper part)
- Sternocleidomastoid
Antagonists: same muscles on the contralateral side
- Trapezius (upper part)
- Sternocleidomastoid
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Secondary Actions of the Semispinalis Capitis
2. Assists with lateral flexion of the head and cervical spine when acting unilaterally
Agonists:
- Splenius capitis
- Sternocleidomastoid
Antagonists: same muscles on contralateral side
- Splenius capitis
- Sternocleidomastoid
Information about cause and effect of Semispinalis Capitis pain: Semispinalis Capitis Neck and Head Pain
An excellent book for those beginning the study of anatomy. Coloring helps memory retention.
For intermediary anatomy students learning skeletal and muscle structure.
For beginning and intermediary anatomy . Muscle overlays on the human body. Excellent visuals!