2.
Sternocleidomastoid (SCM):
Answer: Origin: - Medial 1/3 of clavicle (clavicular head, wider)
- Manubrium of sternum (sternal head, skinny)
Insertion: - Mastoid process of temporal bone
- Lateral ½ of the superior nuchal line of occipital bone
Function: (8) 1. Extension of head @ atlanto-occipital joint
2. Extension of upper neck @ spinal joints (double chin)
3. Flexion of lower neck @ spinal joints
4. Lateral flexion of head @ atlanto-occipital joint
5. Lateral flexion of neck @ spinal joint
6. Contralateral rotation of head @ atlanto-axial joint
7. Contralateral rotation of neck @ spinal joint
8. Elevation of sternum and clavicle (during forced inhalation)
Nerve: Spinal accessory nerve (cranial nerve 11)