Muscles of the Neck and Trunk:
Platysma:
Origin: Fascia over deltoid and pectoralis major muscles
Insertion: Mandible and skin of lower face
Function: (2) 1. Depresses and draws lower lip inferiorly
2. Depresses of mandible @ tempo mandibular joint
Nerve: Facial nerve (cranial nerve 7)
Sternocleidomastoid (SCM):
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)
Anterior scalene:
Origin: Transverse process of C3-C6 (typical CVs)
Insertion: Scalene tubercle on the 1st rib
Function: (4) 1. Flexion of neck @ spinal joint
2. Lateral flexion of neck @ spinal joint
3. Contralateral rotation of neck @ spinal joint
4. Elevation of 1st rib (during deep inhalation) @ sternocostal and costospinal joints
Nerve: Ventral rami of cervical spinal nerves at the corresponding levels
Middle Scalene:
Origin: Transverse process of C2-C7
Insertion: First rib
Function: (3) 1. Flexion of neck @ spinal joint
2. Lateral flexion of neck @ spinal joint
3. Elevation of 1st rib (during deep inhalation) @ sternocostal and costospinal joints
Nerve: Ventral rami of cervical spinal nerves at the corresponding levels
Posterior scalene:
Origin: Transverse process of C5-C7
Insertion: 2nd rib
Function: (2) 1. Lateral flexion of neck @ spinal joint
2. Elevation of 2nd rib (during deep inhalation) @ sternocostal and costospinal joints
Nerve: Ventral rami of cervical spinal nerves at the corresponding levels
Platysma:
Origin: Fascia over deltoid and pectoralis major muscles
Insertion: Mandible and skin of lower face
Function: (2) 1. Depresses and draws lower lip inferiorly
2. Depresses of mandible @ tempo mandibular joint
Nerve: Facial nerve (cranial nerve 7)
Sternocleidomastoid (SCM):
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)
Anterior scalene:
Origin: Transverse process of C3-C6 (typical CVs)
Insertion: Scalene tubercle on the 1st rib
Function: (4) 1. Flexion of neck @ spinal joint
2. Lateral flexion of neck @ spinal joint
3. Contralateral rotation of neck @ spinal joint
4. Elevation of 1st rib (during deep inhalation) @ sternocostal and costospinal joints
Nerve: Ventral rami of cervical spinal nerves at the corresponding levels
Middle Scalene:
Origin: Transverse process of C2-C7
Insertion: First rib
Function: (3) 1. Flexion of neck @ spinal joint
2. Lateral flexion of neck @ spinal joint
3. Elevation of 1st rib (during deep inhalation) @ sternocostal and costospinal joints
Nerve: Ventral rami of cervical spinal nerves at the corresponding levels
Posterior scalene:
Origin: Transverse process of C5-C7
Insertion: 2nd rib
Function: (2) 1. Lateral flexion of neck @ spinal joint
2. Elevation of 2nd rib (during deep inhalation) @ sternocostal and costospinal joints
Nerve: Ventral rami of cervical spinal nerves at the corresponding levels
