Origin: Sternal head :

• Superior apsect of the manubrium of the sternum

            Clavicular Head:

• Medical 1/3 of the clavicle

Insertion: Mastoid process of the temporal bone 

Action: Bilateral:

• flexion of the head and neck 
• contributes to extension of the upper cervical region and head 

          Unilateral: 

• Contralateral rotation of the head and neck
• lateral flexion of the head and neck 

Nerve:  Spinal accessory nerve (CN 11)

Origin: Anterior Scalene:

• Transverse processes of C3-C7

           Middle Scalene:

•  Transverse processes of C2-C7

           Posterior Scalene:

• Transverse processes of C5 - C7 

Insertion: Anterior and middle Scalene:

• First Rib 

               Posterior Scalene:

•  External surface of the second rib 

 Action: Bilateral:

• Flexion of the neck (anterior and middle scalene)
• Assistance with inspiration Via elevation of the first second ribs

            Unilateral:

• Lateral Flexion

Nerve:  Ventral Rami (C3-C7)

Origin: Lower half of ligamentum nuchae and spinous processes of C7- T3

Insertion: Mastoid process and lateral one third of the superior nuchal line 

 Action: Bilateral:

• Extension of the neck and head

            Unilateral:

• Lateral flexion of the head and neck
• Ipsilateral rotation of the head and neck

Nerve:  Dorsal Rami (C2-C8)

Origin: Transverse processes of C1- C3

Insertion: Spinous processes of T3 - T6

 Action: Bilateral:

• Extension of the neck

            Unilateral:

• Lateral flexion of the neck
• Ipsilateral rotation of the neck

Nerve:  Dorsal Rami (C2-C8)

Origin: External occipital protuberance' ligamentum nuchae (on cervical vertebrae), and medial portion of the superior nuchal line

Insertion: Posterior- superior aspect of the lateral one third of the clavicle

 Action:

• Elevation of the scapula 
• Upward rotation of the scapula (with serratus anterior and lower trapezius) 

Nerve: Spinal accessory nerve (cranial nerve XI)

Origin: Zygomatic arch

Insertion: External surface of the mandible, between the angle and the coronoid process of the Ramus 

 Action: Bilateral:

• Elevation of the mandible (closing the mouth)

            Unilateral

• Lateral excursion(Ipsilateral to the side)

Nerve:  Cranial nerve V ( branch of the mandibular nerve)

Origin: Temporal fossa

Insertion: Coronoid process and anterior edge of the ramus of the mandible 

 Action: Bilateral:

• Elevation of the mandible (closing the mouth) 
• Retrusion of the mandible (posterior fibers)

            Unilateral:

• Lateral excursion ( to ipsilateral side)

Nerve:  Cranial nerve V (branch of the mandibular nevre)

Origin: Medial surface of the lateral pterygoid plate

Insertion: Internal surface of the angle and ramus of the mandible 

 Action: Bilateral:

• Elevation of the mandible (closing the mouth) 

            Unilateral:

• Lateral excursion ( to ipsilateral side)

Nerve:  Cranial Nerve V (branch of the mandibular nerve)

Origin: Superior Head:

• Greater wing of the sphenoid bone

           Inferior Head:

• Lateral surface of the lateral pterygoid plate 

Insertion: Near the condyle of the mandible; the superior head also attaches to the articular disc of the TMJ

 Action: Bilateral:

• Depression of the mandible (opening the mouth; inferior head only)
• protrusion of the mandible 

            Unilateral:

• Lateral excursion ( to the contralateral side)

Nerve:  Cranial nerve V( Branch of the mandibular nerve)

Origin: angle of ribs 6-12

 Insertion: common tendon

 Action:  Bilateral: Extension

               Unilateral: lateral flexion

 Nerve:  Dorsal Rami of adjacent Spinal nerves

Origin: angle of ribs 1-6

 Insertion: angle of ribs 6-12

 Action:  Bilateral: Extension

               Unilateral: lateral flexion

 Nerve:  Dorsal Rami of adjacent Spinal nerves

Origin: Transverse processes of C4- C6

 Insertion: Angle of ribs 3-7

 Action:  Bilateral: Extension

               Unilateral: lateral flexion

 Nerve:  Dorsal Rami of adjacent Spinal nerves

Origin: spinous processes located 2-4 vertebral segments above the inferior attachment 

 Insertion: Mamillary processes of L1-L5

 Action:  Bilateral: Extension

               Unilateral: Rotation to the opposite side

 Nerve:  Dorsal Rami of adjacent Spinal nerves C4-S3

 Origin: Mastoid process of temporal bone 

 Insertion: transverse processes of T1 - T5 and near facet joints C3-C7

 Action:  Bilateral: Extension

               Unilateral: lateral flexion

 Nerve:  Dorsal Rami of adjacent Spinal nerves

 Origin: Transverse processes of C2-C6

 Insertion: Transverse processes of T1-T4

 Action:  Bilateral: Extension

               Unilateral: lateral flexion

 Nerve:  Dorsal Rami of adjacent Spinal nerves

 Origin: Transverse processes of T1 - T12

 Insertion: common tendon

 Action:  Bilateral: Extension

               Unilateral: lateral flexion

 Nerve:  Dorsal Rami of adjacent Spinal nerves

 Origin: spinous process of C2

 Insertion: Ligamentum nuchae and spinous processes of C7 - T1

 Action:  Bilateral: Extension

 Nerve:  Dorsal Rami of adjacent Spinal nerves

 Origin: Blends with semispinalis capitis 

 Insertion: blends with semispinalis capitis 

 Action:  Bilateral: Extension

 Nerve:  Dorsal Rami of adjacent Spinal nerves

 Origin: spinous processes of T1- T6

 Insertion: common tendon

 Action:  Bilateral: Extension

 Nerve:  Dorsal Rami of adjacent Spinal nerves