Neck Extensor muscle group

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Table 1: Head Extensor Muscles

Muscle	Origin	Insertion	Innervation	Action
Longissimus capitis	T1-T3 TP C4-C7 TP & articular process	Mastoid process	Spinal nn. Posterior rami (lateral br.) C1 - C5	Bilateral: Head extension Unilateral: Ipsilateral head sidebend, Ipsilateral rotation
Splenius capitis	Nuchal lig. C7-T4 SP	Lateral third of nuchal line Mastoid process	Spinal nn. Posterior rami (lateral br.) C1 - C6	Bilateral: Head and neck extension Unilateral: I/L sidebend, I/L rotation
Splenius cervicis	T3-T7 SP	C1-C4 SP	Spinal nn. Posterior rami (lateral br.) C1 - C6	Bilateral: Head and neck extension Unilateral: I/L sidebend, I/L rotation
Sternocleidomastoid	Manubrium Medial third of Clavicle	Mastoid process Superior nuchal line	CN XI Accessory n. Cervical plexus C1 - C4	Unilateral: I/L cervical sidebend, C/L cervical rotation Bilateral: Head extension, Cervical Flexion, Assists in respiration, Prevents posterior translation during mastication SCJ stabilization

Table 2: Cervical Spine Extensor Muscles

Muscle	Origin	Insertion	Innervation	Action
Spinalis cervicis	C5-T2 SP	C5-T2 SP	Spinal nn. Posterior rami (lateral br.)	Bilateral: Cervical extension, Thoracic extension Unilateral: Cervical ipsilateral sidebend, Thoracic ipsilateral sidebend
Spinalis thoracis	T10-L3 SP and Lateral surfaces	T2-8 SP & Lateral surfaces	Spinal nn. Posterior rami (lateral br.)	Bilateral: Cervical extension, Thoracic extension Unilateral: Cervical ipsilateral sidebend, Thoracic ipsilateral sidebend
Splenius capitis	Nuchal lig. C7-T4 SP	Lateral third of nuchal line Mastoid process	Spinal nn. Posterior rami (lateral br.) C1 - C6	Bilateral: Head and neck extension Unilateral: I/L sidebend, I/L rotation
Splenius cervicis	T3-T7 SP	C1-C4 SP	Spinal nn. Posterior rami (lateral br.) C1 - C6	Bilateral: Head and neck extension Unilateral: I/L sidebend, I/L rotation