Posterior Neck Muscles Flashcards
Sternocleidomastoid Insertion
Lateral surface of mastoid process of temporal bone and lateral half of superior nuchal line
Sternocleidomastoid sternal head origin
Anterior surface of manubrium of sternum
Sternocleidomastoid clavicular head origin
superior surface of medial third of clavical
Sternocleidomastoid innervation
Spinal accessory nerve (CN XI: motor); C2 and C3 nerves ( pain and proprioception)
Sternocleidomastoid action
Unilateral: laterally flexes neck ipsilaterally, rotates the neck contralaterally
Bilateral: (1) Extends neck at atlanto-occipital joints (2) flexes cervical vertebrae (3) extends superior cervical vertebrae while flexing inferior vertebrae so chin is thrust forward (protrusion)
Trapezius origin
Medial third of the superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7-T12
Trapezius insertion
Lateral third of clavicle, acromion, and spine of scapula
Trapezius innervation
Spinal Accessory nerve(CN XI; motor); C2 and C3 nerves (pain and proprioception)
Trapezius action (superior fibers)
Elevates, retracts, and rotates scapula superiorly.
Descending (superior)fibers: elevate pectoral girdle, maintain level of shoulders against gravity or resistance
Splenius Capitis origin
Nuchal Ligament and spinous processes of C7-T3/T4
Splenius Capitis insertion
Lateral aspect of mastoid process and lateral third of superior nuchal line
Splenius Capitis innervation
Posterior rami of middle cervical spinal nerves
Splenius Capitis Action
Unilateral: rotates and laterally flexes head and neck ipsilaterally
bilateral: extend head and neck
Levator Scapulae origin
Posterior tubercles of transverse processes of C1-C4 vertebrae
Levator Scapulae insertion
Medial border of scapula superior to root of scapular spine
Levator Scapulae innervation
Dorsal Scapular nerve (C5); Cervical nerves C3 and C4
Levator Scapulae Action
Elevates scapula and tilts its glenoid cavity inferiorly by rotating scapula
Anterior Scalene Origin
Transverse processes of C3-C6 vertebrae
Anterior Scalene Insertion
1st rib
Anterior Scalene Innervation
Cervical spinal nerves C4-C6
Anterior Scalene action
Flexes cervical spine (anteriorly or laterally)
Anterior Scalene Roots
C4-C6
Middle Scalene Origin
Posterior tubercles of transverse processes of C5-C7 vertebrae
Middle Scalene Insertion
Superior surface of 1st rib; posterior to groove for sub-clavian artery
Middle Scalene Innervation
Anterior rami of cervical spinal nerves
Middle Scalene Action
Flexes neck laterally; elevates 1st rib during forced inspiration
Middle Scalene Roots
C7, C8
Posterior Scalene Origin
Posterior tubercles of transverse processes of C5-C7 vertebrae
Posterior Scalene Insertion
External border of 2nd rib
Posterior Scalene Innervation
Anterior rami of cervical spinal nerves C7 and C8
Posterior Scalene Action
Flexes neck laterally; elevates 2nd rib during forced inspiration
Posterior Scalene Roots
C7, C8
