Myology

Iliocostalis Cervicis

Argosy Publishing

Iliocostalis cervicis           

  • Origin: 3rd-7th ribs
  • Insertion: Transverse processes of C4-C6 vertebrae
  • Function:
    • Bilateral contraction: extends the spine
    • Unilateral contraction: bends the spine laterally to same side
  • Innervation: Lateral branches of the dorsal rami of spinal nerve C8-L1

 

Longissimus muscles

  • Origin:
    • Longissimus cervicis: Transverse processes of T1-T6 vertebrae
    • Longissimus capitis: Transverse processes of T1-T3 vertebrae and transverse and articular processes of C4-C7

      Longissimus Muscles

      Longissimus capitis (red) and Longissimus cervicis (blue) Argosy Publishing

  • Insertion:
    • Longissimus cervicis: Transverse processes of C2-C5 vertebrae
    • Longissimus capitis: Mastoid process of occipital bone
  • Function:
    • Bilateral contraction: extends head
    • Unilateral contraction: flexes and rotates the head to the same side
  • Innervation: lateral branches of dorsal rami spinal nerves

 

Splenius Capitis Argosy Publishing

Splenius Capitis Argosy Publishing

Splenius Cervicis

Splenius Cervicis Argosy Publishing

Splenius muscles

  • Origin:
    • Splenius cervicis: Spinous processes of the T3-T6 vertebrae
    • Splenius capitis: Spinous processes of the C3-T3 vertebrae
  • Insertion:
    • Splenius cervicis: Transverse processes of the C1 and C2
    • Splenius capitis: Lateral superior nuchal line, mastoid process
  • Function:
    • Bilateral contraction: extends the cervical spine and head
    • Unilateral contraction: flexes and rotates the head to the same side
  • Innervation: Lateral branches of dorsal rami of the spinal nerves C1-C6

 

Intertransversarii posterior cervicis

Intertransversarii posteriores cervicis Argosy Publishing

Intertransversarii anterior

Intertransversarii anteriores cervicis Argosy Publishing

Intertransversarii   

  • Origin and insertion:
    • Intertransversarii posteriores cervicis: course between adjacent posterior tubercles of the C2-C7 vertebrae
    • Intertransversarii anteriores cervicis: course between adjacent anterior tubercles of the C2-C7 vertebrae
  • Function:
    • Bilateral contraction: stabilizes and extends the cervical spine
    • Unilateral contraction: bends the cervical spine laterally to the same side
  • Innervation: Dorsal rami of the spinal nerves except for intertransversarii anteriores cervicis (ventral rami of the spinal nerves)

 

Interspinalis Cervicis  Argosy Publishing

Argosy Publishing

Interspinalis cervicis

  • Origin and insertion: Course between the spinous processes of the cervical vertebrae
  • Function: Extends the cervical spine
  • Innveration: Dorsal rami of the spinal nerves

 

Argosy Publishing

Argosy Publishing

Spinalis cervicis    

  • Origin: Spinous processes of the T1-T2 and C5-C7 vertebrae
  • Insertion: Spinous processes of the C2-C5 vertebrae
  • Function:
    • Bilateral contraction: extends the cervical spine
    • Unilateral contraction: bends the cervical spine to the same side
  • Innervation: Dorsal rami of the spinal nerves

 

 

Argosy Publishing

Argosy Publishing

Multifidus

  • Origin and insertion: Courses between the transverse and spinous process (skipping 2-4 vertebrae) of all cervical vertebrae (C2 to the sacrum)
  • Function:
    • Bilateral contraction: extends the spine
    • Unilateral contraction: flexes to the same side and rotates to opposite side
  • Innervation: Dorsal rami of the spinal nerves

 

Semispinalis cervicis Argosy Publishing

Semispinalis cervicis Argosy Publishing

Semispinalis capitis medial fascile Argosy Publishing

Semispinalis capitis medial fascile Argosy Publishing

Semispinalis

  • Origin:
    • Semispinalis cervicis: Transverse processes of the T1-T6
    • Semispinalis capitis: Transverse processes of the C3-T6 vertebrae
  • Insertion:
    • Semispinalis cervicis: Spinous processes of C2-C7 vertebrae
    • Semispinalis capitis: Occipital bone between the superior nuchal line and inferior nuchal
  • Function:
    • Bilateral contraction: extends thoracic spine, cervical spine and head (stabilizes the craniovertebral joints)
    • Unilateral contraction contraction bends the head, cervical spine, and thoracic spine to the same side and rotates them to the opposite side
  • Innervation: Dorsal rami of the spinal nerves

 

Argosy Publishing

Argosy Publishing

Rectus capitis posterior major

  • Origin: Spinous process of the axis
  • Insertion: Middle third of the inferior nuchal line
  • Function:
    • Bilateral contraction: extends the head
    • Unilateral contraction: rotates the head to the same side
  • Innervation: Dorsal ramus of C1 (suboccipotal nerve)

 

Argosy Publishing

Argosy Publishing

Rectus capitis posterior minor

  • Origin: Posterior tubercle of the atlas
  • Insertion: Inner third of the inferior nuchal line
  • Function:
    • Bilateral contraction: extends the head
    • Unilateral contraction: rotates the head to the same side
  • Innervation: Dorsal ramus of C1 (suboccipotal nerve)

 

Argosy Publishing

Argosy Publishing

Obliquus capitis superior

  • Origin: Transverse process of the atlas
  • Insertion: Above the insertion of the rectus capitis posterior major
  • Function:
    • Bilateral contraction: extends the head
    • Unilateral contraction: tilts the head to the same side and rotates it to the opposite side
  • Innervation: Dorsal ramus of C1 (suboccipital nerve)

 

Argosy Publishing

Argosy Publishing

Obliquus capitis inferior

  • Origin: Spinous process of the axis
  • Insertion: Transverse process of the atlas
  • Function:
    • Bilateral contraction: extends the head
    • Unilateral contraction: rotates the head to the same side
    • Innervation: Dorsal ramus of C1 (suboccipital nerve)

 

Argosy Publishing

Argosy Publishing

Longus capitis

  • Origin: Anterior tubercle of the transverse processes of the C3-C6 vertebrae
  • Insertion: Basilar part of the occipital bone
  • Function:
    • Unilateral contraction: tilts and slightly rotates the head to the same side
    • Bilateral contraction: flexes the head
  • Innervation: Direct branches from the cervical plexus (C1-C4)

 

Longus colli superior oblique Argosy Publishing

Longus colli superior oblique Argosy Publishing

Longus colli vertical Argosy Publishing

Longus colli vertical Argosy Publishing

Longus colli (cervicis)     

  • Origin:
    • Vertical (medial) part: anterior sides of the C5-C7 and T1-T3 vertebral bodies
    • Superior oblique part: anterior tubercle of the transverse processes of the C3-C5 vertebrae
    • Inferior oblique part: anterior sides of the T1-T3 vertebral bodies
Longus colli inferior oblique Argosy Publishing

Longus colli inferior oblique Argosy Publishing

  • Insertion:
    • Vertical part: anterior sides of the C2-C4 vertebrae
    • Superior oblique part: anterior tubercle of the atlas
    • Inferior oblique part: anterior tubercle of the transverse processes of the C5 and C6 vertebrae Unilateral contraction: tilts and rotates the cervical spine to the same side
  • Function: Bilateral contraction: flexes the cervical spine
  • Innervation: Direct branches from the cervical plexus (C2-C6)

 

 

Rectus capitis anterior

Rectus capitis anterior side

Argosy Publishing

  • Origin: Lateral mass of the atlas
  • Insertion: Basilar part of the occipital bone
  • Function:
    • Unilateral contraction: lateral flexion at the atlanto-occipital joint
    • Bilateral contraction: flexion at the atlanto-occipital joint
  • Innervation: Ventral ramus of the C1 nerve

 

Argosy Publishing

Argosy Publishing

Rectus capitis lateralis

  • Origin: Transverse process of the atlas
  • Insertion: Basilar part of the occipital bone (lateral to the occipital condyles)
  • Function:
    • Unilateral contraction: lateral flexion at the atlanto-occipital joint
    • Bilateral contraction: flexion at the atlanto-occipital joint
  • Innervation: Ventral ramus of the C1 nerve

 

Scalenes

Posterior scalene Argosy Publishing

Posterior scalene Argosy Publishing

Middle scalene Argosy Publishing

Middle scalene Argosy Publishing

Anterior scalene Argosy Publishing

Anterior scalene Argosy Publishing

  • Origin
    • Anterior scalene; Anterior tubercle of the transverse processes of the C3-C6 vertebrae
    • Middle scalene: Posterior tubercle of the transverse processes of the C3-C7 vertebrae
    • Posterior scalene: Posterior tubercle of the transverse processes of the C5-C7 vertebrae
  • Insertion
    • Anterior scalene: Anterior scalene tubercle of the first rib
    • Middle scalene: First rib (posterior to the groove for the subclavian artery)
    • Posterior scalene: Outer surface of the second rib
  • Function:
    • With the ribs mobile: raises the upper ribs (in inspiration)
    • With the ribs fixed: bends the cervical spine toward the same side (with Unilateral contraction contraction)
    • Flexes the neck (with Bilateral contraction contraction)
  • Innervation:Direct branches from the cervical plexus and brachial plexus (C3-C6)

 

Argosy Publishing

Argosy Publishing

Sternocleidomastoid

  • Origin:
    • Sternal head: manubrium sterni
    • Clavicular head: medial third of the clavicle
  • Insertion: Mastoid process and superior nuchal line
  • Function:
    • Unilateral contraction: tilts the head to the same side, rotates the head to the opposite side
    • Bilateral contraction: extends the head, assists in respiration when the head is fixed
  • Innervation: Accessory, C2

 

Trapezius

Argosy Publishing

Trapezius (only Descending part relevant for neck)     

  • Origin:
    • Descending part: occipital bone (superior nuchal line and external occipital protuberance), the spinous processes of all cervical vertebrae via the nuchal ligament
    • Transverse part: broad aponeurosis at level of T1-T4 spinous processes
    • Ascending part: spinous processes of T5-T12
  • Insertion:
    • Descending part: lateral third of the clavicle
    • Transverse part: Acromion
    • Ascending part: Scapular spine
  • Function:
    • Descending part: tilts the head to the same side and rotates it to the opposite side (with the shoulder girdle fixed), draws the scapula obliquely upward and rotates the glenoid cavity inferiorly
    • Transverse part: draws the scapula medially
    • Ascending part: draws the scapula medially downward
    • Entire muscle: steadies the scapula on the thorax
  • Innervation: Cranial nerve XI (accessory nerve) and cervical plexus (C2-C4)

 

Argosy Publishing

Argosy Publishing

Levator scapulae  

  • Origin: Transverse processes of the C1-C4 vertebrae
  • Insertion: Superior angle of the scapula
  • Function: Inclines the neck toward the same side (when scapula is fixed)
  • Innervation: Dorsal scapular nerve (C4-C5)

 


Bones, Ligaments, Joints