Cervical_Spine_Muscles_1_of_2

Muscles of the Cervical Spine

Learning Objectives

• Understand the muscular and bony anatomy of the cervical spine.

• Recognize the safety considerations when working with the cervical spine.

• Learn the functions of the muscles of the cervical spine.

• Apply anatomical terms to muscle and bone palpations of the cervical spine.

• Study the attachments, actions, and nerve innervation of:

  • Splenius Capitis

  • Splenius Cervicis

  • Rectus Capitis Posterior Major

  • Rectus Capitis Posterior Minor

  • Obliquus Capitis Inferior

  • Obliquus Capitis Superior

  • Sternocleidomastoid

  • Anterior Scalene

  • Middle Scalene

  • Posterior Scalene

Ligaments of the Spine and Thorax

• Ligamentum Nuchae

  • Spans approximately C1-C6 vertebrae.

  • It is a superior and posterior extension of the supraspinous ligament.

• Supraspinous Ligament

  • Connects spinous processes from approximately C7 to L4.

Muscle Groups of the Cervical Spine

Posterior Cervical Spine

• Muscles: Splenius Capitis, Splenius Cervicis, Suboccipital Muscles.

Splenius Capitis and Cervicis

• Actions:

  • Unilateral: Rotate and laterally flex the head and neck to the same side.

  • Bilateral: Extend the head and neck.

• Attachments:

  • Capitis: Inferior one-half of the ligamentum nuchae and spinous processes of C7 to T4.

  • Cervicis: Spinous processes of T3 to T6.

• Insertions:

  • Capitis: Mastoid process and lateral portion of the superior nuchal line.

  • Cervicis: Transverse processes of C1 to C3.

• Nerve Innervation: Cervical nerves.

• Note: Only the capitis has actions on the head due to anatomical positioning.

Suboccipital Muscles

• Muscles include:

  • Rectus Capitis Posterior Major

  • Rectus Capitis Posterior Minor

  • Obliquus Capitis Superior

  • Obliquus Capitis Inferior.

Rectus Capitis Posterior Major

• Action: Extension, ipsilateral rotation, and lateral flexion of the head.

• Origin: Spinous process of the axis (C2).

• Insertion: Lateral portion of the inferior nuchal line of the occiput.

• Nerve: Suboccipital nerve.

Rectus Capitis Posterior Minor

• Action: Extension and protraction of the head.

• Origin: Tubercle of the posterior arch of the atlas (C1).

• Insertion: Inferior nuchal line of the occiput.

• Nerve: Suboccipital nerve.

Obliquus Capitis Superior

• Action: Extension, protraction, and lateral flexion of the head to the same side.

• Origin: Transverse process of the atlas (C1).

• Insertion: Between the nuchal lines of the occiput.

• Nerve: Suboccipital nerve.

Obliquus Capitis Inferior

• Action: Ipsilateral rotation of the atlas (to the same side).

• Origin: Spinous process of the axis (C2).

• Insertion: Transverse process of the atlas (C1).

• Nerve: Suboccipital nerve.

Anteriolateral Cervical Muscles

• Key Muscles: Sternocleidomastoid, Anterior Scalene, Middle Scalene, Posterior Scalene, and others.

• Understand their locations and relationships in the anterior and posterior triangles of the neck.

Sternocleidomastoid Muscle

• Actions:

  • Unilateral: Laterally flex head and neck to the same side, rotate to the opposite side.

  • Bilateral: Flex the neck, assist in elevating the rib cage during inhalation.

• Origin:

  • Sternal Head: Manubrium of sternum.

  • Clavicular Head: Medial one-third of the clavicle.

• Insertion: Mastoid process of the temporal bone and the lateral portion of the superior nuchal line.

• Nerve Innervation: Spinal accessory (XI) nerve, C2, C3.

Scalene Muscles

• Anterior Scalene:

  • Action: Same as above, plus elevates the first rib during inhalation.

  • Origin: Transverse processes of C3-C6.

  • Insertion: First rib.

• Middle Scalene:

  • Action: Similar to anterior, elevates ribs during inhalation.

  • Origin: Transverse processes of C2-C7.

  • Insertion: First rib.

• Posterior Scalene:

  • Action: Elevates the second rib during inhalation.

  • Origin: Transverse processes of C5-C7.

  • Insertion: Second rib.

Study Tips and Exam Preparation

• Prepare for Competency Evaluation #1 on Monday, January 20th, which will cover muscle actions, origin, insertion, and identification of muscles.

• Review PowerPoint on Spinal Anatomy Review before lab to reinforce the material covered in this session.