Middle Scalene Muscle

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

Figure 1: Muscles of the Posterior and lateral neck¹

Figure 2: Muscles of the Neck and Back¹

Figure 3: Hypoglossal nerve, cervical plexus, and their respective branches²

Reading list

• Scalene Muscle³
• ⁴
• MMT⁵

Muscle	Origin	Insertion	Innervation	Action
Middle scalene	C1-C2 TP Posterior tubercle of TP of C3-C7	1st Rib (posterior to groove for subclavian a.)	Anterior Rami C3 - C8	Mobile ribs: Elevates ribs during forced inspiration Fixed ribs (unilateral): I/L C/s sidebend (unilateral) Fixed ribs (bil): C/s flexion, Cervical lateral stabilization

Origin

C1–C2 (transverse processes), C3–C7 (posterior tubercles of transverse processes)⁶

Insertion

1st rib (posterior to groove for subclavian a.)

Innervation

Anterior rami of C3, C4, C5, C6, C7, & C8⁶

Action

• According to Atlas of Anatomy⁶, the scalenes all have the same function:
• With ribs mobile: Elevates upper ribs (during forced inspiration)⁶
• With ribs fixed: Flexes cervical spine to same side (unilateral)⁶, flexes neck (bilateral)⁶

Hypertonicity

Causes

Forward head posture can cause hypertonicity and/or hypertrophy of the Middle Scalene muscle⁷.

Pathologies

Hypertonicity of the middle scalene can cause impingement of the Dorsal Scapular Nerve⁷

Related pathologies

• The Middle Scalene can cause entrapment of the C5 and C6 since these nerves pass through this muscle⁷.
  • This can result in problems with the Long Thoracic Nerve⁷.

References

1.

Betts JG, Blaker W. Anatomy and Physiology. 2nd ed. OpenStax; 2022. https://openstax.org/details/books/anatomy-and-physiology-2e/?Book%20details

2.

Gray H. Anatomy of the Human Body. 20th ed. (Lewis WH, ed.). Lea & Febiger; 1918. https://www.bartleby.com/107/

3.

Donnelly JM, Simons DG, eds. Travell, Simons & Simons’ Myofascial Pain and Dysfunction: The Trigger Point Manual. Third edition. Wolters Kluwer Health; 2019.

4.

Neumann DA, Kelly ER, Kiefer CL, Martens K, Grosz CM. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.

5.

Weinstock D. NeuroKinetic Therapy: An Innovative Approach to Manual Muscle Testing. North Atlantic Books; 2010.

6.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

7.

Dutton M. Dutton’s Orthopaedic Examination, Evaluation, and Intervention. 5th ed. McGraw Hill Education; 2020.