1st Rib (Bone)

Authors

Affiliations

Nathaniel 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

Anatomy

Types of cervical rib:

• Type I: complete cervical rib articulates with the first rib or manubrium of sternum¹
• Type II: incomplete cervical ribs with a free end expanded to form a bulbous tip¹
• Type III: an incomplete rib that is continued by a fibrous band¹
• Type Iv: rib that appears as a short bar of bone with a length of a few millimeters beyond the C7 TP¹

Variations

• Type I: complete cervical rib articulates with the first rib or manubrium of sternum¹
• Type II: incomplete cervical ribs with a free end expanded to form a bulbous tip¹
• Type III: an incomplete rib that is continued by a fibrous band¹
• Type IV: rib that appears as a short bar of bone with a length of a few millimeters beyond the C7 TP¹

Costal Cartilage

The costal cartilage of the 1st rib is at the anterior aspect of the 1st rib and it articulates with the sternum at the 1st sternocostal joint².

Muscle attachments

Table 1: Muscular Origins of 1st Rib

Muscle	Origin	Insertion	Innervation	Action
Serratus anterior	1-9 Ribs	Superior angle of Scapula (costal and dorsal surfaces) Medial border of scapula (costal surface) Medial border of scapula (costal surface) Inferior angle of Scapula (costal & dorsal surfaces)	Long thoracic n. C5 - C7	Superior part: Lowers raised arm Entire mm.: Protraction, Rib elevation (with fixed shoulder) Inferior part: Rotates scapula laterally forward
Subclavius	1st rib	Clavicle (inferior surface)	N. to subclavius C5 - C6	SCJ: Clavicular stabilization

Table 2: Muscular Insertions on 1st Rib

Muscle	Origin	Insertion	Innervation	Action
Anterior scalene	Anterior tubercle of TP of C3-C6	Scalene tubercle of 1st Rib	Anterior Rami C4 - C6	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
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

Elevation

1st rib elevation is a cause of Thoracic Outlet Syndrome³

Hypomobility

1st Rib hypomobility or restriction can be caused by:

• 1st rib subluxation at costotransverse joint

Can result in secondary pathologies, such as:

• Thoracic outlet syndrome (TOS)

• Tests:

  • Cervical Rotation Lateral Flexion
  • Costoclavicular Test

Assessment

Presentation

• Neck and vague ipsilateral upper limb distribution of symptoms (pain and paresthesia)⁴
  • Especially ulnar nerve distribution

Aggravations

Functional

• Restricted and aggravating Neck activity⁴
  • BIL neck rotations⁴
  • BIL lateral-flexions⁴
  • BIL combined movements with extension were the main aggravating activities with restricted range of movement⁴
• Shoulder girdle⁴
• Respiratory activities⁴

Assessment

Onset

Onset was associated with direct traumas, whiplash, shoulder girdle efforts, such as carrying heavy bags or pulling on ipsilateral arm, and shoulder surgery⁴

References

1.

Hooper TL, Denton J, McGalliard MK, Brismée JM, Sizer PS. Thoracic outlet syndrome: A controversial clinical condition. Part 1: Anatomy, and clinical examination/diagnosis. The Journal of Manual & Manipulative Therapy. 2010;18(2):74-83. doi:10.1179/106698110X12640740712734

2.

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

3.

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

4.

Mastromarchi P, May S. First rib dysfunction in patients with neck and shoulder pain: A Delphi investigation. The Journal of Manual & Manipulative Therapy. 2021;29(3):181-188. doi:10.1080/10669817.2020.1824470