Infraspinatus

Description

Illustration of the rotator cuff muscles

Name

• Infraspinatus
• Infraspinatus Muscle

General

• One of the 4 rotator cuff muscles

Gross Anatomy

• Origin: Infraspinous fossa of scapula
  • Particularly from the fibers of the medial two thirds
  • Tendinous fibers from the ridges on the surface
  • Fibers of the infraspinatus fascia which covers it
• Insertion: Greater tubercle of humerus
  • Glides over the lateral border of the spine of the scapula
  • Passing across the posterior part of the joint capsule of the shoulder
  • Inserts on the middle facet of the greater tubercle

Actions

• External rotation of arm

Vascular Supply

• Circumflex Scapular Artery, Suprascapular Artery

Innervation

• Suprascapular Nerve

Anatomic Relationships

• Infraspinatus and supraspinatus are often considered one functional unit
• The fibers course towards the shoulder parallel to teres minor, teres major
• Occasionally, there is an infraspinatus bursa which separates the tendon from the neck of the scapula

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Clinical Significance

• Rotator Cuff Tendinitis
• Rotator Cuff Tear
• Suprascapular Neuropathy
• Shoulder Paralabral Cyst

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See Also

• Shoulder Pain Main
• Physical Exam Shoulder
• Shoulder Anatomy Main

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