Triceps Brachii

Origin

Illustration of the triceps brachii

Triceps Brachii

Name

• Triceps Brachii
• Triceps
• Arm Triceps

General

• Large, thick, 3 headed muscle of the posterior arm
• Primarily responsible for elbow extension, also supporting shoulder extension

Origin

• Long Head
  • Infraglenoid tubercle of the Scapula
• Medial Head
  • Posterior surface of the Humerus (inferior to radial groove)
• Lateral Head
  • Posterior surface of the Humerus (superior to radial groove)

Anatomic Course

• Long and lateral heads merge about two thirds of the way down the humerus to form the superficial tendinous insertion
• The medial head joints the deep surface of the superficial tendinous insertion more distally
• All 3 heads insert together on the proximal olecranon

Insertion

• Insertion onto the Olecranon
  • This is known as the triceps footprint
  • Medially: insertion extends on the posterior end of the ulna
  • Laterally: inserts onto the fascia of the extensor carpi ulnaris

Actions

• All Heads
  • Extension of forearm (at the elbow)
• Long Head
  • Extension and Adduction of the arm (at the shoulder)

Vascular Supply

• Deep Brachial Artery

Innervation

• Radial Nerve (C7-C8)

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Clinical Significance

• Radial Nerve Injury
• Triceps Tendon Injury
• Olecranon Fracture

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See Also

Shoulder

• Physical Exam Shoulder
• Shoulder Anatomy (Main)
• Shoulder Pain (Main)

Elbow

• Physical Exam Elbow
• Elbow Anatomy (Main)
• Elbow Pain (Main)

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