Anterior Thorax Muscles Lecture

Introduction

• Focus on muscles of the anterior thorax
• Discuss both superficial and deep layers
• Explore synergists and antagonists

Key Definitions

• Synergists: Muscles performing the same action.
• Antagonists: Muscles opposing each other's actions.

Pectoralis Major

• Functions:
  • Flexes the arm at the shoulder
  • Adducts the arm at the shoulder
  • Medially rotates the arm
• Synergists:
  • Coracobrachialis (flexion)
  • Latissimus dorsi, Teres major (adduction)
  • Subscapularis (medial rotation)
• Antagonists:
  • Teres major, Latissimus dorsi (extension)
  • Deltoid, Supraspinatus (abduction)
  • Infraspinatus, Teres minor (lateral rotation)

Intercostal Muscles

• External Intercostals:
  • Elevate ribs for inhalation
• Internal Intercostals:
  • Depress ribs for forced exhalation
• Relationship:
  • Antagonistic to each other

Serratus Anterior

• Function:
  • Protracts the scapula
• Synergists:
  • Pectoralis minor
• Antagonists:
  • Rhomboids major/minor, Trapezius

Subclavius

• Depresses the clavicle

Pectoralis Minor

• Function:
  • Protracts the scapula
• Insertion: Coracoid process of the scapula
• Origin: Ribs 2-5
• Synergists:
  • Serratus anterior
• Antagonists:
  • Trapezius, Rhomboids major/minor

Abdominal Wall Muscles

Overview

• Understanding the layers from superficial to deep

External Oblique

• Function:
  • Flexes the vertebral column
  • Compresses abdomen contents
  • Aids in forced exhalation

Internal Oblique

• Function:
  • Flexes the vertebral column
  • Compresses abdomen contents
  • Aids in forced exhalation

Rectus Abdominis

• Function:
  • Flexes the vertebral column
  • Compresses abdomen contents
  • Aids in forced exhalation

Transversus Abdominis

• Function:
  • Compresses abdomen contents
  • Aids in forced exhalation
• Not involved in flexing the vertebral column

Linea Alba

• Connective tissue structure

Pyramidalis

• Tenses the linea alba

Recap

• Review of superficial to deep abdominal muscles
• Highlight functions and structure