Lecture on Muscles of the Upper Extremity

Overview of Muscle Groups

• Anchoring Muscles
  • Muscles anchoring the shoulder blade to the chest.
  • Muscles anchoring the arm to the shoulder blade.
  • Goal: Understand how different muscles move the extremities, not just list them.

Muscles Anchoring Shoulder Blade to Chest

• Levator Scapulae
  • Origin: Inside angle of the shoulder blade.
  • Insertion: Top vertebra in the neck.
  • Function: Elevates scapula, rotates glenoid cavity downward.
• Rhomboids
  • Function: Adducts scapula, pulling it closer to the spine.
• Trapezius
  • Origin: From EOP (External Occipital Protuberance) down to T12.
  • Function: Stabilizes, raises, retracts scapula.
• Serratus Anterior
  • Function: Holds shoulder blade against chest wall.

Muscles Anchoring Arm to Shoulder Blade

• Rotator Cuff Muscles (SITS)
  • Supraspinatus, Infraspinatus, Teres Minor, Subscapularis.
  • Function: Stabilize shoulder joint and assist in arm movements.

Muscles Moving the Upper Arm

• Deltoid
  • Function: Abducts, flexes, and extends the arm.
• Pectoralis Major
  • Function: Adducts and medially rotates the arm.
• Latissimus Dorsi and Teres Major
  • Function: Extend, adduct, and medially rotate the arm.

Muscles Moving the Elbow and Forearm

• Biceps Brachii
  • Function: Flexes elbow, supinates forearm.
• Brachialis
  • Function: Major flexor of the elbow.
• Triceps Brachii
  • Function: Extends the elbow.

Forearm Muscles

• Flexors (Palm side)
  • Pronator Teres, Flexor Carpi Radialis, Palmaris Longus, Flexor Carpi Ulnaris.
  • Function: Flex and pronate the wrist and fingers.
• Extensors (Back side)
  • Extensor Carpi Radialis, Extensor Carpi Ulnaris, Extensor Digitorum.
  • Function: Extend wrist and fingers.

Practical Applications and Considerations

• Use of ski poles to strengthen shoulder muscles while walking.
• Effects of injury or repetitive motion on muscle function (e.g., carpal tunnel syndrome).

Study Tips

• Understand the origin and insertion points to visualize muscle function.
• Use mnemonics to remember muscle groups and functions.
• Relate muscle actions to common movements or injuries for better understanding.