Anatomy notes

Shoulder Muscles Innervation and Functions

1. Shoulder Abduction:

• Muscle: Deltoid
• Nerve: Axillary Nerve
• Spinal Level: C5

2. Elbow Flexion:

• Muscle: Biceps
• Nerve: Musculocutaneous Nerve
• Spinal Levels: C5, C6

3. Elbow Extension:

• Muscle: Triceps
• Nerve: Radial Nerve
• Spinal Level: C7

4. Finger Extension:

• Muscles: Extensor Digitorum Superficialis & Profundus
• Nerve: Radial Nerve
• Spinal Level: C7

5. Finger Flexion:

• Muscles: Flexor Digitorum Profundus & Superficialis
• Nerves: Median & Ulnar Nerves
• Spinal Level: C8

6. Finger Abduction:

• Muscle: First Dorsal Interosseous
• Nerve: Ulnar Nerve
• Spinal Level: T1

7. Thumb Abduction:

• Muscle: Abductor Pollicis Brevis
• Nerve: Median Nerve
• Spinal Level: T1

8. Finger Adduction:

• Muscle: Second Palmar Interossei
• Nerve: Ulnar Nerve
• Spinal Level: T1

Other Shoulder Muscles and Their Functions

• Rhomboideus Muscle:

  • Function: Pulling the arm backward while the hands are on the waist and moving the elbow backward against resistance.

• Serratus Anterior Muscle:

  • Function: Used when pushing a car.

• Supraspinatus Muscle:

  • Innervation: Suprascapular Nerve
  • Function: Lifts arms sideways between 60 and 120 degrees.

• Infraspinatus Muscle:

  • Function: With a flexed elbow, moves the arm inward.

Long Flexors of Fingers

• Flexor Digitorum Profundus: Flexes the distal interphalangeal joints (DIP).
• Flexor Digitorum Superficialis: Flexes the proximal interphalangeal joints (PIP).
• Flexor Pollicis Longus: Flexes the thumb.