Upper Limb Muscles Overview

Upper Limb Muscles Overview

• The upper limb consists of the shoulder, arm, forearm, wrist, and hand
• Muscles of the upper limb can be divided into extrinsic and intrinsic muscles

Extrinsic Muscles

• Originate in the shoulder or arm and insert into the hand
• Responsible for movements of the shoulder, arm, and forearm
• Include:
  • Deltoid
  • Supraspinatus
  • Infraspinatus
  • Teres minor
  • Subscapularis
  • Biceps brachii
  • Brachialis
  • Extensor carpi radialis brevis
  • Extensor carpi radialis longus
  • Extensor carpi ulnaris

Intrinsic Muscles

• Originate and insert within the hand
• Responsible for movements of the hand, fingers, and thumb
• Include:
  • Thenar muscles (thumb muscles):
    • Abductor pollicis brevis
    • Flexor pollicis brevis
    • Opponens pollicis
  • Hypothenar muscles (little finger muscles):
    • Abductor digiti minimi
    • Flexor digiti minimi
    • Opponens digiti minimi
  • Interossei muscles (between metacarpal bones):
    • Palmar interossei
    • Dorsal interossei
  • Lumbrical muscles (between metacarpal and phalanges):
    • First lumbrical
    • Second lumbrical
    • Third lumbrical
    • Fourth lumbrical

Muscle Functions

• Flexion:
  • Biceps brachii
  • Brachialis
  • Flexor carpi radialis
  • Flexor carpi ulnaris
• Extension:
  • Triceps brachii
  • Extensor carpi radialis brevis
  • Extensor carpi radialis longus
  • Extensor carpi ulnaris
• Rotation:
  • Supraspinatus (lateral rotation)
  • Infraspinatus (lateral rotation)
  • Teres minor (lateral rotation)
  • Subscapularis (medial rotation)

Upper Limb Muscles Overview

• The upper limb comprises the shoulder, arm, forearm, wrist, and hand
• The upper limb muscles are divided into extrinsic and intrinsic muscles

Extrinsic Muscles

• Extrinsic muscles originate in the shoulder or arm and insert into the hand
• They are responsible for movements of the shoulder, arm, and forearm
• Extrinsic muscles include:
  • Deltoid
  • Rotator cuff muscles:
    • Supraspinatus
    • Infraspinatus
    • Teres minor
    • Subscapularis
  • Biceps brachii
  • Brachialis
  • Forearm muscles:
    • Extensor carpi radialis brevis
    • Extensor carpi radialis longus
    • Extensor carpi ulnaris

Intrinsic Muscles

• Intrinsic muscles originate and insert within the hand
• They are responsible for movements of the hand, fingers, and thumb
• Intrinsic muscles include:
  • Thenar muscles (thumb muscles):
    • Abductor pollicis brevis
    • Flexor pollicis brevis
    • Opponens pollicis
  • Hypothenar muscles (little finger muscles):
    • Abductor digiti minimi
    • Flexor digiti minimi
    • Opponens digiti minimi
  • Interossei muscles (between metacarpal bones):
    • Palmar interossei
    • Dorsal interossei
  • Lumbrical muscles (between metacarpal and phalanges):
    • First lumbrical
    • Second lumbrical
    • Third lumbrical
    • Fourth lumbrical

Muscle Functions

• Flexion movements:
  • Biceps brachii (flexion of the elbow)
  • Brachialis (flexion of the elbow)
  • Flexor carpi radialis (flexion of the wrist)
  • Flexor carpi ulnaris (flexion of the wrist)
• Extension movements:
  • Triceps brachii (extension of the elbow)
  • Extensor carpi radialis brevis (extension of the wrist)
  • Extensor carpi radialis longus (extension of the wrist)
  • Extensor carpi ulnaris (extension of the wrist)
• Rotation movements:
  • Supraspinatus (lateral rotation of the shoulder)
  • Infraspinatus (lateral rotation of the shoulder)
  • Teres minor (lateral rotation of the shoulder)
  • Subscapularis (medial rotation of the shoulder)

Learn about the muscles of the upper limb, including their divisions, functions, and examples of extrinsic muscles.