Muscles that move wrist:hand:fingers

Intrinsic Muscles of the Hand

• The intrinsic muscles of the hand are vital for the dexterity and precision of hand movements.

  • They originate and insert entirely within the hand.

  • Enable intricate actions such as typing and writing.

Categories of Intrinsic Muscles

1. Thenar Muscles

• Located on the radial aspect of the palm.

  • Include:

    • Abductor pollicis brevis

    • Opponens pollicis

    • Flexor pollicis brevis

    • Adductor pollicis

• Form the thenar eminence (base of the thumb).

• Crucial for thumb movements, allowing precise hand functions.

2. Hypothenar Muscles

• Located on the medial aspect of the palm.

  • Include:

    • Abductor digiti minimi

    • Flexor digiti minimi brevis

    • Opponens digiti minimi

• Form the hypothenar eminence (base of the little finger).

• Aid in the movements of the little finger.

3. Intermediate Muscles

• Act on all fingers, contributing to complex finger movements.

  • Include:

    • Lumbricals

    • Palmar interossei

    • Dorsal interossei

• Important for grip strength and manipulation.

Detailed Functions of Intrinsic Muscles

Thenar Muscles

• Abductor pollicis brevis:

  • Movement: Abduction of the thumb.

  • Origin: Flexor retinaculum; lateral base of proximal phalanx of thumb.

• Opponens pollicis:

  • Movement: Opposition of the thumb.

  • Origin: Flexor retinaculum; anterior of first metacarpal.

• Flexor pollicis brevis:

  • Movement: Flexion of the thumb.

  • Origin: Flexor retinaculum; trapezium.

• Adductor pollicis:

  • Movement: Adduction of the thumb.

  • Origin: Metacarpals 2-4.

Hypothenar Muscles

• Abductor digiti minimi:

  • Movement: Abduction of the little finger.

  • Origin: Pisiform bone; hamate bone.

• Flexor digiti minimi brevis:

  • Movement: Flexion of the little finger.

  • Origin: Hamate bone; flexor retinaculum.

• Opponens digiti minimi:

  • Movement: Opposition of the little finger.

Intermediate Muscles

• Lumbricals:

  • Function: Flex metacarpophalangeal joints; extend interphalangeal joints.

• Palmar Interossei:

  • Function: Adduct and flex fingers at metacarpophalangeal joints.

• Dorsal Interossei:

  • Function: Abduct and flex fingers at metacarpophalangeal joints; extend at interphalangeal joints.

Summary of Muscle Functions

• Intrinsic muscles are essential for fine motor control, enabling various thumb and finger movements including:

  • Abduction

  • Adduction

  • Flexion

  • Extension

  • Opposition

• They allow for the complex and nuanced dexterity needed for everyday tasks.