Muscles and Innervations Quiz

Innervation of Forearm Muscles

• Pronator teres: Innervated by the median nerve, crucial for pronation of the forearm.
• Flexor carpi radialis: Also innervated by the median nerve, assists in wrist flexion and abduction.
• Palmaris longus: Innervated by the median nerve, aids in flexing the wrist.
• Flexor carpi ulnaris: Innervated by the ulnar nerve, responsible for wrist flexion and adduction.
• Flexor digitorum superficialis: Innervated by the median nerve, involved in flexing the proximal interphalangeal joints of the fingers.
• Flexor digitorum profundus: Innervated by both the anterior interosseous nerve and the ulnar nerve, enables flexion of the distal interphalangeal joints.
• Pronator quadratus: Innervated by the anterior interosseous nerve, assists in pronation of the forearm.
• Flexor pollicis longus: Innervated by the anterior interosseous nerve, facilitates thumb flexion.

Innervation of Posterior Forearm Muscles

• Anconeus: Innervated by the radial nerve, assists in elbow extension.
• Brachioradialis: Also innervated by the radial nerve, involved in flexing the forearm at the elbow.
• Extensor carpi radialis longus: Innervated by the radial nerve, responsible for wrist extension and abduction.
• Extensor carpi radialis brevis: Innervated by the deep radial nerve, aids in wrist extension.
• Supinator: Innervated by the deep radial nerve, assists in supination of the forearm.
• Extensor digitorum: Innervated by the posterior interosseous nerve, extends the fingers.
• Extensor digiti minimi: Innervated by the posterior interosseous nerve, extends the little finger.
• Extensor carpi ulnaris: Innervated by the posterior interosseous nerve, contributes to wrist extension and adduction.
• Extensor indicis: Innervated by the posterior interosseous nerve, extends the index finger.
• Abductor pollicis longus: Innervated by the posterior interosseous nerve, allows for thumb abduction.
• Extensor pollicis brevis: Innervated by the posterior interosseous nerve, extends the thumb at the metacarpophalangeal joint.
• Extensor pollicis longus: Innervated by the posterior interosseous nerve, extends the thumb at the interphalangeal joint.

Median Nerve Innervation

• Innervates several anterior forearm muscles crucial for wrist and finger flexion.
• Key muscles include:
  • Pronator teres: Assists in pronation of the forearm.
  • Flexor carpi radialis: Flexes and abducts the wrist.
  • Palmaris longus: Tenses the palmar fascia, aiding grip.
  • Flexor carpi ulnaris: Flexes and adducts the wrist.
  • Flexor digitorum superficialis: Flexes the middle phalanges of the fingers.

Ulnar Nerve Innervation

• Primarily innervates muscles involved in fine motor control and finger coordination.
• Main muscle innervated:
  • Flexor digitorum profundus (ulnar half): Flexes the distal phalanges of the ring and little fingers.

Anterior Interosseous Nerve Innervation

• A branch of the median nerve that innervates deeper forearm muscles.
• Key muscles include:
  • Pronator quadratus: Pronates the forearm effectively.
  • Flexor pollicis longus: Flexes the thumb, contributing to grip strength.

Radial Nerve Innervation

• While not detailed in the provided information, the radial nerve typically innervates muscles responsible for elbow extension, wrist extension, and forearm supination.

Muscles of the Forearm Innervation Overview

• Median Nerve innervates several key muscles responsible for flexion in the forearm and hand, enhancing grip and manipulation.
• Key muscles innervated by the median nerve include:
  • Pronator Teres - facilitates pronation of the forearm.
  • Flexor Carpi Radialis - aids in wrist flexion and radial deviation.
  • Palmaris Longus - assists in wrist flexion and tension of the palmar aponeurosis.
  • Flexor Carpi Ulnaris - involved in wrist flexion and ulnar deviation.
  • Flexor Digitorum Superficialis - flexes the middle phalanges of the fingers.
  • Flexor Digitorum Profundus - primarily flexes the distal phalanges; partly operates under the ulnar nerve for the ring and little fingers.
  • Pronator Quadratus - stabilizes the distal radioulnar joint and pronates the forearm.
  • Flexor Pollicis Longus - moves the thumb by flexing its phalanx.

Radial Nerve Innervation

• Radial Nerve is crucial for extending the forearm and wrist, primarily innervating the posterior compartment.
• Key muscles innervated by the radial nerve include:
  • Anconeus - assists in elbow extension.
  • Brachioradialis - helps flex the forearm, particularly in a neutral position.
  • Extensor Carpi Radialis Longus - extends and abducts the wrist.
  • Extensor Carpi Radialis Brevis - extends the wrist and stabilizes it during grip.
  • Supinator - supinates the forearm.

Specific Nerves and their Muscle Connections

• Deep Radial Nerve branches from the radial nerve and innervates:

  • Extensor Carpi Radialis Brevis - also involved in wrist extension.
  • Supinator - responsible for supinating the forearm.

• Posterior Interosseous Nerve, a branch of the deep radial nerve, innervates:

  • Extensor Digitoris - extends the fingers, playing a key role in hand function.