Muscles of the Forearm Quiz

Front of Forearm Muscles

• Superficial Layer: Muscles are arranged from lateral to medial.

  • Pronator teres
  • Flexor carpi radialis
  • Palmaris longus
  • Flexor carpi ulnaris

• Intermediate Layer:

  • Flexor digitorum superficialis

• Deep Layer:

  • Flexor pollicis longus
  • Flexor digitorum profundus
  • Pronator quadratus

Superficial Muscles of the Front of the Forearm

• Origin: Common flexor origin - medial condyle of the humerus (for all superficial muscles)

• Pronator teres:

  • Nerve supply: Median nerve
  • Action: Pronation

• Flexor carpi radialis:

  • Nerve supply: Median nerve
  • Action: Flexes and abducts the wrist joint

• Palmaris longus:

  • Nerve supply: Median nerve
  • Action: Flexion of the wrist joint; makes the skin tense during hand grip

• Flexor carpi ulnaris:

  • Nerve supply: Ulnar nerve
  • Action: Flexes and adducts the wrist joint

Intermediate Layer Muscles

• Flexor digitorum superficialis:
  • Nerve supply: Median nerve
  • Action: Flexes proximal interphalangeal joints of the medial four fingers

Deep Muscles of the Forearm

• Flexor digitorum profundus:

  • Nerve supply: Lateral 1½ by anterior interosseous branch of median nerve; Medial ¹½ by ulnar nerve
  • Action: Flexes distal interphalangeal joints, middle interphalangeal joints, metacarpo-phalangeal joints of the medial 4 fingers and flexes wrist joint

• Flexor pollicis longus:

  • Nerve supply: Anterior interosseous of median nerve
  • Action: Flexes interphalangeal joint and metacarpo-phalangeal joint of the thumb

• Pronator quadratus:

  • Nerve supply: Anterior interosseous branch of median nerve
  • Action: Pronation

Flexor Retinaculum

• Band of fibrous connective tissue anterior to the carpal bones (palmar surface)
• Prevents flexor tendons from popping out
• Attachments:
  • Medially: pisiform & hook of hamate
  • Laterally: scaphoid & trapezium

Carpal Tunnel

• Median nerve if compressed leads to carpal tunnel syndrome

Back of Forearm Muscles

• Superficial Layer:

  • Brachioradialis
  • Extensor carpi radialis longus
  • Extensor carpi radialis brevis
  • Extensor digitorum
  • Extensor digiti minimi
  • Extensor carpi ulnaris
  • Anconeus

• Deep Layer:

  • Supinator
  • Abductor pollicis longus
  • Extensor pollicis longus
  • Extensor pollicis brevis
  • Extensor indicis

Elbow Joint and Radioulnar Joints

• Elbow Joint:

  • Hinge variety of synovial joint
  • Articulating bones: humero - radial & humero - ulnar
  • Anterior: capitulum & trochlea
  • Posterior: olecranon & trochlear notch

• Ligaments of Elbow Joint:

  • Capsule: attached to the margins of articular surfaces
  • Synovial membrane lines the fibrous capsule
  • Intra-articular fossa: coronoid fossa, radial fossa, olecranon fossa

• Radial Collateral Ligament: extend from lateral epicondyle to lateral part of annular ligament surrounding humerus

• Ulnar Collateral Ligament: extends from medial epicondyle. It has three parts: anterior, posterior, and oblique.

• Annular ligament: holds the head of the radius to the ulna

• Movements of Elbow Joint:

  • Flexion: biceps brachii, brachialis, brachioradialis
  • Extension: triceps brachii

• Radioulnar joints:

  • Superior radioulnar joint: head of the radius and radial notch of ulna (synovial pivot joint)
  • Inferior radioulnar joint: ulnar notch of radius and ulnar head (synovial pivot joint)

• Ligaments of superior radioulnar joint:

  • Annular ligament
  • Quadrate ligament
  • Oblique cord

• Ligaments of inferior radioulnar joint:

  • Capsule surrounds the joint
  • Articular disc has apex and a base

• Movements of Radioulnar Joint:

  • Supination: supinator, biceps brachii (strong supinator in midprone position)
  • Pronation: pronator teres, pronator quadratus

Test your knowledge on the anatomy and functions of the muscles in the forearm. This quiz covers various muscles such as the Flexor carpi ulnaris, Flexor digitorum superficialis, and Pronator teres. Answer questions related to their primary actions and innervations.