Untitled Flashcard Set

Muscle

Primary Action

Strongest/Special Note

Nerve Supply

Biceps Brachii

Flexes arm/forearm, Supinates forearm

Strongest Supinator; most active when supinated

Musculocutaneous nerve

Brachialis

Flexes forearm

Strongest Flexor in all positions; most active when pronated

Musculocutaneous nerve

Brachioradialis

Flexes forearm, can assist supination/pronation

Most active in neutral position (Hammer curls)

Radial nerve

Triceps Brachii

Extends forearm (Long head extends arm)

Main elbow extensor

Radial nerve

Anconeus

Extends forearm, stabilizes ulnar elbow

Assists triceps / joint stability

Radial nerve

Supinator

Supinates forearm

Superficial and deep layers

Radial nerve

Pronator Teres

Pronates forearm, flexes elbow

Deep muscle

Median nerve

Pronator Quadratus

Pronates forearm

Distal, deep, anterior forearm

Median nerve



Upper Extremity Muscles Study Guide

Part 1: Functional Categories Overview

1. Elbow Flexors

  • Biceps Brachii

  • Brachialis (Note: Strongest flexor in all positions!)

  • Brachioradialis

  • Pronator Teres

2. Elbow Extensors

  • Triceps Brachii

  • Anconeus

3. Forearm Supinators

  • Supinator

  • Biceps Brachii (Note: Strongest supinator!)

4. Forearm Pronators

  • Pronator Teres (Innervated by Median nerve)

  • Pronator Quadratus (Innervated by Median nerve)

5. Shoulder Muscles (Not Primary Elbow Movers)

  • Deltoid

  • Coracobrachialis

Part 2: Detailed Muscle Breakdown

1. Biceps Brachii

  • Actions:

    • Flexes arm

    • Flexes forearm at the elbow

    • Supinates forearm

  • Nerve Supply: Musculocutaneous nerve

  • Key Clinical/Functional Notes:

    • Most activated in the supinated position.

    • STRONGEST Supinator!

2. Brachialis

  • Actions: Flexes forearm

  • Nerve Supply: Musculocutaneous nerve

  • Key Functional Notes:

    • Most activated in the pronated position.

    • STRONGEST Flexor overall across all positions.

3. Brachioradialis

  • Actions:

    • Flexes forearm (elbow)

    • Supinates the forearm (at radioulnar joints)

    • Pronates the forearm (at radioulnar joints)

  • Nerve Supply: Radial nerve

  • Key Functional Notes:

    • Most active in the neutral position (crosses into forearm, used in hammer curls).

4. Triceps Brachii

  • Actions: Extends forearm (elbow)

  • Long Head Role: Plays a role in extending the arm

  • Nerve Supply: Radial nerve

5. Anconeus

  • Actions: Extends forearm (elbow) + stabilizes ulnar at the elbow

  • Nerve Supply: Radial nerve

6. Supinator

  • Actions: Supinates forearm at radioulnar joints

  • Nerve Supply: Radial nerve

  • Anatomy Notes: Superficial + deep layer, crosses at forearm.

7. Pronator Teres

  • Actions:

    • Pronates forearm at radioulnar joint

    • Flexes forearm at elbow

  • Nerve Supply: Median nerve

  • Anatomy Notes: Deep.

8. Pronator Quadratus

  • Actions: Pronates forearm at radioulnar joints

  • Nerve Supply: Median nerve

  • Anatomy Notes: Distal, deep, anterior forearm.