Understanding Upper Limb Skeletal Muscles

Oct 27, 2024

Lecture Notes: Skeletal Muscles of the Upper Limb

Introduction

  • Presenter: Patrick
  • Focus: Tips and tricks for remembering skeletal muscles of the upper limb.
  • Method: Presenting muscles in smaller chunks of 4-8 for beginners.

Muscles Originating from the Spine

Trapezius

  • Function: Moves the shoulder; originates from the base of the skull to the lowest thoracic vertebrae.
  • Sections: Upper, middle, lower - still a single muscle.
  • Mnemonic: Looks like a trapezoid.

Latissimus Dorsi

  • Description: Widest muscle from shoulder to shoulder, inserts on humerus.
  • Mnemonic: Latissimus (lateral) + dorsi (back).

Rhomboid Major and Minor

  • Function: Retract shoulder blades.
  • Appearance: Major is rhomboid-shaped; minor is cylindrical.
  • Confusion: With serratus posterior superior (SPS) - Rhomboid is superficial.

Levator Scapulae

  • Function: Elevates scapula.
  • Identification: Attaches high neck vertebrae to top of scapula.

Muscles of the Chest

Pectoralis Major and Minor

  • Major: Big chest muscle.
  • Minor: Smaller, doesn’t reach sternum.

Serratus Anterior

  • Appearance: Jagged, like a bread knife.
  • Location: Contracted when punching forward.

Intercostal Muscles

  • Function: Located between ribs (intercostal = between ribs).

Shoulder Joint Muscles

Deltoid

  • Shape: Like Greek letter delta (triangle).

Rotator Cuff Muscles (SITS)

  • Supraspinatus: Above scapula spine.
  • Infraspinatus: Below scapula spine.
  • Teres Minor: Like an "M" angle with humerus.
  • Subscapularis: Under scapula.

Teres Major

  • Function: Similar to latissimus dorsi.
  • Position: Originates further down scapula and humerus.

Muscles of the Upper Arm

Biceps Brachii and Triceps Brachii

  • Biceps: Two-headed.
  • Triceps: Three-headed.

Coracobrachialis and Brachioradialis

  • Coracobrachialis: Shoulder blade to upper arm.
  • Brachioradialis: Upper arm bone to radius.

Brachialis and Anconius

  • Brachialis: Stubby elbow flexor.
  • Anconius: Extends elbow slightly.

Forearm Muscles

Flexors and Extensors

  • Naming: Based on function/location (e.g., Flexor Carpi Radialis).
  • Palmaris Longus: Missing in some people.

Pronators and Supinators

  • Pronator Teres and Quadratus: Pronate the hand.
  • Supinator: Performs opposite motion, located at elbow.

Hand Muscles

Thenar Mass (Thumb Muscles)

  • Flexor Pollicis Brevis: Flexes thumb.
  • Opponens Pollicis: Opposes thumb.
  • Adductor Pollicis: Adducts thumb.
  • Abductor Pollicis Brevis: Abducts thumb.

Hypothenar Mass (Pinky Muscles)

  • Opponens Digiti Minimi: Opposes pinky.
  • Flexor Digiti Minimi Brevis: Flexes pinky.
  • Abductor Digiti Minimi: Abducts pinky.

Other Hand Muscles

  • Palmaris Brevis: Aids in grip.
  • Lumbricals: Flex carpometacarpal, extend interphalangeal joints (L shape).
  • Interossei Muscles: PAD/DAB mnemonic (Palmar Adducts, Dorsal Abducts).

Conclusion

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  • Features: Videos, articles, quizzes for anatomy students.
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Note: This session covers diverse muscle groups and their functions, including mnemonics and identifying tips, useful for anatomy students.

Full transcript