Lecture Notes: Muscle Naming in Human Anatomy

Introduction

• Main Topic: Naming of the 640 muscles in the human body.
• Key Point: Most muscles are named based on appearance, location, and attachments.
• Benefit: Understanding naming conventions helps in memorizing muscle names.

Characteristics Used in Naming Muscles

1. Shape
2. Size
3. Orientation of Fibers
4. Action
5. Number of Attachments
6. Points of Attachment
7. Location

1. Shape

• Deltoid Muscle: Triangular shape (Greek letter delta).
• Orbicularis Oculi Muscle: Circular shape around the eye (Latin: orbicularis).
• Orbicularis Oris Muscle: Circular shape around the lips.
• Rhomboid Muscles: Parallelogram shape (Greek: rhombus).
• Platysma: Flat and wide (Greek: platus).
• Serratus Anterior Muscle: Beveled edge of a saw (Latin: serrare).

2. Size

• Vastus Muscles (Thigh): Large muscles (Latin: vastus).
• Pectoralis Major and Minor: Major is larger than minor.
• Gluteus Maximus and Minimus: Maximus is the largest in the gluteal region; minimus is the smallest.
• Longus and Brevis: Longus for long muscles; Brevis for short muscles (e.g., abductor pollicis brevis).

3. Orientation of Fibers

• Transverse: Fibers run perpendicular to the midline (e.g., transverse muscle of the tongue).
• Oblique: Fibers run diagonally (e.g., external abdominal oblique muscle).
• Rectus: Fibers run parallel to the midline (e.g., rectus abdominis).

4. Action

• Flexors and Extensors: Flexor hallucis brevis (flexes great toe), extensor digiti minimi (extends little finger).
• Supinators and Pronators: Supinator muscle (supinates forearm), pronator teres (pronates forearm).
• Other Examples: Risorius muscle (smiling muscle), adductor pollicis (adducts thumb), pyloric sphincter (constricts stomach).

5. Number of Attachments

• Biceps Brachii: Two heads (bi = two, ceps = head).
• Triceps Brachii: Three heads.
• Quadriceps Femoris: Four heads.

6. Points of Attachment

• Sternohyoid Muscle: From sternum to hyoid bone.

7. Location

• Tibialis Anterior Muscle: Located over the tibia bone.
• Inferior and Superior: Infrahyoid (below hyoid bone), supraspinatus (above spine of scapula).
• Medialis, Intermedius, Lateralis: Relative to midline (e.g., vastus medialis, vastus intermedius, vastus lateralis).

Summary

• Seven ways muscles are named: shape, size, fiber orientation, action, number of origins, points of attachment, location.
• Examples provided for each naming convention.

Conclusion

• Understanding these conventions aids in remembering muscle names.
• Further learning resources available at Kenhub.com (articles, quizzes, atlases, video tutorials).