Overview of Skeletal and Muscular Systems

Oct 8, 2024

Lecture Notes: Skeletal and Muscular Systems

Introduction

  • Skeletal muscles produce movement by exerting force on tendons.
  • Tendons attach to bones and pull them, enabling movement.
  • Most muscles cross at least one joint and attach to articulating bones.

Muscles and Bones

  • Biceps Brachii & Triceps Brachii:
    • Attached to the humerus.
    • Muscle contraction draws articulating bones together.
  • Origin & Insertion:
    • Origin: Attachment to stationary bone.
    • Insertion: Attachment to movable bone, where action occurs.

Arm Muscles

  • Prime Movers:
    • Pectoralis major (thorax anteriorly).
    • Latissimus dorsi (posterior back).
    • Deltoid (over shoulder).
  • Synergists/Fixators:
    • Stabilize and assist movement of humerus.
    • Muscles include supraspinatus, infraspinatus, teres minor, subscapularis, teres major, and coracobrachialis.

Rotator Cuff Muscles

  • Assist in arm rotation and shoulder joint stabilization.
  • Includes supraspinatus, infraspinatus, teres minor, and subscapularis.

Thorax and Shoulder Girdle Muscles

  • Anterior Muscles:
    • Subclavius, pectoralis minor, and serratus anterior.
  • Posterior Muscles:
    • Trapezius, levator scapula, rhomboid major, and rhomboid minor.

Back Muscles

  • Vertebral Column Support:
    • Splenius capitis and splenius cervicis: flex, extend, and rotate the neck.
  • Erector Spinae:
    • Prime movers of vertebral column extension.
    • Divided into spinalis, longissimus, and iliocostalis.
  • Deep Back Muscles:
    • Semispinalis and rotatores: extend and rotate vertebral column.
  • Spinal Flexors:
    • Longus capitis, longus colli, and quadratus lumborum.

Respiratory Muscles

  • Located in the thorax.
  • External Intercostals: Assist with inspiration.
  • Internal Intercostals: Assist with forced expiration.
  • Diaphragm: Prime mover of inspiration.

Abdominal Muscles

  • External Oblique: Compresses abdomen, aids in respiration, and trunk rotation.
  • Rectus Abdominis: Known as "six-pack."
  • Internal Oblique: Fibers run opposite to external oblique.
  • Transverse Abdominis: Involved in trunk movement.

Pelvic Muscles

  • Pelvic Diaphragm: Supports pelvic floor.
    • Includes levator ani (pubococcygeus, puborectalis, iliococcygeus) and coccygeus.
  • Superficial Perineal Muscles (Males):
    • Bulbospongiosus and ischiocavernosus: support erection.
  • Deep Perineal Muscles:
    • Support central tendon of perineum.
    • Includes deep transverse perineal muscle and external anal sphincter.

Conclusion

  • Additional resources and videos are available for further exploration of these topics.
  • Encouragement to subscribe, like, and share the video for more content.

These notes summarize the key points discussed in Dr. Gonzalez's video on the skeletal and muscular systems, focusing on the roles and functions of various muscle groups within the body.