Muscle Groups Detailed Study Notes

Week 11: Muscle Groups Summary

Page 1: Overview

• Date of lectures: March 30, April 1, and April 3.

Page 2: Review Questions on Muscle Contraction

• Question 1: Which 2 sarcomere proteins interact/form cross-bridges to produce force?

  • Answer: 1. Troponin, 2. Tropomyosin.

• Question 2: Energy from ATP is used to:

  1. Detach myosin head from actin.

  2. Energize myosin head (bend it back).

  3. Actin.

  4. Myosin.

• Question 3: What is the direction of force generation in the structure below?

Page 3: Energy Sources for Muscle Contraction

• To continue contracting and producing force, muscle fibers must produce new ATP.

• Three sources of ATP identified:

  1. Creatine Phosphate.

  2. Anaerobic metabolism.

  3. Aerobic metabolism.

• Discussion of questions:

  • Quickest Energy Source: Anaerobic metabolism (relied on first).

  • Fastest to Produce Energy: Creatine phosphate (during initial seconds of activity).

  • Source with Longest Duration & Most Energy: Aerobic metabolism (theoretically sustainable indefinitely).

• Discussion: Pros and cons of anaerobic vs aerobic metabolism.

Page 4: Learning Outline

• Learning Agenda for Muscle Groups:

  • Monday: Muscle fiber types & Clinical Conditions.

  • Wednesday: Muscle mechanics & Names, Face muscles.

  • Friday: Neck and Trunk muscles, Lower limb muscles.

Page 5: Muscle Fiber Types

• There are different types of muscle fibers:

  • Fast Glycolytic (FG) ('fast twitch'):

  • Slow Oxidative (SO) ('slow twitch'):

Page 6: Fast vs. Slow Muscle Fibers

• Slow Oxidative fibers:

  • Characteristics: High endurance, slower ATP production, less powerful forces.

  • Oxygen storage via blood.

• Fast Glycolytic fibers:

  • Characteristics: Short bursts of powerful force, faster ATP production, prone to fatigue.

Page 7: Muscle Fiber Mix Variability

• Muscles comprise a mix of fiber types.

• Variation in fiber type distribution can occur:

  1. Across specific muscles in different regions of the body.

  2. Among different individuals with the same muscle.

• Example Questions:

  • Muscle with most slow oxidative fibers: Erector spinae (used for posture maintenance).

  • Athlete type with more slow oxidative fibers in the rectus femoris: Elite marathon runner.

Page 8: Clinical Conditions Related to Muscle

• Muscle Tears:

  • Commonly referred to as 'pulled muscle.'

  • Mechanism: Damage to muscle belly and its fibers.

  • Healing: Satellite cells are involved in patching and repairing damaged fibers.

• Location of muscle tears: Can affect muscle, tendon, and associated blood vessels.

Page 9: Rhabdomyolysis

• Definition: Condition where contents from injured muscle fibers can build up to toxic levels, potentially damaging kidney functions.

• Causes: Trauma, extreme physical activity, crush injuries, etc.

Page 10: Muscular Dystrophies

• Definition: A group of over 30 genetic conditions leading to progressive muscle weakness and loss of muscle mass.

• Mechanism: Disruption of genes responsible for muscle protein production.

Page 11: Myasthenia Gravis and Botulism

• Myasthenia Gravis: Autoimmune condition affecting skeletal muscle, particularly facial muscles.

  • Pathophysiology: Immune proteins block acetylcholine (ACh) receptors, preventing muscle contraction.

• Botulinum (botulism): Toxin produced by Clostridium botulinum bacteria;

  • Mechanism: Blocks ACh release, leading to impaired muscle contraction.

Page 12: General Questions

• Open for any further discussions or questions.

Page 13: Muscle Mechanics Overview

• Skeletal muscles typically attach to bones via tendons and cross joints, allowing for movement.

• Muscle Attachments:

  • Origin: Fixed attachment point when muscles contract (typically proximal).

  • Insertion: Moves during muscle contraction (typically distal).

Page 14: Lever System in Movement

• Most movements can be analyzed as lever systems:

  • Fulcrum: The joint.

  • Effort: The force exerted by muscles.

  • Load: The resistance being moved (often the weight of the limb or gravitational force).

Page 15: Muscle Functional Groups

• Muscle Roles:

  • Agonist: Muscle providing the primary force for movement.

  • Synergist: Assists the agonist in movement.

  • Antagonist: Opposes the action of the agonist (creates contrast).

  • Functional muscle groups often work in synergy for specific actions.

Page 16: Skeletal Muscles Overview

• Curriculum covers around 50 skeletal muscles: focuses on main attachment points and functions.

• Practical application in lab sessions where students create helpful tables for studying.

Page 17: Muscle Naming Conventions

• Muscles are often named based on:

  • Location: (e.g., Temporalis for its location near the temporal bone).

  • Attachments: (e.g., Sternocleidomastoid shows origin at sternum and clavicle).

  • Heads: (e.g., Biceps brachii indicates 'two heads').

  • Size: (e.g., Gluteus maximus versus gluteus medius).

  • Shape: (e.g., Trapezius resembles a trapezoid).

  • Fiber Direction: (e.g., Rectus means 'straight').

  • Actions: (e.g., Extensor digitorum: extends fingers).

Page 18: Study Plan for Muscles

• Plan of focus includes:

  • Face muscles (Day 1).

  • Neck/Trunk muscles and Lower limb muscles (Day 2).

  • Upper limb muscles (Day 3).

• Each muscle covered will include origin/insertion points and primary actions.

Page 19: Muscles of the Face

• List of facial muscles:

  1. Epicranius (frontalis & occipitalis).

  2. Temporalis.

  3. Masseter.

  4. Orbicularis oculi.

  5. Orbicularis oris.

  6. Levator labii superioris.

  7. Zygomaticus major.

  8. Buccinator.

  9. Platysma.

• Function: Primarily for facial expression, closing eyes, and other actions.

• Note: Some muscles (like levator labii superioris and platysma) may not be studied in practical labs.

Page 20: Epicranius Muscle Detail

• Epicranius: Composed of 2 parts separated by the galea aponeurosis.

  • Frontalis:

  • Origin: Galea.

  • Insertion: Eyebrow skin.

  • Action: Raises eyebrows.

  • Occipitalis:

  • Origin: Occipital bone.

  • Insertion: Galea.

  • Action: Retracts scalp (pulls scalp posteriorly).

• Alternative name: Occipitofrontalis muscle.

Page 21: Temporalis & Masseter Muscles

• Temporalis:

  • Origin: Temporal fossa.

  • Insertion: Mandible.

  • Action: Elevates mandible (chewing muscle).

• Masseter:

  • Origin: Zygomatic arch.

  • Insertion: Mandible.

  • Action: Elevates mandible (primary muscle for chewing).

Page 22: Orbicularis Oculi & Oris Muscles

• Orbicularis oculi:

  • Origin: Medial orbital bones.

  • Insertion: Eyelids.

  • Action: Closes eyes.

• Orbicularis oris:

  • Origin: Corners of mouth.

  • Insertion: Lips.

  • Action: Puckers lips (as in kissing).

Page 23: Levator Labii Superioris & Zygomaticus Major

• Levator Labii Superioris:

  • Origin: Maxilla.

  • Insertion: Orbicularis oris (upper).

  • Action: Elevates lip ('snarl').

• Zygomaticus Major:

  • Origin: Zygomatic bone.

  • Insertion: Corner of the mouth.

  • Action: Elevates & laterally moves lip corners ('smile').

Page 24: Dimples and Facial Muscles

• Note: Dimples can result from changes to the zygomaticus major muscle (the muscle can split into 2 parts).

Page 25: Buccinator Muscle Details

• Buccinator: Forms lateral walls of the oral cavity.

  • Origin: Maxilla & mandible.

  • Insertion: Orbicularis oris.

  • Action: Pulls cheeks inward (whistling)

Page 26: Platysma Muscle Details

• Platysma: A thin, sheet-like muscle overlining the anterior neck.

  • Origin: Skin over the clavicle region.

  • Insertion: Inferior mandible; skin of lower face.

  • Action: Depresses mandible & tenses skin of neck/lower face.

Page 27: Muscle Identification Query

• Identify muscles: 1. Orbicularis oris, 2. Raises the eyebrows, 3. Zygomaticus major.

Page 28: Learning Outline Repeated

• Same learning outline provided to reinforce topics covered throughout the week.

Page 29: Lever System Components

• Components of a Lever System to Identify:

  1. Effort (muscle).

  2. Fulcrum (joint).

  3. Load (resistance).

• Example of Muscle Activation: Biceps brachii acting to flex elbow while the brachialis acts as a synergist.

Page 30: Relevant Neck & Trunk Movements

• Movements include:

  • Rotation.

  • Flexion & Extension.

  • Lateral Flexion.

  • Changes in thoracic volume linked to breathing.

Page 31: Muscles of the Neck & Trunk

• List of neck and trunk muscles includes:

  1. Sternocleidomastoid.

  2. Splenius capitis.

  3. Erector spinae.

  4. Rectus abdominis.

  5. External oblique.

  6. Internal oblique.

  7. Transversus abdominis.

  8. Diaphragm.

  9. Intercostals.

• Function: Movement of head, neck, back, abdomen, and changes in thoracic cavity volume for breathing.

• Note: Splenius capitis not covered in lab.

Page 32: Sternocleidomastoid Muscle Details

• Sternocleidomastoid:

  • Origin: Sternum & Clavicle.

  • Insertion: Mastoid process (temporal bone).

  • Action: Laterally flexes and flexes the head.

Page 33: Splenius Capitis Muscle Details

• Splenius Capitis:

  • Origin: Thoracic & Cervical vertebrae.

  • Insertion: Occipital & Temporal bones.

  • Action: Laterally flexes and extends the head.

Page 34: Erector Spinae Group

• Erector Spinae: Muscle group includes Iliocostalis, Longissimus, Spinalis (most medial).

• Attachments: Vary from Pelvis, vertebrae, ribs, skull.

• Action: Laterally flexes, extends head/back, helps maintain posture.

Page 35: Erector Spinae and Splenius Capitis

• Question on Muscle Role: Erector spinae acts as a synergist to the splenius capitis for extension of the head.

Page 36: Abdominal Muscles

• Muscle Anatomy & Functions:

• Linea alba: Midline connective tissue band along the abdominal wall.

• Abdominal wall muscle actions:

  • Laterally flex and rotate abdomen.

  • Contributes to abdominal compression (primarily via Transversus abdominis).

• Muscle names include External oblique, Internal oblique, Transversus abdominis, Rectus abdominis.

Page 37: Transverse Section of Abdominal Muscles

• Muscle Layers:

  • Transversus Abdominis:

    • Origin: Ribs & Ilium.

    • Insertion: Linea alba.

  • Internal Oblique:

    • Origin: Ilium.

  • External Oblique:

    • Origin: Ribs.

Page 38: Rectus Abdominis Muscle Details

• Rectus Abdominis:

  • Origin: Pubis.

  • Insertion: Ribs & Xiphoid process (sternum).

  • Encased in a sheath formed from the tendons of lateral abdominal muscles.

  • Notes on connective tissue intersections: Can create a “six/eight-pack.”

Page 39: Anatomy of Abdominal Wall

• Diagram illustrating relationships among abdominal wall muscles.

Page 40: Breathing Muscles

• Diaphragm and Intercostal Muscles: Key roles in breathing by changing thoracic cavity volume.

  • Diaphragm Action:

  • Inhaling: Increases volume to draw air into lungs.

  • Exhaling: Decreases volume to push air out of lungs.

Page 41: Diaphragm Muscle Details

• Diaphragm:

  • Origin: Lower sternum, Ribs & Vertebrae.

  • Insertion: Central tendon (in the center of the diaphragm).

  • Action: It is the main muscle for breathing, flattens during activation.

Page 42: Intercostals Muscles

• External Intercostals:

  • Action: Pull ribs upward, increasing thoracic volume.

• Internal Intercostals:

  • Action: Pull ribs downward, decreasing thoracic volume.

• Note on fiber orientations: Different movements arise due to varying fiber arrangements.

Page 43: Muscles of the Lower Limb

• List of muscles included:

  1. Iliopsoas.

  2. Gluteus maximus.

  3. Gluteus medius.

  4. Adductors (x3).

  5. Gracilis.

  6. Sartorius.

  7. Quadriceps femoris (x4).

  8. Hamstrings (x3).

  9. Tibialis anterior.

  10. Fibularis longus.

  11. Gastrocnemius.

  12. Soleus.

Page 44: Hip and Knee Movements

• Hip and knee movements categorized as:

  • Flexion & Extension.

  • ABduction & ADduction.

  • Medial & Lateral Rotation.

Page 45: Iliopsoas Muscle Group

• Iliopsoas:

  • Origin: Lumbar vertebrae & Iliac fossa.

  • Insertion: Lesser trochanter (femur).

  • Action: Flex hip.

Page 46: Gluteal Muscles

• Gluteus Maximus:

  • Origin: Ilium, Sacrum & Coccyx.

  • Insertion: Femur & Tibia via IT band.

  • Action: Extended hip.

• Gluteus Medius:

  • Origin: Ilium.

  • Insertion: Greater trochanter (femur).

  • Action: ABducts the hip.

Page 47: Adductors of the Hip

• Adductor muscle group:

  • Origin: Pubis.

  • Insertion: Linea aspera (femur).

  • Identified as: Adductor brevis, longus, and magnus.

  • Action: Adduct hip.

Page 48: Gracilis Muscle Detail

• Gracilis:

  • Origin: Pubis.

  • Insertion: Medial tibia.

  • Action: Adducts hip; Flex and medially rotates leg.

• Note: Long strap-like muscle crossing hip & knee joints.

Page 49: Sartorius Muscle Detail

• Sartorius:

  • Origin: Anterior superior iliac spine (Ilium).

  • Insertion: Medial tibia.

  • Action: ABducts & laterally rotates hip; flexes hip & knee.

• Note: Known as the “Tailor muscle” for its cross-legged position.

Page 50: Overview of Quadriceps Femoris vs Hamstrings

• Opposing muscle groups:

  • Quadriceps Femoris: Comprises 4 muscles.

  • Hamstrings: Comprises 3 muscles.

Page 51: Quadriceps Femoris Muscle Details

• Quadriceps Femoris Group:

  • Includes Rectus femoris, Vastus lateralis, Vastus intermedius, Vastus medialis.

  • Origin: Ilium & Femur.

  • Insertion: Tibial tuberosity via patellar tendon.

  • Action: Flex hip; Extend knee.

Page 52: Hamstrings Anatomy

• Hamstring Group:

  • Comprises Biceps femoris, Semimembranosus, Semitendinosus.

  • Action: Extend hip; flex knee.

Page 53: Foot Movements

• Movements include:

  • Plantar flexion & Dorsiflexion.

  • Inversion & Eversion.

Page 54: Tibialis Anterior Muscle Details

• Tibialis Anterior:

  • Origin: Anterior tibia.

  • Insertion: Medial aspect of foot.

  • Action: Dorsiflexion; Inversion.

Page 55: Fibularis Longus Muscle Details

• Fibularis Longus:

  • Origin: Fibula.

  • Insertion: Medial plantar surface.

  • Action: Plantar flexion; Eversion.

Page 56: Gastrocnemius and Soleus Muscles

• Soleus (deep):

  • Origin: Tibia & Fibula.

  • Insertion: Calcaneus via Achilles tendon.

• Gastrocnemius (superficial):

  • Origin: Femur.

  • Insertion: Calcaneus via Achilles tendon.

  • Action: Plantarflexion; Flex knee.

Page 57: Achilles Tendon Overview

• Achilles Tendon:

  • Characteristics: Largest and strongest tendon in the body; acts like a spring during running, offering approximately 90% energy return from elasticity.

Page 58: Review Questions on Muscle Groups

• Antagonist of Hamstrings: Quadriceps femoris.

• Question on identification of muscles:

  • 1. Iliopsoas, 2. Quadriceps Femoris, 3. Erector Spinae.

Page 59: Revised Learning Outline

• Review repetition on muscle mechanics throughout the week to reinforce education.

Page 60: Shoulder Movement Dynamics

• Relevant Movements Include:

  • Flexion & Extension.

  • Abduction & Adduction.

Page 61: Muscles of the Upper Limb - Shoulder

• List of key shoulder muscles:

  1. Trapezius.

  2. Latissimus dorsi.

  3. Pectoralis major.

  4. Deltoid.

  5. Teres minor.

  6. Subscapularis.

  7. Supraspinatus.

  8. Infraspinatus.

Page 62: Trapezius Muscle Details

• Trapezius:

  • Origin: Occipital & Vertebrae.

  • Insertion: Scapula & Clavicle.

  • Action: Multifunctional, including lateral flexion & extension of the head, along with elevation & depression of the scapula.

Page 63: Latissimus Dorsi Muscle Dynamics

• Latissimus Dorsi:

  • Origin: Vertebrae & Ilium.

  • Insertion: Humerus.

  • Action: ADducts & extends the shoulder;

  • Note: Known as the 'swimmer's muscle' due to its role in swimming strokes.

Page 64: Pectoralis Major Muscle Details

• Pectoralis Major:

  • Origin: Sternum & Clavicle.

  • Insertion: Greater tubercle (humerus).

  • Action: ADducts & flexes the shoulder.

Page 65: Deltoid Muscle Anatomy

• Deltoid:

  • Origin: Scapula & Clavicle.

  • Insertion: Deltoid tuberosity (humerus).

  • Action: Multifunctional; flexes, extends, and abducts the shoulder.

Page 66: Rotator Cuff Muscles

• Rotator Cuff Group: Comprised of four muscles:

  1. Supraspinatus.

  2. Infraspinatus.

  3. Subscapularis.

  4. Teres Minor.

  • Common Insertion: Humerus.

  • Function: Stabilizes shoulder joint, with additional specific actions based on the muscle.

  • Mnemonic: “SITS” for easy recall of rotator cuff muscles.

Page 67: Clinical Note on Rotator Cuff Injuries

• Injury Types: Commonly due to:

  • Acute injury causing event.

  • Repetitive overhead motions.

  • Age degeneration, predominantly over 40 years of age.

• Statistics: Approximately 22% of people affected.

Page 68: Muscles Identification Query

• Identify muscle examples: 1. Trapezius, 2. Deltoid, 3. Pectoralis Major, 4. Latissimus Dorsi.

Page 69: Elbow Joint Movements

• Movements in the Elbow:

  • Flexion & Extension.

  • Supination & Pronation.

Page 70: Muscles of the Upper Limb - Elbow

• Key Muscles:

  1. Biceps brachii.

  2. Brachialis.

  3. Brachioradialis.

  4. Triceps brachii.

  5. Supinator.

  6. Pronator teres.

Page 71: Elbow Flexors

• Biceps Brachii:

  • Origin: Scapula.

  • Insertion: Radius.

  • Action: Flexes elbow and shoulder; also supinates.

• Brachialis:

  • Origin: Humerus (mid).

  • Insertion: Ulna.

Page 72: Clinical Note on SLAP Injuries

• Definition: Superior labrum anterior-posterior tears; common in athletes participating in overhead activities.

• Pathophysiology: Repetitive stress on the biceps tendon affects labrum's functionality.

Page 73: Triceps Brachii Anatomy

• Triceps Brachii:

  • Origin: Scapula & Humerus.

  • Insertion: Olecranon process (ulna).

  • Action: Extends elbow and shoulder; known for its three heads as opposed to the two in biceps.

Page 74: Supinator and Pronator Teres Functions

• Supinator:

  • Origin: Humerus & Ulna.

  • Insertion: Radius.

  • Action: Supinates forearm.

• Pronator Teres:

  • Origin: Humerus & Ulna.

  • Insertion: Radius.

  • Action: Pronates forearm.

Page 75: Muscle Identification Challenge

• Identify muscles: 1. Biceps brachii, 2. Brachialis, 3. Brachioradialis.

  • Functional actions: Elbow flexion compared to extension.

Page 76: Muscles of the Wrist

• Key Wrist Flexors/Extensors:

  1. Flexor carpi radialis, 2. Flexor carpi ulnaris, 3. Extensor carpi radialis, 4. Extensor carpi ulnaris.

Page 77: Flexor and Extensor Actions at the Wrist

• Description:

• Flexor Muscles: Originates from Humerus and inserts onto metacarpals and carpals to allow for wrist flexion.

• Extensor Muscles: Functionally opposite, allowing for wrist extension.

Page 78: Flexor Digitorum Overview

• Flexor Digitorum Muscles:

  • Flexor Digitorum Superficialis:

  • Origin: Humerus, Radius & Ulna.

  • Insertion: Middle phalanx of digits 2-5.

  • Action: Flexes fingers.

  • Flexor Digitorum Profundus:

  • Origin: Ulna.

  • Insertion: Distal phalanx of digits 2-5.

  • Action: Flexes fingers.

• Extensor Digitorum Action:

  • Origin: Humerus.

  • Insertion: Distal phalanx of digits.

Page 79: Clinical Note on Carpal Tunnel Syndrome

• Definition: Condition caused by repetitive movements leading to inflammation of tendons and irritation of nerves.

• Impact: Results in symptoms like numbness, tingling, or pain.

Page 80: Helpful Images for Studying

• Reference diagrams and images for anatomical muscles included, particularly of the anterior forearm musculature.

Page 81: Forearm Muscles Overview

• Posterior Compartment Muscles: Diagrams illustrating major forearm muscles for visualization.

Page 82: Fun Quiz on Digit Muscles

• Muscle Identification Game: Match the correct muscle to the digit:

  1. Thumb - Flexor pollicis longus.

  2. Index finger - Flexor indicis profundus.

  3. Little finger - Flexor digiti minimi brevis.

  4. Big toe - Flexor hallucis longus.

Page 83: Questions and Upcoming Content

• Q&A session for further understanding.

• Next week focus: Nervous tissue with reminders on upcoming quizzes (over muscles and their groups) due by April 5 (11:59 PM).

Page 84: Study Images for Review

• Additional study images provided for student reference.

Page 85-89: Anatomical Illustrations

• Supplementary diagrams depicting major muscles in detail; divided into particular regions (anterior, posterior, superficial, deep).

• Useful tools for visual learners, facilitating improved retention of muscle locations and functions.