2-20_UTA_Review_SLIDES_-_Skeletal_Muscles
Page 1: Skeletal Muscle Functions
Skeletal Muscle Overview
Responsible for voluntary movements.
Connected to bones by tendons.
Page 2: Relationship between Muscles and Joints
Muscle Functionality by Joint Position
Muscles crossing a joint influence movements around all axes of rotation associated with that joint.
Locating muscles on the skeleton helps predict movements:
Observe direction of muscle fibers indicating contraction and shortening.
Identify possible movements such as flexion, extension, abduction, adduction, medial rotation, and lateral rotation.
Page 3: Mechanics of Muscle Contraction
Basic Mechanics
Muscles only pull, they do not push.
Example:
Muscle: Biceps
Movement Completed: Flexion at the elbow.
Joint: Elbow
Axis of Rotation: Horizontal
Generality: Muscles crossing the elbow joint affect forearm movement.
Page 4: General Rule of Muscle Movement
Function of Muscles Across Joints:
SC joint: Moves the shoulder.
Shoulder joint: Moves the arm.
Elbow joint: Moves the forearm.
Wrist joints: Move the hand.
Joints of the digits: Move the fingers.
Similar functionality applies for the lower extremity.
Page 5: Rule of Thumb in Muscle Positioning
Muscle Function by Location
Most anterior muscles serve as flexors and medial rotators.
Most posterior muscles function as extensors and lateral rotators.
Abduction and adduction depend on muscle position relative to the joint (superior or inferior).
Page 6: Divisions of the Muscular System
Types of Muscles:
Axial Muscles:
Associated with the head, vertebral column, and thoracic cage (60% of skeletal muscles).
Appendicular Muscles:
Linked to pectoral and pelvic girdles and limbs (40% of skeletal muscles).
Page 7: Muscle Groups of the Head and Neck
Types of Head and Neck Muscles:
Muscles of Facial Expression
Muscles of Mastication
Muscles of the Eye
Muscles of the Tongue
Muscles of the Pharynx
Muscles of the Larynx
Muscles that move the head
Page 8: Muscles of Facial Expression
Key Muscles:
Frontalis: Raises eyebrows.
Obicularis Oris: Puckers lips.
Obicularis Oculi: Closes eyes.
Levator Labii Superioris: Raises lips.
Zygomaticus: Smile muscle.
Buccinator: Tightens cheeks.
Depressor Labii Inferioris: Lowers lips.
Page 9: Muscles of Mastication
Key Muscles:
Masseter: Main muscle for chewing.
Muscles of the Pharynx and Larynx:
Control diameter of windpipe and throat.
Extrinsic Eye Muscles:
Aid in speech, pitch changes, and direct eye movement.
Page 10: Anterior Muscles of the Neck
Suprahyoid Muscles: Elevate hyoid bone and depress mandible.
Infrahyoid Muscles: Depress hyoid bone; elevate larynx & pharynx.
Functions include chewing, talking, swallowing, singing.
Sternocleidomastoid: Functions as a head/neck rotator.
Page 11: Posterior Muscles of the Neck
Functionality:
Head (neck) extensors aid in moving the head backward (looking up).
Page 12: The Vertebral Column
Muscle Attachment:
Primarily attached to spinous processes; some attach to transverse processes.
Function: Maintain trunk erect and extended.
Note: This is the most overworked muscle group; individual muscles not required to be memorized for lectures.
Page 13: Anterior Body Wall
Intercostal Muscles:
Exterior: Pull up and away from each other.
Interior: Pull down and away.
Purpose: Maintain distance between ribs.
Obliques:
Exterior: Pull belly button up and away.
Interior: Pull belly button down and out.
Transverse Abdominis: Flattens abdomen.
Rectus Abdominis: Flexes the trunk.
Page 14: Anterior Body Wall Layers
Muscle Layers:
Most superficial: External obliques
Next layer: Internal obliques
Deeper: Transverse abdominis
Most internal: Rectus abdominis.
Other important structures: Aponeurosis, rectus sheath, linea alba.
Page 15: The Diaphragm
Functionality:
Separates thoracic and abdominal cavities.
Primary muscle of respiration.
Inspiration: Involves contraction of diaphragm.
Expiration: Forceful expiration utilizes abdominal muscles.
Page 16: Pelvic Floor
Key Areas:
Urethral Sphincter: Controls urination.
Anal Sphincter: Controls defecation.
Note: Individual muscles are not required to be memorized.
Page 17: Appendicular Muscles (Limb Muscles)
Important Muscles:
Brachial muscles
Flexor carpi
Palmars longue
Flexor digitorum.
Various adaptations and branches are specified in the notes.
Page 18: Shoulder Muscles
Main Muscles:
Deltoid: Covers shoulder joint and serves as arm abductor.
Rotator Cuff Muscles:
Supraspinatus: Arm abduction.
Infraspinatus: External rotation of the arm.
Teres Minor: External rotation and assists in adduction.
Subscapularis: Internal rotation.
Teres Major: Arm adductor; assists with internal rotation.
Page 19: Anterior Arm Muscles
Key Muscles:
Biceps Brachii: Main elbow flexor.
Brachialis: Assists in elbow flexion.
Coracobrachialis: Assists in shoulder adduction and flexion.
Page 20: Posterior Arm Muscles
Key Muscle:
Triceps Brachii: Role in extending elbow; consists of lateral, long, and medial head origins.
Page 21: Anterior Forearm Muscles
Key Muscles:
Pronator Teres: Arm pronation.
Palmaris Longus: Longest muscle, aids wrist flexion.
Flexor Carpi Muscles: Flex wrist.
Flexor Pollicis: Flexes the thumb.
Flexor Digitorum: Flexes digits 2-5.
Page 22: Posterior Forearm Muscles
Key Muscles:
Supinator: Arm supination.
Brachioradialis: Assists in elbow flexion and pronation/supination.
Extensor Carpi Muscles: Extends wrist.
Extensor Digitorum: Extends digits 2-5.
Extensor Pollicis: Extends thumb.
Page 23: Lower Extremity Muscles
Muscle Overview: Listed key muscles associated with lower extremities; includes gluteal and hamstring muscles among others.
Notable Functions: Highlighted for various actions such as hip extension, abduction, and flexion.
Page 24: Gluteal Muscles Functions
Main Functions:
Hip extension, abduction, and lateral rotation.
Key Muscles:
Gluteus Maximus - Major hip extensor and abductor.
Gluteus Medius - Assists in hip extension and abduction.
Gluteus Minimus - Same function as Gluteus Medius.
Piriformis - Lateral rotator.
Page 25: Muscles of Pelvic Floor and Medial Thigh
Key Muscles:
Hip Flexors: Iliacus and Psoas Major.
Hip Adductors: Adductor Magnus, Longus, Brevis, and Gracilis.
Page 26: Muscles of the Posterior Thigh (Hamstrings)
Key Muscles:
Semimembranosus
Semitendinosus
Biceps Femoris Long Head
Biceps Femoris Short Head
Functions: Hip extensors and knee flexors.
Page 27: Muscle of Anterior Thigh (Quadriceps)
Functions:
Extends knee: Rectus Femoris, Vastus Lateralis, Vastus Intermedius, Vastus Medialis.
FLEXES knee: Sartorius, with insertion at the medial surface of proximal tibia; origin is superior iliac spine.
Page 28: Muscles of Anterior Leg
Functions:
Toe and foot extensors/Dorsi flexors include: Extensor Digitorum Longus, Extensor Hallucis Longus, and Tibialis Anterior.
Page 29: Muscles of Lateral Leg
Main Muscles:
Foot flexors/plantar flexors: Fibularis Longus, Fibularis Brevis.
Other associated muscles include Vastus Medialis, Lateral head of Gastrocnemius, Soleus.
Page 30: Muscles of Posterior Leg
Functions:
Foot flexors/plantar flexors: Gastrocnemius and Soleus.
Toe flexors: Tendons of Flexor Digitorum Longus and Flexor Hallucis Longus.
Page 31: Dorsal Foot Muscles
Function:
Toe extensors; focus on relevant functions rather than specific muscle names.
Page 32: Plantar Foot Muscles
Function:
Toe flexors; focus on relevant functions rather than specific muscle names.