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What is the function of the anterior fibers of the deltoid muscle?
What is the function of the anterior fibers of the deltoid muscle?
The middle fibers of the deltoid muscle are involved in glenohumeral extension.
The middle fibers of the deltoid muscle are involved in glenohumeral extension.
False
What is the origin of the subscapularis muscle?
What is the origin of the subscapularis muscle?
Subscapular fossa
The insertion of the subscapularis muscle is the __________.
The insertion of the subscapularis muscle is the __________.
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Match the deltoid fibers with their respective primary functions:
Match the deltoid fibers with their respective primary functions:
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Which muscle is primarily responsible for the elevation of the scapula?
Which muscle is primarily responsible for the elevation of the scapula?
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The Rhomboid Major and Minor muscles are responsible for the protraction of the scapula.
The Rhomboid Major and Minor muscles are responsible for the protraction of the scapula.
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Where do the Rhomboid Major and Minor muscles originate?
Where do the Rhomboid Major and Minor muscles originate?
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The function of the Levator Scapulae is the elevation of the _____
The function of the Levator Scapulae is the elevation of the _____
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Match the following muscles with their corresponding functions:
Match the following muscles with their corresponding functions:
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What is the primary function of the pectoralis minor?
What is the primary function of the pectoralis minor?
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The serratus anterior originates from the coracoid process of the scapula.
The serratus anterior originates from the coracoid process of the scapula.
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What is the insertion point of the pectoralis minor?
What is the insertion point of the pectoralis minor?
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The _______________ muscle is responsible for protraction of the scapula.
The _______________ muscle is responsible for protraction of the scapula.
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Match the following muscles to their functions:
Match the following muscles to their functions:
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Which of the following muscles originates from the ribs?
Which of the following muscles originates from the ribs?
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The deltoid muscle inserts at the deltoid tuberosity on the humerus.
The deltoid muscle inserts at the deltoid tuberosity on the humerus.
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List one primary function of the deltoid muscle.
List one primary function of the deltoid muscle.
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What is the primary function of the biceps brachii?
What is the primary function of the biceps brachii?
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The teres major is responsible for lateral rotation of the arm.
The teres major is responsible for lateral rotation of the arm.
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Name two muscles found in the anterior compartment of the arm.
Name two muscles found in the anterior compartment of the arm.
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The triceps brachii is primarily responsible for ______ at the elbow.
The triceps brachii is primarily responsible for ______ at the elbow.
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Match the muscle to its function:
Match the muscle to its function:
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What structures are referred to as the 'Major' muscles in the mnemonic?
What structures are referred to as the 'Major' muscles in the mnemonic?
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The long head of the biceps brachii originates from the coracoid process of the scapula.
The long head of the biceps brachii originates from the coracoid process of the scapula.
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What is the insertion point for the biceps brachii?
What is the insertion point for the biceps brachii?
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What is the primary function of the intrinsic muscles of the back?
What is the primary function of the intrinsic muscles of the back?
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The erector spinae muscles are responsible for lateral flexion of the spine when acting unilaterally.
The erector spinae muscles are responsible for lateral flexion of the spine when acting unilaterally.
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List the three vertical columns of the erector spinae muscles.
List the three vertical columns of the erector spinae muscles.
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The __________ muscle originates from the sternum and clavicle and inserts on the mastoid process.
The __________ muscle originates from the sternum and clavicle and inserts on the mastoid process.
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Which muscle primarily contributes to extension of the spine when acting bilaterally?
Which muscle primarily contributes to extension of the spine when acting bilaterally?
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The scalene muscles primarily function to extend the cervical spine.
The scalene muscles primarily function to extend the cervical spine.
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What is the insertion point of the anterior scalene muscle?
What is the insertion point of the anterior scalene muscle?
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The __________ muscles are part of the deep neck muscles and assist in respiration.
The __________ muscles are part of the deep neck muscles and assist in respiration.
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Which of the following muscles is part of the extrinsic muscles of the back?
Which of the following muscles is part of the extrinsic muscles of the back?
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What is the main function of skeletal muscle?
What is the main function of skeletal muscle?
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Passive range of motion does not involve the activation of muscles.
Passive range of motion does not involve the activation of muscles.
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What is the term for the measurement of the amount of movement around a joint?
What is the term for the measurement of the amount of movement around a joint?
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Muscle fiber is also known as a ______.
Muscle fiber is also known as a ______.
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Which type of range of motion involves both muscle activation and assistance from another person?
Which type of range of motion involves both muscle activation and assistance from another person?
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Cardiac muscle cells are elongated like skeletal muscle fibers.
Cardiac muscle cells are elongated like skeletal muscle fibers.
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What type of muscle action does the somatic nervous system control?
What type of muscle action does the somatic nervous system control?
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Study Notes
Lecture Fourteen: The Muscular System – I
-
Learning Objectives:
- Review details of the muscular system.
- Define range of motion (ROM) and how it's assessed in patients.
- Define extrinsic and intrinsic back muscles.
- Differentiate between layers of back muscles.
- Identify origins, insertions, and actions/functions of back, neck, shoulder, and arm muscles.
Introduction to Muscles
- Muscles convert chemical energy (ATP) into mechanical energy (and heat).
- Anatomical terms beginning with "myo" or "mys" refer to muscles.
- Muscle fibers (myofibers) are elongated muscle cells (skeletal or smooth).
- Cardiac muscle cells are not elongated and interconnected.
Our Focus for This Unit (KINE 1101): Skeletal Muscle
- Skeletal muscle is consciously controlled (somatic nervous system).
- Skeletal muscle is rich with blood supply.
- Each muscle fiber has a nerve ending (motor unit) that tells the muscle to contract.
Range of Motion (ROM)
- Active ROM: Movement occurring around a joint or body part with muscle activation.
- Passive ROM: Movement occurring around a joint or body part without muscle activation (manually moved by a healthcare practitioner).
- Active-Assisted ROM: Muscles are activated, but the movement is assisted.
Extrinsic vs. Intrinsic Muscles of the Back
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Extrinsic Muscles:
- Superficial muscles with primary function being upper limb movement.
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Intrinsic Muscles:
- Muscles attached to vertebrae or ribs.
- Primary function is movement and support of the vertebral column.
- Innervation: Posterior rami of spinal nerves.
Intrinsic Muscles of the Back: Erector Spinae
- Three vertical columns of muscle (iliocostalis, longissimus, spinalis).
- Commonly referred to as "I Like Standing" muscles.
-
Function:
- Bilateral: Extension of the spine.
- Unilateral: Lateral flexion of the spine (iliocostalis).
Muscles of the Neck: Splenius Capitis and Cervicis
- Capitis: Insertion onto the skull (mastoid process).
- Cervicis: Insertion onto transverse processes of cervical vertebrae.
-
Function:
- Bilateral: Extension of the spine.
- Unilateral: Ipsilateral lateral flexion and rotation of the head and cervical spine.
Muscles of the Neck: Sternocleidomastoid
- Origins: Sternum & Clavicle
- Insertion: Mastoid Process
-
Function:
- Bilateral: Extension of head/neck; flexion of the neck (inferior cervical vertebrae/sternal head).
- Unilateral: Contralateral rotation, ipsilateral lateral flexion.
Deep Muscles of the Neck: Anterior
- Includes accessory muscles of respiration (longus capitis, anterior scalene, middle scalene, posterior scalene).
- Specific functions for each muscle described.
Extrinsic Muscles: First Layer (Superficial) – Trapezius and Latissimus Dorsi
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Trapezius:
- Origin: Posterior skull and cervical and thoracic vertebrae
- Insertion: Clavicle, acromion and spine of the scapula
- Function(s): Fiber group dependent: elevation, retraction, and upward rotation of scapula (upper/middle fibers) and depression of scapula (lower fibers).
-
Latissimus Dorsi:
- Origin: Lower thoracic and lumbar vertebrae, sacrum & iliac crest
- Insertion: Floor of the intertubercular groove of the humerus
- Function(s): Extension, adduction, and medial rotation of the arm at the glenohumeral joint.
Extrinsic Muscles: Second Layer (Superficial) – Levator Scapulae and Rhomboids
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Levator Scapulae:
- Origin: Cervical spine
- Insertion: Superomedial border of the scapula
- Function(s): Elevation of the scapula.
-
Rhomboid Major & Minor:
- Origin: Cervical and thoracic spine
- Insertion: Medial border of the scapula
- Function(s): Retraction (adduction) of scapula.
Extrinsic Muscles: Third Layer (Superficial) – Serratus Posterior Superior & Inferior
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Serratus Posterior Superior:
- Origin: SPs of lower cervical to upper thoracic spine
- Insertion: First 4 ribs
- Function: Elevation of the ribs.
-
Serratus Posterior Inferior:
- Origin: SPs of lower thoracic vertebrae
- Insertion: Ribs 9-12
- Function: Depression of lower ribs.
Muscles of the Shoulder: Anterior
-
Pectoralis Major:
- Origin: Clavicular and sternal heads.
- Insertion: Lateral lip of the intertubercular groove.
- Function(s): Glenohumeral flexion, medial rotation, and adduction of the arm.
-
Subclavius:
- Origin: First rib (costal cartilage)
- Insertion: Clavicle (inferior surface)
- Function: Depression of the clavicle.
-
Pectoralis Minor:
- Origin: Ribs 3-5
- Insertion: Coracoid process of the scapula
- Function: Depression and downward rotation of scapula.
-
Serratus Anterior:
- Origin: Lateral borders of the ribs
- Insertion: Anteromedial border of the scapula
- Function: Protraction of the scapula.
Muscles of the Shoulder: Lateral
-
Deltoid:
- Origin: Clavicle, acromion, and spine of the scapula
- Insertion: Deltoid tuberosity on the humerus
- Function(s): Fiber group dependent: flexion, abduction, extension, and lateral/external rotation.
- (See details for anterior, middle and posterior portions of this muscle)
Muscles of the Rotator Cuff
-
Subscapularis:
- Origin: Subscapular fossa
- Insertion: Lesser tubercle of the humerus
- Function: Medial (internal) rotation of the glenohumeral joint.
-
Supraspinatus:
- Origin: Supraspinous fossa
- Insertion: Greater tubercle of the humerus
- Function: Initiation of arm abduction (approximately 30 degrees).
-
Infraspinatus:
- Origin: Infraspinous fossa
- Insertion: Greater tubercle of the humerus
- Function: Lateral (external) rotation of the glenohumeral joint
-
Teres Minor:
Origin: Lateral scapular border (superior portion)
- Insertion: Greater tubercle of the humerus
- Function: Lateral (external) rotation of the glenohumeral joint.
Summary: The Rotator Cuff
- Known as the "SITS" muscles, where each muscle letter stands for its name
- Common function is to create a cuff around the glenohumeral joint to stabilize the joint.
Muscles of the Shoulder: Posterior (Teres Major)
-
Teres Major:
- Origin: Lateral scapular border (inferior)
- Insertion: Medial lip of the intertubercular groove on the humerus
- Function: Extension, adduction, and medial (internal) rotation of the arm at the glenohumeral joint.
Muscular Compartments of the Arm
- Anterior: Flexor compartment ("flexion of the forearm at the elbow") - biceps brachii (long and short heads), coracobrachialis, brachialis
- Posterior: Extensor compartment ("extension of the forearm at the elbow") - triceps brachii (medial, lateral, and long heads)
The Arm: Anterior Compartment – Biceps Brachii
- Origins: Long head - supraglenoid tubercle of scapula; Short head - coracoid process.
- Insertion: Radial tuberosity.
- Function: Primary = Supination of forearm; Flexion of elbow joint, accessory flexor of GH joint.
Supination vs. Pronation
- This describes the movements of the forearm relating to the radius, ulna, and biceps brachii muscles. Details included.
The Arm: Anterior Compartment – Coracobrachialis and Brachialis
-
Coracobrachialis:
- Origin: Coracoid process
- Insertion: Anterior humerus (shaft)
- Function: Flexion of the arm at the glenohumeral joint.
-
Brachialis:
- Origin: Anterior shaft of the humerus
- Insertion: Ulnar tuberosity
- Function: Flexion of the forearm at the elbow.
Exception to Arm Compartments – Brachioradialis
- Brachioradialis: Stretches across the elbow joint, from the lateral supracondylar ridge of the humerus to the styloid process of the radius.
- Function: Flexion of forearm at the elbow.
- Tested in neutral position.
The Arm: Posterior Compartment – Triceps Brachii
- Origins: Long head - infraglenoid tubercle of scapula; Lateral & Medial Heads - posterior shaft of humerus.
- Insertion: Olecranon of the ulna.
- Function: Extension of the elbow joint.
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Description
Test your knowledge on the functions, origins, and insertions of the deltoid and subscapularis muscles. Match the various deltoid fibers with their primary functions and learn about the muscles responsible for the elevation of the scapula. This quiz will enhance your understanding of upper body anatomy.