Podcast
Questions and Answers
What is the primary action of the serratus anterior muscle?
What is the primary action of the serratus anterior muscle?
Which structures pierce the clavipectoral fascia?
Which structures pierce the clavipectoral fascia?
What happens to the scapula if the serratus anterior is paralyzed?
What happens to the scapula if the serratus anterior is paralyzed?
How does the clavipectoral fascia interact with the pectoralis minor muscle?
How does the clavipectoral fascia interact with the pectoralis minor muscle?
Signup and view all the answers
Where does the first digitation of the serratus anterior arise from?
Where does the first digitation of the serratus anterior arise from?
Signup and view all the answers
What is the main action of the whole pectoralis major muscle?
What is the main action of the whole pectoralis major muscle?
Signup and view all the answers
Which muscle is responsible for pulling the scapula downward and assisting in deep inspiration?
Which muscle is responsible for pulling the scapula downward and assisting in deep inspiration?
Signup and view all the answers
Where does the pectoralis major muscle insert?
Where does the pectoralis major muscle insert?
Signup and view all the answers
What is the origin of the pectoralis minor muscle?
What is the origin of the pectoralis minor muscle?
Signup and view all the answers
What nerve innervates the subclavius muscle?
What nerve innervates the subclavius muscle?
Signup and view all the answers
Which anatomical structure is located deep to the pectoralis major muscle?
Which anatomical structure is located deep to the pectoralis major muscle?
Signup and view all the answers
What are the names of the two heads of the pectoralis major muscle?
What are the names of the two heads of the pectoralis major muscle?
Signup and view all the answers
What action is primarily associated with the serratus anterior muscle?
What action is primarily associated with the serratus anterior muscle?
Signup and view all the answers
What action is primarily facilitated by the latissimus dorsi muscle?
What action is primarily facilitated by the latissimus dorsi muscle?
Signup and view all the answers
Which nerve innervates the rhomboid muscles?
Which nerve innervates the rhomboid muscles?
Signup and view all the answers
What is the primary function of levator scapulae?
What is the primary function of levator scapulae?
Signup and view all the answers
Which of these structures does NOT contribute to the thoracolumbar fascia?
Which of these structures does NOT contribute to the thoracolumbar fascia?
Signup and view all the answers
What action do the rhomboid major and minor muscles perform?
What action do the rhomboid major and minor muscles perform?
Signup and view all the answers
Which muscles assist the latissimus dorsi when climbing?
Which muscles assist the latissimus dorsi when climbing?
Signup and view all the answers
What are the quadrangular and triangular spaces primarily associated with?
What are the quadrangular and triangular spaces primarily associated with?
Signup and view all the answers
What is the primary role of the thorax in relation to the muscles discussed?
What is the primary role of the thorax in relation to the muscles discussed?
Signup and view all the answers
What is the primary action of the teres minor muscle?
What is the primary action of the teres minor muscle?
Signup and view all the answers
Which nerve supplies the deltoid muscle?
Which nerve supplies the deltoid muscle?
Signup and view all the answers
Which muscle is primarily responsible for the adduction and medial rotation of the arm?
Which muscle is primarily responsible for the adduction and medial rotation of the arm?
Signup and view all the answers
What action do the upper fibers of the trapezius muscle perform?
What action do the upper fibers of the trapezius muscle perform?
Signup and view all the answers
Which part of the scapula does the teres major muscle originate from?
Which part of the scapula does the teres major muscle originate from?
Signup and view all the answers
What is the action of the subscapularis muscle?
What is the action of the subscapularis muscle?
Signup and view all the answers
Which muscle is NOT part of the deep layer of muscles in the back?
Which muscle is NOT part of the deep layer of muscles in the back?
Signup and view all the answers
Which action is NOT associated with the teres minor muscle?
Which action is NOT associated with the teres minor muscle?
Signup and view all the answers
What is the primary action of the anterior fibers of the deltoid muscle?
What is the primary action of the anterior fibers of the deltoid muscle?
Signup and view all the answers
Which nerve innervates the deltoid muscle?
Which nerve innervates the deltoid muscle?
Signup and view all the answers
What is the origin of the supraspinatus muscle?
What is the origin of the supraspinatus muscle?
Signup and view all the answers
What specific action is initiated by the supraspinatus muscle?
What specific action is initiated by the supraspinatus muscle?
Signup and view all the answers
Which muscle is responsible for stability of the shoulder joint?
Which muscle is responsible for stability of the shoulder joint?
Signup and view all the answers
What is the insertion point of the deltoid muscle?
What is the insertion point of the deltoid muscle?
Signup and view all the answers
Which muscle's primary action is lateral rotation of the arm?
Which muscle's primary action is lateral rotation of the arm?
Signup and view all the answers
What is the action performed by the middle fibers of the deltoid muscle?
What is the action performed by the middle fibers of the deltoid muscle?
Signup and view all the answers
Study Notes
Pectoral Region
- The pectoral region is located in the chest, defined by the pectoralis major muscle.
- It contains the mammary gland in females.
- The pectoral region is composed of 5 layers:
- Skin
- Superficial fascia
- Deep fascia, known as pectoral fascia
- Pectoralis major muscle
- Subclavius muscle, clavipectoral fascia, and muscles
Muscles of the Pectoral Region
-
Pectoralis Major
- Origin:
- Clavicular head: anterior surface of medial half of clavicle
- Sternocostal head: anterior surface of sternum and upper six costal cartilages
- Insertion: Lateral lip of intertubercular groove of humerus by a bilaminar tendon
- Innervation: Medial and lateral pectoral nerves
- Action:
- Adduction and medial rotation of the arm
- Clavicular head: Flexion of the arm
- Origin:
-
Pectoralis Minor
- Origin: Outer surfaces of 3rd to 5th ribs near their costal cartilages.
- Insertion: Coracoid process of scapula
- Innervation: Medial and lateral pectoral nerves
- Action:
- Pulls scapula downward
- Protracts scapula
- Helps with deep inspiration by pulling on the ribs
-
Subclavius
- Origin: Upper surface of first costochondral junction.
- Insertion: Groove on the inferior surface of the middle one-third of the clavicle.
- Innervation: Nerve to subclavius (C5, C6)
- Action: Prevents excessive movements of the clavicle.
-
Serratus Anterior
- Origin: 8 digitations from the outer surfaces of the upper 8 ribs midway between the angle and their costal cartilage.
- Insertion: Anterior surface of medial border of scapula.
- Innervation: Long thoracic nerve (C5, C6, C7)
- Action:
- Powerful protraction of the scapula
- Rotation of the scapula upward to put the arm overhead
- Keeps medial border of scapula close to thoracic wall
- Helps with deep inspiration
Clavipectoral Fascia
- A thickened part of the deep fascia between the pectoralis minor and the clavicle.
- Encloses the subclavius muscle.
- Covered by the clavicular head of pectoralis major.
- Pierced by four structures:
- Cephalic Vein
- Thoraco-acromial artery
- Lateral pectoral nerve
- Lymphatics
- Splits to enclose pectoralis minor and continues downwards as the suspensory ligament of the axilla, connecting to the axillary fascia (the floor of the axilla).
Shoulder Region
-
Deltoid
- Origin:
- Anterior fibers: Anterior border of lateral 1/3 of clavicle
- Middle fibers: Lateral border of acromial process
- Posterior fibers: Lower lip of the crest of the spine of scapula
- Insertion: Deltoid tuberosity at the middle of the lateral surface of the humerus.
- Innervation: Axillary nerve (C5, C6)
- Action:
- Anterior fibers: Flexion and medial rotation of the arm.
- Middle fibers: Abduction of the arm from 15-90 degrees.
- Posterior fibers: Extension and lateral rotation of the arm.
- Origin:
-
Supraspinatus
- Origin: Medial 2/3 of the supraspinous fossa of the scapula.
- Insertion: Highest impression on the greater tuberosity of the humerus.
- Innervation: Suprascapular nerve (C5, C6).
- Action:
- Stability of the shoulder joint.
- Initiation of abduction of the arm to 15 degrees at the shoulder joint.
-
Infraspinatus
- Origin: Medial 2/3 of the infraspinous fossa of the scapula.
- Insertion: Middle impression on the posterior surface of the greater tuberosity of the humerus.
- Innervation: Suprascapular nerve (C5, C6).
- Action:
- Stability of the shoulder joint.
- Lateral rotation of the arm.
-
Teres Minor
- Origin: Upper 2/3 of posterior surface of the lateral border of the scapula.
- Insertion: Inferior impression on the posterior surface of the greater tuberosity of the humerus.
- Innervation: Axillary nerve (C5, C6).
- Action:
- Stability of the shoulder joint.
- Adduction and lateral rotation of the arm.
-
Teres Major
- Origin: Lower 1/3 of posterior surface of the lateral border of the scapula.
- Insertion: Medial lip of the bicipital groove.
- Innervation: Lower subscapular nerve (C5, C6).
- Action:
- Stability of the shoulder joint.
- Medial rotation, adduction, and extension of the arm.
-
Subscapularis
- Origin: Medial 2/3 of subscapular fossa.
- Insertion: Lesser tuberosity of the humerus.
- Innervation: Upper and lower subscapular nerves.
- Action:
- Stability of the shoulder joint.
- Adduction and medial rotation of the arm.
Muscles of the Back
-
Superficial Layer
- Trapezius
- Latissimus dorsi
-
Deep Layer
- Levator Scapulae
- Rhomboids minor and major
Muscles of Back - Deep Layer
-
Trapezius
- Origin:
- Skull: External occipital protuberance, medial 1/3 of superior nuchal line
- Neck: Ligamentum nuchae and spine of C7
- Thorax: All thoracic spines and supraspinous ligament
- Insertion:
- Upper fibers: Back of lateral 1/3 of clavicle.
- Middle fibers: Medial border of acromion process and upper lip of crest of spine of scapula.
- Lower fibers: Tubercle of crest of spine of scapula.
- Innervation:
- Motor: Spinal root of the accessory nerve (XI)
- Sensory (Proprioception): C3 and C4
- Action:
- Upper fibers: Elevates tip of the shoulder
- Middle fibers: Retraction of scapula
- Lower fibers: Depress scapula, assist in rotating scapula upward during abduction from 90-180 degrees.
- Origin:
-
Latissimus Dorsi
- Origin:
- Posterior 1/3 of outer lip of iliac crest
- Thoracolumbar fascia
- Spine of lower six thoracic vertebrae
- Lower 3-4 ribs
- Back of inferior angle of scapula
- Insertion: Floor of bicipital groove.
- Innervation: Thoracodorsal nerve (C6, C7, C8)
- Action:
- Adduction, medial rotation, and extension of the arm
- Deep expiration
- Helps with climbing with pectoralis major by acting from insertion.
- Origin:
-
Levator Scapulae
- Origin: Transverse processes of C1 to C4 vertebrae.
- Insertion: Dorsal surface of medial border of scapula between the spine and superior angle.
- Innervation: C3 to C4 and dorsal scapular nerve (C5)
- Action:
- Elevates scapula with upper fibers of trapezius
- Rotates scapula downward
-
Rhomboid Minor
- Origin: Lower portion of ligamentum nuchae, spinous processes of C7 and T1.
- Insertion: Dorsal surface of medial border of scapula at the root of spine of scapula.
- Innervation: Dorsal scapular nerve (C5)
- Action:
- Retracts with middle fibers of trapezius
- Rotates scapula downward
-
Rhomboid Major
- Origin: Spinous processes of T2 to T5 vertebrae.
- Insertion: Dorsal surface of medial border of scapula between the spine and inferior angle.
- Innervation: Dorsal scapular nerve (C5)
- Action:
- Like rhomboid minor
Quadrangular and Triangular Spaces
- Located just below the shoulder joint.
- Provide passage for neurovascular structures.
-
Quadrangular space: Boundaries:
- Superior: Teres minor muscle.
- Inferior: Teres major muscle.
- Medial: Long head of triceps brachii.
- Lateral: Humerus.
-
Triangular space: Boundaries:
- Superior: Teres minor muscle.
- Inferior: Teres major muscle.
- Medial: Lateral border of scapula.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge of the pectoral region, including its anatomical layers and muscle functions. This quiz covers key muscles such as the pectoralis major and minor, along with their origins, insertions, and actions. Perfect for students of anatomy and physiology.
