22 Questions
What is the action of the pectoralis minor muscle?
Scapula protraction, depression and medial rotation
Which nerve innervates the pectoralis minor muscle?
Medial pectoral nerve
What is the origin and insertion of the pectoralis minor muscle?
O: anterior surface of ribs 3-5, I: coracoid
What is the action of the serratus anterior muscle?
Scapula protraction, lateral rotation and keeps scapula against thoracic wall
Which nerve innervates the serratus anterior muscle?
Long thoracic nerve
What is the origin and insertion of the serratus anterior muscle?
O: lateral surfaces of ribs 1-8/9, I: medial border of scapula
What are the actions of the trapezius muscle?
Scapula elevation, lateral rotation, retraction and depression
Which nerves innervate the trapezius muscle?
Accessory nerve (motor) and anterior rami of C3 and C4 (sensory)
What is the origin and insertion of the trapezius muscle?
O: nuchal line and external occipital protuberance of occipital bone; ligamentum nuchae; C7-T12 spinous processes, I: scapula spine, acromion and lateral clavicle
What is the action of the levator scapulae muscle?
Scapula elevation
What is the origin and insertion of the latissimus dorsi muscle?
The origin of the latissimus dorsi muscle is the T7-12 spinous processes, iliac crest, and lower 3-4 ribs, and the insertion is the intertubercular sulcus of the humerus.
What is the origin and insertion of the lower (or k.a. lower) subscapular nerve?
The origin of the lower subscapular nerve is the inferior angle of the scapula, and the insertion is the intertubercular sulcus of the humerus.
What is the action of the triceps brachii (long head) muscle?
The triceps brachii (long head) muscle is responsible for forearm extension at the elbow, as well as being an accessory adductor and extensor of the GH joint.
What is the origin and insertion of the triceps brachii (long head) muscle?
The origin of the triceps brachii (long head) muscle is the infraglenoid tubercle of the scapula, and the insertion is the olecranon process of the ulna.
What is the action of the supraspinatus muscle?
The supraspinatus muscle is a rotator cuff muscle that acts as a GH joint stabilizer and initiates GH abduction (first 15˚).
What is the origin and insertion of the supraspinatus muscle?
The origin of the supraspinatus muscle is the supraspinous fossa of the scapula, and the insertion is the greater tubercle of the humerus.
What is the action of the infraspinatus muscle?
The infraspinatus muscle is a rotator cuff muscle that performs lateral rotation of the GH joint.
What is the origin and insertion of the infraspinatus muscle?
The origin of the infraspinatus muscle is the infraspinous fossa of the posterior scapula, and the insertion is the greater tubercle of the humerus.
What is the action of the teres minor muscle?
The teres minor muscle is a rotator cuff muscle that performs lateral rotation of the GH joint.
What is the origin and insertion of the teres minor muscle?
The origin of the teres minor muscle is the lateral border of the scapula, and the insertion is the greater tubercle of the humerus.
What is the action of the subscapularis muscle?
The subscapularis muscle is a rotator cuff muscle that performs medial rotation of the GH joint.
What is the origin and insertion of the subscapularis muscle?
The origin of the subscapularis muscle is the subscapular fossa of the anterior scapula, and the insertion is the lesser tubercle of the humerus.
Study Notes
Muscles of the Scapula and Arm
Pectoralis Minor Muscle
- Rotates the scapula downwards and forwards
- Innervated by the medial pectoral nerve
- Origin: 3rd to 5th ribs
- Insertion: coracoid process of the scapula
Serratus Anterior Muscle
- Rotates the scapula upwards and forwards, helping to raise the arm
- Innervated by the long thoracic nerve
- Origin: 1st to 9th ribs
- Insertion: anterior surface of the scapula
Trapezius Muscle
- Elevates, depresses, and rotates the scapula
- Innervated by the spinal accessory nerve and the cervical nerves (C3 and C4)
- Origin: base of the skull, ligamentum nuchae, and spinous processes of the 7th cervical and 1st thoracic vertebrae
- Insertion: spine of the scapula, acromion process, and lateral clavicle
Levator Scapulae Muscle
- Elevates the scapula
Latissimus Dorsi Muscle
- Origin: spinous processes of the 7th thoracic to 12th thoracic vertebrae, thoracolumbar fascia, and iliac crest
- Insertion: intertubercular groove of the humerus
Lower Subscapular Nerve
- Origin: 5th and 6th cervical vertebrae
- Insertion: subscapularis muscle
Triceps Brachii (Long Head) Muscle
- Extends the elbow joint
- Origin: infraglenoid tubercle of the scapula
- Insertion: olecranon process of the ulna
Supraspinatus Muscle
- Abducts the arm
- Origin: supraspinous fossa of the scapula
- Insertion: greater tubercle of the humerus
Infraspinatus Muscle
- Laterally rotates the arm
- Origin: infraspinous fossa of the scapula
- Insertion: greater tubercle of the humerus
Teres Minor Muscle
- Laterally rotates the arm
- Origin: lateral border of the scapula
- Insertion: greater tubercle of the humerus
Subscapularis Muscle
- Medially rotates the arm
- Origin: subscapular fossa of the scapula
- Insertion: lesser tubercle of the humerus
Test your knowledge of scapula movements and muscle actions with this quiz! Learn about muscles like the Pectoralis Minor and Serratus Anterior, their innervation, origins, and insertions. Challenge yourself and improve your understanding of these important muscles.
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