Podcast
Questions and Answers
Which of the following muscles is not part of the rotator cuff?
Which of the following muscles is not part of the rotator cuff?
The trapezius muscle is responsible for which action(s)? (Select all that apply)
The trapezius muscle is responsible for which action(s)? (Select all that apply)
The deltoid muscle is innervated by which nerve?
The deltoid muscle is innervated by which nerve?
Which of the following muscles is not innervated by the radial nerve?
Which of the following muscles is not innervated by the radial nerve?
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Which muscle is responsible for supination of the forearm?
Which muscle is responsible for supination of the forearm?
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Which of the following muscles is not part of the anterior compartment of the forearm?
Which of the following muscles is not part of the anterior compartment of the forearm?
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Which muscle is responsible for extension of the wrist joint?
Which muscle is responsible for extension of the wrist joint?
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The flexor digitorum superficialis muscle inserts on the proximal phalanges of the fingers.
The flexor digitorum superficialis muscle inserts on the proximal phalanges of the fingers.
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The extensor digitorum muscle is innervated by the posterior interosseous nerve.
The extensor digitorum muscle is innervated by the posterior interosseous nerve.
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The abductor pollicis longus muscle is responsible for which action?
The abductor pollicis longus muscle is responsible for which action?
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What is the primary function of the supinator muscle?
What is the primary function of the supinator muscle?
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The extensor indicis muscle is responsible for the extension of which finger?
The extensor indicis muscle is responsible for the extension of which finger?
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Study Notes
Muscles of the Shoulder
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Trapezius: Originates from the superior nuchal line, external occipital protuberance, and spinous processes of C7 to T12 vertebrae. Inserts on the superior edge of the scapula, acromion, and posterior border of the lateral clavicle. Innervated by the accessory nerve (XI). Elevates, rotates, and depresses the scapula, abducting the humerus.
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Deltoid: Originates from the spine of the scapula, acromion, and anterior border of the clavicle. Inserts on the deltoid tuberosity of the humerus. Innervated by the axillary nerve (C5, C6). A major abductor of the arm, also assists with flexion and extension.
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Levator Scapulae: Originates from the transverse processes of C1-C4 vertebrae. Inserts on the posterior surface of the medial border of the scapula. Innervated by branches from the anterior rami of C3 and C4 spinal nerves. Elevates the scapula.
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Rhomboids (minor & major): Originate from the ligamentum nuchae and spinous processes (minor: CVII, T1; major: TII-TV). Insert on the posterior surface of the medial scapula border. Innervated by the dorsal scapular nerve (C4, C5). Elevates and retracts the scapula.
Muscles of the Posterior Scapular Region
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Supraspinatus: Originates from the supraspinous fossa of the scapula. Inserts on the greater tubercle of the humerus. Innervated by the suprascapular nerve (C5, C6). Initiates abduction of the arm (first 15 degrees).
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Infraspinatus: Originates from the infraspinous fossa of the scapula. Inserts on the greater tubercle of the humerus. Innervated by the suprascapular nerve (C5, C6). Rotates the arm laterally.
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Teres Minor: Originates from the upper two-thirds of the posterior surface of the scapula next to the lateral border. Inserts on the greater tubercle of the humerus. Innervated by the axillary nerve (C5, C6). Rotates the arm laterally.
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Teres Major: Originates from the posterior surface of the inferior angle of the scapula. Inserts on the medial lip of the intertubercular sulcus of the humerus. Innervated by the inferior subscapular nerve (C5, C6, C7). Medially rotates and extends the arm.
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Long Head of Triceps Brachii: Originates from the infraglenoid tubercle of the scapula. Inserts with the medial and lateral heads on the olecranon process of the ulna. Innervated by the radial nerve (C6, C7, C8). Extends the forearm at the elbow and can adduct/extend the arm.
Muscles of the Anterior Wall of the Axilla
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Pectoralis Major: Originates from the medial half of the clavicle, sternum, and costal cartilages 1-7. Inserts on the lateral lip of the intertubercular sulcus of the humerus. Innervated by the medial and lateral pectoral nerves (C5-T1). Flexes, adducts, and medially rotates the arm.
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Subclavius: Originates from the first rib. Inserts onto the clavicle. Innervated by the nerve to subclavius (C5, C6). Depresses the clavicle and stabilizes the sternoclavicular joint.
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Pectoralis Minor: Originates from ribs 3-5. Inserts on the coracoid process of the scapula. Innervated by the medial pectoral nerve (C8, T1). Depresses and protracts the scapula.
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Serratus Anterior: Originates from the lateral surfaces of upper ribs 1-8. Inserts on the medial border of the scapula. Innervated by the long thoracic nerve (C5, C6, C7). Protracts and rotates the scapula, stabilizing the scapula on the thoracic wall.
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Subscapularis: Originates from the subscapular fossa of the scapula. Inserts on the lesser tubercle of the humerus. Innervated by the upper and lower subscapular nerves (C5, C6, C7). Medially rotates the arm.
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Teres major: see the previous section.
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Latissimus Dorsi: Originates from the lower six thoracic vertebrae, lumbar vertebrae, iliac crest and the lower three ribs. Inserts on the intertubercular sulcus of the humerus. Innervated by the thoracodorsal nerve (C6, C7, C8). Adducts, medially rotates, and extends the arm.
Muscles of the Anterior Compartment of the Arm
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Coracobrachialis: Originates from the coracoid process. Inserts on the medial shaft of the humerus. Innervated by the musculocutaneous nerve (C5, C6, C7). Flexes and adducts the arm.
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Biceps Brachii: Originates from the supraglenoid and coracoid tubercle of the scapula. Inserts on the radial tuberosity. Innervated by the musculocutaneous nerve (C5, C6). Flexes the forearm at the elbow and supinates the forearm, as well as flexes the arm.
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Brachialis: Originates from the anterior shaft of the humerus. Inserts on the tuberosity of the ulna. Innervated by the musculocutaneous nerve ( C5-C7). Primarily flexes the forearm at the elbow.
Muscles of the Posterior Compartment of the Arm
- Triceps Brachii: Originates from the infraglenoid tubercle of the scapula, posterior humerus (medial and lateral heads). Inserts on the olecranon of the ulna. Innervated by the radial nerve (C6-8). Extends the forearm at the elbow.
Muscles Having Parts That Pass Through the Axilla
- Biceps Brachii and Coracobrachialis
Muscles of the Anterior Compartment of the Forearm
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Flexor Carpi Ulnaris: Originates from the medial epicondyle of the humerus and olecranon. Inserts on the pisiform, hamate hook. Innervated by ulnar nerve (C7-T1). Flexes and adducts the wrist
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Palmaris Longus: Originates from the medial epicondyle of the humerus.. Inserts on the palmar aponeurosis. Innervated by median nerve (C7, 8). Flexes the wrist joint.
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Flexor Carpi Radialis: Originates from the medial epicondyle of the humerus. Inserts on the base of metacarpals II and III. Innervated by the median nerve (C7, C8). Flexes and abducts the wrist.
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Pronator Teres: Originates from medial epicondyle, ulnar head (coronoid process). Inserts on lateral surface of radius. Innervated by median nerve (C6, 7). Pronates the forearm.
Muscles of the Posterior Compartment of the Forearm
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Brachioradialis: Originates from the proximal lateral supracondylar ridge of the humerus. Inserts on the lateral side of the distal end of the radius. Innervated by the radial nerve. Accessory flexor of elbow, extends and abducts the wrist.
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Extensor Carpi Radialis Longus: Originates from the lateral supracondylar ridge of the humerus. Inserts on the dorsal surface at the base of metacarpal II. Innervated by the radial nerve (C6, 7). Extends and abducts the wrist .
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Extensor Carpi Radialis Brevis: Originates from the lateral epicondyle of the humerus. Inserts on the dorsal surface at the base of metacarpal III. Innervated by the radial nerve (C7,8). Extends and abducts the wrist
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Extensor Carpi Ulnaris: Originates from the lateral epicondyle of the humerus and posterior border of the ulna. Inserts on the base of metacarpal V. Innervated by the deep branch of the radial nerve (C7, 8). Extends and adducts the wrist
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Extensor Digitorum: Originates from the lateral epicondyle of the humerus., Inserts on the extensor hood of the digits. Innervated by the deep branch of the radial nerve (C7, 8). Extends the digits and wrist.
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Extensor Digiti Minimi: Originates from the lateral epicondyle of the humerus. Inserts on the extensor hood of the little finger. Innervated by the posterior interosseous nerve (C7, 8). Extends the little finger.
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Extensor Carpi Ulnaris: Originates in the lateral epicondyle of the humerus. Inserts on the base of metacarpal V. Innervated by the posterior interosseous nerve (C7, 8). Extends and adducts the wrist
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Anconeus: Originates from the lateral epicondyle of humerus. Inserts on the olecranon and posterior surface of the ulna. Innervated by the radial nerve. Accessory extensor of the elbow
Deep Layer of Muscles in the Posterior Compartment of the Forearm
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Supinator: Originates from the lateral epicondyle of the humerus. Inserts on the lateral surface of the radius. Innervated by the posterior interosseous nerve (C6, 7). Assists with supination of the forearm.
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Abductor Pollicis Longus: Originates from the surface of ulna and radius. Inserts on the base of metacarpal I. Innervated by the posterior interosseous nerve (C7, 8). Abducts the thumb.
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Extensor Pollicis Brevis: Originates from the radius. Inserts on the base of proximal phalanx of the thumb. Innervated by the posterior interosseous nerve (C7, 8). Extends the thumb.
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Extensor Pollicis Longus: Originates from the ulna. Inserts on the base of distal phalanx of the thumb. Innervated by the posterior interosseous nerve (C7, 8). Extends the thumb.
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Extensor Indicis: Originates from the ulna. Inserts on the extensor hood of the index finger. Innervated by the posterior interosseous nerve (C7, 8). Extends the index finger.
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Description
Test your knowledge on muscle anatomy, particularly focusing on the rotator cuff and forearm muscles. This quiz covers various muscles, their actions, innervations, and specific functions. Perfect for students studying anatomy and physiology!
