Human Anatomy: Muscles Quiz

DENT111 Anatomy

• Upper limb muscles are detailed, but small muscle groups are not, only their functions.
• Carpal tunnel syndrome is related to the median nerve.
• The deltoid muscle has three parts: clavicular, acromial, and spinal.
• The deltoid muscle is an abductor of the glenohumeral joint, with an abduction range of 15 degrees.

Upper Limb Muscles

• The main muscles of the shoulder and upper limb are shown in an anterior and posterior view.
• Muscle names include Trapezius, Pectoralis major, Deltoid, Coracobrachialis, Brachialis, Brachioradialis, Biceps, Pronator teres, Palmaris longus, Flexor carpi ulnaris, Extensor carpi radialis (longus and brevis), Extensor carpi ulnaris, Triceps, Latissimus dorsi.

Shoulder and Arm Muscles

• Posterior view of the upper arm muscles include supraspinatus, infraspinatus, teres minor, long head of tricep brachii, teres major, posterior cutaneous nerve, medial intermuscular septum, acromion, greater tubercle of humerus, deltoid, lateral head of triceps brachii muscle, tendon of triceps brachii muscle, brachioradialis, ulnar nerve, extensor carpi radialis longus muscle, anconeus muscle, extensor carpi radialis brevis muscle, flexor carpi ulnaris muscle, and extensor carpi ulnaris muscle.

Deltoid (M. Deltoideus)

• Has three parts: pars clavicularis, pars acromialis, pars spinalis.
• Abduction, range up to 15°.
• Anterior, lateral, and posterior deltoid are identified and their functions are described.

Deltoid (M. Deltoideus)

• All fibers abduct the shoulder.
• Anterior fibers flex the shoulder, medially rotate the shoulder, and horizontally adduct the shoulder.
• Posterior fibers extend the shoulder, laterally rotate the shoulder, and horizontally abduct the shoulder.
• The attachment points are the lateral one-third of clavicle, acromion, and spine of scapula and deltoid tuberosity.
• Innervation is by the axillary nerve from the brachial plexus.

Trapezius

• Has three parts: pars superior, pars media, pars inferior.
• Shapes are triangular.
• Assists with abduction, up to 90°

Trapezius

• The trapezius muscle does not attach to the humerus.
• Origins include the nuchal line, spinous processes of cervical and thoracic vertebrae, and ligamentum nuchae.
• Insertions are on the scapula
• Innervation: accessory nerve
• Action: elevation, depression, retraction, and rotation of the scapula, extension of the head and neck.

Latissimus Dorsi

• The only upper limb muscle that attaches to the lumbar vertebrae.
• Actions: extending, adducting, and medially rotating the shoulder.
• Originates from the spinous processes of the lower six thoracic vertebrae, three or four lower ribs, and the iliac crest.
• Inserts on the crest of the lesser tubercle of the humerus.
• Innervated by the thoracodorsal nerve.

Teres Major

• Actions: extends, adducts, and medially rotates the arm.
• Originates on the lateral border of the scapula
• Inserts on the crest of lesser tubercle of the humerus.
• Innervated by the lower subscapular nerve.

Rotator Cuff Muscles

• Include supraspinatus, infraspinatus, teres minor, and subscapularis.
• These muscles stabilize the shoulder joint.

Supraspinatus

• Abducts the shoulder and stabilizes the head of the humerus in the glenoid cavity.
• Origin: supraspinous fossa of the scapula.
• Insertion: greater tubercle of the humerus.
• Innervation: suprascapular nerve

Teres Minor

• Laterally rotates, extends, and horizontally abducts the arm.
• Originates from the lateral 2/3s of scapular dorso-lateral border
• Inserts on the greater tubercle.
• Innervation: axillary nerve

Infraspinatus

• Laterally rotates, extends, and horizontally abducts the shoulder.
• Originates from the infraspinous fossa of the scapula.
• Inserts on the greater tubercle of the humerus.
• Innervation: suprascapular nerve

Subscapularis

• Medially rotates the shoulder and stabilizes the head of the humerus in the glenoid cavity.
• Originates from the subscapular fossa of the scapula.
• Inserts on the lesser tubercle of the humerus.
• Innervation: upper and lower subscapular nerves.

Rhomboid Major and Minor

• Their only function is to retract the scapula.
• Rhomboid major originates from T2-T5 vertebrae and inserts on the medial border of the scapula.; innervated by the dorsal scapular nerve
• Rhomboid minor originates from C7-T1 vertebrae and inserts on the root of the medial border of the scapula.; innervated by the dorsal scapular nerve.

Levator Scapulae

• Unilaterally: Elevates the scapula, downwardly rotates the scapula, laterally flexes the head and neck, and rotates the head to the same side.
• Bilaterally: Extends the head and neck
• Origin: transverse processes of C1-C4 vertebrae.
• Insertion: medial border of scapula.
• Innervation: Dorsal scapular and cervical nerves

Serratus Anterior

• With the origin fixed: Abducts the scapula, depresses the scapula, holds the medial border of the scapula against the rib cage, and assists in forced inhalation.
• Origin: upper eight or nine ribs.
• Insertion: anterior surface of medial border of scapula.
• Innervation: long thoracic nerve

Pectoralis Major

• All fibers adduct the shoulder and medially rotate the shoulder.
• Upper fibers: flex the shoulder, horizontally adduct the shoulder.
• Lower fibers: extend the shoulder.
• Origin: medial half of clavicle, sternum, and costal cartilages of ribs 1-6/7.
• Insertion: crest of greater tubercle of humerus.
• Innervation: medial and lateral pectoral nerves

Pectoralis Minor

• Depresses the scapula, abducts the scapula, tilts the scapula anteriorly, and assists in forced inhalation.
• Origin: ribs 3-5.
• Insertion: coracoid process of scapula.
• Innervation: medial pectoral nerve

Subclavius

• Draws the clavicle inferiorly and anteriorly, elevates the first rib to assist in inhalation, and stabilizes the sternoclavicular joint.
• Origin: first rib and its costal cartilage.
• Insertion: inferior and lateral aspect of clavicle.
• Innervation: nerve to subclavius muscle

Biceps Brachii

• Flexes the elbow and forearm, and flexes the shoulder.
• Origins: coracoid process of scapula (short head), supraglenoid tubercle of scapula (long head).
• Insertion: tuberosity of the radius and aponeurosis of the biceps brachii.
• Innervation: musculocutaneous nerve

Triceps Brachii

• Extends the elbow, extends the shoulder, and adducts the shoulder.
• Origins: Infraglenoid tubercle of the scapula (long head), posterior surface of the proximal half of the humerus (lateral head), posterior surface of the distal half of the humerus (medial head).
• Insertion: olecranon process of the ulna.
• Innervation: radial nerve

Coracobrachialis

• Flexes and adducts the shoulder.
• Origin: coracoid process of the scapula.
• Insertion: medial surface of the mid-humeral shaft.
• Innervation: musculocutaneous nerve

Forearm and Arm Muscles

• Biceps brachii, Brachialis, Brachioradialis, Pronator teres, Palmaris longus, Flexor carpi ulnaris, Flexor carpi radialis, Supinator, Pronator Quadratus, are among others.

Brachialis

• Flexes the elbow.
• Origin: distal half of the anterior surface of the humerus.
• Insertion: tuberosity and coronoid process of the ulna.
• Innervation: musculocutaneous nerve

Brachioradialis

• Flexes the elbow, assists in pronation and supination of the forearm when these movements are resisted.
• Origin: lateral supracondylar ridge of humerus.
• Insertion: styloid process of radius.
• Innervation: radial nerve

Extensors of the Wrist and Fingers

• Include: extensor expansion, tendons of extensor digitorum, extensor pollicis longus, extensor pollicis brevis, abductor pollicis longus, extensor digitorum, extensor carpi radialis brevis, extensor carpi radialis longus, extensor carpi ulnaris.

Extensor Carpi Radialis Longus and Brevis

• Extend the wrist, abduct the wrist, and assists in flexing the elbow.
• Origin: lateral supracondylar ridge of humerus.
• Insertion: longus - base of second metacarpal, brevis - base of third metacarpal.
• Innervation: radial nerve

Extensor Carpi Ulnaris

• Extends and adducts the wrist
• Origin: lateral epicondyle of humerus.
• Insertion: base of fifth metacarpal.
• Innervation: radial nerve

Extensor Digitorum

• Extends the second through fifth fingers, assists in extending the wrist.
• Origin: lateral epicondyle of humerus.
• Insertion: middle and distal phalanges of second through fifth fingers
• Innervation: radial nerve

Anconeus

• Assists in forearm extension at the elbow joint, stabilizes the elbow joint.
• Origin: lateral epicondyle of humerus.
• Insertion: lateral surface of olecranon.
• Innervation: radial nerve

Extensor Indicis

• Function not specified in the provided text.

Flexors of the Wrist and Fingers

• Pronator teres, Flexor Carpi Radialis, Palmaris Longus, Flexor Carpi Ulnaris, Flexor Digitorum Superficialis, Flexor Digitorum Profundus

Flexor Carpi Radialis

• Flexes and abducts the wrist, flexes the elbow.
• Origin: medial epicondyle.
• Insertion: bases of second and third metacarpals
• Innervation: median nerve

Palmaris Longus

• Tenses the palmar fascia, flexes the wrist, and flexes the elbow.
• Origin: medial epicondyle.
• Insertion: flexor retinaculum and palmar aponeurosis.
• Innervation: median nerve

Flexor Carpi Ulnaris

• Flexes and adducts the wrist, assists in flexing the elbow.
• Origin: humeral head - medial epicondyle of humerus, ulnar head - posterior surface of the proximal half of ulna.
• Insertion: pisiform and base of fifth metacarpal.
• Innervation: ulnar nerve

Flexor Digitorum Superficialis

• Flexes the second through fifth fingers at the metacarpophalangeal and proximal interphalangeal joints, flexes the wrist.
• Origin: medial epicondyle of humerus, ulnar collateral ligament, coronoid process of ulna, and shaft of radius.
• Insertion: sides of middle phalanges of second through fifth fingers.
• Innervation: median nerve

Flexor Digitorum Profundus

• Flexes the second through fifth fingers at the metacarpophalangeal and distal interphalangeal joints, assists in flexing the wrist.
• Origin: anterior and medial surfaces of proximal three-quarters of ulna.
• Insertion: bases of distal phalanges of second through fifth fingers, palmar surface.
• Innervation: medial and ulnar nerves

Pronator Teres

• Pronates the forearm, assists in flexing the elbow.
• Origin: medial epicondyle of humerus, common flexor tendon, and coronoid process of ulna
• Insertion: middle of lateral surface of radius
• Innervation: median nerve

Pronator Quadratus

• Pronates the forearm.
• Origin: medial, anterior surface of distal ulna.
• Insertion: lateral, anterior surface of distal radius.
• Innervation: median nerve

Supinator

• Supinates the forearm.
• Origin: radial collateral ligament, annular ligament, and supinator crest of ulna.
• Insertion: lateral surface of proximal shaft of radius.
• Innervation: radial nerve

Muscles of the Thumb and Hand

• Includes numerous muscles as Abductor pollicis longus, Extensor pollicis longus and brevis, Flexor pollicis longus, Flexor pollicis brevis, Opponens pollicis, Adductor pollicis.

Short Muscles of the Thumb

• Includes Abductor pollicis brevis, Flexor pollicis brevis, Opponens pollicis, Adductor pollicis.

Abductor Pollicis Brevis

• Abducts the thumb.

Flexor Pollicis Brevis

• Flexes the thumb.

Opponens Pollicis

• Opposes the thumb.

Adductor Pollicis

• Adducts the thumb

Muscles of the Hand

• Includes several muscles like several intrinsic and extrinsic muscles

Lumbricals of the hand

• Four muscles that assist in thumb and finger movements

Palmar Interossei

• Function in adducting the fingers

Dorsal Interossei

• Abducts the fingers and acts on the metacarpophalangeal joints.

Abductor Digiti Minimi

• Abducts the little finger

Flexor Digiti Minimi Brevis

• Flexes the little finger

Opponens Digiti Minimi

• Opposes the little finger.

Other Structures (Bursa)

• Includes subacromial, subcoracoid, and subdeltoid bursae, suprascapularis, coracoid, acromioclavicular, and subcoracoid bursae are among others

References

• Palastanga, N. and Soames, R. (2012), Anatomy and Human Movement: Structure and Function.
• Biel, A. (2014), Trail Guide to the Body
• Tortora, G.J., and Grabowski, S.R. (2000) Principles of Anatomy and Psychology.

Test your knowledge on the human muscular system with this quiz focusing on important muscle functions and anatomy. Explore questions about the deltoid muscle, rotator cuff, and elbow joint flexion. Perfect for students of anatomy or anyone interested in human physiology!