Upper Limb - Muscles Flashcards
Pectoralis minor
Origin - 3rd-5th ribs near their costal cartilages
Insertion - coracoid process of scapula
Innervation - medial pectoral nerve
Action - depresses the shoulder
Serratus anterior
Origin - lateral parts of ribs 1-8
Insertion - anterior surface of the medial surface of the scapula
Innervation - long thoracic nerve
Action - protracts the scapula and holds it against thoracic wall. Rotates scapula allowing arm to be raised above 90 degrees.
Pectoralis major
Origin - clavicle (clavicular head). Sternum and ribs (sternocostal head)
Insertion - intertubercular groove of humerus
Innervation - medial and lateral pectoral nerves
Action - adduct and medically rotate the humerus. Clavicular head can perform flexion.
Biceps brachii
Origin - supraglenoid tubercle (long head) and coracoid process (short head) of the scapula.
Insertion - radial tuberosity
Innervation - musculocutaneous nerve
Action - supination of the forearm (main), flexion of elbow and flexion of shoulder.
Brachialis
Origin - Distal half of anterior surface of humerus
Insertion - coronoid process and tuberosity of ulna
Innervation - musculocutaneous nerve and small lateral portion is radial nerve
Action - main flexor at the elbow
Coracobrachialis
Origin - Coracoid process of scapula
Insertion - medial surface of the humerus at the level of the deltoid tuberosity
Innervation - musculocutaneous nerve
Action - flexion at the shoulder, resists dislocation of shoulder
Triceps brachii
Origin - infraglenoid tubercule of scapula (long head), posterior surface of humerus inferior to radial groove (medial head) and posterior surface of humerus superior to radial groove (lateral head)
Insertion - olecranon of ulna
Innervation - radial nerve
Action - chief extension of forearm. Long head resist dislocation of humerus during adduction
Anconeus
Origin - lateral epicondyle of the humerus
Insertion - lateral surface of the olecranon
Innervation - radial nerve
Action - moves the ulna during pronation and extends the elbow joint
Supraspinatus
Origin - supraspinous fossa of the scapula
Insertion - greater tuberosity of the humerus
Innervation - Suprascapular nerve
Action - adducts the arm 0-15 degrees then assists the deltoid 15-90 degrees
Infraspinatus
Origin - infraspinous fossa of the scapula
Insertion - greater tubercule of the humerus
Innervation - Suprascapular nerve
Action - laterally rotates the arm
Subscapularis
Origin - subscapular fossa of scapula
Insertion - lesser tubercule of the humerus
Innervation - upper and lower subscapular nerves
Action - medially rotates the arm
Teres minor
Origin - middle part of lateral border of scapula
Insertion - greater tubercule of the humerus
Innervation - axillary nerve
Action - laterally rotates the arm
Deltoid
Origin - lateral third of clavicle, acromion and spine of scapula
Insertion - deltoid tuberosity of the humerus
Innervation - axillary nerve
Action - anterior part flexes arm, middle part abducts arm and posterior part extends arm.
Teres major
Origin - posterior surface of the interior angle of the scapula
Insertion - Intertubercular groove of humerus
Innervation - lower subscapular nerve
Action - adducts and medially rotates the arm
Trapezius
Origin - external occipital protuberance of skull, nuchal ligament and spinous processes of C7-T12 vertebrae
Insertion - lateral third of clavicle, acromion and spine of scapula
Innervation - accessory nerve
Action - superior part elevates scapula, middle part retracts scapula, inferior part depresses scapula. Superior and inferior parts work together to rotate the scapula, elevating the glenoid cavity.
Trapezius
Origin - external occipital protuberance of skull, nuchal ligament and spinous processes of C7-T12 vertebrae
Insertion - lateral third of clavicle, acromion and spine of scapula
Innervation - accessory nerve
Action - superior part elevates scapula, middle part retracts scapula, inferior part depresses scapula. Superior and inferior parts work together to rotate the scapula, elevating the glenoid cavity.
Latissimus dorsi
Origin - spinous process of T7-12 vertebra, iliac crest, thoraco-lumbar fascia and inferior 3 ribs.
Insertion - floor of Intertubercular groove of humerus
Innervation - thoracodorsal nerve
Action - extends, adducts and medially rotates the arm
Levator scapulae
Origin - transverse processes of C1-4 vertebrae
Insertion - superior part of the medial border of the scapula
Innervation - dorsal scapula nerve
Action - elevates scapula and rotates the glenohumeral cavity inferiorly.
Rhomboid minor
Origin - spinous processes of C7 & T1 vertebrae
Insertion - medial border of the scapula, at the level of the spine
Innervation - dorsal scapula nerve
Action - retract and rotate scapula, depressing the glenoid cavity
Rhomboid major
Origin - spinous processes of T2-5 vertebrae
Insertion - medial border of scapula, inferior to spine
Innervation - dorsal scapula nerve
Action - retract and rotate scapula, depressing the glenoid cavity