OIANs 1

• The medial attachment for the trapezius muscle is the medial third of superior nuchal line, external occipital protuberance, nuchal ligament and the spinous process of C7-T12 vertebrae
• lateral attachment size for the trapezius muscle is the lateral third of clavicle, acromion and spine of scapula
• the innervation site for the trapezius muscle is at the spinal accessory nerve (CN XI; motor fibers) and C3, C4 spinal nerves (pain and proprioceptive fibers)
• The main actions for the trapezius muscle include descending (superior) part elevates, ascending (inferior) part depresses, and middle part (or all parts together) retracts scapula; descending and ascending parts act together to rotate the glenoid cavity superiorly
• The medial attachment of the Latissimus dorsi muscle is the spinous processes of inferior six thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior three or four ribs
• the lateral attachment site of the latissimus dorsi is the floor of the intertubercular sulcus (groove) of humerus
• the innervation of the latissimus dorsi is at the thoracodorsal nerve (C6, C7, C8)
• the main actions of the latissimus dorsi : extends, adducts, and medially rotates shoulder joint; raises body toward arms during climbing
• Levator scapulae muscle's medial attachment site is at the posterior tubercles of transverse processes of C1-C4 vertebrae
• Lateral attachment site of the Levator scapulae is at the medial border of scapula superior to root of spine
• the innvervation site for levator scapulae is at the dorsal scapular (C5) and cervical (C3 +C4) spinal nerves
• The main actions of the levator scapulae : elevates scapula and rotates glenoid cavity inferiorly
• the medial attachment for the rhomboid major is at the spinous processes of T2-T5 vertebrae
• the lateral attachment of the rhomboid minor is the triangular area at the end of the scapular spine
• the lateral attachment of the rhomboid major is the medial border of the scapula from level of spine to inferior angle
• the medial attachment of the rhomboid minor are the nuchal ligament, spinous processes of C7 and T1 vertebrae
• the innervation for rhomboid major and minor are the dorsal scapular nerve (C4, C5)
• the actions of the rhomboid major and minor: retracts scapula and rotates the glenoid cavity inferiorly; fix scapula to thoracic wall
• the proximal attachment of the pectoralis major:

  clavicular head: anterior surface of medial half of clavicle

  sternocostal head: anterior surface of the sternum, superior six costal cartilages, aponeurosis of external oblique muscle
• the distal attachment of the pectoralis major is at the lateral lip of intertubercular sulcus (groove) of the humerus
• the innervation of the pectoralis major are at the lateral and medial pectoral nerves, clavicular head (C5, C6), sternocostal head (C7, C8, T1)
• the main actions of the pectoralis major: adducts and medially rotates the shoulder joint, draws scapular anteriorly and inferiorly. Acting alone-- clavicular head flexes shoulder joint and sternocostal head and extends it from the flexed position
• the proximal attachment for the pec minor is at the 3rd-5th ribs near their costal cartilages
• the distal attachment for the pec minor is at the medial border and superior surface of the coracoid process of the scapula
• the innervation for the pec minor are the medial pectoral nerve (C8, T1) and lateral pectoral nerve
• the main action of the pec minor: stabilizes scapula by drawing inferiorly and anteriorly against thoracic wall
• the proximal attachment for the serratus anterior is at the external surfaces of the lateral parts of the 1-8 ribs
• the distal attachment of the serratus anterior is at the anterior surface of the entire medial border of the scapula
• the serratus anterior is innervated the long thoracic nerve (C5,C6,C7)
• the main actions of the serratus anterior: protracts the scapula and holds it against thoracic wall; rotates scapula
• the proximal attachment for the deltoid is at the lateral third of the clavicle, acromion, and spine of the scapula
• distal attachment of deltoid is at the deltoid tuberosity of the humerus
• innervation of deltoid is the axillary nerve (C5, C6)
• main actions of deltoid:

  clavicular (anterior) part flexes and medially rotates shoulder joint

  acromial (middle) part abducts the shoulder joint

  spinal (posterior) part extends and laterally rotates shoulder joint
• the proximal attachment for the supraspinatus muscle is at the supraspinous fossa of the scapula
• the distal attachment of supraspinatus muscle is at the superior facet of the greater tubercle of humerus
• the supraspinatus is innervated by the suprascapular nerve (C4, C5, C6)
• actions of the supraspinatus muscle: initiates and assists deltoid in abduction of shoulder joint and acts with other rotator cuff muscles
• infraspinatus muscle's proximal attachment site is at the infraspinous fossa of the scapula
• distal attachment of infraspinatus: middle facet of greater tubercle of humerus