Muscles Flashcards
Anterior axio-appendicular muscles
- serratus anterior
- pectoralis major
- pectoralis minor
Serratus anterior
- O: external surface of lateral parts of 1st-8th ribs
- I: anterior surface of medial border of scapula
- N: long thoracic nerve (C5-C7)
- A:
Pectoralis major
- O: clavicular head (anterior surface of medial half of clavicle); sternocostal head (anterior surface of sternum, superior six costal cartilages, and aponeurosis of external oblique muscle
- I: lateral lip of intertubercular sulcus of humerus
- N: lateral and medial pectoral nerves; clavicular head and sternocostal head
- A: adducts and medially rotates humerus; draws scapula anteriorly and inferiorly; clavicular head flexes humerus; sternocostal head: extends it from flexed position
Pectoralis minor
- O: 3rd-5th ribs near their costal cartilage
- I: medial border and superior surface of coracoid process of scapula
- N: medial pectoral nerve (C8, T1)
- A: stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall
Posterior axio-appendicular muscles
(superficial) -trap -latissimus dorsi (deep) -rhomboid major -rhomboid minor -levator scapulae
trap
- O: Medial third of superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7–T12 vertebrae
- I: Lateral third of clavicle; acromion and spine of scapula
- N: Spinal accessory nerve (CN XI) (motor fibers) and C3, C4 spinal nerves (pain and proprioceptive fibers)
- A: Descending part elevates; ascending part depresses; and middle part (or all parts together) retracts scapula; descending and ascending parts act together to rotate glenoid cavity superiorly
lat dorsi
- O: Spinous processes of inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs
- I: Floor of intertubercular sulcus of humerus
- N: Dorsal scapular (C4, C5) and cervical (C3, C4) nerves
- A: Extends, adducts, and medially rotates humerus; raises body toward arms during climbing
levator scapulae
- O: Posterior tubercles of transverse processes of C1–C4 vertebrae
- I: Medial border of scapula superior to root of scapular spine
- N: Dorsal scapular (C4, C5) and cervical (C3, C4) nerves
- A: Elevates scapula and rotates its glenoid cavity inferiorly by rotating scapula
rhomboid minor and major
-O: Minor: nuchal ligament; spinous processes of C7 and T1 vertebrae
Major: spinous processes of T2–T5 vertebrae
-I: Minor: smooth triangular area at medial end of scapular spine
Major: medial border of scapula from level of spine to inferior angle
-N: Dorsal scapular nerve (C4,C5)
-A: Retract scapula and rotate its glenoid cavity inferiorly; fix scapula to thoracic wall
Scapulohumeral muscles
- deltoid
- supraspinatus
- infraspinatus
- teres minor
- teres major
- subscapularis
deltoid
-O: Lateral third of clavicle; acromion and spine of scapula
-I: Deltoid tuberosity of humerus
-N: Axillary nerve (C5, C6)
-A: Clavicular (anterior) part: flexes and medially rotates arm
Acromial (middle) part: abducts arm
Spinal (posterior) part: extends and laterally rotates arm
supraspinatus
- O: Supraspinous fossa of scapula
- I: Superior facet of greater tubercle of humerus
- N: Suprascapular nerve (C4,C5, C6)
- A: Initiates and assists deltoid in abduction of arm and acts with rotator cuff muscle
infraspinatus
- O: Infraspinous fossa of scapula
- I: Middle facet of greater tubercle of humerus
- N: Suprascapular nerve (C5, C6)
- A: Laterally rotates arm; and acts with rotator cuff muscles
teres minor
- O: Middle part of lateral border of scapula
- I: Inferior facet of greater tubercle of humerus
- N: Axillary nerve (C5, C6)
- A: Laterally rotates arm; and acts with rotator cuff muscle
teres major
- O: Posterior surface of inferior angle of scapula
- I: Medial lip of intertubercular sulcus of humerus
- N: Lower subscapular nerve (C5,C6)
- A: Adducts and medially rotates arm
subscapularis
- O: Subscapular fossa (most of anterior surface of scapula)
- I: Lesser tubercle of humerus
- N: Upper and lower subscapular nerves (C5,C6, C7)
- A: Medially rotates arm; as part of rotator cuff, helps hold head of humerus in glenoid cavi