Lecture: Thorax and movements of the scapula

Origin: anterior surfaces of ribs 3-5 (or 2-4)

Insertion: coracoid process of scapula

• Action: with ribs fixed, draws scapula foward and downward

Origin:by a series of muscle slips from ribs 1-8(or9)

Insertion: entor anterior aurface of vertebral border of scapula

• Action: rotates scapula so that its inferior anfle moves laterally up and down, prime mover to protract and hold scpaula against chest wall

Origin: constal cartilage of rib 1

Insertion: groove on inferior surface of clavicle

• Action: helps stabilize and depress pectoral girdle

Origin: occipital bone, ligamentum nuchae, and spinous processes of C7 and all thoracic vertebrae

Insertion: a continuous insertion along acromion and spone of scapula and lateral third of clavicle

• action: stabilizes, raises, retracts, and rotates scapula

origin: transverse processes of c1-C4


insertion: medial border of the scapula, superior to the spine

• action: elevates/adducts scapula

Origin: spinous processe of C7 and T1 (minor) and spinous processes of T2-T5 (major)

Insertion: medial border of scapula

Action: Stabilizes scapula

origin: sternal end of clavicle, sternum, cartilage of ribs 1-6 (or 7), and aponeurosis of external oblique muscle

insertion: fibers converge to insert by a short tendon into intertubercular sulcus and greater tuberacle of humerus

• action: prime mover of arm flexion; rotates arm medially, adducts arm

Pectoralis Major

Latissmus Dorsi

Deltoid

Infraspinatus

Supraspinatus

Teres Minor

Subscapular

• They...
• 1. reinforce the capsule of the shoulder
• 2. act as synergists and fixators

Origin: embraces insertion of the treapezius, lateral third of clavicle; acrominon and spine of scapula

Insertion: deltoid tuberosity of humerus

• Action: prime mover of arm abduction when all its fibers contract simultaneously

Origin: indirect attachment via lumbodorsal fascia into spines of lower siz thoracic vertebrae, lumbar vertebrae, lower 3 to 4 ribs, and iliac crest; also from scapulas's inferior angle

Insertion: spirals around teres major to insert in floor of intertubular sulcus of humerus

• action: primse mover of arm extension; powerful arm adductor, medially rotates arm at shoulder

origin: subscapular fossa of scapula

insertion: lesser tubercle of humerus

action: chief medial rotator of humerus

Origin: supraspinaous fossa of scapula

Insertion: superior pare of greater tubercle of humerus

Action: intiates abductions

Origin: infraspinous fossa of scapula

Insertion: greater tubercle of humerus posterior to insertion of supraspinatus

Action: rotates humerus laterally

Origin: posterior surface of scapula at inderior angle

Insertion: crest of lesser tubercle on anterior humerus insertion of tendon fused with that of latissmus dorsi

Action: extends, medially rotates, and adducts humerus

Origin: coracoid process of scapula

Insertion: medial surface of humerus shaft

Action: flexion and adduction of the humerus