Shoulder Girdle Muscles Flashcards Preview

Anatomy > Shoulder Girdle Muscles > Flashcards

Flashcards in Shoulder Girdle Muscles Deck (18)
Loading flashcards...
1
Q

Supraspinatus

A

Posterior

Origin: supraspinous fascia, supraspinous fossa

Insertion: greater tubercle of humerus

Action: holds humerus in socket, tenses capsule, abducts arm

2
Q

Infraspinatus

A

Posterior

Origin: infraspinous fossa, spine of scapula, infrapinous fascia

Insertion: greater tubercle of humerus

Action: external rotation of arm

3
Q

Teres Minor

A

Posterior

Origin: lateral border of scapula

Insertion: lower facet of greater tubercle of humerus

Action: weak external rotator of arm

4
Q

Deltoid

A

Posterior, 3 parts

Clavicular origin: lateral third of clavicle
Acromial origin: acromion process of scapula
Spinal origin: inferior border of scapular spine

Insertion: all attached to deltoid tuberosity

Action: principal abductor of shoulder

5
Q

Subscapularis

A

Posterior

Origin: subscapular fossa

Insertion: lesser tubercle of humerus, proximal part of crest

Action: internal rotation of arm

6
Q

Teres Major

A

Posterior

Origin: lateral border of scapula near inferior angle

Insertion: Lesser tubercle of humerus

Action: retroversion of arm towards midline, little medial rotation, helps in adduction

7
Q

Lattimus Dorsi

A

Posterior

Origin: spinous process of 7th- 12th thoracic vertebra

Insertion: lesser tubercle of humerus

Action: lowers raised arm, adducts it, when adducted… pulls it backward and medially, pulls shoulders backward and downward, works during forced expiration

8
Q

Coracobrachialis

A

Anterior

Origin: coracoid process

Insertion: medial surface of humerus, in line with crest of lesser tubercle

Action: anteverts arm and retains humeral head in articular facet

9
Q

Pectoralis Minor

A

Anterior

Origin: 3rd to 5th ribs

Insertion: coracoid process of scapula

Action: lowers and rotates the scapula

10
Q

Pectoralis Major

A

Anterior

Clavicular origin: medial half of anterior surface of clavicle
Sternocostal origin: sternal membrane and cartilages of 2nd to 6th ribs
Abdominal origin: anterior layer of uppermost part of rectus sheath (lower abdominal sheath)

Insertion: crest of greater tubercle of humerus

Action: when arm is adducted…. clavicular and sternal parts produce ante version, all parts work to lower the raised arm, adduct arm and rotate it medially

sternocostal and abdominal part work to lower shoulder anteriorly

accessory muscle for inspiration when arms are fixed (helps move thorax)

11
Q

Rhomboid Minor

A

Posterior

Origin: spinous process of 6th to 7th cervical vertebrae

Insertion: medial border of scapula

Action: press scapula against chest wall and retract scapula toward vertebral column (like rhomboid major)

12
Q

Rhomboid Major

A

Posterior, caudal then minor is up

Origin: spinous process of 1st-4th thoracic vertebrae

Insertion: medial border of scapula, caudal to rhomboid minor

Action: ction: press scapula against chest wall and retract scapula toward vertebral column (like rhomboid minor)

13
Q

Levator Scapulae

A

Posterior

Origin: posterior tubercles of transverse processes of 1st to 4th cervical vertebrae

Insertion: superior angle of scapula and adjacent part of medial border

Action: elevates scapula while rotating the inferior angle medially

14
Q

Serratus Anterior

A

Posterior

Origin: surface of 1st to 9th ribs

Insertion:
Superior origin: superior angle of scapula
Intermediate part: medial border of scapula
Inferior part: attached near inferior angle of scapula

Action: pulls scapula anteriorly (essential for anteverting arm), superior and inferior parts press scapula into thorax, inferior part rotates scapula laterally and pulls the inferior angle and lateral forward for elevation of the arm, all parts work together to lift ribs when shoulder girdle is fixed

15
Q

Subclavius

A

Anterior

Origin: osteochondral junction of 1st rib

Insertion: subclavian groove on inferior surface of clavicle

Action: pulls clavicle toward sternum, stabilizes sternoclavicular joint

16
Q

Omohyoid

A

Anterior- 2 bellied muscle

Origin: upper border (margin) of scapula near scapular notch

Insertion: lateral third of the lower border of the hyoid bone

Action: dilates internal jugular vein beneath it

17
Q

Trapezius

A

Descending part origin: superior nuchal line, external occipital protuberance and nuchal ligament
Insertion: lateral third of clavicle

Transverse part origin: 7th cervical to 3rd thoracic vertebrae (spinous process, supraspinous ligaments)
Insertion: acromial end of clavicle, acromion, and spine of scapula

Ascending part origin: 2/3 to 12th thoracic vertebra
Insertion: spinal tigons or adjacent part of scapula

Action: stabilizes scapula and clavicle posteriorly, pulls scapula and clavicle posteriorly, ascending/descending parts rotate scapula and produces slight elevation of shoulder

18
Q

Sternocleidomastoid

A

Origin: sternum, the other from clavicle

Insertion: mastoid process and superior nuchal line