Shoulder Girdle-origin/insertion/action

Question 1

What is the shoulder/pectoral girdle?

Answer 1

The attachment point of the upper-limb to the axial skeleton

Question 2

What is the relationship between stability and mobility?

Answer 2

If something has high mobility then its stability is poor and vice versa

Question 3

Does the shoulder girdle have high mobility or stability?

Answer 3

High mobility due to ball and socket, therfore prone to injury.

Question 4

What are the 7 joints/articulations of the pectoral girdle?

Answer 4

sternocostal, sternoclavicular, acromioclavicular, glenohumeral, costovertebral, scapulothoracic, interclavicular

Question 5

What is the range of motion and joint type for the Sternoclavicular joint?

Answer 5

Saddle joint. Movements include full elevation to 60 degrees between the clavicle and midline. Anterior and posterior movement. 25-30 degree protraction and retraction

Question 6

What are the ligaments of the sternoclavicular joint?

Answer 6

Interclavicular, costoclavicular, sternoclavicular

Question 7

Interclavicular Ligament

Answer 7

Limits superior and lateral displacement of the clavicle

Question 8

Costoclavicular Ligament

Answer 8

Main support, limits all ranges of motion except depression

Question 9

Sternoclavicular ligament

Answer 9

Limits anterior and posterior glide of clavicle

Question 10

What is the acromioclavicular joint type?

Answer 10

Plane joint

Question 11

What does the acromioclavicular do?

Answer 11

Serves as a restriction to over-head arm movements

Question 12

What are the ligaments of the acromioclavicular joint?

Answer 12

Coracoclavicular, acromioclavicular, coracoacromioal

Question 13

Coracoclavicular ligament

Answer 13

Conoid and trapezoid, primary restraint to vertical displacement

Question 14

Acromioclavicular ligament

Answer 14

Prevents separation of clavicle and scapula. Prevents posterior and anterior displacement

Question 15

Coracoacromial ligament

Answer 15

Forms roof over the glenohumeral joint. Protection for bursa and supraspinatus tendon. Provides limit to superior humeral head movement

Question 16

Scapulothoracic joint.

Answer 16

Physiologic articulation between rib cage and scapula.

Question 17

What are the movements of the scapulothoracic joint?

Answer 17

Elevation, depression, adduction, abduction, upward rotation, downward rotation

Question 18

What is the function of the scapulothoracic joint?

Answer 18

Allows the arm to abduct beyonf 120 degrees. Allowed by the glenohumeral joint, 1 degree of scapular rotation for every 2 degrees of humeral abduction.

Question 19

What three directions does the scapulothoracic joint move in?

Answer 19

Protraction and retraction (30-60), superior and inferior rotation (60), elevation and depression (30)

Question 20

What are the muscles that protract the scapula?

Answer 20

Serratus anterior, pectoralis major, and pectoralis minor

Question 21

What muscles retract the scapula?

Answer 21

Trapezius (middle part) and the rhomboids

Question 22

Serratus Anterior:

Answer 22

Origin: External layer of the lateral parts of rubs 1-8
Insertion: Anterior surface of the medial border of the scapula
Action: Protracts the scapula and holds it against the thoracic wall; rotates the scapula in an upward direction
Innervation: Long thoracic nerve

Question 23

What does a blow to the serratus anterior induce

Answer 23

Winging

Question 24

Pectoralis Major

Answer 24

Origin: 2 heads, clavicular head (anterior surface of the medial half of the clavicle) and sternocostal head (anterior surface of the sternum, superior six costal cartilages, aponeurosis of external oblique muscle)
Insertion: Lateral lip of the intertubercular groove of the humerus
Actions: Adducts and medially rotates the humerus. Draws the scapula anteriorly and inferiorly. Acting alone the clavicular head flexes the humerus, and the sternocostal head will extend the humerus from a flexed position.
Innervation: Lateral and medical pectoral nerves. Clavicular head, sternocostal head.

Question 25

Pectoralis Minor

Answer 25

Origin: Ant. surface of ribs 3,4,5 Insertion: Coracoid process of the scapula Action; anchors, depresses, protracts the scapula Innervation: medical pectoral

Question 26

Trapezius (Middle fibers)

Answer 26

Origin: Spinous processes of the first-fifth thoracic vertebrae Insertion: Medial margin of the acromion and superior lip of the spine of scapula Action: retracts scapula Innervation: Spinal accessory nerve

Question 27

Rhomboids

Answer 27

Origin: Spinous processes of the thoracic vertebrae 2-5 (major). Ligamenteum Nuchae, spinous process of 7th cervical and 1st thoracic vertebrae (minor) Insertion; Fibrous attachment to the medial border of the scapula between the spine and inferior angle (major). Medial border of the scapula, at the root of the spine of the scapula (minor). Action: Adducts and elevates the scapula, downwardly rotates the scapula Innervation: Dorsal scapular nerve

Question 28

Which muscles elevate the scapula

Answer 28

Levator scapulae, trapezius, rhomboids

Question 29

Trapezius (upper fibres)

Answer 29

Origin: External occipital protuberance, ligamentum nuchae and spinous process of the 7th cervical vertebrae Insertion: Lateral 1/3 of the clavicle and acromion process of scapula Action: Elevates scapula Innervation: Spinal Accessory nerve

Question 30

Levator Scapulae

Answer 30

Origin: Transverse processes of the first 4 cervical vertebrae Insertion: Medial border of the scapula, between the superior angle and the root of the spine Action: Elevates scapula and assists with downward rotation of the scapula. Can also assist with lateral flextion of c-spine or extension of the c-spine if the scapula is stabilized by other muscles Innervation: Cervical 3+4 and dorsal scapular nerve

Question 31

What muscles cause depression of the scapula?

Answer 31

Trapezius (lower part) , subclavius, pectoralis minor, gravity

Question 32

Trapezius (lower fibres)

Answer 32

Origin: Spinous processes of the 6th-12th thoracic vertebrae Insertion; Tubercle at the apex of the spine of the scapula Action: Depresses the scapula Innervation: Spinal accessory nerve

Question 33

Which muscles rotate the scapula upward?

Answer 33

Trapezius (upper/lower fibres), serratus anterior

Question 34

Which muscles downwardly rotate the scapula?

Answer 34

Levator scapulae, rhomboids, pectoralis minor, gravity