Chapter Four - Shoulder Girdle, Shoulder Joint and Movements

Question 1

What are the general components of the axial and the appedicular skeleton?

Answer 1

Axial (refers to axis):

Skull

Vertebral column

Thoracic cage

Appendicular (refers to appendages, i.e., extremities):

Pectoral (Shoulder) girdle

Upper limb

Pelvic girdle

Lower limb

Question 2

What composes each shoulder girdle? It attaches what to what?

Answer 2

Each shoulder (pectoral) girdle (L and R) consists of a scapula (shoulder blade) and a clavicle (collar bone). The shoulder girdle attaches upper limb to the axial skeleton.

Note that humerus is not part of the shoulder girdle.

Question 3

What are the different parts of the scapula that we have to know?

Answer 3

Parts:

Superior and inferior angle (labelled 1 and 2)

Spine

Acromion

Coracoid process

Glenoid cavity

Question 4

What are the three joints in which the clavicle takes place? What are they called and what type of joints are they?

Answer 4

Joints:

Sternoclavicular joint (synovial with

fibrocartilaginous disc)

Acromioclavicular joint (synovial)

Coracoclavicular joint (syndesmosis) –

pair of short ligaments between clavicle and coracoid process

Note:

strut function

shoulder separation (AC joint!)

fracture—relation to major vessels and nerves of upper extremity

Question 5

Name the six movements of the scapula.

Answer 5

Elevation

Depression

Protraction

Retraction

Lateral rotation (inferior angle* moves laterally)

Medial rotation (inferior angle moves medially,

i.e., returns to anatomical position)

Question 6

The clavicle can move at two joints. Which ones?

Answer 6

Movement is at:

1. Sternoclavicularjoint
2. Acromioclavicularjoint

Question 7

The clavicle has three different types of possible movements. What are they? What are the three planes in which the clavicle can move?

Answer 7

Movements of the clavicle:

1. Elevation and depression of the distal end of the clavicle
2. Anterior and posterior movement of the distal end
3. Anterior and posterior rotation along the long axis

Movement is in 3 planes:

• anterior – posterior
• superior – inferior

• rotation

Note: When the scapula moves so does the clavicle!

Question 8

Name the five muscles that move the scapula. How do they move it?

Answer 8

Trapezius - elevates, retracts and depresses scapula

Rhomboids (major and minor) - retract scapula

Levator scapulae - elevates scapula

Serratus anterior – protracts scapula

Pectoralis minor – protracts and stabilizes

Question 9

Give the origin, insertion, action and innervation of the trapezius.

Answer 9

Origin: external occipital protuberance, nuchal ligament, spinous processes of C7 – T12 vertebrae

Action: superior fibers elevate scapula, middle fibers retract scapula, inferior fibers depress scapula; it also laterally rotates scapula during arm abduction

Insertion: entire length of spine of scapula, acromion, lateral third of clavicle

Nerve: Spinal accessory nerve (cranial nerve XI)

Question 10

Give the origin, insertion, action and innervation of the rhomboid major and minor.

Answer 10

Origin: spines of T2-T5 vertebrae (R. major) and spines of C7 and T1 vertebrae (R. minor)

Action: Retract scapula; medially rotate scapula, elevate the medial border of the scapula

Insertion: medial border of the scapula below the spine (R. major) and at the root of the spine (R. minor)

Nerve: Dorsal scapular nerve (C5)

Question 11

Give the origin, insertion, action and innervation of the levator scapulae.

Answer 11

Origin: Transverse processes of C1 - C4 vertebrae

Action: Elevates and medially rotates scapula

Insertion: Superior angle of scapula

Nerve: Dorsal scapular nerve (C5)

Question 12

Give the origin, insertion, action and innervation of the serratus anterior.

Answer 12

Origin: Anterior aspect of ribs 1 - 9

Action: Protracts and laterally rotates scapula

Insertion: Anterior surface (costal surface) of the medial border of scapula

Nerve: Long thoracic nerve

Question 13

Give the origin, insertion, action and innervation of pectoralis minor.

Answer 13

Origin: Ribs 3 - 5

Action: protracts and stabilizes scapula, raises ribs in forced inspiration

Insertion: Coracoid process of scapula

Nerve: Medial pectoral nerve

Question 14

What type of joint is the shoulder (glenohumoral) joint?

Answer 14

Synovial joint, ball-and-socket type

Question 15

How many axes does the GH joint have?

Answer 15

Multiaxial joint; the widest range of motion of all joints

Question 16

What are the articulating bones or the glenohumeral joint?

Answer 16

Articulating bones:

1. head of humerus
2. glenoid fossa of scapula

Question 17

What is the glenoid labrum?

Answer 17

Glenoid labrum: fibrocartilaginous rim attached to the margin of glenoid fossa, it deepens the socket.

Question 18

What are the 7 movements of the arm at the shoulder joint?

Answer 18

• Flexion
• Extension
• Abduction
• Adduction
• Medial rotation
• Lateral rotation
• Circumduction

Question 19

There are two types of muscles that move the arm at the shoulder joint: the muscles that attach the upper limb to the axial skeleton, and the muscles that the upper limb at the shoulder girdle. Which are they for both categories?

Answer 19

Muscles that move the arm at the shoulder joint

1) Muscles that attach upper limb to the axial skeleton:

Pectoralis major

Latissimus dorsi

2) Muscles that attach upper limb to the shoulder girdle:

Deltoid

Rotator cuff muscles (4)

Teres major

Question 20

What is the origin, insertion, action and innervation of pectoralis major?

Answer 20

Origin: clavicle, sternum, costal cartilages of ribs 1-6

Action: Adducts, flexes and medially rotates arm (note: can also extend arm when arm is flexed)

Insertion: lateral lip of the intertubercular (bicipital) grove of humerus

Nerve: Medial and Lateral pectoral nerves

Question 21

Give the main anatomical parts of the humerus, with a drawing.

Answer 21

We have muscles attaching on the lateral and medial lip, and in the intertubercular groove

Question 22

Give the origin, insertion, action and innervation of latissimus dorsi.

Answer 22

Origin: spinous processes from T8 to sacrum, iliac crest, lower 3-4 ribs, inferior angle of scapula

Action: Extends, adducts and medially rotates arm, keeps inferior angle of scapula against the chest wall

Insertion: bicipital groove of humerus

Nerve: Thoracodorsal nerve

Question 23

Give the origin, insertion, action and innervation of deltoid.

Answer 23

Origin: lateral third of clavicle, acromion, and spine of scapula

Action: Abduction, flexion, medial rotation, extension, and lateral rotation of the arm

Insertion: deltoid tuberosity of the humerus

Nerve: Axillary nerve

Question 24

Name the rotator cuff muscles.

Answer 24

Group of 4 “SITS” muscles:

1. Supraspinatus
2. Infraspinatus
3. Teres minor
4. Subscapularis

Question 25

Give the function and innervation of the rotator cuff muscle: supraspinatus.

Answer 25

1. Supraspinatus: initiates abduction of the arm (first 15 degrees; deltoid is the main abductor). Nerve: Suprascapular nerve (C5, C6).

Question 26

Give the function and innervation of the rotator cuff muscle: infraspinatus.

Answer 26

2. Infraspinatus: lateral rotation or arm. Nerve: Suprascapular nerve.

Question 27

Give the function and innervation of the rotator cuff muscle: teres minor.

Answer 27

3. Teres minor: lateral rotation or arm. Nerve: Axillary nerve (C5, C6).

Question 28

Give the function and innervation of the rotator cuff muscle: subscapularis.

Answer 28

4. Subscapularis: main medial rotator of the arm. Nerve: Upper and lower subscapular nerves (C5, C6)

Question 29

Give the origin, insertion, action and innervation of teres major.

Answer 29

Origin: inferior angle of scapula (posterior surface)

Action: Adducts and medially rotates arm

Insertion: medial lip of intertubercular groove

Nerve: Lower subscapular nerve