Ch 9- shoulder girdle

Question 1

Shoulder girdle

Joint motions

Answer 1

• activities of scapula and clavicle, five muscles attach to the scapula, clavicle, or both, providing motion of the shoulder girdle
• elevation/depression, protraction/retraction (synonymous to abduction/adduction), upward and downward rotation

Question 2

Shoulder joint

Motions of shoulder joint

Answer 2

• scapula and humerus, also called glenohumeral joint
• flexion, extension, hyperextension, abduction, adduction, medial and lateral rotation, horizontal abduction and adduction, nine muscles cross the joint and are the prime movers, has few ligaments

Question 3

Sternoclavicular joint * (know all parts)

Joint motions

3 ligaments supporting this joint

Answer 3

• formed by articulation between manubrium and medial end of clavicle, this synovial joint provides the shoulder girdle with its only direct attachment to the trunk
• elevation/depression in frontal plane, protraction/retraction in transverse plane, rotation along the vertical axis of the bone
• sternoclavicular, costoclavicular, and interclavicular ligaments

Question 4

Acromioclavicular joint * (know all parts)

Ligaments

Answer 4

• connects the acromion process of the scapula and the acromial end of the clavicle
• superior and inferior acromioclavicular ligaments, coracoclavicular ligament, and coracoacromial ligament

Question 5

Scapulothoracic articulation

Answer 5

pg 131 The articulation of the anterior surface of the scapula against the posterior ribs

Question 6

Scapulohumeral rhythm

Answer 6

describes the 2:1 ratio of normal motion between the glenohumeral and scapulothoracic joints; the first 30 degrees of shoulder joint motion is pure shoulder joint motion, after that, every 2 degrees of shoulder flexion or abduction that occurs, the scapula upwardly rotates 1 degree

humeral head-roll, glenoid fossa-glide

Question 7

Clinical implication

Answer 7

any exercise performed in abduction or flexion should be done in the externally rotated position

Question 8

Upper Trapezius

Answer 8

O- occipital bone, nuchal ligament on upper cervical spinous processes
I- outer third of clavicle, acromion process
A- scapular elevation and upward rotation
N- Cranial Nerve XI (accsessory)

Question 9

Middle Trapezius

Answer 9

O- Spinous processes of C7 through T3
I- Scapular spine
A- scapular retraction (prime mover)
N- Cranial Nerve XI (accessory)

Question 10

Lower Trapezius

Answer 10

O- Spinous processes of middle and lower thoracic vertebrae
I- Base of the scapular spine
A- scapular depression and upward rotation
N- Cranial Nerve XI (accessory)

Question 11

Levator scapula

Answer 11

O- transverse processes of first 4 cervical vertebrae
I- vertebral border of scapula
A- scapular elevation and downward rotation
N- dorsal scapular nerve (C5)

Question 12

Rhomboids

Answer 12

O- spinous processes of C7 through T5
I- vertebral border of scapula
A- scapular retraction, elevation, and downward rotation
N- dorsal scapular nerve (C5)

Question 13

Serratus anterior

Answer 13

O- lateral surface of the upper eight ribs
I- anterior vertebral border of the scapula
A- scapular protraction and upward rotation
N- long thoracic nerve (C5, C6, C7)

Question 14

Pectoralis minor

Answer 14

O- anterior surface, 3rd through 5th ribs
I- coracoid process of scapula
A- scapular depression, protraction, downward rotation, and tilt
N- medial pectoral nerve (C8, T1)

Question 15

Prime movers of shoulder girdle: Retraction (combo of adduction and downward rotation)

Protraction (combo of abduction and upward rotation)

Elevation

Depression

Upward rotation

Downward rotation

Scapular tilt

Answer 15

• Middle trapezius, rhomboids
• serratus anterior, pectoralis minor
• upper trapezius, levator scapula, rhomboids
• lower trapezius, pectorals minor
• upper and lower trapezius, serratus anterior (lower fibers)
• rhomboids, levator scapula, pectoralis minor
• pectoralis minor

Question 16

Postural influence:

Rounding of the shoulders

Answer 16

scapula protracted, rhomboids and middle trapezius (scapular retractors) in a chronically stretched position (these become weak and overstretched), pectoralis minor placed on slack and adaptively shortens over time

Question 17

Rhomboids and levator scapula are ____ ____ the trapezius

Answer 17

directly underneath

Question 18

Pectoralis minor is ___ to the pectoralis major

Answer 18

deep

Question 19

Serratus anterior originates ____ and runs ____

Answer 19

anteriorly; posteriorly

Question 20

Companion motions of shoulder girdle that must occur with shoulder joint motion

Answer 20

Shoulder joint: Shoulder girdle:
Flexion Upward rotation, protraction
Extension Downward rotation, retraction
Hyperextension Scapular tilt
Abduction Upward rotation
Adduction Downward rotation
Medial rotation Protraction
Lateral rotation Retraction
Horizontal abduction Retraction
Horizontal adduction Protraction

Question 21

Muscles that form the FORCE COUPLE responsible for upward/downward rotation of scapula of shoulder girdle:
Scapula upward rotation*(more clinically relevant [around 28 mins shoulder comp])

Scapula downward rotation

Answer 21

-upper trapezius muscle pulls up, lower trapezius muscle pulls down, and lower fibers of serratus anterior muscle pull outward in a horizontal direction

-pectoralis minor pulls down, rhomboid muscles pull in, and levator scapula pulls up
downward rotation of scap must accompany extension of shoulder joint

Question 22

Reversal of muscle action of shoulder girdle muscles and clinical significance

Answer 22

• shoulder girdle stabilized: lower trapezius and pectoralis minor can reverse their actions and assist in elevating the trunk, this is useful during crutch walking (they elevate the pelvis when the arms are stabilized)
• scapula stabilized: levator scapula can move the neck, assists the splenius cervicis in ipsilateral bending and rotation of neck

Question 23

Clavicular fractures

Answer 23

most frequently broken bone in children, usually result from a fall on lateral aspect of shoulder or on outstretched hand, clavicle usually breaks in middle

Question 24

around 3.30 anat shoulder girdle (something about the humeral head moves in relation to scapular motion)

Answer 24

around 19 mins she talks about scap winging and the serratus anterior and long thoracic nerve; “lonely lat” is to remember lateral pectoral nerve only innervates pectoralis major but medial pec nerve innervates BOTH pec minor and major

Question 25

How does humeral head move relative to humeral movement? around 40 mins anat shoulder

Answer 25

It glides opposite to distal arm’s motion, if moving arm in anterior plane the humeral head is gliding posterior, if external rotation then humeral head is gliding anteriorly

Question 26

What is force coupling?

Answer 26

Different muscles moving in different directions to produce same movement

Question 27

What actions/muscles are involved with tucking in a shirt?

Answer 27

Actions: scapular depression, internal and external rotation, abduction and adduction, horizontal abduction and adduction, scapular elevation

Muscles: lower trap, latissimus dorsi, delts, upper trap, levator scapula

Question 28

What actions/muscles are involved with hooking a necklace?

Answer 28

Actions: scapular retraction, horizontal abduction, force coupling of upward rotation of scap, shoulder flexion

Muscles: rhomboids, middle traps