Anatomy and Kinesiology Shoulder Girdle/Shoulder Joint
There are four sets of motions that occur at the shoulder joint. Which joints occur: a. in the frontal plane around the sagittal axis b. in the transverse plane around the vertical axis c. in the sagittal plane around the frontal axis.
A. Abduction, Adduction B. medial rotation, lateral rotation c. Flexion, extension
Lie prone on a table with your arm over the edge and with your shoulder flexed 90 degrees, elbow extended and a weight in your hand. Lift the weight away from the table in a sideward motion a. What is the shoulder joint motion? b. What type of contraction (isometric, concentric, eccentric) is occurring? c. What muscles are prime movers in this shoulder joint motion?
A. Horizontal shoulder abduction B. concentric C. Rear delt, infraspinatus, teres minor
Given that the scapula is shaped somewhat like a triangle, a. What landmark is commonly used to determine the direction the scapula is rotating? b. what direction is the landmark moving if the scapula is rotating upwardly?
A. Inferior angle When the scapula moves away from the vertebral column, the motion is scapular upward rotation. When it moves back toward the vertebral column to the starting position, the motion is scapular downward rotation.
Which type of scapular motion can only happen in conjunction with glenohumeral joint motions?
Angular motions
Name two reasons why the anterior deltoid is a stronger flexor than the coracobrachialis.
Anterior Deltoid It is a larger muscle Passes farther from the axis of rotation of the shoulder and therefore it is stronger (longer moment arm)
The trapezius muscle is usually referred to and described as one. From a functional perspective, why is the trapezius muscle separated into three muscles?
Because the three different attachments of the trapezius muscle produce three different lines of pull, the three parts have different muscle actions.
Identify the shoulder girdle motion: Closing a window by pulling downward (shoulder extension)
Downward Rotation
Shoulder extension
Downward rotation, retraction
Identify the shoulder girdle motion: Carrying a heavy suitcase (no shoulder motion)
Elevation
Name and define the biomechanical terms used to describe the combined action when raising your hand over your head.
Force couple: a situation in which two or more muscles pull in different, often opposite, directions to accomplish the same motion
Which shoulder joint muscles do not attach to the scapula?
Latissiumus dorsi anterior deltoid pectoralis major
What is the result of limited sternoclavicular motion on the shoulder girdle motion?
Limited motion in all directions
Muscles involved in scapula downward rotation
Middle Traps levator scapula rhomboids pec minor
Lie prone on a table with your arm over the edge and with your shoulder flexed 90 degrees, elbow flexed to 90 degrees and a weight in your hand. Lift the weight away from the table in a sideward motion a. does the flexing elbow shorten the force arm? b. does flexing the elbow shorten the resistance arm? c. Why is this exercise easier?
No Yes The resistance arm is shorter so the effort is decreased.
Muscles involved in scapular tilt
Pec minor
Muscles involved in scapula depression
Pec minor lower traps
The pectoralis minor muscle is deep to what muscle?
Pectoralis major
As you look at the lateral chest wall, the serratus anterior is deep to what two muscles?
Pectoralis major and latissimus dorsi
Identify the shoulder girdle motion: Reaching across the table (shoulder flexion)
Protraction
Attaches to the posterior vertebral border of the scapula:
Rhomboids Levator scapula
Starting at the inferior angle and going clockwise, name the shoulder girdle muscles that attach to the posterior surface of the right scapula.
Rhomboids Lower and middle trapezius muscles Levator scapula muscle Upper trapezius muscle
Which joints of the shoulder complex produce movement when your hand is reached over your head?
SC joint, AC joint and scapulothoracic articulation
Shoulder girdle motion: Fastening your seatbelt with your left hand
Scapula downward rotation, protraction
Scapula Protraction and Retraction
Scapula moves away from posterior midline. Scapula moves toward posterior midline
scapula elevation and depression
Scapula moves in a superior or inferior direction
Lie prone on a table with your right arm hanging over the side of the table and holding a weight in your right hand. Using only shoulder girdle motion and no shoulder joint motion, pull the weight straight up from the floor. What joint motion is occurring at the shoulder girdle? What muscles are the prime movers of this shoulder girdle action? Is this an open-chain or closed-chain activity?
Scapular Retraction Middle Traps Rhomboids Open
What scapular motion is always needed to allow for any overhead reaching activity at the glenohumeral joint?
Scapular Upward Rotation
Sit in a chair that has arms; place your hands on the armrests in a position that puts your shoulders in hyperextension. Push down on the armrests and raise your buttocks off the seat of the chair. What shoulder girdle motion is accompanying the shoulder flexion action (from hyperextension to neutral)? What muscles are prime movers in this shoulder girdle motion? Is this a concentric or eccentric activity?
Scapular depression Lower trapexius, pectoralis minor, upper trapezius, serratus anterior Concentric
Shoulder girdle motion: Tucking and holding a book under your arm
Scapular downward rotation
Which shoulder girdle motions are mostly linear?
Scapular elevation/depression and protraction/retraction are more linear.
Lie prone on a table with your right arm hanging over the side of the table and holding a weight in your right hand (Fig. 9-28). Move your arm up and out by doing shoulder horizontal abduction. What shoulder girdle motion is accompanying shoulder horizontal abduction? What muscles are prime movers in this shoulder girdle motion? Is this a concentric, eccentric, or isometric contraction?
Scapular retraction Rhomboids and middle trapezius Concentric
Shoulder girdle motion: Putting your billfold in your left back pocket with your left hand
Scapular tilt and retraction
Which shoulder girdle motions are mostly angular?
Scapular upward and downward rotation are more angular.
Shoulder girdle motion: Reaching up to get hold of your seat belt (drivers side with left hand)
Scapular upward rotation Scapular retraction
Shoulder girdle motion: Placing a book on an upper bookshelf
Scapular upward rotation, protraction
Shoulder joint motion: Reaching up to get hold of your seat belt (drivers side with left hand)
Shoulder abduction, Lateral (external) rotation
Shoulder joint motion: Tucking and holding a book under your arm
Shoulder adduction
Shoulder joint motion: Fastening your seatbelt with your left hand:
Shoulder adduction, medial rotation
Shoulder joint motion: Placing a book on an upper bookshelf
Shoulder flexion
What are the SITS muscles, and why are they called "rotator cuff muscles"?
Supraspinatus Infraspinatus Teres minor Subscapularis These muscle help keep the head of the humerus against the glenoid fossa during joint motion
Describe circumduction and the shoulder joint movements involved.
The circular arc of the upper extremity formed by a combination of the shoulder motions, flexion, abduction, adduction, extension
Why are the rhomboid muscles described as one muscle?
The rhomboid muscles, however, have the same line of pull and thus the same muscle action. There is no functional difference between the rhomboid muscles.
Raising your hand over your head requires the combined action of which three shoulder girdle muscles?
The serratus anterior plus the upper and lower trapezius muscles
Identify the structures that make up the shoulder complex.
The shoulder complex includes the scapula, clavicle, humerus, sternum, and rib cage.
Identify the structures that make up the shoulder girdle.
The shoulder girdle includes the articulations between the scapula and clavicle.
Identify the structures that make up the shoulder joint.
The shoulder joint includes the scapula and humerus. .
Scapular winging
The vertebral border of the scapula moves away from the rib cage.
Attaches on the spinous process of the vertebra
Upper Traps Middle Traps Lower Traps Rhomboids
Shoulder girdle muscles that attach to the vertebral column
Upper Traps Middle Traps Lower Traps Rhomboids Levator Scapula
While standing, grasp some light weights in your hands and perform a shoulder shrug. What muscle(s) contract to perform this motion, and what type of contraction are they performing? Next, lower down from the shrug position. What muscle(s) contract to perform this motion, and what type of contraction are they performing?
Upper trapezius and Levator scapula concentric Upper trapezius and levator scapula eccentric
Shoulder girdle muscle that attaches to the skull
Upper traps
Shoulder girdle muscles that attach to the clavicle.
Upper traps
Attaches to the spine of the scapula
Upper traps middle traps lower traps levator scapula
Identify the shoulder girdle motion: Opening a window by pulling up (Shoulder flexion)
Upward rotation
Identify the shoulder girdle motion: Combing your hair in the back
Upward rotation and retraction
What landmarks can be used to determine whether a model of an unattached bone is a right or left humerus?
With the humerus in the vertical position, the bicipital groove facing anteriorly, and the head facing medially, the right humeral head faces toward the left.
How is the shoulder joint motion affected by the absence of scapulohumeral rhythm?
Without this shoulder girdle movement, one cannot normally and completely raise the arm above the head.
Regarding the Pectoralis major: Which portion of it is effective in shoulder flexion? In what part range is it more effective? Why?
a. Clavicular portion b. first part of range- to approx 60 degrees c. it's vertical line of pull makes it more effective in the early part of the range and less so as it approaches a more horizontal line of pull.
Lie in a prone position with your legs together, hands on the table next to your shoulders, with your fingers pointing forward (Fig. 9-29). Push up with your hands as far as you can while straightening your elbows, bending your knees, and keeping your back straight. What shoulder girdle motion is occurring? What muscles are prime movers in this shoulder girdle motion? Is this an open-chain or closed-chain activity?
a. Scapular protraction and upward rotation Serratus anterior, pectoralis minor, upper and lower trapezius Closed
Using a lat pull-down machine of the Universal Gym (or some other comparable apparatus), reach up and grasp the handles. Pull down while keeping your arms moving in the frontal plane. What shoulder girdle motions are accompanying shoulder adduction and lateral rotation? What muscles are prime movers in these shoulder girdle motions? Is this a concentric or eccentric activity?
a. Scapular retraction and downward rotation Middle trapezius, rhomboids, levator scapula, pectoralis minor Concentric contraction; the external weight is greater than the pull of gravity. Therefore, it is an accelerating force, not a decelerating one.
The coracoid process is on the ________ surface of the scapula
anterior
The rhomboid muscles are located ___________ to the trapezius.
deep
Shoulder adduction
downward rotation
The xiphoid process is ________ to the body of the sternum.
inferior
The glenoid fossa is on the ______________ aspect of the scapula
lateral
Attaches on the transverse processes of the vertebra
levator scapula
Attaches to the superior angle of the scapula
levator scapula
Shoulder girdle muscles that attach to the vertebral border of scapula.
levator scapula rhomboids serratus anterior
Attaches to the base of the spine of the scapula
lower trapezius
The vertebral border is on the ____________ side of the scapula.
medial
Scapular tilt
occurs when the shoulder joint goes into hyperextension
Attaches to the coracoid process
pectoralis minor
The spine is on the ____________ side of the scapula.
posterior
Shoulder horizontal adduction
protraction
Shoulder medial rotation
protraction
Shoulder external rotation
retraction
Shoulder horizontal abduction
retraction
Shoulder Hyperextension
scapular tilt
Shoulder girdle motion: Reaching over top of head to touch lobe of the contralateral ear:
scapular upward rotation
A person has scapular winging. What muscle is involved?
serratus anterior
Attaches to the anterior vertebral border of the scapula
serratus anterior
Which muscle is located between the ribcage and the scapula?
serratus anterior
Shoulder girdle muscles that attach to the ribs
serratus anterior Pec minor
Shoulder joint motion: Reaching over top of head to touch lobe of the contralateral ear:
shoulder abduction
The back stroke in swimming involves what collective joint motion in the shoulder joint?
shoulder circumduction
Shoulder joint motion: Putting your billfold in your left back pocket with your left hand
shoulder hyperextension medial rotation
List the joints that make up the shoulder girdle
sternoclavicular acromioclavicular scapulothoracic
Which fossa is located on the anterior surface of the scapula?
subscapular fossa
Name the shoulder joint muscles attaching on the anterior surface of the scapula.
subscapularis coracobrachialis muscles short head of biceps brachii muscle
The upper trapezius muscle is _______ to the levator scapula muscle.
superficial
The clavicle is _________ to the first rib.
superior
The spine of the scapula divides the posterior surface into which two fossae?
supraspinous fossa infraspinous fossa
Name the shoulder joint muscles attaching on the posterior surface of the scapula.
teres major teres minor infraspinatus supraspinatus posterior deltoids
Scapula upward rotation and downward rotation
the inferior angle of the scapula rotates up and away from the vertebral column
What is scapulohumeral rhythm?
the movement relationship between the shoulder girdle and the shoulder joint. After the first 30 degrees, for every 2 degrees of shoulder joint flexion or abduction, the shoulder girdle rotates upwardly 1 degree.
Why is the scapulothoracic joint not a true joint?
there is no bone to bone articulation
Muscles involved in scapula upward rotation
trapezius (upper and lower) serratus anterior
Muscles involved in scapula elevation
upper trapezius, levator scapula, rhomboids,
Shoulder abduction
upward rotation
Shoulder flexion
upward rotation, protraction
