Ch 8 Structure and Function of the Shoulder Complex

deltoid

-anterior portion produces glenohumeral flexion and horizontal abduction and contributes to medial rotation -middle portion produces glenohumeral abduction -posterior produces glenohumeral ext. and horizontal adduction and contributes to lateral rotation

pectoralis major

-as a unit, produces glenohumeral adduction, medial rotation, horizontal adduction -clavicular portion alone assists w glenohumeral flexion -sternocostal portion alone assists w/ glenohumeral extension

supraspinatus

-compresses humeral head into fossa, providing stability -initiates shoulder abduction -produces superior roll of humeral head -generates a small amount of lateral rotation

long head of triceps and biceps at glenohumeral joint

-tendons of each muscle assist w/ inferior glide of humeral head -long head of triceps assists w/ shoulder ext. -long head of biceps assists w/ shoulder flexion

infraspinatus, subscapularis, teres minor

-together they produce an inferior glide of the humeral head as the humerus elevates -subscapularis provides medial rotation and anterior shoulder stability -infraspinatus and teres minor produce lateral humeral rotation

coracohumeral ligament

forms a tunnel for the long head of the biceps tendon; contributes to humeral head stability

coracoacromial ligament

forms the coracoacromial arch and can be involved in subacromial impingement of structures

downward scapula rotators

levator scapulae, pectoralis minor, rhomboids

scapula depressors

lower trapezius, latissimus dorsi, pectoralis minor

latissimus dorsi

major adductor and extensor of the glenohumeral joint

scapula retractors

middle and lower trapezius, rhomboids

glenohumeral stabilizer muscles

muscles that control the humeral head and assist w/ maintaining the head's orientation within the glenoid fossa

scapula stabilizer muscles

muscles that stabilize the scapula against the thorax and orient the scapula (glenoid fossa_ w/ the humeral head during glenohumeral movement

teres major

produces glenohumeral medial rotation and adduction; assists w/ extension

bones of glenohumeral joint

scapula and humerus

scapula protractor

serratus anterior

coracoclavicular ligament

stabilizes the clavicle w/ the scapula at the acromioclavicular joint

rotator cuff muscles

supraspinatus, infraspinatus, subscapularis, and teres minor, which form a protective cuff around the humeral head

upward scapula rotators

upper and lower trapezius, serratus anterior

scapula elevators

upper trapezius, levator scapulae, rhomboids

Dysfunction of which of the following muscles could lead to impingement of subacromial structures during shoulder scaption? A. Serratus anterior B. Pectoralis major C. Deltoid D. Latissimus dorsi

A

Which muscle performs shoulder flexion? A. Anterior deltoid B. Infraspinatus C. Middle deltoid D. Supraspinatus

A

Which muscle produces scapular protraction? A. Serratus anterior B. Rhomboid major C. Lower trapezius D. Pectoralis major

A

Which of the following muscles are dynamic stabilizers of the glenohumeral joint? A. Supraspinatus, infraspinatus, subscapularis, and teres minor B. Anterior, middle, and posterior deltoid C. Supraspinatus, infraspinatus, subscapularis, and serratus anterior D. Upper and lower trapezius and serratus anterior

A

What are the arthrokinematic motions of the humeral head as the arm returns to the anatomical position after reaching upward into a cabinet? A. Rolls medially, glides superiorly B. Rolls laterally, glides inferiorly C. Rolls inferiorly, glides superiorly D. Rolls superiorly, glides inferiorly

C

During arm elevation, which of the following movements occur at the sternoclavicular (SC) joint? A. Protraction at the SC joint B. Posterior rotation of the clavicle at the SC joint C. No movement at the SC joint D. Anterior rotation of the clavicle at the SC joint

B

What are the primary muscles that extend the shoulder? A. Posterior deltoid and long head of the biceps B. Posterior deltoid, latissimus dorsi, long head of the triceps, and pectoralis major C. Anterior deltoid and long head of the biceps D. Anterior deltoid, latissimus dorsi, triceps, and pectoralis minor

B

What concurrent motion at the glenohumeral joint should occur with shoulder abduction? A. Glenohumeral internal rotation B. Glenohumeral external rotation C. Both options 1 and 2, depending on the load on the arm D. Neither option 1 nor 2

B

Which muscle produces scapular retraction? A. Serratus anterior B. Rhomboid major C. Deltoid D. Pectoralis major

B

Which of the following bones form the shoulder complex? A. Clavicle, scapula, and humerus B. Sternum, clavicle, scapula, and humerus C. Scapula and humerus D. Sternum, ribs, scapula, and humerus

B

Which of the following muscle groups act to produce upward rotation of the scapula? A. Lower trapezius, rhomboids, and serratus anterior B. Upper and lower trapezius and serratus anterior C. Upper and middle trapezius and pectoralis minor D. Levator scapulae, pectoralis minor, and rhomboids

B

What is scapulohumeral rhythm? A. 2:3 ratio of scapula to humeral movement after 30 degrees of abduction or 60 degrees of flexion B. An unequal amount of scapula to humeral movement after 20 degrees of glenohumeral movement C. 2:1 ratio of humeral to scapula movement after 30 degrees of abduction or 60 degrees of flexion D. An equal amount of scapula to humeral movement after 60 degrees of glenohumeral movement

C

What is the function of anterior and posterior tilting of the scapula during glenohumeral motion? A. Allows the scapula to move independently of the humerus B. Allows the scapula to maintain contact with horizontal curvature of the thorax C. Allows the scapula to maintain contact with curvature of the rib cage and orients glenoid fossa with humeral head D. Allows the inferior orientation of the glenoid fossa to maintain the humeral head in the fossa

C

What is the purpose of the scapula to move during arm elevation? A. Lengthens the moment arm for the rotator cuff muscle B. Shortens the movement arm for the rotator cuff muscle C. Allows for optimal muscle contraction of the infraspinatus D. Allows for optimal muscle contraction of the pectoralis major

C

What motion is expected of the scapula during arm elevation? A. Scapula elevation B. Scapula retraction C. Scapula upward rotation D. Scapula downward rotation

C

Why does movement of the sternoclavicular (SC) joint produce movement at the scapula? A. The clavicle articulates with the scapula at the scapulothoracic joint. B. Movement of the acromioclavicular (AC) joint and the SC joint are independent of scapular movement. C. The clavicle articulates with the scapula at the AC joint. D. Movement does not occur at the SC joint.

C

What are the arthrokinematic motions of the humeral head during shoulder flexion? A. Rolls medially, glides superiorly B. Rolls laterally, glides inferiorly C. Rolls inferiorly, glides superiorly D. Rolls superiorly, glides inferiorly

D

What is the contribution of motion between the glenohumeral (GH) joint and the scapulothoracic (ST) joint? A. 30 degrees GH joint and SC joint; 120 degrees acromioclavicular (AC) joint B. 30 degrees GH and AC joint; 120 degrees SC joint C. 60 degrees GH joint; 120 degrees ST joint D. 60 degrees ST joint; 120 degrees GH joint

D

What joints are moving during normal shoulder flexion? A. Glenohumeral joint B. Scapula thoracic joint C. Acromioclavicular joint D. All of the above

D

What motion occurs at the scapula during shoulder elevation? A. Anterior tilting and downward rotation B. Posterior tilting and downward rotation C. Anterior tilting and upward rotation D. Posterior tilting and upward rotation

D

Which muscle contributes to external rotation of the glenohumeral joint? A. Anterior deltoid B. Pectoral major C. Teres major D. Infraspinatus

D

Which muscle initiates shoulder abduction? A. Anterior deltoid B. Infraspinatus C. Middle deltoid D. Supraspinatus

D

Which of the following muscle groups act to produce downward rotation of the scapula? A. Lower trapezius, rhomboids, and serratus anterior B. Upper and lower trapezius and serratus anterior C. Upper and middle trapezius and pectoralis minor D. Levator scapulae, pectoralis minor, and rhomboids

D

Which of the following statements BEST describes scapular upward rotation? A. The glenoid fossa rotates superiorly; the inferior scapular angle rotates downward. B. The glenoid fossa rotates inferiorly; the inferior scapular angle rotates upward. C. The glenoid fossa rotates inferiorly; the inferior scapular angle rotates downward. D. The glenoid fossa rotates superiorly; the inferior scapular angle rotates upward.

D

bones of shoulder complex

clavicle, sternum, scapula, humerus