Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            ts at 
the GH joint are flexion and extension, abduction and adduction, 
and internal and external rotation (Fig. 5.30). Often, a fourth 
motion is defined at the GH joint: horizontal adduction and 
abduction (also called horizontal flexion and extension, respectively). 
The motion occurs from a starting position of 90 degrees of 
abduction. The humerus moves around a vertical axis of rotation: 
anteriorly during horizontal adduction and posteriorly during 
horizontal abduction.
Reporting the range of motion at the GH joint uses the ana­
tomic position as the 0-degree or neutral reference point. In the 
sagittal plane, for example, flexion is described as the rotation of 
the humerus anterior to the 0-degree position. Extension, in con­
trast, is described as the rotation of the humerus posterior to the 
0-degree position.
Virtually any purposeful motion of the GH joint involves 
motion at the scapulothoracic joint, including the associated 
movements at the SC and AC joints. The following discussion, 
however, focuses primarily on the isolated kinematics of the GH 
joint.
Abduction and Adduction
Abduction and adduction are traditionally defined as rotation of 
the humerus in the near frontal plane around an axis oriented in 
the near anterior-posterior direction (see Fig. 5.30). Normally, the 
healthy person has about 120 degrees of abduction at the GH 
joint, although a range of values has been reported.84,118 Full 
abduction of the shoulder complex requires a simultaneous 
approximate 60 degrees of upward rotation of the scapula; these 
kinematics were introduced previously in this chapter.
FIG. 5.29  An anterior view of a frontal plane cross-section of the right 
glenohumeral joint. Note the subacromial and subdeltoid bursa within 
the subacromial space. Bursa and synovial lining are depicted in blue. 
The deltoid and supraspinatus muscles are also shown. 
Glenoid labrum
Synovial membrane
Capsular ligament
Subacromial bursa
Supraspinatus
and tendon
Deltoid
Subdeltoid
bursa
Axillary
pouch
FIG. 5.30  The osteokinematics of the glenohumeral joint includes abduc­
tion and adduction (purple), flexion and extension (green), and internal 
and external rotation (blue). Note that each axis of rotation is color-coded 
with its corresponding plane of movement. 
Internal
rotation
External
rotation
Flexion
Extension
Adduction
Abduction
FIG. 5.31  The arthrokinematics of the right glenohumeral joint during 
active abduction. The supraspinatus is shown contracting to direct the 
superior roll of the humeral head. The taut inferior capsular ligament 
(ICL) is shown supporting the head of the humerus like a hammock (see 
text). Note that the superior capsular ligament (SCL) remains relatively 
taut because of the pull from the attached contracting supraspinatus. 
Stretched tissues are depicted as long black arrows. 
Subacromial
bursa
Supraspinatus
pull
Supraspinatus
pull
I
C
L
 
S
C
L 
S
L
I
D
E
 
R
O
L
L
 
AB
D
U
C
T
I
O
N 
	
Chapter 5    Shoulder Complex	
1

            Quiz: