8 Questions
What is the primary function of the shoulder girdle?
To link the upper extremity to the trunk
What is unique about the shoulder girdle in terms of bony constraints?
It has no bony constraints, relying on soft tissues for stability
What is the result of the four joints of the shoulder complex acting together?
Mobility greater than that afforded by any one individual articulation
In which plane does abduction of the shoulder complex occur?
Coronal plane
What is the term for rotation about the long axis of the humerus?
Internal-external rotation
What type of joint allows for a wide range of motion at the expense of stability?
Joint with no bony constraints
What is traditionally measured to describe the range of motion of the shoulder complex?
All of the above
What movement of the spine affects the ability of the shoulder complex to position the upper extremity?
Movement of the spine
Study Notes
The Shoulder Girdle
- The shoulder girdle is the link between the upper extremity and the trunk, enabling hand positioning in space.
- It is the most dynamic and mobile joint in the body, consisting of four articulations: glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic.
Characteristics of the Shoulder Girdle
- The absence of bony constraints allows for a wide range of motion, but at the expense of stability.
- Stability is provided entirely by soft tissues.
Kinematics and Anatomy
- The four joints work together to produce intricate motions necessary for normal hand positioning in space.
- The shoulder complex's ability to position the upper extremity is also augmented by spinal movement.
Range of Motion of the Shoulder Complex
- Shoulder range of motion is measured in terms of flexion, extension, abduction, and internal-external rotation.
- Forward elevation (flexion) averages 167° in men and 171° in women, limited by tension on the joint capsule.
- Extension (posterior elevation) averages 60°, limited by tension on the joint capsule.
- Abduction in the coronal plane is limited by bony impingement of the greater tuberosity on the acromion.
This quiz covers the anatomical structure and functions of the shoulder girdle, including its articulations and muscular structures. Learn about the range of motion and stability of the shoulder joint.
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