What bones make up the pectoral (shoulder) girdle, and what are their main points of articulation?
The pectoral girdle consists of the clavicle (collarbone) and the scapula (shoulder blade). The clavicle articulates medially with the sternum and laterally with the scapula at the acromion process. The scapula articulates with the clavicle at the acromion process and with the humerus at the glenoid cavity.
Why is the shoulder joint considered the most mobile joint in the body?
The shoulder joint is the most mobile because the glenoid cavity of the scapula is shallow, allowing the humerus to move freely. Additionally, the scapula and clavicle have limited articulations, which increases the range of motion.
How does the structure of the scapula contribute to arm mobility?
The scapula only articulates with the clavicle and the humerus, allowing it to move significantly as the arm moves, which enhances overall arm mobility.
What is the function of the acromion process in the pectoral girdle?
The acromion process is the part of the scapula that articulates with the clavicle, forming the top of the shoulder and helping connect the arm to the axial skeleton.
What two bones make up the pectoral (shoulder) girdle?
The pectoral girdle is made up of the clavicle (collarbone) and the scapula (shoulder blade).
Where does the clavicle articulate medially and laterally?
The clavicle articulates medially with the sternum and laterally with the scapula at the acromion process.
What is the function of the acromion process in the pectoral girdle?
The acromion process is the part of the scapula that articulates with the clavicle, forming the top of the shoulder and connecting the arm to the axial skeleton.
Why is the shoulder joint considered the most mobile joint in the body?
The shoulder joint is the most mobile because the glenoid cavity is shallow, allowing the humerus to move freely, and the scapula and clavicle have limited articulations, increasing range of motion.
How does the structure of the scapula contribute to arm mobility?
The scapula only articulates with the clavicle and humerus, allowing it to move significantly as the arm moves, which enhances overall arm mobility.
What is the glenoid cavity and what role does it play in the shoulder joint?
The glenoid cavity is a shallow depression on the scapula that forms the socket for the humerus, enabling the wide range of motion in the shoulder joint.