Final answer:
The appendicular muscles serve to stabilize the pelvic and pectoral girdles, control limb movements, and work in synergistic or antagonistic groups. The limited range of the pelvic girdle is contrasted by the greater mobility of the pectoral girdle, with the upper limbs specially adapted for a variety of activities compared to the lower limbs' focus on support and stability.
Step-by-step explanation:
The appendicular muscles include those that stabilize the pectoral and pelvic girdles, those that control movements of the upper and lower limbs, and those that operate in synergistic or antagonistic groups. The appendicular muscles of the lower body work to position and stabilize the pelvic girdle, providing a stable foundation for the lower limbs. The pelvic girdle, being connected with the sacrum at the axial skeleton's base, supports the body with a limited range of motion compared to the pectoral girdle. The muscles of the thigh and lower limbs are less versatile in their movements but are more powerful and sizable which is crucial for body stabilization, posture, and movement.
The muscles of the shoulder and upper limb are categorized into several groups including muscles that stabilize the pectoral girdle, and those that move the arm, forearm, wrists, hands, and fingers. The pectoral girdle allows for a wide range of movement for the upper limbs, highlighting the contrast in functional demands between the upper and lower limbs. Our upper limbs are adaptable, enabling a vast array of activities, while our lower limbs are designed for weight-bearing, stability, and locomotion.