Skeletal muscles can be categorized into various types based on their shape. Some common types of skeletal muscle based on shape include:
Fusiform muscles: Fusiform muscles are spindle-shaped muscles that taper at both ends. These musclesiceps and gastrocnemius (calf) muscles.
Pennate muscles: Pennate muscles have fascicles that are arranged at an angle to the tendon, giving them a feather-like appearance. These muscles have a larger number of muscle fibers, allowing them to generate more force. Examples of pennate muscles include the deltoid and rectus femoris muscles.
Parallel muscles: Parallel muscles have muscle fibers that run parallel to the direction of pull. These muscles are well-suited for endurance activities and provide a greater range of motion. Examples of parallel muscles include the rectus abdominis and sartorius muscles.
Convergent muscles: Convergent muscles have a broad origin that converges into a single tendon. These muscles are versatile and can produce a variety of movements. Examples of convergent muscles include the pectoralis major and trapezius muscles.
Circular muscles: Circular muscles, also known as sphincter muscles, have fibers arranged in a circular pattern around an opening or orifice. These muscles can contract to close off a passage or opening. Examples of circular muscles include the orbicularis oculi around the eye and the anal sphincter muscles.
These are some of the common types of skeletal muscles based on their shape, each with its own unique characteristics and functions.