leg
Definition
A leg is a limb that is used for locomotion in vertebrates. Legs are made up of bones, muscles, and tendons. The bones of the leg provide support and structure, while the muscles and tendons allow the leg to move.
The bones of the leg include the thighbone (femur), the shinbone (tibia), and the fibula. The muscles of the leg include the quadriceps femoris, the hamstrings, and the gastrocnemius. The tendons of the leg connect the muscles to the bones.
The leg is a complex structure that allows us to walk, run, and jump. It is also important for balance and posture.
How can the word be used?
The bird hopped away on its tiny legs.
Different forms of the word
Noun: Leg is the part of the body that is used for walking, running, and jumping. It is attached to the body at the hip and ends at the foot.
Adjective: Leggy is an adjective that describes something that has long legs. For example, a leggy model is a model that has long legs.
Verb: To leg is to walk or run on one's legs. For example, to leg it is to run away quickly.
Etymology
The word "leg" comes from the Old English word "leogan", which also means "leg". It was first used in English in the 8th century.
The Old English word "leogan" is thought to be derived from the Proto-Germanic word *lagaz, which also means "leg".
Question
What is a leg?
AQA Science Exam Question and Answer
Question:
Explain the structure and function of the human leg, highlighting the roles of bones, muscles, and joints in enabling movement. Provide an example of a specific leg movement and the muscles involved in performing it.
Answer:
The human leg is a remarkable example of biomechanical efficiency, composed of various components that work in tandem to facilitate movement. The leg's primary structural elements are bones, muscles, and joints.
Bones form the framework of the leg, providing stability and support. The femur, the longest bone in the body, connects the hip to the knee, while the tibia and fibula form the lower leg, connecting the knee to the ankle. These bones serve as anchor points for muscles and allow for the articulation of joints.
Muscles play a crucial role in leg movement. They contract and relax to generate force, enabling motion. For instance, the quadriceps in the front of the thigh contract to extend the leg, while the hamstrings at the back facilitate flexion. The calf muscles (gastrocnemius and soleus) are responsible for plantar flexion of the ankle, crucial for activities like walking and running.
Joints provide flexibility and allow movement between bones. The knee joint, formed by the femur, tibia, and patella, facilitates flexion and extension, while the hip joint permits a wide range of motion, including abduction, adduction, and rotation.
As an example, consider kicking a soccer ball. The quadriceps contract to extend the knee, and the hamstrings flex the hip while controlling the knee's movement. Simultaneously, the calf muscles contract to point the toes, enhancing the power of the kick.
In summary, the human leg's intricate interplay of bones, muscles, and joints enables a wide range of movements essential for everyday activities and athletic pursuits.