What are a mouse’s legs? - briefly
A mouse has four slender, fur‑covered limbs ending in small, clawed digits. The forelimbs bear five toes each, the hind limbs four, allowing rapid scurrying and agile climbing.
What are a mouse’s legs? - in detail
Mouse limbs consist of four slender appendages, each built for rapid movement, climbing, and tactile exploration. The structure can be divided into three main regions: the proximal thigh (or forelimb humerus in the forelegs), the intermediate shank, and the distal foot.
The proximal segment contains a single long bone—femur in the hind limbs and humerus in the forelimbs—connected to the pelvis or scapula by a ball‑and‑socket joint. This joint permits a wide range of motion essential for leaping and digging. Surrounding the bone, a layer of muscle fibers, including the quadriceps femoris and gluteus complex, generates powerful extension forces.
The shank comprises two parallel bones. In the hind limbs these are the tibia and fibula; in the forelimbs they are the radius and ulna. The tibia bears most of the load, while the fibula serves as a stabilizing strut. Muscles such as the gastrocnemius and extensor digitorum attach to these bones, enabling flexion, extension, and precise foot placement.
The distal foot ends in a series of small, articulated bones called phalanges. Each foot typically has five digits, though the first digit (the hallux) is reduced. The digits terminate in sharp, keratinized claws that can be retracted slightly for digging and extended for climbing. The pads beneath the claws contain dense, hairless skin with a high concentration of mechanoreceptors, providing feedback on surface texture and pressure.
Key anatomical features include:
- Joint types: hip and shoulder ball‑and‑socket joints; knee and elbow hinge joints; ankle and wrist pivot joints.
- Muscle groups: extensors, flexors, abductors, and adductors arranged in compact bundles to fit the mouse’s small frame.
- Tendons and ligaments: strong, elastic structures that transmit muscular force to the bones and stabilize joints during rapid acceleration.
- Sensory elements: vibrissae (whisker‑like hairs) located on the feet, and numerous Merkel cells in the pads, allowing the animal to detect minute vibrations and textures.
- Vascular supply: femoral and brachial arteries deliver oxygenated blood; a network of capillaries supports high metabolic demand during sustained activity.
These components work together to produce a limb capable of swift sprints (up to 13 m s⁻¹), vertical jumps, and intricate maneuvers in confined spaces. The combination of lightweight bone, powerful muscle, and sensitive tactile surfaces defines the functional efficiency of a mouse’s legs.