SINCE the publication of Prof. Zygmund's “Trigonometric Series” in 1935, there has been considerable demand for another book dealing with trigonometric integrals. Prof. Titchmarsh's book meets this ...

A muscle strain (pulled muscle) happens when muscle fibers overstretch, causing sudden pain, swelling, weakness, or bruising. Strains often affect the lower back, neck, shoulders, or hamstrings.

Neck pain or stiffness often results from poor posture, muscle strain, or an awkward sleeping position. However, it can also signal injury or illness. Common neck pain symptoms include stiffness, ...

Tools and resources to help you understand and manage a range of sleep disorders.