Longissimus insertion includes which of the following?

• A. Mastoid process and transverse processes of cervical and thoracic vertebrae
• B. Spinous processes of the vertebrae
• C. Ischial tuberosity
• D. Occipital condyle

Answer: (A)

Longissimus is a major erector spinae muscle with fibers that attach to the mastoid process of the temporal bone and to the transverse processes of the cervical and thoracic vertebrae. The capitis portion inserts on the mastoid process, while the cervicis and thoracis portions insert on the transverse processes (and, for thoracis, into the ribs as well). So, inserting at the mastoid process and the transverse processes of the cervical and thoracic vertebrae is exactly what this muscle does.

Spinous processes are typical insertion for spinalis, the ischial tuberosity is for some hip/ thigh muscles, and the occipital condyle is not a standard insertion site for longissimus.