Longissimus thoracis et lumborum The
longissimus thoracis et lumborum is the intermediate and largest of the continuations of the erector spinae. In the lumbar region (longissimus lumborum), where it is as yet blended with the
iliocostalis, some of its fibers are attached to the whole length of the posterior surfaces of the
transverse processes and the
accessory processes of the
lumbar vertebrae, and to the anterior layer of the
lumbodorsal fascia. In the thoracic region (longissimus thoracis), it is inserted, by rounded tendons, into the tips of the transverse processes of all the thoracic vertebrae, and by fleshy processes into the lower nine or ten
ribs between their
tubercles and
angles.
Longissimus cervicis The
longissimus cervicis (transversalis cervicis), situated medial to the longissimus thoracis, arises by long, thin tendons from the summits of the transverse processes of thoracic vertebræ 1–5, and is inserted by similar tendons into the posterior tubercles of the transverse processes of
cervical vertebrae 2–6.
Longissimus capitis The
longissimus capitis (trachelomastoid muscle) lies medial to the longissimus cervicis, between it and the
semispinalis capitis. It arises by tendons from the transverse processes of the upper five thoracic vertebrae, and the
articular processes of the lower four cervical vertebrae, and is inserted into the posterior margin of the
mastoid process, beneath the
splenius capitis and
sternocleidomastoid. It is almost always crossed by a tendinous intersection near its insertion. ==See also==