368 THE MUSCULAR SYSTEM. "7 
Internal to the insertion of each is the origin ofa slip of the accessorius muscle 
(m. ilio-costalis dorsi), which, arising from the lower six ribs internal to the ilio- 
costalis, is inserted in line with it by similar slips into the upper six ribs. 
The cervicalis ascendens (m. ilio-costalis cervicis) arises in the same way by 
six slips from the upper six ribs, internal to the insertions of the accessorius. It — 
forms a narrow band, which, extending into the neck, is inserted into the posterior 
tubercles of the transverse processes of the fourth, fifth, and sixth cervical vertebre, 
behind the scalenus posticus. The ilio-costalis, accessorius, and cervicalis ascendens 
form together a continuous muscular column, and constitute the outermost group 
of the component elements of the erector spine. 
The longissimus dorsi is the largest element in the erector spine. Mostly 
tendinous on the surface at its origin, it becomes fleshy in the upper part of the 
loin, and is inserted, by an inner and an outer series of slips, externally into nearly 
all the ribs, and internally into the transverse processes of the thoracic and the 
accessory processes of the upper lumbar vertebre. It is prolonged upwards into the 
ScALENUS MEDIUs — 
LEVATOR ANGULI SCAPULE 
Posterior SPLENIUS COLLI 
tubercles of 
transverse } 
processes 
| SCALENUS 
Evy =) «MANTICUS 
ScALENUS PosTICUS —— : \) Wie Anterior 
Toe i RECTUS CAPITIS | tubercles of 
~~ANTICUS MAJOR [transverse 
processes 
CERVICALIS ASCENDENS —— 
TRANSVERSALIS CERVICIS —— 
~Lonauts COLLI 
TRACHELO-MASTOID _ 
COMPLEXUS- 
Articular eg | SEMISPINALIS COLLI ———_/—— ———— 
MULTIFIDUS SPINE —— 
Fic. 271.—ScHEME OF MuscULAR ATTACHMENTS TO CERVICAL VERTEBR2. 
neck by its association with the common origin of two muscles, the transversalis 
cervicis and the trachelo-mastoid. 
The transversalis cervicis (m. longissimus cervicis) has an origin from the 
transverse processes of the upper six thoracic vertebre, internal to the insertions 
of the longissimus dorsi. Extending upwards into the neck, it is inserted, under- 
neath the cervicalis ascendens and splenius colli muscles, into the posterior tubercles 
of the transverse processes of the second, third, fourth, fifth, and sixth cervical 
vertebre. 
The trachelo-mastoid (m. longissimus capitis) arises, partly by an origin 
common to it and the previous muscle, from the transverse processes of the upper 
six thoracic vertebree, and partly by an additional origin from the articular pro- 
cesses of the lower four cervical vertebrae. Separating from the transversalis 
cervicis, the muscle ascends through the neck as a narrow band which intervenes 
between the splenius capitis and complexus, and is inserted into the mastoid process 
beneath the former muscle. 
The longissimus dorsi, with its cervical prolongations, forms the middle column 
of muscles in the erector spine. 
The spinalis dorsi arises by tendinous fibres from the lower two thoracic and 
upper two lumbar spinous processes, and also directly from the tendon of the 
longissimus dorsi. It is a narrow muscle which, lying close to the thoracic spinous 
processes internal to the longissimus dorsi and complexus, is inserted into the 
