a THE MUSCLES OF THE BACK. 369 
upper (four to eight) thoracic spines. This muscle is not prolonged into the neck. 
It conceals the next group of muscles, and forms the innermost column of the 
erector spinee muscle. . 
The erector spine muscle is bound down by the vertebral aponeurosis, and 
is concealed by the more superficial muscles (sterno-mastoid, trapezius, levator 
yy E 
\ + 
COMPLEXUS MUSCLE 
OBLIQUUS SUPERIOR Se OneroTD 
RECTUS CAPITIS POSTICUS MAJOR 
OBLIQUUS INFERIOR ; 
STERNO-MASTOID -SPLENIUS CAPITIS 
COMPLEXUS MUSCLE 
SPLENIUS COLLI 
LEVATOR ANGULI SCAPULZ 
Na ERANSVERSALIS COLLI 
CERVICALIS ASCENDENS 
TRACHELO-MASTOID 
SCALENI, MEDIUS AND POSTICUS 
( ACCESSORIUS 
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WN ~ + = ~ 
} i \y NY a SEMISPINALIS DORSI 
SEMISPINALIS DORSI 
Middle layer of lumbar fascia 
: : , Vertebral aponeurosis (cut 
Vertebral aponeurosis (cut) ertebral ay sis (cut) 
: Lumbar fascia 
OBLIQUUS INTERNUS ABDOMINIS OBLIQUUS INTERNUS ABDOMINIS 
ORIGIN OF ERECTOR SPINA OBLIQUUS EXTERNUS ABDOMINIS 
Vertebral aponeurosis (cut) 
ORIGIN OF GLUTEUS MAXIMUS 
Fic. 272.—DEEPER MUSCLES OF THE BACK. 
scapule, rhomboids, splenius, serrati postici). It covers the ribs posteriorly, and 
partially conceals the semispinales and complexus muscles. 
The complexus muscle (m. semispinalis capitis) closely resembles in position 
and attachments the trachelo-mastoid. It takes origin from the transverse 
processes of the upper six thoracic and the articular processes of the lower four 
cervical vertebra, internal to the transversalis cervicis and trachelo-mastoid. It 
has an additional origin also from the spinous process of the last cervical vertebra. 
It forms a broad muscular sheet which extends upwards in the neck, to be inserted 
between the superior and inferior curved lines of the occipital bone. The inner 
24 
