Figure 1-22
Superficial layer of back muscles.

The superficial back muscles are the splenius capitis and splenius cervicis. The splenius capitis originates on the spinous processes of the seventh cervical and upper thoracic vertebrae and inserts on the occipital bone and mastoid process of the temporal bone. The splenius cervicis originates on the spinous processes of the third to sixth thoracic vertebrae and inserts on the transverse processes of the upper two or three cervical vertebrae. Both muscles are found deep to the trapezius and medial to the levator scapulae. (Figure 1-22)

Deep to the rhomboids, is the small serratus posterior superior muscle. Deep to the latissimus dorsi lies the serratus posterior inferior muscle. These thin muscles may only appear as slips of fascia and probably function as respiratory muscles. (Figures 1-21; 1-22)