**5.6 Muscles of the spine**

• M. erector spinae:

M. iliocostalis: This long muscle originates from the wing of the ilium and inserts into the transverse processes of the lumbar vertebrae, the ribs and transverse processes of the last two cervical vertebrae. As such, a lumbar and thoracic part can be discerned (**Figures 28** and **29**).

### **Figure 29.**

*Left lateral view of the abdominal muscles. A: Superficial musculature with 1: m. latissimus dorsi, 2: fascia thoracodorsalis, 3: m. serratus ventralis, 4: m. obliquus externus abdominis, 5: m. obliquus internus abdominis, 6: m. pectoralis abdominalis, 7: lamina externa vaginae m. recti abdominis. B. Deep musculature with 1: m. intercostalis externus, 2: m. transversus abdominis, 3: m. rectus abdominis, 4: fascia transversalis, 5: m. psoas minor, 6: m. psoas major, 7: m. quadratus lumborum, 8a: m. iliocostalis lumborum, 8b: m. iliocostalis thoracis 9a: m. longissimus lumborum, 9b: m. longissimus thoracis.*

*Anatomy of the Rhesus Monkey (*Macaca mulatta*): The Essentials for the Biomedical Researcher DOI: http://dx.doi.org/10.5772/intechopen.99067*

#### **Figure 30.**

*Lateral views of the pectoral muscles. A: superficial layer, B: deeper layer, C: deepest layer. 1a: m. pectoralis superficialis pars sternocapsularis, 1b: m. pectoralis superficialis pars sternalis, 1c: m. pectoral superficialis pars abdominalis, 2: m. obliquus externus abdominis, 3: m. serratus ventralis, 4: m. serratus dorsalis, 5: m. subscapularis, 6: m. teres major, 7: m. latissimus dorsi, 8: m. pectoral profundus, 9: m. biceps brachii, 10: m. subclavius, 11: m. sternocostalis, 12: m. scalenus medius, 13a: m. cleidodeltoideus, 13b: m. acromiodeltoideus, 13c: m. spinodeltoideus, 14: m. latissimus dorsi.*

M. longissimus dorsi: This long, cylindrical muscle that is covered by the thoracodorsal fascia lies medial to the former muscle and runs from the ilium to the mastoid process. Insertions can be found into the lumbar, thoracic and cervical vertebrae and the ribs (pars lumbalis, thoracis, cervicis and capitis) (**Figure 28**).

M. spinalis: This is the deepest muscle of this group. The origins and insertions are the spinal processes (**Figures 28** and **29**).

• M. transversospinalis:

M. semispinalis (capitis) = m. complexus: This muscle was described earlier with the muscles of the dorsal and lateral cervical region (**Figure 28**).

Mm. multifidi et rotatores: These muscles lie very deep against the vertebrae. With their origins and insertions on the transverse processes and into the spinal processes, they can rotate the vertebral column.

