MUSCLES OF THE BACK. 201 



another between its tendon and that of the teres major. The muscle fre- 

 quently receives a small fasciculus from the scapula as it crosses its inferior 

 angle. 



Relations. By its superficial surface with the integument and superficial 

 fascia ; the latter is very dense and fibrous in the lumbar region ; and with 

 the trapezius. By its deep surface from below upwards, with the erector 

 spinae, serratus posticus inferior, intercostal muscles and ribs, rhomboideus 

 major, inferior angle of th*e scapula and teres major. The latissimus dorsi, 

 with the teres major, forms the posterior border of the axilla. 



Second Layer. 



* 



Dissection. This layer is brought into view by dividing the two pre- 

 ceding muscles near their insertion, and turning them to the opposite 

 side. 



The LEVATOR ANGULI SCAPULA arises by distinct slips, from the 

 posterior tubercles of the transverse processes of the four upper cervical 

 vertebrae, and is inserted into the upper angle and posterior border of 

 the scapula, as far as the triangular smooth surface at the root of its 

 spine. 



Relations. By its superficial surface with the trapezius, sterno-mastoid 

 and integument. By its deep surface with the splenius colli, transversalis 

 colli, cervicalis ascendens, scalenus posticus, and serratus posticus supe- 

 rior. The tendons of origin are interposed between the attachments of the 

 scalenus posticus in front, and the splenius colli behind. 



The RHOMBOIDEUS MINOR (rhombus, a parallelogram with four equal 

 sides) is a narrow slip of muscle, detached from the rhomboideus major 

 by a slight cellular interspace^ It arises from the spinous process of the 

 two last cervical vertebrae and ligamentum michaB, and is inserted into the 

 edge of the triangular surface, on the posterior border of the scapula. 



The RHOMBOIDEUS MAJOR arises from the spinous processes of the last 

 cervical and four upper dorsal vertebrae and from the inter-spinous liga- 

 ments ; it is inserted into the posterior border of the scapula as far as its 

 inferior angle. The upper and middle portion of the insertion is effected 

 by means of a tendinous band which is attached in a longitudinal direction 

 to the posterior border of the scapula. 



Relations. By their superficial surface the two rhomboid muscles are 

 in relation with the trapezius, and the rhomboideus major with the latis- 

 simus dorsi and integument. By their deep surface they cover in the ser- 



. ** , 



ratus posticus superior, part of the erector spinae, the intercostal muscles 

 and ribs. 



Third Layer. 



Dissection. The third layer consists of muscles which arise from the 

 spinous processes of the vertebral column, and pass outwards. It is brought 

 into view by dividing the levator anguli scapulae near its insertion, and 

 reflecting the two rhomboid muscles upwards from their insertion into the 

 scapula. The latter muscles should now be removed. 



The SERRATUS POSTICUS SUPERIOR is situated at the upper part of the 

 thorax ; it arises by the ligamentum nuchae, from the spinous processes of 

 the three last cervical and those of the two upper dorsal vertebrae. The 

 ipuscle passes obliquely downwards, and outwards, and is inserted by four 



