362 THE MUSCLES OF THE PIG 



The longissimus costanun extends to the wing of the atlas. 



The spinalis et semispinalis can be separated without much difficulty from 

 the longissimus dorsi, the division from the common mass of the loins beginning 

 about the first lumbar vertebra. 



The multifidus resembles that of the horse. 



Interspinales are present, as Avell as distinct intertransversales of the back 

 and loins. 



Muscles of the Tail 



The dorsal and lateral sacro-coccygei arise as far forward as the last lumbar 

 vert.ebra. Gurlt explains the twist of the tail as being due to the spiral arrangement 

 of the insertions of the tendons. 



Muscles of the Thoracic Limb 



MUSCLES OF the SHOULDER GIRDLE 



The trapezius is very wide, its line of origin extending from the occipital bone 

 to the tenth thoracic vertebra. There is no clear division between its two parts, 

 which are both inserted into the scapular spine. 



The omo-transversarius resembles that of the ox. 



The rhomboideus consists of three parts. The cervical part (Rhomboideus 

 cervicalis) is greatly developed, its origin extending from the second cervical to the 

 sixth thoracic vertebra. The cephalic part (Rhomboideus capitis) arises with the 

 splenius on the occipital bone, and is inserted with the cervical part. The thoracic 

 part (Rhomboideus thoracalis) extends as far back as the ninth or tenth thoracic 

 vertebra. 



The latissimus dorsi is attached to the four ribs preceding the last. It is 

 inserted into the medial tuberosity of the humerus. 



The brachiocephalicus divides into two parts, the cleido-mastoideus and 

 cleido-occipitalis, which arise on the mastoid process and nuchal crest respectively, 

 and unite at the fibrous vestige of the clavicle. 



The anterior superficial pectoral muscle is thin. The posterior superficial pec- 

 toral muscle is divided into two parts, one of which ends on the humerus, the other 

 on the fascia of the forearm. The anterior deep pectoral muscle resembles that of 

 the horse, but its origin does not extend behind the first two chondro-sternal joints. 

 The posterior deep pectoral muscle is very long. 



The cervical part of the serratus ventralis is greatly developed, its origin ex- 

 tenchng from the wing of the atlas to the upper part of the fifth rib, and passing 

 under the thoracic part; the latter resembles that of the ox. 



MUSCLES OF THE SHOULDER 



The deltoid is undivided; it arises from the aponeurosis covering the infra- 

 spinatus, and it ends largely on the deltoid ridge, but partly on the fascia of the arm. 



The supraspinatus is large; it has a small attachment to the medial tuberosity 

 and ends chiefly on the lateral tuberosity of the humerus. There is a bursa between 

 the tendon and the anterior part of the lateral tuberosity. 



The infraspinatus is wide; it is inserted into a depression below the posterior 

 division of the lateral tuberosity. There is a bursa between the tendon and the 

 tuberosity. 



The teres minor is large and rounded; it ends on a tubercle between the 

 lateral and deltoid tuberosities of the humerus. 



