314 MUSCLES OF THE PIG 



MUSCLES OF THE TAIL 

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

 vertebra. 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 l)one 

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

 which are both inserted into the scapular spine. 



The omo-transversarius reseml)les that of the ox. 



The rhomboideus consists of three i:)ortions. The cervical portion (Rhom- 

 boideus cervicalis) is greatly developed, its origin extending from the second cervi- 

 cal to the sixth thoracic vertebra. The cephalic portion (Rhomboideus capitis) 

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

 The dorsal portion (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 internal lip of the bicipital groove. 



The mastoido-humeralis divides into two parts, the cleido-mastoideus and 

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

 and unite at the fibrous vestige of the clavicle. 



The anterior superficial pectoral is thin. The posterior superficial pectoral 

 is divided into parts, one of which ends on the humerus, the other on the fascia 

 of the forearm. 



The deep pectoral is clearly divided into two parts. The scapular portion 

 resembles that of the horse, l)ut its origin does not extend behind the first two 

 chondro-sternal joints. The posterior deep pectoral is very long. 



The cervical portion of the serratus magnus is greatly developed, its origin 

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

 under the thoracic portion; 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 ends chiefly on the external tuberosity of the 

 humerus. 



The infraspinatus is inserted into a depression below the posterior division of 

 the external tuberosity. 



The teres minor is w(>ll developed; it ends on a tubercle l^etween the external 

 and deltoid tul)erositios of the humerus. 



The subscapularis and teres major have no remarkable features. 



The coraco-brachialis is short and undivided. 



The capsularis is very small and frequently absent. 



MUSCLES OF THE ARM 

 The biceps brachii is fusiform and not greatly developed. Its tendon of origin 

 is roundetl and passes through the capsule of the shoulder joint. The tendon of 

 insertion is bifid, entUng on the radius and ulna. 



