LIGAMENTS AND MUSCLES OF THE HORSE. 41 



4. Transversalis Abdominis. 



Origin. — From the lower extremities or Ccartilages of the hist 

 ten ribs, and from the lumbar transverse processes. 



InsertioR.— To the linea alba and ensiform cartilage of the 

 sternum. 



^c^iW. — Similar to the oblique muscles, 



5. Retractor Costae. 



Ori(jin.— From the first two or three lumbar transverse pro- 

 cesses. 



Insertion. — To the posterior border of the last rib. 



Action. — To assist in expiration. 



]\''ote.—This smaU muscle is usually described as a part of the 

 internal oblique muscle. 



Poupaut's Ligament. 



This is formed by the reflection of the-aponeurosis of the ex- 

 ternal oblique. 

 It may be described as having two surfaces two borders, and 



two extremities. 

 The anterior surface is concave, forming inwardly the posterior 

 boundary of the inguinal canal, and outwardly giving at- 

 tachment to the internal oblique muscle. 

 The posterior surface is convex and covers the sartorius, iliacus, 

 and psoas magnus muscles ; also the femoral artery and 

 crural nerve. 

 The lower border is the line of continuity with the external 



que. 

 The upper border is thin, and fuses with the sublumbar fascia. 

 The inner extremity is attached to the pubes, and the outer to 

 the external angle of the ilium. 



EXTERNAL SCAPULAR REGION. 



1. Antea-spinatus. 3. Deltoid. 



2. Postea-spinatus. 4. Teres minor (or Postea-spinafus minor). 



C 



