PELVIS. 167 



§ 441. Costa — Rib. — The costa or rib proper is tlie bony part of the arch extend- 

 ing from the capitellum to the Arthron costicartilaginis. It has two extremities — 

 vertebral or dorsal and sternal or ventral ; two surfaces — ectal and ental • two edges — 

 cephalic and caudal. The vertebral end bears the capitellum : the ectal surface is next 

 the skin ; the cephalic edge faces toward the head. 



§ 442. Costicartilago — Costal cartilage. — The cartilaginous continuation of the rib 

 which passes from the sternal end of the diaphysis toward the sternum (§ 423, Fig. 49). In 

 the figure it is deeply shaded and is between the Arthron costicartilaginis and the meso- 

 sterneber. 



§ 443. Diaphysis (Costae) — Shaft. — The diaphysis of the rib is the part between the 

 tuberculum and the Arthron costicartilaginis. 



§ 444. Ligamentum interarticulare, az. — Interarticular ligament. — This is a strong, 

 smooth, band-like ligament connecting, through the floor of the neural canal, the heads 

 of opposite ribs {2d to 11th pairs inclusive) ; (§ 434). 



§ 445. Mesosternebra, az. — The square area between the sternal ends of the costal 

 cartilages represents the caudal end of the 5th mesosterneber (g 424, Fig. 49), 



§ 446. Tuberculum — Tubercle. — The tuberculum is an elevation on the ectal surface 

 of the rib just at the end of the cervix. It bears a smooth arthral facet which articulates 

 (diarthrodially) with the diapophysis of the 7th thoracic vertebra (Fig. 52 and § 433). 



PELVIS. 



General References to the Pelvis.— Straus-Durckheim, x^, I, 499, and II, 63 ; Quain, 

 A, I, 100, 122, 159 ; Gray, A, 245 ; Chauveau (Fleming), A, 91,161 ; Chauveau, A, 75, 152 ; 

 Leyh, A, 166, 212 ; Flower, A, 281 and 33 ; Humphrey, A, 438 ; Jouliu. 1 ; Mivart, 8 

 and 11) ; Wilder, 10. A chronological bibliography is given at the end of the last. 



§ 447. Preparation. — The soft parts were fully removed by one 

 of the processes already described (§§ 244^256). Parts of the first 

 and second sacral vertebrse were removed mth nippers to expose the 

 Arthron ilio-sacrale. To show the lines of junction between the 

 ilium, ischium, Os pubis and Os cotyloideum, it is necessary to 

 prepare the pelvis of a cat retaining its milk teeth. 



§ 448. Arthron ilio-sacrale — Ilio-sacral articulation.— This is 

 the articulation between the sacrum and the ilium. In the figure 

 the arthral surface on the ilium is brought into view by the re- 

 moval of part of the sacrum. The caudal third of this surface is 

 diarthrodial,, the cephalic two thirds amphiarthrodlal ; the motion, 

 however, is very limited. 



The lateral masses of only the first sacral vertebra articulate 

 directly with the ilium. 



§ 449. Crista ilii — Iliac crest. — The iliac crest is the prominent 

 dorso-cephalic iDroiection of the ilium (Fig. 30, 51, § 230). 



§ 450. Fm. (Foramen) obturatoriusn — Obturator or thyroid 

 foramen. — The large oblong space bounded by the os pubis and 

 the ischium. 



