4 TOPOGRAPHICAL ANATOMY OF THE 



They are further inseparably blended until the middle of the neck is 

 reached, where a short rounded tendon terminates the common fleshy 

 belly. The combined muscle, up to this point, is narrow and flattened, 

 is in contact with its fellow of the opposite side of the neck, and lies 

 between the sterno-cephalic muscle and the trachea. At the inter- 

 mediate tendon the sterno-hyoid and sterno-thyroid muscles separate. 



The sterno-ltyoid'^ muscle continues along the trachea, in contact 

 with its fellow muscle, and is inserted into the body of the hyoid bone. 



The sterno-thyroid'^ onuscle diverges from the middle line, passes 

 between the trachea and the omo-hyoid muscle, and is inserted, by a 

 thin narrow tendon, to the lateral surface of the thyroid cartilage, near 

 its caudal border (the ventral part of the oblique line of the cartilage). 



Fig. 1. — Key-outline to indicate the plane of the sections of the neck and 

 head, illustrated in later figures. 



The small nerve supplying these muscles should be looked for 

 medial to the external maxillary vein, and afterwards on the ventral- 

 lateral border of the trachea. It is derived from the first and second 

 cervical nerves. 



M. OMOHYOIDEUS. — The origin of the omo-hyoid^ muscle from the 

 subscapular fascia is revealed during the dissection of the thoracic limb. 

 Its thin, flattened belly crosses the deep face of the brachio-cephalic 

 muscle (to which it is firmly bound), and passes obliquely over the 

 lateral surface of the trachea to reach the body of the hyoid bone, to 



1 Sternum [L.], aripvov (sternon) [Gr.], breast or chest ; i-oetS^s (hyceides), [Gr.], 

 U-shaped, from the resemblance of the human hyoid bone to the letter U. 



- Sternum [L.], aripvov (sternon) [Gr.], breast or chest ; dvpeoi (thyreos) [Gr.]. a 

 shield ; elSos (eidos) [Gr.], form, from the shield-like cartilage (thyroid) to which the 

 muscle is attached. 



2 &/AOS (onios) [Gr.], shoulder ; voe^^i (hyoeides) [Gr.], U-shaped. 



