506 



COLLEGE ZOOLOGY 



Deltoid 



Biceps 



Flexors 

 of hand 



PectoroJis 

 major 



Rectus abdominis 

 External oblique 



Sartorius 



Quadriceps femoris 



Adductor 



Gracilis 



Vastus medialis 



Soleus 

 Gastrocnemius 



Annular ligament 



Sternocleidomastoideus 



Trapezius 



Deltoid 



Pectoralis minor 



Triceps 



Biceps 



Serratus 

 anterior 



Extensors 



of hand 



nternal 



oblique 



Carpal ligament 



Gluteus maximus 



Tensor fascia 

 iota 



Gastrocnemius 



Peroneus 

 Tibialis anticus 



Tendon of Achilles 



Figure 374. Superficial muscles. Muscles of man with the external oblique and pectoralis 

 major removed from the left side to show others that lie beneath. 



Cardiac heart muscle 



The cardiac muscle in the vertebrate heart 

 consists of cells that are less distinctly 

 striated than those in skeletal muscle. These 

 fibers are connected with one another so 

 that they form a syncytium. Impulses pass 

 quickly through the ventricles of the heart 

 due to these connections, and the reaction 

 is that of one large muscle cell. The auto- 

 matic rhythmic contraction of the heart, 



day after day, as long as we live, is its most 

 striking characteristic. 



Muscles of the face 



Some of the muscles of the face, of 

 which there are about 30, and of the neck 

 are shown in Fig. 375. The facial muscles 

 make possible the expression of many emo- 

 tional states. The primates have the greatest 

 development of these muscles, but some 



