128 TOPOGPvAPHICAL ANATOMY OF THE 



fifth cerebral, or trigeminal, and leaves the cranium by the foramen 

 rotundum. The close relation of the branches of this nerve and the 

 internal maxillary artery in the pterygo-palatine fossa has already been 

 remarked. The branches of the nerve are as follows : — 



(1) iV. zygomaticuyt. — The slender zygomatic nerve was encountered 

 in the orbit which it gains by piercing- the periorbita. It has been seen 

 to follow the lateral rectus muscle and end in the skin of the lower 

 eyelid. 



(2) N. infraorhitalis. — From its size and direction, the infraorbital 

 nerve mio"ht be regarded as the main continuation of the maxillary. It 

 enters the infraorbital canal in company with the artery of the same 

 name. 



(3) N. sphenopalatiiius. — The spheno-palatine nerve is broad and 

 flat, and will be found crossing the pterygoid process of the sphenoid 

 bone and the perpendicular part of the palatine, where it divides into 

 the lesser and greater palatine and posterior nasal nerves, (a) The 

 lesser palatine nerve (n. palatinus minor) accompanies the artery of the 

 same name into the soft palate. (6) The greater ijolatine nerve 

 (n. palatinus major) also follows the artery that bears a like name. 

 (c) The posterior nasal nerve (n. nasalis posterior) enters the nasal 

 cavity by the spheno-palatine foramen. 



Spheno-palatine plexus and ganglia. — If the maxillarj^ nerve be 

 raised from the surface of the bone on which it lies, the spheno-palatine 

 plexus (plexus sphenopalatinusj, in which several small ganglia are 

 entangled, will be exposed. Afferent fibres to tbe ganglia are derived 

 from the spheno-palatine nerve (sensory) and the nerve (Vidian) of the 

 pterygoid canal (motor and sympathetic). Efferent fibres supply the 

 periorbita and form a network around the branches of the internal 

 maxillary artery. 



Dissection. — Clear away the remains of the diverticulum of the 

 auditory tube and examine the structures ventral to tlie epistropheus and 

 the base of the skull. 



M. LONGUS CAPITIS. — The long muscle of the head arises from the 

 transverse processes of the fourth and third and the body of the second 

 cervical vertebrae, and ends on the tubercles at the junction of the 

 occipital and sphenoid bones, in a tendinous insertion common to the 

 muscles of the two sides of the body. The terminal part of the muscle 

 is in contact with its fellow, and between the diverticula of the auditory 

 tubes. 



M. RECTUS CAPITIS VENTRALis. — The ventral straight muscle of the 

 head is small, fleshy and short. Its fibres arise from the ventral arch 



