1390 



SUKFACE AND SUKGICAL ANATOMY. 



artery before it pierces the sheath, that is to say, as it lies in the cellular tissue 

 between the carotid sheath and the prevertebral fascia. In order to reach the 

 vessel in that situation the surgeon should keep outside the sheath of the thyreoid 

 gland, between it and the carotid sheath which is retracted laterally along with the 

 infra-hyoid muscles. When the inferior thyreoid artery has been ligatured the 

 posterior branch of the superior thyreoid artery furnishes a sufficient blood-supply 

 to the inferior parathyreoid gland. 



Triangles of the Neck. The lateral aspect of the neck is divided into 

 an anterior and a posterior triangle by the sterno-mastoid muscle; the former 

 is further subdivided into digastric, carotid, and muscular triangles by the digastric 

 and omo-hyoid muscles. The posterior triangle is subdivided into occipital and 

 subclavian portions by the posterior belly of the omo-hyoid. 



The sterno-mastoid muscle forms one of the most important superficial land- 



Apex of mastoid process 



Hypoglossal nerve 



Bifurcation of common 

 carotid artery 



Sterno-mastoid 

 Carotid tubercle 

 Apex of lung 

 Brachial plex 



Subclavian artery 

 1st part axillary artery ' 

 Coracoid process x 



Acromio- 

 clavicular joint 



Zygomatic process of frontal 

 Zygomatic arch 



Temporal artery 



Facial nerve 



Transverse process of atlas 



External maxillary artery 



Submaxillary gland 



Anterior belly of digastric 

 Tip of greater cornu of hyoid b 

 Tip of superior cornu of thyre 

 "cartilage 

 Body of hyoid bone 



-Proininentia laryngea 

 Cricoid cartilage 

 sthmus of thyreoid gland 



vicular head of sterno-masl 

 .Sternal head of sterno-mastoi 



Bifurcation of 



innominate artery 



Infra-clavicular foss 



Upper border ol 

 manubrinm stei 



Greater tubercle 

 of humerus 



tubercle 01 

 humerus 

 Intertubercular sulcus 



FIG. ] 089. SIDE OF THE NECK. 



marks of the neck. The anterior border of the muscle, the more distinct of the 

 two, may be felt along its whole extent. Between the prominent sternal origin 

 and the broad ribbon-Like clavicular origin is a slight triangular depression which 

 overlies the inferior part of the internal jugular vein. 



By dividing the cervical fascia along the anterior and posterior borders of the 

 muscle the surgeon is able to displace the muscle backwards and forwards so as to 

 obtain free access to the structures deep to it. If the posterior fibres of the muscle 

 are divided at their clavicular and mastoid attachments the muscle can be still more 

 freely mobilised. In dividing the fascia along its posterior border the cutaneous 

 branches of the cervical plexus are generally divided, but care is taken not to 

 injure the accessory nerve. Should it be found necessary to remove the upper 

 third or more of the muscle, the divided end is stitched to the levator scapula or 

 to the scalenus medius, according to the amount resected. In dividing the muscle 

 completely across at the lower part of the neck, as is done, for example, in 

 congenital wry-neck, the close relation of the anterior and external jugular veins 

 to its corresponding borders must be kept in mind. After division of the muscle, 



