84 A MANUAL OF ANATOMY. 



Floor is formed by the scalenus anticus and longus colli 

 muscles. 



Contents. Arteries: Common carotid, inferior thyroid, 

 and vertebral. 



Veins: Internal jugular, vertebral, middle thyroid. 



Nerves : Superficial cervical, pneumogastric, recurrent 

 laryngeal, descendens and communicans hypoglossi, sym- 

 pathetic. 



Parts of the larynx, trachea, thyroid gland, lymphatic 

 glands, sternohyoid, and sternothyroid muscles. 



The posterior triangle is divided by the posterior belly of 

 the omohyoid into the occipital and subclavian triangles. 



The Occipital Triangle. 



Boundaries. By the posterior border of the sterno- 

 mastoid, the anterior border of the trapezius, and the pos- 

 terior belly of the omohyoid muscles. 



Floor is formed by the splenius capitis et colli, the 

 levator anguli scapulae, scalenus medius and posticus. 



Contents. Arteries : Occipital, muscular, superficial cer- 

 vical, and transverse cervical. 



Veins : Posterior external jugular, transverse cervical. 



Nerves : The ascending and descending branches of 

 the cervical plexus, and the spinal accessory. 



Lymphatic glands. 



The Subclavian Triangle (Mohrenheint s Fossa). 



Boundaries. The posterior border of the sternomastoid, 

 the posterior belly of the omohyoid, and the clavicle. 



Floor is formed by the scalenus posticus and medius. 



Contents. Arteries : Second and third portions of the 

 subclavian, and its suprascapular, transverse cervical, and 

 superior intercostal (and usually the posterior scapular, see 

 page 113) branches. 



