OF THE UPPER EXTREMITY. 



3tl 



connection with the lungs, as well as directly by means of the central tendon 

 to which the pericardium is attached. The abdominal viscera are also pushed 

 down (the liver, to the extent of nearly three inches), so that these organs are 

 no longer protected by the ribs. During expiration, when the Diaphragm is 

 passive, it is pushed up by the action of the abdominal muscles ; the cavity of 

 the abdomen (with the organs contained in it), encroaches upon the chest, by 

 which the lungs and heart are compressed upwards, and the vertical diameter 

 of the thoracic cavity diminished. The Diaphragm is passive when raised or 

 lowered, by the abdominal organs, independently of respiration, in proportion 

 as they are large or small, full or empty; hence the oppression felt in the chest 

 after a full meal, or from flatulent distension of the stomach and intestines. 



In all expulsive acts the Diaphragm is called into action, to give additional 

 power to each expulsive effort. Thus, before sneezing, coughing, laughing, 

 and crying ; before vomiting ; previous to the expulsion of the urine and feces, 

 or of the foetus from the womb, a deep inspiration takes place. 1 



MUSCLES AND FASCIAE OF THE UPPER EXTEEMITY. 



The Muscles of the Upper Extremity are divisible into groups, correspond- 

 ing with the different regions of the limb. 



Anterior Thoracic Region. 

 Pectoralis Major. 

 Pectoralis Minor. 



Flexor Profundus Digitorum. 

 Flexor Longus Pollicis. 

 Pronator Quadratus. 



Subclavius. 



Lateral Thoracic Region. 

 Serratus Majrrms. 



Deltoid. 



Acromial Region. 



Anterior Scapular Region. 

 Subscapularis. 



Posterior Scapular Region. 



Supraspinatus. 

 Infraspinatus. 

 Teres Minor. 

 Teres Major. 



Anterior Humeral Region. 

 Coraco-brachialis. 

 Biceps. 

 Brachialis Anticus. 



Posterior Humeral Region. 



Triceps. 

 Subanconeus. 



Anterior Brachial Region. 

 Pronator Radii Teres. 

 Flexor Carpi Radialis. 

 Palmaris Longus. 

 Flexor Carpi Ulnaris. 

 Flexor Sublimis Digitorum. 



Radial Region. 

 Supinator Longus. 

 Extensor Carpi Radialis Longior. 

 Extensor Carpi Radialis Brevior. 



Posterior Brachial Region. 



f" Extensor Communis Digito- 

 rum. 



Extensor Minimi Digiti. 



Extensor Carpi Ulnaris. 



Anco'neus. 



Supinator Brevis. 



Extensor Ossis Metacarpi Pol- 

 licis. 



Extensor Primi Internodii Pol- 

 licis. 



Extensor Secundi Internodii 

 Pollicis. 



Extensor Indicis. 



OQ 



Hi 

 0, 



Muscles of the Hand. 



Radial Region. 

 Abductor Pollicis. 

 Flexor Ossis Metacarpi Pollicis (Oppo- 



nens). 



Flexor Brevis Pollicis. 

 Adductor Pollicis. 



Ulnar Region. 

 Palmaris Brevis. 



1 For a detailed description of the general relations of the Diaphragm, and its action, refer to 

 Dr. Bibson's Medical Anatomy. 



