THE FRONT OF THE ARM 



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muscular septum is stronger than the lateral. It is easily traced 

 from the medial epicondyle to the insertion of the coraco- 

 brachialis muscle. The distal half of the lateral intermuscular 

 septum is quite definite from the lateral epicondyle to the inser- 

 tion of the deltoid muscle. The two septa, together with the 

 humerus, divide the arm into an anterior and a posterior osteo- 

 fascial compartment. 



Structures in the Anterior Compartment. The anterior 

 osteo-fascial compartment has been opened by the reflection 

 of the anterior part of the deep fascia ; the relative positions 

 of its contents must now be examined. The contents are : 

 Three muscles which belong mainly to the arm, the biceps, 



Medial inter- 

 muscular septum 



Lateral inter- 

 muscular septum 



FIG. 41. Diagram (after Turner) to show how the Arm 

 is divided by the intermuscular septa and the bone into an 

 anterior and a posterior compartment. These compartments 

 are represented in transverse section. 



the coraco - brachialis, and the brachialis ; parts of two 

 muscles which belong chiefly to the forearm the brachio- 

 radialis and the extensor carpi radialis longus ; parts of the 

 terminal branches of all the cords of the brachial plexus 

 except the axillary nerve ; the brachial artery, its venae 

 comites, part of the basilic vein, with accompanying lymph 

 vessels and a few small brachial lymph glands which lie 

 along the course of the brachial artery. 



The biceps brachii is the most anterior muscle ; under 

 cover of its distal half and closely applied to the anterior 

 aspect of the humerus is the brachialis, whilst the slender 

 coraco-brachialis lies along the medial side of the proximal 

 half of the biceps. The brachio-radialis and the extensor 



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