DISSECTION OF THE UPPEK LIMB. 



and an- 

 terior. 



Two circum 

 flex arteries 



anterior ; 



posterior, 



its offsets. 



One circum 

 flex nerve, 



which ends 

 in deltoid : 



branches, 

 articular ; 



posterior ; 



anterior. 



Infraspi- 

 natus : 



origin, 



insertion, 



relations, 



arrived at. In clearing the fat from the space a branch of the 

 nerve to the teres minor muscle is to be sought close to the border 

 of the scapula, where it is surrounded by dense fibrous tissue. 



Arching outwards in front of the humerus is the small anterior 

 circumflex artery, which should also be cleaned. 



The CIRCUMFLEX ARTERIES arise near the termination of the 

 axillary trunk (p. 24) ; they are two in number, and are named 

 anterior and posterior from their position to the humerus. 



The anterior branch (fig. 7, p. 23) is a small artery, which arises 

 from the outer side of the axillary and courses outwards beneath the 

 coraco-brachialis and biceps muscles, and ascends in the bicipital 

 groove to the articulation and the head of the humerus ; it anasto- 

 moses with small offsets of the posterior circumflex. 



The posterior circumflex artery (fig. 13, a), much larger than the 

 anterior, winds backwards through a quadrilateral space between 

 the humerus and the long head of the triceps, in company with the 

 circumflex nerve, and ends in large branches, in which it anastomoses 

 with the acromio-thoracic artery. 



Branches are given from it to the shoulder-joint, to the teres 

 minor, the long head of the triceps, and the integument*. It 

 anastomoses with the anterior circumflex artery round the neck of 

 the humerus and with branches of the superior profunda artery 

 in the substance of the triceps. 



The CIRCUMFLEX NERVE (fig. 13, 1 ) leaves the armpit with the 

 posterior circumflex artery and bends round the humerus, beneath 

 the deltoid muscle, in which it ends. Many large branches enter the 

 deltoid ; and one or two filaments pierce the fore part of the muscle 

 and become cutaneous. 



Branches. As the nerve passes backwards it gives an articular 

 filament to the under-part of the shoulder-joint. Behind the 

 humerus it splits into two parts, an anterior and a posterior. The 

 posterior part furnishes (1) a branch to the teres minor, which has a 

 reddish gangliform swelling upon it, (2) a few twigs to the back 

 part of the deltoid, and (3) cutaneous branches which turn round 

 the edge of the muscle. The anterior part passes round the humerus 

 with the posterior circumflex artery, and enters the fore part of the 

 deltoid muscle, a few twigs passing through the muscle to the skin 

 over it. 



The INFRASPINATUS MUSCLE (fig. 1 3, B) occupies the infraspinous 

 fossa of the scapula, and extends to the upper end of the humerus. 

 The muscle arises from the lower surface of the spine of the scapula, 

 from the dorsal surface of the bone below that process, except at the 

 neck and the narrow area along the axillary border where the teres 

 muscles are attached, and from a special fascia covering it. Its 

 fibres converge to a tendon, which is inserted into the middle 

 impression on the great tuberosity of the humerus, and joins with 

 the tendons of the supraspinatus and teres minor. The fleshy fibres 

 arising from the spine overlie the tendon of the muscle. 



A part of the muscle is subcutaneous ; but the upper portion is 

 concealed by the deltoid, and the lower angle by the latissimus 



