70 LABORATORY MANUAL OF HUMAN ANATOMY 



Arteries. 



(a) Cutaneous rami of ramus acromialis and ramus deltoideus of A. 



thoraco-acromialis. 

 Veins. 



(a) Tributaries of cephalic vein. 



Nerves. (Fig. 18.) 



(a) Posterior supraclavicular nerves (Nn. supraclaviculares poste- 



riores) (0. T. sup ra-acromial branches). 



(6) Lateral cutaneous nerve of the upper arm (N. cutaneus brachii 

 lateralis) (0. T. cutaneous branch of circumflex). Look for the 

 trunk of this hooking around the posterior margin of M. del- 

 toideus five centimetres above its insertion; dissect it carefully 

 throughout its course in the superficial fascia. 



Deep Fascia. 



Eemove the superficial fascia and study the appearance and 

 attachments of 



(a) Deltoid fascia (fascia deltoidea). 



(b) Subscapular fascia (fascia subscapularis) . 



(c) Supraspinous fascia (fascia supraspinata) . 



(d) Infraspinous fascia (fascia infraspinata). 



Deltoid Muscle (M. deltoideus) and the So-called Quadrilateral and 

 Triangular Spaces. 



Hold the scapula down with hooks to make the fibres of the 

 deltoid muscle tense, and carefully remove the deep fascia from 

 its surface. Study carefully the form, position, origin, insertion, 

 action, and innervation of the muscle. Note especially the three 

 parts of the muscle corresponding to the three distinct muscles 

 in the cat, deltoclavicular, delto-acromial, and deltospinal of 

 Strauss-Durckheim. How does the texture of the middle portion 

 (delto-acromial) differ from that of the anterior and posterior 

 portions? (Of. Poirier et Charpy, Fig. 83.) Look for a subcu- 

 taneous acromial bursa (bursa subcutanea acromialis). (Of. 

 Spalteholz, Fig. 349. ) Does one exist in your cadaver ? 



Place the posterior surface of the limb on the table, and 

 examine the area through which the A. circumflexa humeri pos- 

 terior and the N. axillaris pass to the back part of the shoulder. 

 How is this area, "quadrilateral space," bounded above, 

 below, lateralward, and medialward? Clean the surfaces and 

 edges of the muscles of this region. What is the so-called "tri- 

 angular space?" How is it bounded above, below, and lateral- 

 ward? Follow the A. circumflexa scapulae (0. T. dorsalis 

 scapulae) through this space. 



Place the anterior surface of the limb on the table, and ex- 

 amine the boundaries of the quadrilateral and triangular 

 spaces from behind. 



