78 LABORATORY MANUAL OF HUMAN ANATOMY 



Make an incision through the fascia brachii along the middle 

 line of the front of the upper arm and a circular incision proxi- 

 mal to the lacertus fibrosus. Reflect the fascia brachii from the 

 front of the arm in two flaps, medial and lateral, until the strong 

 lateral and medial intermuscular septa are reached, 



(a) Medial intermuscular septum (septum intermusculare [humeri] 



mediate) (0. T. internal intermuscular septum). 



(b) Lateral intermuscular septum (septum intermusculare [humeri] lat- 



erale) (0. T. external intermuscular septum). 



Structures in Front of the Intermuscular Septa (Anterior Compart- 

 ment of Arm). (See also Fig. 20.) 



Arteries. 



Arrange the axillary artery and vein and the divided nerves of the 



brachial plexus in their proper order and tie them to a small stick, 



four centimetres long, placed transversely. Fasten this with a loop of 



cord to the processus coracoideus. Clean the brachial artery carefully 



throughout its whole extent and study its relations. 



(a) Brachial artery (A. brachialis). At what point does it begin? 



Where and how does it end? With what veins, nerves, 



and muscles does it enter into relation in the various 



parts of its course? Study the mode of origin, course, 



and distribution of the following branches : 



(aa) Deep artery of upper arm (A. prof undo, brachii) (0. T. 



superior profunda). Note its relation to the radial 

 nerve. Its branches and general distribution will be 

 studied later. 



(ab) Superior ulnar collateral artery (A. collateralis ulnaris 



superior) (0. T. inferior profunda). Note its relation 

 to the ulnar nerve. How does it arise? 



(ac) Inferior ulnar collateral artery (A. collateralis ulnaris in- 



ferior) (0. T. anastomotica magna). Note its anterior 

 and posterior divisions. 

 Veins. 



(a) Brachial veins (Vv. brachiales). 



(aa) Radial veins (Vv. radiales). 



(ab) Ulnar veins (Vv. ulnar es}. 



(ac) Basilic veins (Vv. basilicae), portions beneath fascia 



brachii. 



(b) Cephalic vein (V. cephalica), portion in a duplicature of the fascia 



brachii. 



Nerves. 



(a) Medial cutaneous nerve of upper arm (N. cutaneus brachii me- 



dialis) (0. T. lesser internal cutaneous, or nerve of Wrisberg). 



(b) Medial cutaneous nerve of forearm (N. cutaneus antibrachii me- 



dialis) (0. T. internal cutaneous). 



These nerves (a) and (b) have been studied before, with the exception 

 of their parts subjacent to the fascia brachii. 



