Limbs Forearm Pathways Notes

1. Pathways to the Forearm 
1. Blood Supply 
1. Aorta  L subclavian or brachiocephalic to R subclavian  axillary  below teres major  brachial artery  
1. Ulnar  posterior arm, medial wrist and hand 
2. Radial  anterior arm, lateral wrist  over styloid process to anatomical snuff box between extensor palmaris longus and brevis  hand 
2. Blood Drainage 
1. Cephalic from lateral wrist 
2. Basilic from medial wrist 
3. Cephalic and basilic merge with intermediate antebrachial  axillary  subclavian  brachiocephalic  SVC
3. Nerve Supply 
1. Afferent 
1. Somatic 
1. Musculocutaneous nerve from lateral skin and anterior muscles  lateral cord  superior and middle trunks  C4-C7  dorsal roots  spinal cord 
2. Medial cutaneous of the forearm  lateral cord  superior and middle trunks  C4 – C7  dorsal roots  spinal cord 
3. Radial nerve from the posterior muscles and skin  Posterior cord  superior, middle, and inferior trunks  C4- T1  dorsal roots  spinal cord 
4. Ulnar nerve to flexors  medial cord  inferior trunk  C8-T1  dorsal roots  spinal cord 
5. Median nerve to flexors  
1. Medial cord  inferior trunk 
2. Lateral cord  superior and medial trunks 
3. Trunks  C4-T1  dorsal roots  spinal cord 
2. Autonomic 
1. N/A
2. Efferent 
1. Somatic 
1. Spinal cord  C4-T1  ventral roots  brachial plexus  
1. Superior and middle trunks  lateral cord  
1. Musculocutaneous nerve  medial skin and muscles of forearm 
2. Median nerve  flexors of the forearm 
2. Superior, Middle, and Inferior Trunks  posterior cord  
1. Radial nerve  extensors of the posterior fore arm 
3. Inferior trunk  medial cord  
1. Median nerve  flexors of the forearm 
2. Ulnar nerve  flexors in the forearm 
2. Autonomic
1. Sympathetic  
1. IML  ventral roots  ventral rami of cervical spinal nerves  white rami  cervical sympathetic ganglion  Ach synapse to postganglionic fiber  gray rami  cervical spinal nerves  brachial plexus  
1. Musculocutaneous to lateral skin and anterior muscles (lateral cord)
2. Medial cutaneous of the forearm (medial cord)
3. Radial nerve to posterior skin and extensors (posterior cod)
4. Ulnar nerve to flexors (medial cord)
5. Median nerve to flexors (medial cord or lateral cord)
6. All of the above  dorsal roots  spinal cord