الثلاثاء، 15 سبتمبر 2015

Brachial Plexus

1:15 م  ,   


Brachial Plexus

* Is a somatic nerve plexus formed by the ventral rami ( roots ) of the lower 4 cervical nerves ( C5 – C8 ) and the 1st thoracic nerve ( T1 ).
* Its responsible for the motor innervation of the all muscles of upper extremity ( with the exception of the trapezius, and the levator scapula.
* The Brachial Plexus supplies all the cutaneous innervation of the upper limb, except for the area of the axilla ( which is supplied by the supraclavicular nerve ), and the area of dorsal scapula which is supplied by cutaneous branch of the dorsal rami.
* The Brachial Plexus is subdivided into roots, trunks, divisions, cords, and branches.
  • The union of C5, and C6 forms the superior trunk.
  • The nerve root of C7 forms the medial trunk.
  • The union of C8, and T1 forms the inferior trunk.
  • The union of anterior divisions of superior, and medial trunk give the lateral cord, while the anterior division of lower trunk gives the medial cord.
  • The posterior divisions of all trunks form the posterior cord of brachial plexus.
* This classification of cords according to their sites around the axillary artery.


* The branches of the different parts of the brachial plexus :

  •  Root Dorsal scapular nerve ( C5 ).
    Long thoracic nerve ( C5, 6, and 7 ).
    Upper trunk

    		 Nerve to subclavius ( C5, and 6 ).
    Suprascapular nerve.
    Lateral cord

    		 Lateral pectoral nerve.
    Musculocutaneous nerve.
    Lateral root of median nerve.
    Medial cord Medial pectoral nerve.
    Medial cutaneous nerve of the arm, and forearm.
    Ulnar nerve.
    Medial root of median nerve.
    Posterior cord Upper of lower subscapular nerves.
    Thoracodorsal nerve.
    Axillary nerve.
    Radial nerve.
 




* Blood Supply of the Brachial Plexus

The blood supply of the brachial plexus is based largely on the subclavian (which becomes the axillary) artery and its branches, and variations exist.



Sources :
- Snell anatomical book, 8 Edition ( 446 – 447 – 771 – 772  ) .
- Grants anatomical book, 13 Edition ( 490 –  515 –  516 – 517  ) .
- Atlas of Human Anatomy, 6 Edition- Frank H. Netter, M.D ( Plate 416 – 461 –  462 - 463 ) .
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