1. It can be your worst
nightmares unless you
follow up your lectures a
day by day
2. Doctors love to ask a bout
it in the exams
3. Medical important …
you’ll know it by yourself
Vertebral column:
33 vertebrae
 5 of them fuse to make the
sacrum
= considered 1 bone
 4 fuse to form the coccyx
= considered 1 bone
26 bone
Here it’s different
In the thoracic
part:
Each spinal nerve
arises from its
corresponding
segment below
the corresponding
vertebra
Is a network of nerve fibers
(anterior rami) running from
the spinal cord, formed by
the lower four cervical and
first thoracic (C5  T1 )
Proceeds through the neck,
axilla, into the arm
Gives off many nerves that
supply the shoulder, chest,
and arms
Terminal
branches
cords
divisions
trunks roots
c5
lateral
posterior
anterior
superior
c6
posterior
middle
c7
c8
medial
Lateral cord:
Musculocutaneous nerve (1)
Lateral root of median nerve
(2)
Lateral pectoral nerve (3)
MLL
anterior
inferior
Medial cord:
Ulnar nerve (4)
Medial root of median nerve (5)
Medial pectoral nerve (6)
Medial cutaneous nerve of the
arm(7)
Medial cutaneous nerve of the
forearm(8)
UMMMM
T1
Posterior cord:
Upper subscapular nerve (9)
Lower subscapular nerve (10)
Middle subscapular nerve =
Nerve to latissimus dorsi =
thoraco dorsal (11)
Axillary nerve (12)
Radial nerve (13)
ULMAR