dermatome
an area of skin supplied with afferent nerve fibers by a single dorsal
(posterior) spinal root, the sensory portion, usually horizontally displaced
(except C1 which has no sensory function)
myotome
a group of muscles which is innervated by a single spinal nerve root;
innervation of skeletal muscle by the ventral root
Ventral roots (anterior roots)
allow motor neurons to exit the spinal cord
Dorsal roots (posterior roots)
allow sensory neurons to enter the spinal cord
dorsal ramus (posterior division)
carries sensory innervation from and motor innervation to a specific segment
in the back
,ventral ramus (anterior division)
supplies ventrolateral (structures in body wall and limbs) on the anterior
aspects of the trunk
nerve plexus
a network of highly complex interconnected nerves, nerve fibers from different
spinal nerves are sorted and recombined so that all fibers going to a specific
body part are put together, these are used for sensory blockade
cervical plexus
arises from C1-C5, sensory innervation to the scalp, neck, and upper
shoulder, motor innervation to the neck, thoracic cavity, and skin
phrenic nerve
the __ is one of the largest branches of the cervical plexus, supplies the
diaphragm, injury can lead to hemi-diaphragmatic dysfunction
C1-C4
distribution: 5 of the extrinsic laryngeal muscles
C2-C3
, distribution: Skin of upper chest, shoulder, neck and ear
C3-C5
distribution: diaphragm
AD
C1-C5
Levator scapulae, scalene muscles, SCM and Trapezius
brachial plexus
innervates pectoral girdle and upper limb, originates from C5-T1, possibly
minor contribution from C4 or T2
lateral
cord of the brachial plexus, divides into the lateral branch of the median nerve
and terminates into the musculocutaneous nerve
medial
cord of the brachial plexus, divides into the medial branch of the median nerve
and terminates into the ulnar nerve