Lecture 6, Spine, Spinal Cord & Thorax

Question 1

Two Muscles of The Neck

Answer 1

platysma - is a broad, thin sheet of muscle in the subcuntaneous tissue of the neck, covers the anterolateral aspect of the neck and like other muscles of facial expression
SCM - divides each side of the neck into anterior and lateral cervical regions
unilateral activation - flexes the cervical vertebral column to the same side (lateral flexion) and rotates the head to the opposite side
bilateral activation - thrusts the chin forward when your head is level and elevate the head by dorsally extending the upper cervical joints
trapezius - critical role in controlling scapula which controls the upper limb
scalenes (anterior, middle, posterior) - located deep in relation to the sternocleidomastoid muscle, lateral to the cervical spine, connecting the vertebrae to the first two ribs

Question 2

Cervical enlargement and Lumbosacral enlargement

Answer 2

C.E - extends from the C4 through the T1 segments of the spinal cord, and most of the anterior rami of the spinal nerves arising from it form the brachial plexus of nerves
L.E - extends from the L1 through the S3 segments of the spinal cord, contribute to the lumbar and sacral plexuses of nerves

Question 3

Parts of the Spinal Cord and Meninges

Answer 3

conus medullaris - tapering distal end of a spinal cord, may terminate as high as T12 or as low as L3
cauda equina - the spinal nerve roots arising from the lumbosacral enlargement and the conus medullaris form it, and it is the bundle of spinal nerve roots running inferior to the spinal cord through the subarachnoid space
Filum terminale internum - descends among the spinal nerve roots in the cauda equina, it consists of primarily of pia mater, intermum eventually becomes externum (serves as an anchor for the inferior ends of the spinal cord and dural sac)