2. Cross sections Flashcards
eye
\the three layers of the eyeball consist of the outer fibrous sclera, the
middle vascular choroid and the inner layer of the retina. The sclera is continuous
posteriorly with the dural cuff that surrounds the optic nerve, and is continuous
anteriorly with the cornea.
Contents of the globe: the posterior part contains vitreous humour, which is a
colourless transparent gel and which constitutes about 80% of the total contents.
Anteriorly, the vitreous body is bounded by the capsule of the lens and its
suspensory ligaments. These ligaments extend to the ciliary body, which is a
direct anterior continuation of the choroid and comprises the muscle involved
in accommodation of the lens. The ciliary body also secretes aqueous humour
into the anterior chamber, where it circulates before draining via spaces in the
trabecular meshwork through the canal of Schlemm. The anterior chamber of the
eye contains the iris, which itself is a forward continuation of the choroid via
the ciliary body.
The Neck at the Level of C6
C6 is the level of the cricoid cartilage whose lower border marks the beginning of the
trachea. Immediately posterior is the oesophagus, which is separated from the body
of the sixth cervical vertebra only by the pretracheal fascia
Immediately anterior is
the isthmus of the thyroid. Posterolaterally is the carotid sheath, which encloses the
common carotid artery, the internal jugular vein and the vagus nerve. Behind the
sheath lies part of the sympathetic chain. Immediately lateral to the vertebral body are
the vertebral artery and vein, beyond which are the scalene muscles. Between these lie
the trunks of the brachial plexus.
The Lumbar Region at the Level of L3
Immediately anterior to the vertebral body are the aorta (on the left) and the inferior
vena cava (on the right).
On the lateral surface on each side lies the sympathetic trunk.
Immediately lateral to the vertebral body at this level lies the psoas major
muscle.
Further lateral are the lower poles of the kidney.
Posterior to the vertebral body is the vertebral canal, which,
at the level of L3, contains the theca (comprising the dura and arachnoid maters),
within which are CSF and the cauda equina.
The theca is surrounded by the epidural space.
This is minimal anteriorly because the dura is closely apposed to the vertebral body.
The vertebral arch is completed by the pedicles, transverse processes, laminae and spinous processes.
The Lower Thoracic Region at the Level of T10
Remember that you are effectively looking up at the image, and so the left side of
the patient is on the right as you view it. The structures are as identified on the CT
image reproduced in Figure 2.15 and show the liver, stomach, spleen and blood
vessels.
