These are selected images from the transverse oblique
sequence (left and right). In the transverse oblique sequence, images
are perpendicular to the line of sight when viewing the supine patient
(with arms at the sides) from the shoulder toward the opposite hand.
The imaging plane of the transverse oblique sequence is aligned
to the course of the arteries, which allows a long continuous arterial
segment to be viewed in a single image. Note that imaging the arteries also
displays the nerves (such as the C8-T1 nerve roots, which are labeled
in the images), since they bind to the arteries. Thus, compression
of the subclavian artery also indicates compression of the brachial plexus.
Compression of the subclavian artery is further a reflection of the compression
of the venous drainage of the brachial plexus because veins are more
compressible than arteries.
The transverse oblique sequence cross-references the
coronal sequence to display costoclavicular compression of
the external jugular vein against the bicuspid valve within the
subclavian vein on the first rib. These images clearly display
the tense backward displaced subclavian artery (SA) with binding
nerve roots on the pleura with compression by the anterior scalene
(AS), right greater than left. Observe the lower intensity gray
signal of the subclavian artery (SA) in the region of the anterior
scalene (AS) in the right view. The mildly dilated vertebral
vein (VV) in the left view reflects increased collateral
circulation. The images also display the close proximity
of the axillary vein (AXV) to the axillary artery
(AX, only labeled on left image) within the supraclavicular
fossa posterior-medial to the pectoralis minor muscle (PMI),
left greater than right.
A few labels have been placed on the image to assist with
identification of landmark anatomy. The sternocleidomastoid
muscles (STM), internal jugular veins (J), common carotid
arteries (CC), external jugular vein (XJ), trachea (T),
esophagus (E), anterior scalene muscles (AS), clavicles (C),
subclavius muscles (SUB), axillary artery (AX),
axillary veins (AXV), subclavian arteries (SA), C8-T1
nerve roots (C8-T1) which give rise to the ulnar nerves,
vertebral vein (VV), spinal cord (SPC), first fascicle of
the serratus anterior muscles (FSA), pectoralis minor
muscles (PMI), right lung (RL), and left lung (LL) are
labeled for reference.