Subclavian triangle
Encyclopedia
The subclavian triangle (or supraclavicular triangle, omoclavicular triangle), the smaller division of the posterior triangle, is bounded, above, by the inferior belly of the Omohyoideus; below, by the clavicle
; its base is formed by the posterior border of the Sternocleidomastoideus.
Its floor is formed by the first rib with the first digitation of the Serratus anterior.
The size of the subclavian triangle varies with the extent of attachment of the clavicular portions of the Sternocleidomastoideus and Trapezius, and also with the height at which the Omohyoideus crosses the neck.
Its height also varies according to the position of the arm, being diminished by raising the limb, on account of the ascent of the clavicle, and increased by drawing the arm downward, when that bone is depressed.
This space is covered by the integument, the superficial and deep fasciæ and the Platysma, and crossed by the supraclavicular nerves.
Just above the level of the clavicle, the third portion of the subclavian artery
curves lateralward and downward from the lateral margin of the Scalenus anterior
, across the first rib
, to the axilla, and this is the situation most commonly chosen for ligaturing
the vessel.
Sometimes this vessel rises as high as 4 cm. above the clavicle; occasionally, it passes in front of the Scalenus anterior, or pierces the fibers of that muscle.
The subclavian vein lies behind the clavicle, and is not usually seen in this space; but in some cases it rises as high as the artery, and has even been seen to pass with that vessel behind the Scalenus anterior.
The brachial plexus
of nerves lies above the artery, and in close contact with it. Passing transversely behind the clavicle are the transverse scapular vessels; and traversing its upper angle in the same direction, the transverse cervical artery
and vein.
The external jugular vein
runs vertically downward behind the posterior border of the Sternocleidomastoideus, to terminate in the subclavian vein
; it receives the transverse cervical and transverse scapular veins, which form a plexus in front of the artery, and occasionally a small vein which crosses the clavicle
from the cephalic.
The small nerve to the Subclavius also crosses this triangle about its middle, and some lymph glands are usually found in the space.
Clavicle
In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...
; its base is formed by the posterior border of the Sternocleidomastoideus.
Its floor is formed by the first rib with the first digitation of the Serratus anterior.
The size of the subclavian triangle varies with the extent of attachment of the clavicular portions of the Sternocleidomastoideus and Trapezius, and also with the height at which the Omohyoideus crosses the neck.
Its height also varies according to the position of the arm, being diminished by raising the limb, on account of the ascent of the clavicle, and increased by drawing the arm downward, when that bone is depressed.
This space is covered by the integument, the superficial and deep fasciæ and the Platysma, and crossed by the supraclavicular nerves.
Just above the level of the clavicle, the third portion of the subclavian artery
Subclavian artery
In human anatomy, the subclavian arteries are two major arteries of the upper thorax , below the clavicle . They receive blood from the top of the aorta...
curves lateralward and downward from the lateral margin of the Scalenus anterior
Scalenus anterior
The Scalenus anterior , also known as anterior scalene muscle, lies deeply at the side of the neck, behind the Sternocleidomastoideus.-Anatomy:...
, across the first rib
Rib
In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...
, to the axilla, and this is the situation most commonly chosen for ligaturing
Ligature (medicine)
In surgery or medical procedure, a ligature consists of a piece of thread tied around an anatomical structure, usually a blood vessel or another hollow structure to shut it off. With a blood vessel the surgeon will clamp the vessel perpendicular to the axis of the artery or vein with a hemostat,...
the vessel.
Sometimes this vessel rises as high as 4 cm. above the clavicle; occasionally, it passes in front of the Scalenus anterior, or pierces the fibers of that muscle.
The subclavian vein lies behind the clavicle, and is not usually seen in this space; but in some cases it rises as high as the artery, and has even been seen to pass with that vessel behind the Scalenus anterior.
The brachial plexus
Brachial plexus
The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...
of nerves lies above the artery, and in close contact with it. Passing transversely behind the clavicle are the transverse scapular vessels; and traversing its upper angle in the same direction, the transverse cervical artery
Transverse cervical artery
The transverse cervical artery is a branch of the thyrocervical trunk, running at a higher level than the suprascapular artery.-Path:...
and vein.
The external jugular vein
External jugular vein
The external jugular vein receives the greater part of the blood from the exterior of the cranium and the deep parts of the face, being formed by the junction of the posterior division of the retromandibular vein with the posterior auricular vein.-Path:...
runs vertically downward behind the posterior border of the Sternocleidomastoideus, to terminate in the subclavian vein
Subclavian vein
The subclavian veins are two large veins, one on either side of the body. Their diameter is approximately that of the smallest finger.-Path:Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle...
; it receives the transverse cervical and transverse scapular veins, which form a plexus in front of the artery, and occasionally a small vein which crosses the clavicle
Clavicle
In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...
from the cephalic.
The small nerve to the Subclavius also crosses this triangle about its middle, and some lymph glands are usually found in the space.