(2.29)
Let's look at the veins, arteries and nerves of the shoulder region. As you'll see, the main bundle of vessels and nerves lies behind the clavicle, and behind both pectoral muscles, as it passes from the base of the neck to the underside of the upper arm. To understand how things are arranged up here, where the main vessels come up out of the chest, and the main nerves emerge from the vertebral column, there are some key structures that we need to understand: the first ribs, the cervical vertebrae, and the scalene muscles. Let's take a look at them.
Here's the first rib, below and behind the clavicle. This much of it is bone and this much of it is costal cartilage. The two first ribs define the opening at the top of the chest: the superior thoracic aperture. The main artery to the upper extremity, the subclavian artery, crosses the first rib here. The subclavian vein crosses it here, right behind the medial end of the clavicle. Here are the vertebrae: the first thoracic with the first rib; and the seventh, sixth and fifth cervical. Let's take the clavicle away so that we can see the vertebrae better.
The main spinal nerves to the upper extremity emerge here, between the transverse processes. The spinal nerves that we're concerned with are numbered C5, C6, C7, C8, and T1.
These two landmark muscles, the anterior scalene, and the middle scalene, which are attached to the first rib here, and here, guard the exit of these vital structures. The vein runs in front of the anterior scalene, the artery runs behind it. Between the two scalene muscles, the roots of the brachial plexus also emerge.
There are two posssibly confusing things that we have to live with. The first is ...
(2.29)
Let's look at the veins, arteries and nerves of the shoulder region. As you'll see, the main bundle of vessels and nerves lies behind the clavicle, and behind both pectoral muscles, as it passes from the base of the neck to the underside of the upper arm. To understand how things are arranged up here, where the main vessels come up out of the chest, and the main nerves emerge from the vertebral column, there are some key structures that we need to understand: the first ribs, the cervical vertebrae, and the scalene muscles. Let's take a look at them.
Here's the first rib, below and behind the clavicle. This much of it is bone and this much of it is costal cartilage. The two first ribs define the opening at the top of the chest: the superior thoracic aperture. The main artery to the upper extremity, the subclavian artery, crosses the first rib here. The subclavian vein crosses it here, right behind the medial end of the clavicle. Here are the vertebrae: the first thoracic with the first rib; and the seventh, sixth and fifth cervical. Let's take the clavicle away so that we can see the vertebrae better.
The main spinal nerves to the upper extremity emerge here, between the transverse processes. The spinal nerves that we're concerned with are numbered C5, C6, C7, C8, and T1.
These two landmark muscles, the anterior scalene, and the middle scalene, which are attached to the first rib here, and here, guard the exit of these vital structures. The vein runs in front of the anterior scalene, the artery runs behind it. Between the two scalene muscles, the roots of the brachial plexus also emerge.
There are two posssibly confusing things that we have to live with. The first is that there's a nerve root named C8, even thought there's no eighth cervical vertebra. The second confusing thing is that the main artery and vein change their names as they go along: here they're called the subclavian vessels, here they're called tha axillary vessels, and from here on down they're called the brachial vessels. The structures themselves don't change, just the names.