EXTERNAL JUGULAR VEIN

It is called external jugular vein because of its relatively superficial position in the neck as compared to the internal jugular vein which is present deep into the neck. It has two pair of valves i.e. lower pair (at the level of entrance into subclavian vein) and upper pair (4 cm above clavicle). It is covered by platysma, superficial fascia and skin.

Course:

It is formed by the combination of posterior division of the retromandibular vein and the posterior auricular vein (within the parotid gland on either side of the mandible i.e. lower jaw) .Then, it runs perpendicularly downward and after emerging from the parotid gland it follows the posterior edge of the masseter muscle of the jaw, and crosses the sternocleidomastoid muscle (it is separated from this muscle by an investing layer of deep cervical fascia) obliquely and enters the subclavian triangle by perforating its deep fascia and ends into the subclavian vein (lateral to the junction of subclavian vein and the internal jugular vein).

Tributaries:

The most important tributaries of this vein include:

• Posterior external jugular vein.

• Anterior jugular vein.

• Suprascapular vein.

• Transverse cervical vein and sometimes occipital vein.

Drainage:

It collects blood from the outer structure of head including the scalp and deep portions of the face.

INTERNAL JUGULAR VEIN

Course:

It starts at the base of the brain (skull), in the posterior compartment of the jugular foramen (large aperture in the base of the skull bone), it begins as direct continuation of the sigmoid sinus. At its origin, it is somewhat dilated and this dilatation is called superior bulb (lies in the jugular fossa of the temporal bone, under the middle ear cavity). The vein then runs down the side of the neck (on each side) in a vertical direction (being lateral to the internal carotid and common carotid artery) and it ends behind the sternal end of the clavicle at the root of the neck (junction between neck and thorax) by joining the subclavian vein to form the brachiocephalic vein. A little above its end, the internal jugular vein has another dilatation, called the inferior bulb (lies beneath the lesser supra clavicular fossa).

Tributaries:

Tributaries include:

• Inferior petrosal sinus

• Common facial vein

• Lingual vein

• Pharyngeal veins

• Superior thyroid vein and middle thyroid vein

• In the middle of the neck, the internal jugular vein may communicate with the external jugular vein by oblique jugular vein which runs across the anterior border of the sternocleidomastoid muscle

Drainage:

It collects blood from the brain and outer portions of the face and neck.

SOME IMPORTANT CLINICAL ASPECTS

Jugular venous pressure (JVP) is important clinically as  elevated pressure can be a sign of disease of the right side of the heart. These veins are relatively superficial and are not protected by tissues like bone or cartilage so they are susceptible to damage. As the internal jugular vein is large, central and relatively superficial, it is often used to place venous lines.