Occipital Artery: Causes, Symptoms, Complications, And Treatment

It rests upon the tentorium cerebelli, Occipital lobe/area is located in the rearmost side of the forebrain covered with the occipital bone of the skull which forms the back and base of the skull and encircles the spinal cord. Its key function is to process visual data of the brain like visuospatial processing and face recognition, distance and depth perception, color determination, and memory formation.

A crucial part of the occipital area, the Occipital Artery is one of the posterior branches of the external carotid artery opposite the facial artery which is mainly located within the solid connective tissue of the occipital bone.

The external carotid artery is known as one of the major arteries of the head and neck which aids blood supply in the face and neck region. The external carotid artery has eight branches which include the Occipital Artery with its key function to supply blood in deep muscles of the sternomastoid muscles, neck, and back of the scalp.

The Occipital Artery begins its presence between the mastoid and transverse process of the atlas. The transverse process guards the blood vessels located in the transverse foramen and acts as an attachment point for muscles that are responsible for smooth movement of the neck. While the mastoid process provides a bridge to attach those muscles. Both mastoid and transverse processes of the atlas are located in the back part of the temporal bone of the neck located behind the ear, which is also known as the house structure of the ears.

From the lower lateral walls of the skull (temporal bone) the artery makes its way behind the back of the digastric muscle (a small muscle located just below the jaw), crossing the carotid artery, the internal jugular vein, the hypoglossal, vagus nerve, and accessory nerve to the side border of the rectus capitis lateralis ( paired muscle in the upper neck just below the back of the head on each side).

After making its way pass through rectus capitis lateralis the Occipital Artery crosses the temporal bone occipital grove. After this point, the Occipital Artery changes its direction by moving deeply upwards into the cervical fascia of the neck, which further goes more deeply into the superficial fascia of the scalp.

After the Occipital Artery reaches the superficial fascia, it divides into small branches which cover the whole skin at the back of the scalp. Generally, these branches can be categorized into two branches, that is the upper and lower branches. The key function of the upper branch is to pass accessory nerves descending into the deep part of the sternocleidomastoid. On the other hand, lower branches receive nerves descending back from the sternocleidomastoid.

The other side of the Occipital Artery which begins behind the temporal bone connects to the rear part of the cranial fossa with the help of a mastoid branch, which later submerges into the floor of the cranial cavity.

Anatomical variations that may have seen rare cases (approximately 15% of cases) originate from the thyrocervical trunk, internal carotid, internal carotid, inferior thyroid, and vertebral arteries. Also, variations that can be seen in occipital arteries is in the mutual origin from the external carotid named the occipital auricular trunk.

Other rare mutations ( found in 20% of cases) may include the initial connection of the posterior meningeal artery arising from the Occipital Artery instead of ascending pharyngeal artery.

Key points to understand:

• The internal jugular vein is responsible for collecting impure blood from the brain to the superficial parts of the face and neck.
• The hypoglossal nerve or the twelfth cranial (skull) nerve supports the muscles of the tongue for motor function.
• The vagus nerve is known as the longest cranial nerve which controls the parasympathetic nerve center that communicates motor functions and impulses that take place in every organ of the body.
• The accessory nerve or eleventh cranial nerve supports the muscles in the neck and shoulders to control everyday lateral flexion or the movement needed for tilting the neck and head to either side.
• The occipital grove is a part of the temporal bone, which includes many important muscles like the sternocleidomastoid, which assists with neck movement.

Apart from upper and lower branches, the Occipital Artery can specifically categorize into six types naming:

• The sternocleidomastoid artery: is the first branch that arises after the Occipital Artery reaches the superficial fascia. This artery makes a division between the upper and lower branches in the carotid triangle.
• Descending branch/muscular branches: Known as the largest of all branches of the Occipital Artery, descending branch starts at the back of the posterior belly of the digastric muscle or back of the neck. Descending branch further divides into two parts:
  • The first one is the large muscle bundle, which supplies the trapezius muscle and extends from the back of the head and neck to the shoulder.
  • The second one is an artery of the neck that connects to the vertebral artery which is the major source of blood to the brain.

  As the name suggests its key function of the descending branch is, while the branch descends, it supplies the posterior deep back muscles which give off several muscular branches which includes rectus capitis lateralis, stylohyoid, obliquus capitis inferior, digastric, obliquus capitis superior, rectus capitis posterior major, semispinalis capitis, splenius capitis, rectus capitis posterior minor, and splenius cervicis muscles. Muscular branches act as a supplier of the digastric which is located below the jaw and longus capitis (prevertebral muscle in the neck).

• Auricular branch: The auricular branch provides a structure with vessels in the skin of the posterior aspect of the auricle, The key function of the auricular branch supplies blood to the back of the ears.
• Mastoid branch: Originated from the insertion of the semispinalis capitis muscle, the mastoid branch enters the posterior cranial fossa from the mastoid foramen.
• Occipital branches: Occipital branch mainly provides a tissue structure with vessels of the occipitofrontalis muscle in the occipital belly. Which gives off two branches that supply the dura mater that is meningeal and mastoid branches.
• Meningeal branch: One of the key supplies of the dura mater of the posterior cranial fossa, the meningeal branch variably goes to the meninges from the skull apertures including parietal foramen, foramen magnum, jugular foramen, condylar canal.

As we all know the main function of the artery is to supply oxygenated blood to the muscles all over the body, in the case of the Occipital Artery the supply is limited to the upper neck and scalp region. However, it is not its only function that is performed by the Occipital Artery, as the branches not only sustain on the surface, the deeper branches of the Occipital Artery supply oxygen-rich blood to the deeper muscles of the neck, face, head, and ears.

Yes, in normal cases one can feel the palpitation of the Occipital Artery neck and back of the ear. However in some cases, due to the smaller size of the artery or thick neck, pulsation of the Occipital Artery is hard or almost impossible to detect.

Even though the Occipital Artery plays a very important part in regulating blood supply to different parts of the skull, head, neck, and face, medical conditions related to any damage or abnormality are rarely reported in medical records connected to any underlying disease or to any health condition. However, there are some cases related to the Occipital Artery:

• Pseudoaneurysm of the Occipital Artery: It is an uncommon sequela of head injury caused by post-traumatic pseudoaneurysms of the extracranial arteries in the scalp. Patients have shown prolonged headache and formation of a lump followed by minor head injury with a pulsating, tender, and enlarging mass in the left Occipital Artery. Computed tomographic angiography is the test recommended to diagnose the lesion to be a pseudoaneurysm of the Occipital Artery.
• Occipital neuralgia: It is a medical condition in which one can see significant natural or external damage or anything that creates an irritates or compresses in the occipital nerve located in the back of the skull which can lead to pain between the back of the head and the scalp followed by numbness, trauma, tingling, weakness, and possible damage in the back of the neck.
• Aneurysms: One of the most uncommon types of medical conditions associated with the Occipital Artery refers to a weakening of an artery wall that creates a bulge or distention of the artery. Scientists believe illness that may trigger aneurysms is an autoimmune disease, infection, or trauma—blunt force, penetrating, or surgical. In most conditions, aneurysms do not show symptoms and are not dangerous, yet some cases may lead to life-threatening internal bleeding.

Summary: Occipital area can be detected in the rearmost side of the forebrain covered with the occipital bone of the skull which forms the back and base of the skull and encircles the spinal cord. The main function of the Occipital Artery is to supply oxygen into the upper neck and scalp region.