Middle Cerebral Artery

The Internal carotid artery divides into middle cerebral artery and anterior cerebral artery. The middle cerebral artery travels to the lateral fissure.

The middle cerebral artery is divided into 4 parts:
M1 segment, horizontal, from the internal carotid artery to the lateral fissure
M2 segment, insular, designates the branches located inside the Sylvian fissure (to the top of the Sylvian fissure)
M3 segment, opercular, denominates the branches located between the top of the Sylvian fissure and the cerebral cortex
M4 segment, cortical, refers to arterial branches on the surface of the cerebral cortex.

The anterior cerebral arteries irrigate:
• a large part of the surface of the cerebral hemisphere, except the convexity and the inferior temporal gyrus
• anterior pole of temporal lobe
• nucleus caudatus
• internal capsule
• putamen, globus pallidus
• external capsule.

MRI of the brain, Time-of-Flight, axial MIP, circle of Willis (magnification). Image 1.    1, MCA Bifurcation (genu). 2, Middle cerebral artery (M1). 3, Internal carotid artery (right side). 4, Anterior cerebral artery (A1). 5, Internal carotid artery (left side). 6, Middle cerebral artery (left side).

MRI of the brain, Time-of-Flight, axial MIP, circle of Willis (magnification). Image 1.    1, MCA Bifurcation (genu). 2, Middle cerebral artery (M1). 3, Internal carotid artery (right side). 4, Anterior cerebral artery (A1). 5, Internal carotid artery (left side). 6, Middle cerebral artery (left side).

MRI of the brain, Time-of-Flight, axial MIP, circle of Willis (magnification). Image 2.    1, Middle cerebral artery (M4). 2, Middle cerebral artery (M3). 3, Middle cerebral artery (M2). 4, Middle cerebral artery (M1). 5, Internal carotid artery (left side). 6, Middle cerebral artery (left side).

MRI of the brain, Time-of-Flight, axial MIP, circle of Willis (magnification). Image 2.    1, Middle cerebral artery (M4). 2, Middle cerebral artery (M3). 3, Middle cerebral artery (M2). 4, Middle cerebral artery (M1). 5, Internal carotid artery (left side). 6, Middle cerebral artery (left side).

MRI of the brain, Time-of-Flight, axial MIP, circle of Willis (magnification). Image 3.    1, Middle cerebral artery (M4). 2, Middle cerebral artery (M3). 3, Middle cerebral artery (M2). 4, Middle cerebral artery (M1). 5, Internal carotid artery (left side). 6, Middle cerebral artery (left side). 7, Basilar artery. 8, Posterior cerebral artery.

MRI of the brain, Time-of-Flight, axial MIP, circle of Willis (magnification). Image 3.    1, Middle cerebral artery (M4). 2, Middle cerebral artery (M3). 3, Middle cerebral artery (M2). 4, Middle cerebral artery (M1). 5, Internal carotid artery (left side). 6, Middle cerebral artery (left side). 7, Basilar artery. 8, Posterior cerebral artery.

Anatomy of the Middle Cerebral Artery (MCA)

The middle cerebral artery (arteria cerebri media) is the largest of the carotid arteries that supply blood to the brain(1). 

This artery also supplies blood to the primary sensory and motor areas of the face, hand, throat, and arm(2).

Anatomically, the MCA is divided into two segments (M1 and M2)(3). However, in radiology and surgery, the middle cerebral artery is divided into four parts (M1, M2, M3, and M4)(4).

M1 Segment of the MCA

This segment is also called the horizontal segment or the sphenoid part of the MCA. The M1 segment is laterally located from the middle cerebral artery to the Sylvian fissure’s depths(5). It separates the frontal and parietal lobes.

M2 Segment of the MCA

The middle cerebral artery’s insular or M2 segment includes the trunks in the insula or the small portion of the cerebral cortex(6). This segment, laterally located along the Sylvian fissure, ends in the cerebral cortex(7).

M3 Segment of the MCA

The M3 or the MCA’s opercular part starts on the circular sulcus and ends at the Sylvian fissure’s surface(8). This segment is nearly adherent to the temporal and frontoparietal opercula’s surface, reaching the superficial part of the Sylvian fissure(9).

M4 Segment of the MCA

The MCA’s cortical part or M4 segment extends to the cortical surface of the cerebral hemisphere from the Sylvian fissure(10). These M4 segments are thin and composed of anterior and intermediate branches(11). 

Medical Relevance of the Middle Cerebral Artery 

The middle cerebral artery is typically associated with acute stroke(12). This condition happens when an embolism (blockage of the blood vessel) lodges in the MCA. 

This lodging in the MCA may also cause an ischemic stroke(13). 

Overall, the MCA is the most pathologically affected blood vessel(14).

Berry aneurysm or saccular aneurysm (enlargement of the artery) also happens in the MCA(15). This condition is due to the weakening and outpouching of the blood vessels(16).

Another condition that happens in the branches of the MCA is the lenticulostriate infarct. This condition is caused by a cardiac embolism(17).

These disorders in the MCA may be diagnosed using medical imaging methods, like MRI and CT scans.

Radiology and the Middle Cerebral Artery

One way of examining the middle cerebral artery is through radiology methods. Radiology uses imaging technology to diagnose diseases so that appropriate treatment may be prescribed(18). 

Among the radiological techniques used are ultrasound, X-ray, mammography, fluoroscopy (the study of moving body structures), magnetic resonance imaging (MRI), and computed tomography (CT) scans(19).

A study evaluated if the hyperintense middle cerebral artery (MCA) sign produced using MRI technology has prognostic value in subacute infarct associated with stroke diagnosis(20). The researchers compared the MRI results with CT scans.

They found that the images of the hyperintense MCA produced using MRI have prognostic relevance due to their high National Institutes of Health Stroke Scale (NIHSS) scores(21). This scale is used to quantify repercussions and impairments caused by stroke(22).

Magnetic Resonance Imaging (MRI)

The magnetic resonance imaging (MRI) scan uses radio waves and magnets to produce a three-dimensional image of the body’s inner structures(23). This procedure is said to be useful in examining the brain and spinal cord(24).

Clinicians also use MRI to examine the brain’s functional anatomy and assess the effects of trauma, stroke, and degenerative diseases, like Alzheimer’s disease(25).

According to a study, an MRI scan may provide insights into focal cerebral ischemia dynamics (reduced blood flow in a specific part of the brain)(26). 

MRI was used to study the MCA occlusion or the cause of hemodynamic stroke(27). This research suggests that MRI is significant in studying the middle cerebral artery and the disorders associated with it.

Computed Tomography (CT) Scan

Computed tomography (CT) scan is another way to examine the middle cerebral artery and the brain as a whole. This procedure uses X-ray images from different angles of the brain(28). 

CT scans are typically performed to examine internal injuries caused by traumas(29). This method helps in determining tumors, blood clots, and internal bleeding. It may also help detect and monitor cancer, liver masses, lung nodules, and heart diseases(30).

Conclusion

The middle cerebral artery (MCA) is essential in stroke pathology (blood interruption in the brain). It is one of the essential tracts in the brain in which blood vessels flow. 

Diagnoses of diseases and disorders associated with the MCA may be made using radiological methods, such as CT scan and MRI scan. These radiological procedures may detect blood clots, brain tumors, and other diseases.

  1. Harnsberger HR, Osborn AG, Ross JS, Moore KR, Salzman KL, Carrasco CR, Halmiton BE, Davidson HC, Wiggins RH. Diagnostic and Surgical Imaging Anatomy: Brain, Head and Neck, Spine. 3rd ed. Salt Lake City, Utah. Amirsys. 2007.
  2. Bourjat P, Veillon F. Imagerie radiologique tête et cou. Paris, Vigot. 1995.
  3. Gouazé A, Baumann JA, Dhem A. Sobota. Atlas d’Anatomie humaine. Tome 3. Système nerveux central, système nerveux autonome, organe des sens et peau, vaisseaux et nerfs périphériques. 1er éd. Paris, Maloine. 1977.
  4. Kahle W, Cabrol C. Anatomie. Tome 3: Système nerveux et organe des sens. 1er éd. Paris, Flammarion. 1979.
  5. AMAIOS Anatomy, (n.d.), Middle cerebral artery – Arteria cerebri media, retrieved from https://www.imaios.com/en/e-Anatomy/Anatomical-Parts/Middle-cerebral-artery
  6. The Internet Stroke Center, (n.d.), Blood Vessels of the Brain, retrieved from http://www.strokecenter.org/professionals/brain-anatomy/blood-vessels-of-the-brain/
  7. Ibid.
  8. Ibid.
  9. Ibid.
  10. Ibid.
  11. Navarro-Orozco D, Sánchez-Manso JC. Neuroanatomy, Middle Cerebral Artery. [Updated 2020 Aug 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526002/
  12. The Internet Stroke Center, Op. Cit.
  13. Ibid.
  14. Ibid.
  15. Navarro-Orozco, D., Op. CIt.
  16. Nogles TE, Galuska MA. Middle Cerebral Artery Stroke. [Updated 2020 Aug 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556132/
  17. Physiopedia, (n.d.), Middle Cerebral Artery, retrieved from https://www.physio-pedia.com/Middle_Cerebral_Artery
  18. Ibid.
  19. Ibid.
  20. Ibid.
  21. Ibid.
  22. Medline Plus, (n.d.), Imaging and radiology, retrieved from https://medlineplus.gov/ency/article/007451.htm
  23. Ibid.
  24. Lam WW, Wong KS, So NM, Metreweli C. Hyperintense middle cerebral artery sign using MRI. Clin Radiol. 2003 Jul;58(7):542-4. doi: 10.1016/s0009-9260(03)00062-x. PMID: 12834637.
  25. Ibid.
  26. NIH, (n.d.), Stroke Scale, retrieved from https://www.stroke.nih.gov/documents/NIH_Stroke_Scale_508C.pdf
  27. Medline Plus, (n.d.), MRI Scans, retrieved from https://medlineplus.gov/mriscans.html#:~:text=Magnetic%20resonance%20imaging%20(MRI)%20uses,the%20brain%20and%20spinal%20cord.
  28. Ibid.
  29. Radiology Info, (n.d.) Magnetic Resonance, Functional (fMRI) – Brain, retrieved from https://www.radiologyinfo.org/en/info.cfm?pg=fmribrain#:~:text=Magnetic%20resonance%20imaging%20(MRI)%20is,radiation%20(x%2Drays).
  30. Gerriets T, Stolz E, Walberer M, Müller C, Kluge A, Kaps M, Fisher M, Bachmann G. Middle cerebral artery occlusion during MR-imaging: investigation of the hyperacute phase of stroke using a new in-bore occlusion model in rats. Brain Res Brain Res Protoc. 2004 Feb;12(3):137-43. doi: 10.1016/j.brainresprot.2003.08.006. PMID: 15013464.
  31. Ibid.
  32. Mayo Clinic, (n.d.), CT Scan, retrieved fom https://www.mayoclinic.org/tests-procedures/ct-scan/about/pac-20393675#:~:text=A%20computerized%20tomography%20(CT)%20scan,than%20plain%20X%2Drays%20do.
  33. Ibid.
  34. Ibid.
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