[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Spine](https://durgical.com/en/anatomy/region/spine/) › Posterior spinal arteries [Cardiovascular system](https://durgical.com/en/anatomy/system/cardiovascular-system/) · [Spine](https://durgical.com/en/anatomy/region/spine/) # Posterior spinal arteries The posterior spinal arteries are two small arteries down the back of the [spinal cord](https://durgical.com/en/anatomy/spinal-cord/); they feed the part that carries position sense and fine touch. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=spine&select=posterior_spinal_arteries&side=r) Opens in the Durgical app, no sign-up needed. ## What it is Two small arteries running down the back of the spinal cord. ## What it does Supply the back third of the cord, which carries position sense and fine touch. ## Key points - Paired vessels on the back of the cord, running along the line where the dorsal rootlets enter (posterolateral sulci) - They form a richer network than the [anterior spinal artery](https://durgical.com/en/anatomy/anterior-spinal-artery/), fed by more, smaller posterior segmental medullary arteries (about 10–20 vs about 6–10 anterior), so [posterior cord](https://durgical.com/en/anatomy/posterior-cord-of-the-brachial-plexus/) infarcts are rare - Infarction causes loss of vibration and joint position sense below the level (sensory ataxia) with movement largely spared: the mirror image of anterior spinal artery syndrome ## Key facts **Origin** Vertebral artery or posterior inferior cerebellar artery (PICA), one on each side **Branches** Paired longitudinal channels along the posterolateral sulci; reinforced by posterior segmental medullary arteries; pial plexus **Supplies** Posterior third of the cord: dorsal columns and posterior horns ## Relations **Course** From the [vertebral artery](https://durgical.com/en/anatomy/vertebral-artery/) or the posterior inferior cerebellar artery beside the medulla, each descends along a posterolateral sulcus to the [conus medullaris](https://durgical.com/en/anatomy/conus-medullaris/), joined at intervals by posterior segmental medullary arteries **Medial** The dorsal columns (fasciculus [gracilis](https://durgical.com/en/anatomy/gracilis-muscle/) and fasciculus cuneatus), between the two arteries **Lateral** Dorsal nerve rootlets entering the cord **Superficial** Pia mater and, outside it, the subarachnoid space, the arachnoid and the dura ## Examination - Romberg test: steady with the eyes open but swaying or falling with them closed points to loss of joint position sense (dorsal columns) - Vibration with a tuning fork and joint position at the [big toe](https://durgical.com/en/anatomy/great-toe/): loss below a level suggests dorsal column damage ## On imaging MRI shows bright T2 signal in the back of the cord; vitamin B12 deficiency (subacute combined degeneration) and other dorsal column disorders can look similar and are part of the differential. ## Clinical notes - A pial arterial network (vasocorona) around the cord links the posterior and anterior systems, which partly protects against a single blocked vessel - Posterior spinal artery infarcts can be one-sided, so the sensory loss may be limited to one side of the body - Dorsal column loss from vitamin B12 deficiency or tabes dorsalis comes on slowly; a sudden onset with restricted diffusion on MRI points instead to a posterior spinal artery infarct ## Test yourself Think of the answer, then tap the question to see it. ## From which vessels do the posterior spinal arteries arise? From the vertebral artery or the posterior inferior cerebellar artery (PICA), one on each side. ## What part of the cord do the posterior spinal arteries supply? The posterior third: the dorsal columns and the posterior horns. ## What does a posterior spinal artery infarct cause, and why is it rare? Loss of vibration and joint position sense below the level (sensory ataxia) with movement spared; rare because the paired arteries form a rich network. ## Which bedside test points to dorsal column loss from a posterior spinal artery infarct? The Romberg test: the person is steady with eyes open but sways or falls with them closed, from lost joint position sense. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/posterior-spinal-arteries/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** arteriae spinales posteriores TA2 4527 **Official Spanish (DeCS)** Arterias espinales posteriores **English (TA2)** Posterior spinal arteries **Also called** arteriae spinales dorsales ## Related - [Anterior spinal artery](https://durgical.com/en/anatomy/anterior-spinal-artery/) - [Spinal cord](https://durgical.com/en/anatomy/spinal-cord/) Sources: Terminologia Anatomica (TA2); [Neuroanatomy, Spinal Cord](https://www.ncbi.nlm.nih.gov/books/NBK559056/); Tratado de anatomía humana (9.ª ed.), tomo II, Libro V Sistema nervioso central, sección 1: Médula espinal. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/posterior-spinal-arteries/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/posterior-spinal-arteries/