Atlas of Human Anatomy by Netter

[Plate 163, Spinal Nerve Origin: Cross Sections]

Meninges

Dura mater: Tough fibroelastic membrane

Is continuous with the inner (meningeal) layer of the cranial dura

Attached to the margins of the foramen magnum and posterior longitudinal ligament

Separated by the epidural space from vertebral periosteum

Extends as a sac from the margin of the foremen magnum to the level of S2

Pierced by spinal nerves

Anchored to the coccyx by the external filum terminale

Forms dural root sleeves covering the spinal nerves before fusing with the epineurium

Arachnoid mater: Delicate, avascular, fibroelastic membrane lining dural sac

Opposed (held to inner surface) to dura by CSF pressure

Is external to the subarachnoid space, between arachnoid and pia, containing CSF, traversed by strands of connective tissue

(arachnoid trabeculae)

Contains the lumbar cistern, an enlargement of subarachnoid space between L2 (end of spinal cord) and S2 (end of dural sac)

Pia mater: Highly vascular innermost layer covering roots of spinal nerves

Continues as the filum terminale

Suspends the spinal cord within the dural sac by lateral extensions between the anterior and posterior roots, called denticulate

ligaments

Dermatomes: a well-defined strip of skin extending from the anterior to the posterior midline, supplied by a single spinal nerve

Cervical supply neck and upper limb

Thoracic supply trunk (T1 also supplies upper limb)

C5 abuts T1 on the superior anterior chest wall

Lumbar predominantly supply anterior lower limb

Sacral predominantly supply posterior lower limb

Level Somatic Supply

C5 Clavicles

T4 Nipples