Vertebral Column, Spinal Cord and Spinal Meninges

Gross Anatomy


Vertebral Column, Contents of the Vertebral Canal


Anatomy Tables for Today's Topic

Bones of the Back
Spinal Meninges

Bones of the Back

Bone Structure Description Notes

occipital

the bone forming the posterior surface of the skull and posterior portion of the skull base it articulates superolaterally with the parietal bones through the lambdoid suture, anteroinferiorly with the temporal bone and anteriorly with the body of the sphenoid bone
external occipital protuberance a low process on the external surface of the occipital bone in the midline it is an attachment site for the ligamentum nuchae; the superior nuchal lines of the two sides meet in the midline at the external occipital protuberance; also known as: inion
inferior nuchal line a low ridge that runs transversely on the external surface of the squamous part of the occipital bone inferior to the superior nuchal line it is an attachment site for deep neck muscles
superior nuchal line a low ridge that runs transversely on the external surface of the squamous part of the occipital bone it is an attachment site the for the trapezius and splenius mm.
occipital condyle a low, wide projection from the inferior surface of the lateral part of the occipital bone paired; it articulates with the atlas
vertebra one of a series of irregular bones that form the spine a vertebra has two parts: the vertebral body and the vertebral arch; there are 33 vertebrae total: 7 cervical, 12 thoracic, 5 lumbar, 5 fused to form the sacrum, 4 coccygeal; features of a typical vertebra include: body, pedicles, transverse processes, laminae, articular processes, spinous process
vertebral body the largest part of the vertebra it is shaped like a short cylinder; adjacent vertebral bodies articulate through a symphysis
vertebral arch the ring of bone formed by the paired pedicles and paired laminae of the vertebra the transverse processes and spinous process are attached to the neural arch; the neural arch protects the spinal cord
pedicle short strong process that extends posteriorly from the posterolateral surface of the vertebral body paired; it connects the body with the transverse process; it is marked by superior & inferior vertebral notches;
transverse process a lateral process the extends from the junction of the pedicle and the lamina of the vertebra a site for muscle attachment and rib articulation
lamina a broad flat plate of bone located between the transverse process and the spinous process of the vertebra paired; it is flattened markedly in the anteroposterior direction; ligamenta flava span the interval between the laminae of adjacent vertebrae
articular processes processes that project inferiorly and superiorly from the junction of the lamina and pedicle of the vertebra two pair on each vertebra (superior and inferior); the superior articular processes of one vertebra articulate with the inferior processes of the adjacent vertebra through synovial joints
vertebral notch a notch on the superior and inferior surface of the vertebral pedicle the superior vertebral notch of one vertebra combined with the inferior vertebral notch of the adjacent vertebra forms the intervertebral foramen
intervertebral foramen an opening between the pedicles of adjacent vertebrae adjacent vertebral notches form the intervertebral foramen; an opening for passage of the spinal nerve
vertebral canal a canal formed by the combination of the vertebral foramina of all vertebrae it contains the spinal cord, meninges, epidural fat and the internal vertebral plexus of veins
vertebral foramen the opening formed by the body and the vertebral arch when all vertebrae are articulated, the combined vertebral foramina form the vertebral canal
spinous process a posterior midline process arising from the junction of the two laminae of the vertebra an important site of muscle attachment
cervical vertebrae   the seven vertebrae of the neck cervical vertebrae have the features of the typical vertebra plus all have transverse foramina (for passage of the vertebral artery); C2-C6 have bifid spinous processes; cervical vertebrae have relatively small bodies; several cervical vertebra are named: atlas, axis, vertebra prominens
atlas (C1) the first cervical vertebra atlas has no vertebral body, only anterior and posterior arches; it articulates with the occipital bone and the odontoid process of the axis
axis (C2) the second cervical vertebra the odontoid process (dens) projects superiorly from its body; it articulates with the anterior arch of the atlas
vertebra prominens the seventh cervical vertebra it has a long, non-bifid spinous process which is prominent at the nape of the neck, hence its name
thoracic vertebrae   the 12 vertebrae associated with the thoracic region thoracic vertebrae have the features of a typical vertebra plus they are characterized by long slender spines that project inferiorly; they have facets for articulation with ribs; thoracic vertebrae have bodies of intermediate size
costal articular facet on the body small smooth areas at the junction of the body and the vertebral arch most thoracic vertebrae have 2 costal facets on each side (one superior and one inferior); the superior costal facet of one vertebra and the inferior costal facet of the adjacent vertebra both articulate with the head of the same rib; also known as demifacets
costal articular facet on the transverse process a small smooth area on the transverse process of the thoracic vertebra it articulates with the articular facet on the tubercle of the rib
lumbar vertebrae   the 5 vertebrae located in the lumbar region lumbar vertebrae have the features of a typical vertebra plus they are characterized by short, blunt spines that project posteriorly; lumbar spines do not overlap making the lumbar level a good one for spinal tap; lumbar vertebrae are built strong and have the largest bodies of all vertebrae
sacrum   a triangular bone that is the posterior skeletal element forming the pelvis it is formed by 5 fused vertebrae; the sacrum and two os coxae bones form the pelvis
anterior sacral foramina openings on the anterior surface of the sacrum there are four pairs; each transmits the ventral primary ramus of the respective sacral spinal nerve; branches of the lateral sacral aa. and vv. reach the sacral canal by passing through these openings
posterior sacral foramina openings on the posterior surface of the sacrum there are four pairs; each transmits the dorsal primary ramus of the respective sacral spinal nerve
promontory the anterior aspect of the body of the first sacral vertebra the body of the fifth lumbar vertebra sits on the body of the first sacral vertebra; the anterior longitudinal ligament attaches to the promontory
sacral canal the opening in the center of the sacrum it is the continuation of the vertebral canal at sacral vertebral levels
articular surface the roughened area located on the lateral surface of the sacrum this surface articulates with the ilium in the sacroiliac articulation; a synovial joint
body the central portion of the sacrum the body is equivalent to the bodies of the other vertebra
base the superior surface of the sacrum the base of the sacrum articulates with the fifth lumbar vertebra through an intervertebral disk
sacral hiatus an opening on the posterior surface of the sacrum in the midline it is a normal feature that results from the failure of fusion of the laminae of the fifth sacral segment (and sometimes the fourth) during development
ala the lateral portion of the sacrum paired; it projects laterally from the body of the sacrum; it represents the fused costal and transverse processes of the first sacral vertebra
coccyx   the most inferior portion of the vertebral column the coccyx results from the fusion of the four coccygeal vertebrae; it may be a single bone or the first coccygeal vertebra may be separated from the other three; it articulates with the fifth sacral segment; coccygeal vertebrae are reduced in complexity, having no pedicles, laminae or spines
scapula   the bone of the shoulder the scapula floats in a sea of muscles, so it is difficult to fracture; it articulates with only one bone - the clavicle at the coracoclavicular and acromioclavicular joints
superior border the superior edge of the scapula the superior border of the scapula is marked by the scapular notch laterally
medial border the border of the scapula that runs from the superior angle to the inferior angle it is an important site of muscle attachments for the intermediate layer of back muscles
superior angle the angle of the scapula formed at the union of the superior and medial borders it is the attachment site for the levator scapulae m.
lateral border the portion of the scapula that runs inferomedially from the infraglenoid tubercle to the inferior angle it is an important site of muscle attachments for the teres major m., teres minor m. and the long head of the triceps brachii m.; it has a groove for passage of the circumflex scapular a.
inferior angle the angle of the scapula formed by the union of the medial and lateral borders the inferior angle of the scapula often has a slip of origin of the latissimus dorsi attached to it
glenoid cavity the articular surface located at the junction of the superior and lateral borders of the scapula it articulates with the head of the humerus; it is deepened by a fibrocartilaginous rim called the glenoid labrum
supraglenoid tubercle a projection of bone located superior to the glenoid cavity it is the attachment site for the tendon of the long head of the biceps brachii m.
infraglenoid tubercle a projection of bone located inferior to the glenoid cavity it is the attachment site of the tendon of the long head of the triceps brachii m.
spine a heavy ridge that runs from the medial border of the scapula to the acromion process it supports the acromion process; it divides the posterior surface of the scapula into a supraspinatous fossa and an infraspinatous fossa
scapular notch a notch on the superior border of the scapula located medial to the attachment of the coracoid process it is bridged by the superior transverse scapular ligament; the suprascapular a. passes superior to the superior transverse scapular ligament and the suprascapular n. passes inferior to it (Army goes over the bridge, Navy goes under the bridge)
coracoid process a beak-like process that projects anteriorly from the lateral end of the superior border of the scapula it is the attachment site for the short head of the biceps brachii m., the coracobrachialis m., the pectoralis minor m. and the coracoacromial and coracoclavicular ligaments
acromion a broad, flat process located at the lateral end of the scapular spine it articulates with the clavicle through a synovial joint (acromioclavicular joint)
supraspinatous fossa a broad depression located superior to the spine of the scapula it is the site of origin of the supraspinatus m.
infraspinatous fossa a broad depression located inferior to the spine of the scapula it is the site of origin of the infraspinatus m.

Spinal Meninges

Organ Location/Description Notes
meninges three layers of connective tissue covering the brain and spinal cord; dura mater, arachnoid mater, and pia mater meninges provide protection and nourishment of the brain, brainstem and spinal cord
dura mater outermost of the meningeal layers covering the brain and spinal cord "tough mother"; it is the most durable of the meninges and provides support and protection for the brain and spinal cord; two types are described which differ in structure: cranial and spinal
epidural space the space external to the sac of spinal dura mater within the vertebral canal the epidural space contains epidural fat and the internal vertebral plexus of veins which is valveless (clinically relevant)
arachnoid mater intermediate one of the three layers of meninges arachnoid mater is a thin membrane which is pressed against the inner surface of the dura mater by cerebrospinal fluid pressure; arachnids are spiders and the arachnoid mater is so named because it has a thin, web-like appearance
subarachnoid space the space between the arachnoid mater and the pia mater subarachnoid space contains cerebrospinal fluid and spider web-like filaments
pia mater delicate membrane that lies on the surface of the brain and spinal cord "delicate mother", it is the most delicate of the meninges; this layer faithfully follows all surface contours of the brain and spinal cord; pia mater has 2 specializations: denticulate ligament and filum terminale internum
denticulate ligament a lateral extension of pia mater from the spinal cord denticulate ligament attaches to the dura mater to anchor the spinal cord; it forms a scalloped free border; there are 2 (one on each side)
filum terminale thread-like extension of the pia mater from the conus medullaris of the spinal cord filum terminale internum is best seen between vertebral levels L2 and S2; it becomes enclosed within the filum terminale externum
coccygeal ligament thread-like extension of the dura mater below the end of the dural sac at S2 it attaches to the coccyx; also known as the coccygeal ligament


Other Tables of Interest:


Back Region


Upper Limb

All Anatomy Tables

Tables Organized by System Tables Organized by Region


Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of tables edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.