Region 4 - Back Flashcards
What are the vertebral notches?
Indentations superior and inferior to each pedicle
Form the IV foraminae
What does the superior vertebral notch on C1 form?
A groove for the vertebral artery
In the atlas, what separates the vertebral foramen and the foramen for the dens?
Transverse ligament of the atlas
What structures of C1 support a superior and inferior articular surface on each side?
Lateral masses
What are the bony prominences on the anterior and posterior arches of C1?
Anterior and posterior tubercles
What do the superior articular surfaces of C1 articulate with?
Occipital condyles
What is the purpose of the grooves on the dens of C2?
Attachments of alar ligaments
What is the purpose of the posterior articular facet at the base of the dens?
Attachment of the transverse ligament of the atlas
What do the anterior and posterior tubercles on the transverse processes of C3-C7 do?
Create a groove between them for spinal nerves
What are the projections on the lateral aspects of the bodies of C3-C7 called?
Uncinate processes
How are the articular facets of thoracic vertebrae orientated?
Nearly vertically
Superior facets face posteriorly
Inferior facets face anteriorly
What does the orientation of the articular facets of thoracic vertebrae allow?
Some rotation
How can the spinous processes of thoracic vertebrae be described?
Long and sloping
What shape do the bodies of lumbar vertebrae have?
Kidney-shaped
What additional processes are present on each transverse process of lumbar vertebrae?
Accessory process
What additional processes are present on each superior articular process of lumbar vertebrae?
Mammillary process
What is the function of the additional processes on the transverse and superior articular processes of lumbar vertebrae?
Muscle attachment
How are the articular facets of lumbar vertebrae orientated?
Superior facets face posteromedially
Inferior facets face anterolaterally
How does the orientation of the articular facets of lumbar vertebrae affect movement in this region?
They grip each other to allow flexion-extension without much rotation
Where is the base of the sacrum?
The most superior part
What is the name given to the inwardly projecting, anterior part of the body of S1?
Sacral promontory
What names are given to the sacral equivalents of the IV foraminae?
Anterior and posterior sacral foraminae
What do the spinous processes of sacral vertebrae form?
Median crest
What do the articular processes of sacral vertebrae form?
Intermediate crest
What do the transverse processes of sacral vertebrae form?
Lateral crest
What feature of the coccyx allows articulation with the sacrum?
Coccygeal cornu
Why do IV discs not ossify?
They are secondary cartilaginous joint (symphyses)
Hyaline and fibrocartilage
What is the general function of the superficial extrinsic muscles of the back?
Connect to appendicular skeleton
What is the general function of the intermediate extrinsic muscle of the back?
Superficial (secondary) respiratory muscle
What are the superficial extrinsic back muscles?
Trapezius Latissimus dorsi Rhomboid major Rhomboid minor Levator scapulae
What are the intermediate extrinsic back muscles?
Serratus posterior superior
Serratus posterior inferior
What are the origins of the serratus posterior superior?
Nuchal ligament
Spinous processes C7-T3
What are the insertions of the serratus posterior superior?
Superior borders ribs 2-4
What is the innervation to the serratus posterior superior?
Intercostal nerves 2-5
What are the origins of the serratus posterior inferior?
Spinous processes T11-T12
What are the insertions of the serratus posterior inferior?
Inferior borders of ribs 8-12 (near angles)
What is the innervation to the serratus posterior inferior?
Anterior rami T9-T12
What is the general function of the intrinsic back muscles?
Maintain posture
Control movements of the vertebral column
What muscles make up the superficial layer of the intrinsic back muscles?
Splenius muscles
What muscle group makes up the intermediate layer of the intrinsic back muscles?
Erector spinae muscle group
What is the general innervation to the intrinsic back muscles?
Posterior rami of spinal nerves
What are the common origins of the splenius muscles?
Nuchal ligament
Spinous processes C7-T3/4
What are the insertions of the splenius capitis?
Mastoid process
Lateral 1/3rd superior nuchal line
What are the insertions of the splenius cervicis?
Tubercles of transverse processes C1-C3/4
What are the functions of the splenius muscles?
Movements of head/neck:
- Extension
- Rotation
- Lateral flexion
What are the functions of the intermediate intrinsic back muscles?
Unilaterally flex vertebral column ipsilaterally Bilaterally: - Extend spine - Posture - Antigravity
From lateral to medial, what are the intermediate intrinsic back muscles?
Iliocostalis
Longissimus
Spinalis
What are the common origins of the erector spinae muscles?
Posterior iliac crest
Posterior sacrum and sacroiliac ligaments
Spinous processes of sacral and lower lumbar vertebrae
Supraspinous ligament
What are the parts of the iliocostalis muscle?
Lumborum
Thoracis
Cervicis
What are the insertions of the iliocostalis muscle?
Angles of lower ribs
Cervical transverse processes
What are the parts of the longissimus muscle?
Thoracis
Cervicis
Capitis
What are the insertions of the longissimus muscle?
Ribs (between tubercles and angles)
Thoracic and cervical transverse processes
Mastoid process
What are the parts of the spinalis muscle?
Thoracis
Cervicis
Capitis
What are the insertions of the spinalis muscle?
Upper thoracic spinous processes
Cranium
What are the parts of the semispinalis muscle?
Thoracis
Cervicis
Capitis
What are the origins of the semispinalis muscle?
Transverse processes of C4-T12
What are the insertions of the semispinalis muscle?
Occipital bone
Thoracic and cervical spinous processes
Where is the multifidus muscle thickest?
Lumbar region
What is the orientation of multifidus muscle fibres?
Pass superomedially to spinous processes 2-4 vertebrae above
What is the function of the multifidus muscles?
Provide stability during movement
In what region are the rotatores best developed?
Thoracic
What is the orientation of the rotatores fibres?
Pass superomedially to junction of laminae and transverse processes 1-2 vertebrae above
What are the functions of rotatores?
Stability
Some rotation
Where are the levator costarum muscles found?
Thoracic rregion
What are the origins of the levator costarum muscles?
Transverse processes C7-T11
What are the insertions of the levator costarum muscles?
Upper ribs borders (immediately inferior to preceding vertebra)
In what regions are the interspinale muscles well developed?
Cervical
Lumbar
What is the function of the interspinale muscles?
Extension
In what regions are the intertransversarii well developed?
Cervical
Lumbar
What are the functions of the intertransversarii?
Stabilisation
Some lateral flexion
Where does the anterior longitudinal ligament run from and to?
From skull base
To sacrum
What do the deep fibres of the anterior longitudinal ligament do?
Bidn adjacent vertebrae together
What do the superficial fibres of the anterior longitudinal ligament do?
Span multiple segments
How many layers of dense collagen are in the anterior longitudinal ligament?
3
What is the function of the anterior longitudinal ligament?
Prevents hyperextension
Where does the posterior longitudinal ligament run from and to?
From C2
To sacrum
What is the posterior longitudinal ligament attached to?
Posterior aspects of IV discs mainly
plus margins of vertebral bodies
What runs between the posterior longitudinal ligament and the vertebrae?
Fat and vessels
Between ligament and bony posterior vertebral body surface
What is the function of the posterior longitudinal ligament?
Prevent posterior herniation of IV disc
Also limits flexion weakly
What do the ligamenta flava lie?
Connecting laminae of adjacent vertebrae
What are the functions of the ligamenta flava?
Reinforce wall of vertebral canal posteriorly
Limit flexion
Help maintain curvatures
Describe the interspinous ligaments?
Connect adjacent spinous processes
Thin, weak and membranous
Describe the supraspinous ligament?
Connects tips of spinous processes
Runs from C7 to sacrum
Cord-like
What is the function of the interspinous and supraspinous ligaments?
Limit flexion
How can the intertransverse ligaments be described in the cervical spine?
Scattered
How can the intertransverse ligaments be described in the thoracic spine?
Fibrous
How can the intertransverse ligaments be described in the lumbar spine?
Membranous
What is the function of the intertransverse ligaments?
Limit lateral flexion
What are the origins of the nuchal ligament?
External occipital protuberance
Posterior border foramen magnum
What are the insertions of the nuchal ligament?
Spinous processes C1-C7
What are the functions of the nuchal ligament?
Muscle attachment
Limits flexion
Where does the spinal cord run?
From the foramen magnum to L1/L2
What is the ending of the spinal cord called?
Conus medullaris
Where is the cervical enlargement?
C4-T1
Where is the lumbosacral enlargement?
L1-S3
What are cervical spinal nerves named after?
Vertebra below (except C8)
What are the other spinal nerves named after?
Vertebra above
What is the filum terminale?
Remnant of caudal part of spinal cord
Where is the filum terminale internum found and where does it extend to?
Within dural sac
Extends to lower border S1/S2
What does the filum terminale externum do?
Attaches dura inferiorly to coccyx
What is contained within the epidural space?
Internal vertebral venous plexuses (Anterior and Posterior)
Epidural fat
What connect the arachnoid to the pia?
Arachnoid trabeculae
What is the enlargement of the subarachnoid space called and where is it found?
Lumbar cistern
L2-S2
What does spinal pia mater cover?
Spinal cord
Nerve roots
Spinal blood vessels
What are the denticulate ligaments?
Pia mater running on either side of the spinal cord between posterior and anterior nerve roots
What do the denticulate ligaments do?
Suspend cord in dural sac
Where does the anterior spinal artery arise?
From vertebral arteries at level of medullar oblongata (in a y-shaped fashion)
(Singular and descends in midline)
Where do the two posterior spinal arteries arise from?
Vertebral arteries
OR
Posterior inferior cerebellar arteries
Where do the spinal arteries run?
From medulla to conus medullaris
What supports the spinal arteries?
Anterior and posterior segmental medullary arteries derived from spinal branches of
- Ascending cervical arteries
- Deep cervical arteries
- Vertebral arteries
- Posterior intercostal arteries
- Lumbar arteries
What supplies the nerve roots?
Radicular arteries
What drains the spinal cord?
Medullary vein -> Radicular veins -> Internal vertebral venous plexus -> Anterior and posterior spinal veins