Anatomy of Back, Vertebral Column and Spinal Cord Flashcards
What are the functions of the back?
Maintenance of posture
Movement of limbs and trunk
What are the 3 parts of the trapezius?
Descending (superior)
Transverse (middle)
Ascending (inferior)
What are the muscles of the back from superior to inferior?
Trapezius
Teres major (rotator cuff muscle)
Latissimus dorsi
Erector spinae
What are the extrinsic back muscles?
Levator scapulae
Rhomboids
Trapezius
Latissimus dorsi
What are the 2 groups of intrinsic back muscles?
Erector spinae (superficial) Transversospinalis (deep)
Describe the erector spinae muscles?
3 vertical muscle groups located lateral to the spin
Where do the erector spinae muscles attach?
Superiorly- individual muscle fibres attach to rib, transverse process or spinous process
Inferiorly- sacrum & iliac crest
Where are the transversospinalis muscles located?
Within grooves between transverse and spinous processes
Where do the individual muscle fibres of transversospinalis muscles attach?
Between: vertebra and skull vertebra and rib vertebra and another vertebra sacrum and vertebra
What innervates the intrinsic back muscles?
Segmental nerves as per dermatome and myotome pattern
Posterior rami branches
What are the muscles of the anterolateral abdominal wall from deep to superficial?
Transversus abdominis
Internal oblique
External oblique
Which muscles extend the spine?
Erector spinae contracts bilaterally
N.B Unilateral contraction gives rise to lateral flexion
Which muscles flex the spine?
Psoas major and rectus abdominis
What does the vertebral arch consist of?
2 pedicles
2 lamina
What is the role of the intervertebral foramen?
Form between adjacent vertebrae
Spinal nerves are found here
What is the role of facet joints?
Form between articular processes of adjacent vertebrae
Can be affected by arthritis
Describe intervertebral discs?
Found between the bodies of adjacent vertebrae
Form strong attachments and so can herniate
Where are there no intervertebral discs?
None between C1-C2
Sacrum/coccyx is fused
What is the name and function of the outer fibrous ring of the intervertebral disc?
Annulus fibrosis
Provides strong bond
What is the name and function of the inner soft pulp of the intervertebral disc?
Nucleus pulposus
Flexibility and protection
What are the ligaments of the spine and their functions?
Ligamentum flavum- short, connects adjacent laminae to spinal cord
Posterior longitudinal ligament- prevents over-flexion of spine
Anterior longitudinal ligament- prevents over-extension of spine
Supraspinous ligament- connects tips of spinous processes- strong + fibrous
Interspinous ligament- connects superior and inferior surfaces of adjacent spinous processes- weak + membranous
How do the anterior and posterior longitudinal ligaments differ?
Anterior- attaches to anterior of vertebra and is broad and strong
Posterior- attaches to posterior of vertebra and is narrow and weak
What are the common features of the cervical vertebrae?
Transverse foramen
Bifid spinous process
Triangular shaped vertebral foramen
What are the features of C1- atlas?
No body or spinous process
Posterior and anterior arch instead
What are the features of C2-axis?
Odontoid process
Projects superiorly from body
What are the features of C7?
Vertebrae prominens
First palpable spinous process
What movements does the Atlanta-occipital joint facilitate?
Flexion + extension of the neck
Little lateral flexion and rotation
How many synovial articulations does the atlanto-axial joint have?
Three
2 between inferior articular facets of atlas and superior articular facets of axis
1 between anterior arch of atlas and odontoid process of the axis
What is the main movement of the atlanto-axial joint?
Rotation
Saying “no”
Where is the sacral hiatus found?
Inferior end of sacral canal
Where is local anaesthesia injected in caudal anaesthesia?
Into the sacral hiatus to anaesthetise sacral spinal nerve roots of caudal equina
Where does the spinal cord begin?
Foramen magnum continuous with medulla oblongata
Where does the spinal cord end?
Vertebral level L1/L2
What is the end of the spinal cord called?
Conus medullaris
Where does the caudal equina supply?
All spinal nerve roots from L2 to Co
What are the 3 layers of meninges that surround the spinal cord?
Pia mater
Arachnoid mater
Dura mater
What surrounds the meninges?
Epidural fat
What is a laminectomy?
Removal of one or more spinous processes and the adjacent lamina
What is a laminectomy used for?
Used to access spinal canal at posterior of spinal cord to relieve pressure on spinal cord/nerve roots
What clinical conditions would indicate a laminectomy?
Tumour, herniated disc, bone hypertrophy
