1.3 Cervical spine & neck Flashcards
Neck regions
Post: back of neck/vertebral region, posterior triangle, sternomastoid region
Ant: anterior triangle, root of neck
Features of ‘typical’ cervical vertebrae
- transverse foraminae
- bifid spinous process
- articular surfaces oriented at 45degree
- C7 (atypical) has longest spinous process (vertebra prominens)
- uncinate processes (guide movement in sagittal planes
Variations of (cervical) vertebral column
- Variations reflecting developmental changes, occurs in 1% population
- Occurs at transitional regions
- Cranial & caudal shifts
- Structures develop as all vertebrae have costal facets, but only thoracic usually develop ribs.
- Cervical rib: elongation of anterior tubercle
- Can compress and irritate structures emerging from neck.
Atypical cervical vertebrae
ATLAS
- no vertebral body
- anterior & posterior arches
- facet for dens
- saucer-shaped upper surfaces for occipital condyles
- long transverse process
AXIS
- dens (odontoid process) - developmental body C1, allows rotational movement of ring of bone
- surfaces on dens for articulation with anterior arch of atlas
Joints of cervical spine
Superior (suboccipital) joints
- atlanto-occipital (0-C1)
- atlanto-axial (C1-2)
Inferior joints (C2-C7)
- intervertebral discs
- facet joints
Describe the IV discs and the uncovertebral joints of the cervical vertebrae?
- Thick IV discs with central nucleus help form cervical lordosis.
- Cervical bodies are the relative largest throughout vertebral column. And act in the same way as lumbar discs (weight-bearing).
-Uncinate processes (‘Uncovertebral joint of Luschka’) form on superior margins of body and guide movement.
Atlanto-axial joints
- 3 synovial joints specialised for rotation (no IV disc)
- median pivot joint between dens of C2 and anterior arch of atlas
- 2 lateral facet joints angulated close to transverse plane
- allow approximately 50% of rotation of cervical spine + small amount of F/E & LF
Longitudinal ligaments of cervical spine
Between atlas & axis
- PAOM posterior atlanto-occipital membrane (ligamentum flavum)
B/w axis & occiput
- TM tectorial membrane/membrana tectoria (PLL)
- AAOM anterior atlanto-occipital membrane (ALL)
- Ligamentum nuchae
*all ligaments resist movements in sagittal plane (F/E)
Specialised ligaments between occiput & C2
Transverse ligaments - stabilise dens, prevents posterior translation of dens into vertebral canal
*rheumatoid arthritis causes lax of this ligament
Alar ligaments - ‘check’ range of rotation of atlas around dens
*susceptible to injury when head flexed & rotated & muscles relaxed
Other posterior ligaments = TM, AAOM. PAOM, LN
Facet joints of cervical vertebrae
Plane synovial joints, oriented at 45deg between coronal & horizontal planes (more horizontal in childhood, resulting in an increase in the risk of subluxation)
Upper facets more vertical, lower facets more horizontal
Facet surfaces bear weight & susceptible to injury, particularly in hyperextension
Fascia of neck
- Superficial fascia
- Deep cervical fascia
- investing layer
- pretracheal layer
- prevertebral layer
- carotid sheath
*potential space between 2 adjacent fascia can result in build up of pus, blood or infected material
Muscles of neck
- Superficial (trapezius, sternomastoid, global muscles) act on shoulder girdle.
- Anterior (hyoid muscles) stabilise hyoid bone/mouth
- Prevertebral responsible for head and neck flexion
- Lateral vertebral laterally flex & rotate head
- Postvertebral muscles extend neck and head.
Sterno(cleido)mastoid
- Separates anterior from posterior triangle in neck.
- Lies within 2 folds of investing fascia.
- Has 2 heads: manubrium of sternum, medial third of clavicle
- Innervated by XI cranial nerve (like trapezius, both are branchial arch muscles)
Actions:
- Bilaterally: flex neck (when in extended position)
- Unilaterally: laterally flexes to same side & rotates to opposite side
Anterior (‘strap’) muscles
- Suprahyoid & infrahyoid muscles
- Deep to investing fascia
- Act to steady or move the hyoid bone & larynx
Prevertebral (anterior vertebral) muscles
- Located deep to prevertebral fascia
- Flex and LF neck
- Act as ‘local’ muscles/segmental stabilisers
- Longus colli maintains curvature of cervical lordosis
