(4.2) Functional Anatomy of the Cervical Spine Flashcards
Describe the anatomy of the cervical spine
- 7 vertebrae
- Cervical lordosis
- Smallest & most mobile vertebrae
- C1 called Atlas
- C2 called Axis
- Designed for motion, positioning of eyes, ears and nose
Describe the anatomy of C1 (Atlas)
- Supports the head
- Articulates superiorly occiput & inferiorly with Axis
- No vertebral body, spinous process or discs
- Ring-like
- Large transverse process with transverse foramen
Describe the anatomy of C2 (Axis)
- pivot on which C1 & the head rotates
- Dens projects superiorly from body
- Anterior facet articulates with atlas
- Sup articular facets articulate with inf facets atlas
- Inferior facets articulate with sup facets C3
- Large prominent spinous process
What are the upper cervical ligaments?
- Anterior/Posterior atlanto-occipital
- Tectorial membrane
- Apical
- Alar
- Transverse of atlas
- Accessory atlanto-axial
Where is the Anterior/Posterior atlanto-occipital ligament?
extend b/t occiput and arches of atlas
Where is the Tectorial membrane ligament?
Connects the posterior body of axis to occiput
Where is the Apical ligament?
It is a short & thick ligament that stretches from the tip of the dens to the foramen magnum
What does the alar ligament do?
- obliquely upwards from apex of dens to occipital condyles
- limits contralateral rotation
Where is the accessory atlanto-axial ligament do?
Upwards/laterally from base of dens to lateral mass of atlas
What does the transverse ligament of the atlas do?
- passes b/t medial tubercles of atlas
- holds odontoid in place
Describe the atlanto-occipital joint
- pivot joint
- articulation b/t superior art facets of atlas and occipital condyles skull
- ball and socket synovial joint
What are the movements of the atlanto-occipital joint?
- Flexion (10 degrees)
- Extension (20 degrees)
- Lateral flexion (15-20 degrees)
- Rotation (10-14 degrees)
Describe the atlanto-axial joint (C1/2)
- most mobile segment in spine
- 3 synovial joints
- one central atlanto-odontoid joint (double joint)
- two lateral atlanto-axial joints (plane joints)
Describe the anatomy of C3-7
- Typical
- Anterior body
- Posterior arch formed by pedicles, articular processes, lamina and spinous processes
- Sup & inf articular processes
- Transverse processes
What are the ligaments in C3-7?
- Anterior longitudinal
- Posterior longitudinal
- Ligamentum flavum
- Ligamentum nuchae
- Interspinous
- Intertransverse
What is the function of the intervertebral disc?
- allows relative motion between vertebral bodies
- absorbs, transmits load
Describe the anatomy of intervertebral discs
- largely avascular
- innervated by sinuvertebral nerve
- nutrition by metabolite diffusion
- named by the vertebral bodies above/below
Describe the cervical spinal nerves
- 8 pairs
- nerve roots exit via intervertebral foramina
- cranial nerves numbered by vertebra below (except C8)
- opposite to L and T spine
What action do nerve roots C1-C2 innervate?
Chin tuck
What action do the nerve root C5 innervate?
Shoulder abduction
What action do nerve root C3 innervate?
Head side flexion
What action do nerve root C4 innervate?
Shoulder elevation
What actions does the nerve root C6 innervate?
Elbow flexion and wrist extension
What action does the nerve root C8 innervate?
Thumb extension
What action does the nerve root C7 innervate?
Elbow extension & wrist flexion
What action does the nerve root T1 innervate?
Finger abduction/adduction
What nerve is responsible for the bicep jerk reflex?
C6
What nerve is responsible for the triceps jerk reflex?
C7
What is the brachial plexus?
- network spinal nerves supplying UL
- Originates C5-T1 spinal nerves
- 5 roots, 3 trunks, 6 divisions, 3 cords, 5 terminal branches
What are the nerves branching from the brachial plexus?
- musculotaneous
- axillary
- radial
- median
- ulnar
Sternocleidomastoid
- 2 heads
- O: Sternum + medial clavicle
- I: Mastoid process, nuchal line
- A: lateral flexion, contralateral rotation, flex mid lower C-spine, extend upper C-spine
Anterior Scalene
- O: anterior tubercles T-pro C3-6
- I: 1st rib
- A: lateral flex, contra rotation, flexion
Medius Scalene
- O: posterior tubercles of T-pro C2-7
- I: 1st rib
- A: lat flex, flexion
Posterior Scalene
- O: posterior tubercles of T-pro C4-6
- I: 2nd rib
- A: lateral flexion
Longus Colli
O:
- Superior: ant tubercles T-pro C3-C5
- Intermediate: ant surface C5-T3
- Inferior: ant surface T1-T3
I:
- Superior: ant tubercle C1
- Intermediate: ant surface C2-C4
- Inferior: ant tubercles T-pro C5-C6
Longus Capitus
- O: ant tubercle T-pro C3-6
- I: Occiput
- A: flex upper cranio-cervical region
Rectus Capitus Anterior & Lateralis
- O: T-pro axis
- I: Occiput & occipital condyle
- A: Flex & Lateral Flex
Splenius Cervicis
- O: Spinous process T3-6
- I: Posterior tubercles t-pro C1-3
- A: Lat flex, ipsilateral rotation, extension
Splenius Capitis
- O: Lower ligamentum nuchae + spinous process C7-T4
- I: Mastoid process
- A: Lat flex, ipsilateral rotation, extension
Suboccipital muscles
- Attach b/t atlas, axis & occiput
- Fine-tuned head movement
What are the muscles of the Erector Spinae?
- Spinalis cervicis
- Spinalis capitis
- Longissimus cervicis
- Longissimus capitis
- Iliocostalis cervicis
- All lat flex, rotation, extension
What are the Transversospinal muscles?
- Semispinalis capitis
- Semispinalis cervicis
- More finely contolled mvmt
Upper Trapezius
- O: Occiput, ligamentum nuchae, S-pro C7
- I: Lateral 1/3rd clavicle
- A: Elevate and stabilize scapula, head and neck extension, lat flexion
Levator Scapula
- O: T-pro C1-4
- I: Medial border of scapula
- A: Stabilize scapula, head and neck extension, lateral flex, rotation
What are the interbody vertebral joints?
- From C2-3 down
- Fibrocartilaginous
- AF/NP change response to motion/load
What are uncovertebral joints?
- small synovial
- C3-7
- reinforce disc postero-laterally
- prevent posterior translation
- allow flexion & extension
What are facet joints?
- aka zygapophyseal
- formed superior and inferior facets
- orientated 45 degree angle
- as descends facets face more vertically (less rotation)
