Cervical Spine Flashcards
How many vertebrae make up the cervical spine?
7
What type of curve are the cervical vertebrae arranged in?
Lordotic
What are the two anatomically distinct and functionally different segments of the cervical spine?
The superior or suboccipital segment and the inferior segment.
What vertebrae make up the superior or suboccipital segment?
The atlas and the axis.
What vertebrae make up the inferior segment of the spine?
The inferior surface of C2 to the superior surface of T1.
Where did the Atlas or C1 get its name?
From a figure in Greek mythology whose job was to hold up the world on his shoulders.
Describe the Atlas’s structure
It’s a ring like structure with its transverse dimension greater than its antero-posterior dimension. It has oval-shaped lateral masses on either side and two short transverse processes.
What is the widest vertebrae?
The C1 or Atlas
What is missing from the Atlas that makes it unique?
It doesn’t have a vertebral body.
What is the anterior part of the very large vertebral foramen occupied by?
The odontoid process or dens of the axis
What is on the posterior surface of the anterior arch of the Atlas or C1?
A facet for articulation with the odontoid process.
What is found anteriorly and posteriorly on the midline of the Atlas?
Posterior tubercle and anterior tubercle
What age does the posterior neural arch of the atlas fully fuse?
3
What age does the anterior neural arch fully fuse?
7
Where does the C1 articulate?
Above with the occipital condyles of the skull and below with the second cervical vertebra or Axis.
Unlike most vertebrae, what is the atlas missing posteriorly?
A spinous process
What is the bony pillar on the superior surface of the vertebral body of the axis?
The odontoid process or dens.
What does the odontoid process or dens form?
It acts as a pivot for the atlas and forms the atlanto-axial joint.
What is convex?
having an outline or surface curved like the exterior of a circle or sphere
What is concave?
having an outline or surface that curves inward like the interior of a circle or sphere
What is oblique?
neither parallel nor at a right angle to a specified or implied line; slanting
What is medial?
situated in the middle
What runs through the vertical foramen of the transverse processes?
The vertebral artery.
Describe the facet joints of C2.
They are broad and flat to allow maximum mobility in relation to the atlas above and the C3 below.
At what level is there a beginning of a spinous process?
C2
What is bifid?
Divided into two equal parts or split as seen in the bifid appearance of the spinous process.
Describe C3 - C7.
They are similar in their construction and are referred to as typical vertebrae.
What shape are the vertebral bodies?
Saddle-shaped
What does the laterally raised upper surface of the superior plateau form?
The unciform process
The inferior vertebral plateau resemble?
The superior vertebral plateau.
How are the articular facets attached to the vertebral body?
By pedicles
What is lateral to the pedicles?
Transverse processes
Why are the superior and inferior borders of the transverse processes curved?
To accommodate the spinal nerve as it exits the neural canal.
How is the posterior vertebral arch completed?
By the laminar which meet in the midline to form the bifid spinous process.
What is C7 also know as?
Vertebra prominens
Why is C7 known as the vertebrae prominens?
Because it is especially large and can easily be felt under the skin.
Does the vertebral artery run through the foramina of C7?
No. It runs anteriorly to the vertebrae.
What shape does the vertebral foramen form?
A triangular shape. It is very wide, as the cord is thickest in the cervical spine as it exits the skull.
Where is the spinal cord the thickest?
As it exits the skull.
What are lateral masses?
They are masses of denser bone on the right and left lateral aspects of the posterior cervical spine.
What is superior and inferior to the lateral masses?
The superior and inferior articular processes
What’s the average inter-facet distance?
9mm to 16mm with an average of 13mm.
Describe the lateral mass of C7.
It’s’ more elongated and thinner than at higher levels.
Name the cervical ligaments.
Occipito-Atlantal Atlanto-Axial Occipito-Axial Transverse Avterior Longitudinal Posterior Longitudinal Interspinous Supraspinous Ligamentum Flavum
Describe the Occipito-Atlantal
The Occipito-Atlantal ligamentous complex consits of four components, the anterior and posterior and the two thicker lateral ligaments.
Describe the Atlanto-Axial ligaments
Four major ligaments extending from the atlas to the axis. Anterior, posterior and two lateral.
Describe the Occipito-Axial
Four ligaments connect the occiput to C2.
How many ligaments originate from the odontoid process?
3.
What are the alar ligaments or check ligaments?
Ligaments extending laterally from the tip of the odontoid to the occipital condyles.
What is the apical ligament?
It extends from the tip of the odontoid process to the anterior aspect of the foramen magnum.
What is the foramen magnum?
the hole in the base of the skull through which the spinal cord passes
Describe the transverse ligaments.
Diamond shaped and stabilises the atlanto-axial complex. It extends from the Atlas behind the Dens, to insert on the opposite anterolateral portion of the atlas.
What is the cruciform ligament?
The entire ligament complex that contains the transverse ligaments and the fascicles.
Describe the anterior longitudinal ligament.
the ALL consists of thick, longitudinally orientated fibres extending from the axis anteriorly to the sacrum. The fibers adhere to the annulus.
Describe the Posterior Longitudinal Ligament
The PLL is weaker than the ALL. The fibres are less dense. It runs from the axis caudally to the sacrum. Like the ALL it adheres to the vertebrae at the superior and inferior margins and to the annulus of the disc.
Describe the Interspinous ligament.
The interspinous ligament connects each adjacent spinous process. The interspinous ligament is part of the ligamentum nuchae.
Describe the Supraspinous ligament.
A very strong band connecting the tips of the neighbouring spinous process. It extends from C7 to the sacrum. Above C7 these ligaments are port of the ligamentum nuchae.
Ligamentum Flavum
Or yellow ligament that extends longitudinally from the anterior surface of the lamina above to the superior margin and posterior surface of the lamina below. It originates at C2 and terminates at the sacrum. It thickens as it moves down the spine.
What are the 3 functions of the cervical muscles?
To move the head and neck
To suspend and move the entire shoulder girdle
To suspend, fix and elevate the thoracic inlet
The muscles in this area are found in?
Paired groups
What are these pairs of cervical muscles attached to?
The skull and spinous processes
What 3 groups are the posterior muscles divided into?
Superficial
Intermediate
Deep
What is the most superficial muscle?
The trapezius. It originates from the external occipital protuberance and the medial nuchal line of C7 and extends to the spinous process of T12.
Name an intermediate muscle.
Splenius Capitis
Name 4 deep cervical muscles.
Semispinalis Capitis
Semispinalis Cervicis
Multifidus
Erector Spinae
What is the nuchal line?
The nuchal lines are four curved lines on the external surface of the occipital bone
What is the mastoid process?
The mastoid process is a conical prominence projecting from the undersurface of the mastoid portion of the temporal bone.
What muscles superficially cover the sub-occipital region of the cervical spine?
The trapexius, the splenius capitis and the semispinalis capitis muscles
What muscle originates from the spinous process of the axis?
The rectus capitis posterior major muscle
What muscle runs obliquely cephalad from the spinous process of the axis to the inferodorsal aspect of the transverse process of the atlas?
The obliquus capitis inferior
The suboccipital triangle is bounded superiorly and medially by what?
The rectus capitis major muscle
What covers the suboccipital triangle?
The semispinalis capitis and the atlanto-occipital membrane
What 3 groups are the antero-lateral muscles of the cervical spine divided into?
Superficial
Intermediate
Deep
Name an antero-lateral superficial muscle.
Platysma - a thin muscle found just beneath the subcutaneous tissue, it spans the deltoid to the upper pectoral fascia
What are the intermediate muscles of the antero-lateral muscle group?
Sternocleidomastoid
Hyoid
Strap
What are the deep muscles of the antero-lateral muscle group?
Longus Colli Longus Capitis Rectus Capitis Anterior Rectus Capitis Lateralis Scalenus Anterior Scalenus Medius Scalenus Posterior
At what cervical vertebra does the spinal cord enlarge?
C3
At what vertebra does the spinal cord reach its maximum diameter?
C6
Why does the spinal cord enlarge between C3 and C6?
Due to the increased nerve supply to the upper limbs
How much can the cervical portion of the spinal cord stretch to facilitate flexion and extension?
up to 25%
How is each cervical nerve root named?
After hte number of hte pedicle that it passes over on its exit, except for the 8th cervical nerve, which lies between C7 and T1 pedicles.
What does the nerve proper divide into?
Several branches called rami
What are the branches of the cervical rami?
The dorsal ramus
The ventral ramus
The meningeal ramus
The rami communicares
What does the dorsal ramus innervate?
The skin of the back, the skin on the back of the head and tissues of dee muscles
What does the ventral ramus innervate?
Skin, tissues and muscles of the neck, chest, abdominal wall, both pairs of limbs and the pelvic area.
What does the meningeal ramus innervate?
The vertebrae, spinal meninges, and spinal blood vessels
What does the rami communicares innervate?
The visceral structures
What is a plexus?
An arrangement of ventral rami that are sorted and recombined so that each peripheral nerve has the correct fibres from each rami
What composes the cervical plexus?
The ventral rami of the spinal verves C1-C4.
What are the groups of cervical plexuses?
Cutaneous sensory nerves
Branches of the Ansa Cervicalis
Phrenic Nerves
What is the Brachial plexus?
Is made up of the ventral rami of C5-C8 and T1 spinal nerves.
What do the neurovascular structures of the cervical spine include?
Cord Nerve roots Carotid artery Vertebral artery Sympathetic chain Veins and vessels to the spinal cord
What supplies the brain with blood?
Two vertebral arteries
Two internal carotid arteries
What does blood from the vertebral artery supply?
Blood from the vertebral artery supplies the cerebellum, brainstem and posterior, occipital, part of the cerebellum.
What do the internal carotid arteries supply?
The remainder of the brain and eyes.
What is the major blood supply to the cervical spinal cord?
The vertebral artery
Where does the vertebral artery originate?
The subclavian artery
What else does the vertebral artery supply?
The vertebrae Meninges Spinal cord Zygapophyseal (facet) joints Posterior nerve root ganglia Cranial nerve roots
At what level does the vertebral artery enter the transverse foramen?
C6
Describe the path of the vertebral artery.
The artery ascends towards the skull traveling through the transverse foramen of each vertebra, then winds around the lateral mass of and posterior arch of the atlas.
What do the vertebral arteries form when they join together beyond the foramen magnum?
The basilar artery
The interaction of the occiput (C0) and the atlas at the occipito-cervical junction is dominated by the relationship between what two joints?
The atlanto-occipital joints
What is the atlanto-occipital joints comprised of ?
Superior articular surfaces
Lateral masses of the atlas
Occipital condyles
What movements does the atlanto-occipital joint allow?
Axial rotation, flexion and extension and lateral flexion.
What are the 3 articulations between the atlas and axis?
The atlanto-odontoid joint (central)
2 lateral atlanto-axial joints
