Week 2 - finished Flashcards
- Name the parts of a typical cervical vertebra.
Vertebral body: Small & rectangular. Uncinate processes project from the superior lateral surface to articulate with the vertebra above, forming the synovial uncovertebral joints. These jts limit side bending.& with age, limit IVD protrusion.
Vertebral Canal: Triangular & Relatively large to accommodate the cervical enlargement of the spinal cord but at C6, the spinal cord takes up 75% of the vertebral canal.
Pedicles: Small and project posterolaterally to form the medial boundary of the transverse foramen. Continuous with the articular processes to allow transfer to load between the body and the articular pillars. The two vertebral notches form the intervertebral foramen (IVF) which faces obliquely anterior, at about 45degrees to sagittal & inferiorly at about 10degrees to horizontal. The spinal nerve fills about 1/5 of the IVF.
Transverse Processes: Composed of anterior and posterior bars (or roots), joined by the intertubercular lamella. These bars end as ant. & post. tubercles.
- The anterior tubercles of C4-6 give attachment to the anterior scalene, longus colli and longus capitis.
- The posterior tubercles give attachment to splenius cervicis, iliocostalis cervicis, levator scapulae and medial and posterior scalenes.
The foramen of the TP is bounded by the pedicle the anterior and posterior bars of the TP and the intertubercular lamella. These foramina give passage to the vertebral a. & several vertebral v.’s down to C6 but only accessories at C7.
Articular Processes: Superior articular processes and their facets face posteriorly, superiorly and slightly medially. Inferior articular processes and their facts face anteriorly, inferiorly and slightly laterally. The facets are large, flat and oval-shaped. Facet joints are angled at approximately 45 degrees to horizontal. Superior and inferior processes form articular pillars which help to support the weight of the head
Laminae: Are thin so that there is space between them posteriorly. This space is filled by the ligamentum flavum
Spinal Processes: Short and bifid for attachment of ligamentum nucha and many deeps spinal extensors.
- What features of the first cervical vertebrae makes them atypical?
Atlas or C1: a ring, comprising anterior and posterior arches, separated by two lateral masses.
Anterior Arch:
- Smaller of the two arches
- Anterior tubercle, found on anterior surface, gives attachment to ALL and longus colli.
- Facet of the dens: found on posterior surface. This facet forms a diarthrodial joint with the odontoid process (dens) of C2. (Note that the dens occupies a position homologous to the body of the atlas)
Posterior Arch:
- Forms 2/3 of the ring of the atlas
- Posterior Tubercle: found on posterior surface, gives attachment to the ligamentum nuchae and rectus capitis posterior minor.
- Superior surface has a groove for the vertebral arteries & the suboccipital nerves (dorsal ramus of C1)
Lateral Masses:
- Left and right located between the two arches
- Oriented such that the anterior aspect is more medial than the posterior
- Consist of superior and inferior articular processes
- Superior articular facet: concave and angles slightly medially
- Inferior articular facets: flat, oval shaped and face slightly medially
The vertebral foramen can be divided into thirds: One third is filled with the dens, another third with spinal cord and the remainder is ‘free space’, filled with adipose, vessels, ligaments and meninges.
Transverse Processes:
- Large and palpable between the mastoid and the angle of the mandible
- Single tubercle (not double like typical cervicals): Contains large foramen
- What features of the second cervical vertebrae make them atypical?
Axis
Peg shaped, 1.5 cm bone attached to the superior surface of the body of C2
Articular facet on anterior surface for articulation with the anterior arch of C1
Pedicles: Thick and attached toward the superior aspect of the body
Superior Articular Processes:
- Lie almost flush with the pedicle. Convex superiorly, with a central ridge and anterior and posterior aspects slope inferiorly
Transverse Processes:
- Small, without separate anterior and posterior bars/roots
- Face obliquely, superiorly and laterally
- Contain foramen which is an angular canal for the vertebral artery
- What features of the seventh cervical vertebrae makes them atypical?
Vertebra Prominens or C7
Spinous Process:
- Very prominent and projects directly posteriorly
- Not bifid
- Attachment site for many muscles (traps, rhomboids, serratus posterior, splenius, spinalis, semispinalis, multifidus, interspinales)
Transverse Processes:
- Small, short anterior tubercles and large posterior tubercle
- Pleural cupula attaches to posterior tubercle
- Foramina usually give passage to accessory arteries and veins only.
- List the articulations between the typical cervical vertebrae.
Zygapophyseal Joints:
- Facet joints lie at about 45 degrees to the horizontal plane.
- Upper cervical facet joints are angled at about 35 degrees to horizontal and lower cervical facet joints are angled at about 65 degrees to horizontal.
- Thin articular capsules which are much longer and looser than thoracic and lumbar regions
- Synovial folds project into all cervical facet joints
- Facet joints of the cervical spine are weight bearing
Intervertebral Joints: Note that there are no intervertebral joints between the occiput and atlas or the atlas and the axis.
- The annulus of the IVD, in the cervical spine, contains pain sensitive and proprioceptive fibre.
- The ALL is strongly attached to the cervical IVDs
- Cervical IVD are about 2/5 as tall as the vertebral bodies
Typical Cervical Articulations: - C2-T1 combined: Flexion/Extension: 91 degrees Side bending (unilateral): 51 degrees Rotation (unilateral): 33 degrees
Note that side bending is limited by the uncinate processes
- What are the parts of the transverse atlanto-axial ligament? What is its role?
Forms part of the cruiciate ligament.
Holds the dens on the posterior part of the anterior arch of the atlas.
The superior and inferior longititudanal parts hold the transverse part in place.
AKA Cruciform Ligament Cross shaped ligament composed of three parts:
Transverse ligament:
- Runs horizontally between the lateral masses of the atlas in the groove on the posterior aspect of the dens.
- Anterior surface lined by cartilage to form synovial joint with dens.
- Holds atlas in position and allows C1 to pivot on C2
- Prevents compression of the spinal cord during flexion of the head and neck
- Rupture (traumatic), laxity (RA) or agensis (Down’s) of the transverse part creates possibility of dens contacting spinal cord
Superior longitudinal band (SLB)
- Runs from the transverse ligament to the anterior rim of the foramen magnum.
- Maintains proper position of transverse ligament.
- Located between tectorial membrane and apical ligament of the odontoid process.
Inferior longitudinal band (ILB)
- Runs between the transverse ligament and the body of C2.
- Maintains proper position of transverse ligament.
SLB and ILB may act together to limit flexion of the occiput and atlas on the axis. An increase in this space is indicative if pathologic subluxation or tear of the transverse ligament.
- List the prevertebral muscles.
Longus Colli
- Commonly involved in loss of cervical lordosis and cervical extension injuries
- Vertical portion joins bodies, inferior oblique from T1-3 bodies to TP C5/6, superior oblique from TPC3-5 to anterior tubercle of atlas
Longus Capitis
- TPs C3-6 to occiput anterior to foramen magnum Rectus capitis anterior and lateralis
Scalenes: Join the upper ribs to the upper cervicals. - Anterior TP C4-6 to 1st rib - Middle C4-6TPs to 1st rib - Posterior C4-6 to 2nd rib.
Anterior scalene is very tendinous and unforgiving (difficult to stretch). The anterior and middle scalenes are closely related to the neurovascular bundle of the neck and may be implicated in thoracic outlet syndrome
Rectus capitis anterior and lateralis connect the C1 to the occiput
- List the muscles of the posterior compartment of the neck.
Trapezius Levator scrapulae Splenius capitis and cerivicus Semispinallis o TPs to SPs and occiput
Trapezius – very tendinous (touch, resilient) at CT junction Flat, continuous with ligt nuchae EOP, sup nuchal line, ligt nuchae, SPs to clavicle, spine of scap and acromion.
Fibres converge on deltoid tubercle of spine of scap Works synergistically with anterior muscles
Levator scapulae:
Medial scap to C3/4 Thick, cable like, powerful, Applies compression and shear, Acts as a guy wire.
Active stabiliser to prevent anterior shear (is this why the superior medial scap is always tender) analogous to deep ES in lumbars
Splenius (capitis SPs to occiput and cervicis SPs to TPs):
Thin, flat and almost indistinguishable from traps in the Cv region.
Attaches to mastoid (as does longissimus and SCM). These act to check motions of the head in all directions and minimise mvt during healing.
Semispinalis:
TPs to SPs and occiput Large, fusiform, workhorse.
Palpate between SPs and articular pillars/facets.
Maintains cervical lordosis (curve collapses without it).
Greater occipital nerve passes through Multifidus analogue
- List the suboccipital muscles. What is their innervation?
Innervated by suboccipital nerve (C1).
Fine tune and control head.
Alar lig.s ensure O-C2 acts as a unit.
Rectus capitis posterior major = C2 SP to inferior nuchal line.
Rectus capitis posterior minor = posterior tubercle of C1 to inferior nuchal line.
Inferior oblique = C2 SP to C1 TP.
Superior oblique = TP of C1 to occiput.
- List the names and locations of the deep layers of cervical fascia. What is the role of the deep cervical fascia?
Fascia
Platysma lies in the subcutaneous tissue, arising from deep delto-pectoral fascia to the mandible. Supplied by cervical branch of CNVII.
Deep cervical fascia has three layers:
investing, pretracheal, prevertebral.
- Investing layer: Most superficial, surrounds neck deep to subcutaneous fascia. Splits into deep & superficial layers to invest traps and SCM. Attaches to superior nuchal line, mastoid process, zygomatic arches, mandible, hyoid and Cv SPs superiorly and manubrium, clavicles, acromion and spine of scapula inferiorly. Continuous with the periosteum of C7 SP and nuchal ligament. (deep and superficial layers attach posterior and anterior forming suprasternal space)
- Pretracheal layer: Thin and limited to anterior neck. Muscular part surrounds strap muscles, Visceral part encloses thyroid, trachea and oesophagus and continues superiorly as buccopharangyeal fascia. Extends from hyoid to thorax, blending with fibres of pericardium. Continuous with fascia of pharynx and carotid sheaths. Thickening forms pulley for digastric.
- Prevertebral layer: Sheath for vertebral column and muscles. Fixed to cranial base. Blends with endothoracic fascia and fuses with ALL at about T3. Extends laterally as the axillary sheath surrounding the brachial plexus and axillary vessels. Invests cervical part of sympathetic trunks
Carotid sheath:
Blends with investing and prevertebral fascia anteriorly and prevertebral fascia posteriorly
Contains common and internal carotid arteries, IJV, vagus, some lymph nodes, carotid sinus nerve and sympathetic fibres.
Communicates freely with mediastinum and cranial cavity.
Retropharyngeal space is a large, important interfascial space. Potential space consisting of loose connective tissue between prevertebral and buccopharyngeal fascia. The alar fascia attaches to the midline of the buccopharyngeal fascia from cranium to C7 and blends with the carotid sheath, dividing the space.
Allows mvt of pharynx, oesophagus, larynx and trachea relative to vertebral column during swallowing.
Closed superiorly by cranial base, each side by carotid sheath. Opens into superior mediastinum.
- Which arteries supply structures in the neck?
The subclavian artery and common carotid arteries are both branches of the brachiocephalic trunk.
Common carotid:
Ascends in the neck, giving off no branches. Common divides into internal and external. Internal supplies the internal cranium. External gives of branches in neck to supply thyroid, pharynx, tongue, face and external head. Before its bifurcation is the expansion of the carotid sinus which contains pressure receptors to monitor blood pressure. The carotid body is found at the bifurcation – it monitors blood oxygen & CO2 levels and is supplied by CNIX & X. The external carotid supplies the neck and face.
Subclavian arteries:
Begin posterior to the SC joints, ascend through the superior thoracic aperture to enter the root of the neck. The apex is between the posterior and anterior scalenes; It then arches over the lateral border of the 1st rib to enter the upper extremity.
- Vertebral artery branches off and ascends between longus and scalenes.
- The thyrocervical trunk, internal thoracic artery and costocervical trunk are also branches of the subclavian.
Pathway of the vertebral artery?
First branch of subclavian artery.
Courses between longus colli and anterior scalene.
Enters TP of C6 & Ascends through foramina of TPs of C6 to C2.
After passing through the foramen of the TP of C2, it takes a 45 degree lateral turn to reach the more laterally placed transverse foramen of C1. Note that extension with rotation usually impairs blood flow between C1 and C2 in the vertebral artery on the opposite side.
Passes through foramen of C1 posterior and medial to rectus capitis lateralis.
Winds medially around superior articular process of C1 in a groove in the posterior arch, passing beneath posterior atlanto-occipital membrane (where a posterior ponticle may be present) .
Pierces dura and arachnoid and courses superiorly through foramen magnum.
- List the significant neural structures present in the neck.
Cervical Plexus:
The cervical plexus is formed by the anterior rami of C2-4 posterior to the SCM in the prevertebral fascia.
Nerves from this plexus supply the diaphragm, most of the hyoid muscles and the skin over the anterior and lateral neck, clavicle and shoulder to rib 2.
Note that there are 8 cervical nerve roots. The C1 emerges between the occiput and atlas. C8 emerges between C7 and T1.
Brachial Plexus:
Brachial plexus formed by the anterior rami of C5 – T1 forms between the anterior and middle scalenes and pass through the root of the neck into the upper extremity.
SNS:
Sympathetic nerves pass through the root of the neck.
Sympathetic trunk lies anterior to the longus muscles in the carotid sheath. Superior (C2), middle (C6) and inferior (C7) cervial ganglia form part of the trunk. The inferior ganglion frequently combines with the first thoracic ganglion as the stellate ganglion anterior to the neck of rib 1 and TP of C7.
The paraspinal sympathetic trunk contains superior, middle and inferior cervical ganglia. Small nociceptive fibers travel with the sympathetics and synapse in the upper thoracic cord. Nociceptive input from the cervical spine can cause mm-sk change in upper thoracic spine and ribs.
- Where is the vertebral artery most vulnerable?
The vertebral artery artery is most vulnerable;
- at the acute angulation at C6-7
- to productive change in and around the intertransverse foramen of C6-1
- at the atlanto-occipital junction
Describe cervical hyper extension:
Forceful extension may crush the vertebral arch or cause hangman’s fracture or may rupture the ALL or anulus of the disc
