1. PHARYNX, CRANIOVERTEBRAL JOINTS, PREVERTEBRAL REGION
STEVEN J. ZEHREN, PH.D.

2. SUBDIVISIONS OF PHARYNX

3. C6 Sphenoid sinus Pharyngeal tubercle of occipital bone NASOPHARYNX
Soft palate
OROPHARYNX
Root of tongue
Epiglottis
Vertebral bodies
LARYNGOPHARYNX C6
The pharynx is part of both the respiratory and digestive systems (ie, parts of the pharynx transmit both air and food). It is divided into three parts: 1) nasopharynx (behind the nasal cavity) which extends from the sphenoid and occipital bones (above) to the soft palate (below) 2) oropharynx (behind the oral cavity) which extends from the soft palate to the epiglottis and 3) laryngopharynx (behind the larynx) which extends from the epiglottis to the lower border of the cricoid cartilage. The laryngopharynx is continuous with the esophagus below (at level of CV6), but anteriorly it opens into the larynx.
2. Thus the pathway for air flow is nasal cavity > nasopharynx > oropharynx > laryngopharynx > larynx > trachea.
3. The pathway for food is oral cavity > oropharynx > laryngopharynx > esophagus.
Cricoid cartilage
Trachea
Esophagus

4. PHARYNX IN POSTERIOR VIEW
Base of skull
(5 cm)
Note how the pharynx tapers (funnel-shaped) from the base of the skull (widest part, 5 cm.) to its junction with the esophagus (narrowest part of entire digestive tract, 1.5 cm.). Is it any wonder that a bolus of food or foreign object might become trapped at this point?
CV6
(1.5 cm)
Esophagus

5. NASOPHARYNX (MUCOSA INTACT)
Pharyngeal tonsil
Orifice of auditory tube
Choana
Pharyngeal recess
Torus tubarius
Torus levatorius
Salpingopharyngeal fold
Uvula
Pharyngeal
isthmus
The SUPERFICIAL FEATURES OF THE NASOPHARYNX are seen in this plate.
In the lateral wall of the nasopharynx is the OPENING OF THE AUDITORY TUBE. The TORUS TUBARIUS is a mucosal bulge just above the opening of the auditory tube and is produced by the underlying cartilage of the tube. Posterior to the torus is a blind cul-de-sac, the PHARYNGEAL RECESS. Cancers sometimes develop here. In the roof of the nasopharynx is a mass of lymphatic tissue, the (NASO)PHARYNGEAL TONSIL. The nasopharyngeal tonsil can become swollen ("adenoids") to the point that the respiratory passage is blocked and the child must breathe through the mouth. If not treated, persistent mouth breathing can lead to malgrowth of the face. The tonsils involute after puberty.
Note also the torus levatorius and salpingopharyngeal fold. These mucosal elevations are produced by underlying muscles.
3. The opening connecting the nasopharynx with the nasal cavity is the choana (pleural choanae); that connecting the nasopharynx with the oropharynx is the pharyngeal isthmus. The pharyngeal isthmus is bounded anteriorly by the uvula (of soft palate) and posteriorly by the wall of the pharynx.

6. NASOPHARYNX (MUCOSA REMOVED)
Cartilage of auditory tube
Tensor (veli) palatini
Levator (veli) palatini
Salpingopharyngeus
The PHARYNGEAL MUCOSA HAS BEEN REMOVED TO EXPOSE THE UNDERLYING MUSCLES AND OTHER STRUCTURES. Note the cartilage of the auditory tube and three muscles: tensor palati, levator palati and salpingopharyngeus. These muscles are used in swallowing.

7. PHARYNGOTYMPANIC (AUDITORY) TUBE
Orient: Coronal Section
The auditory tube connects the nasopharynx with the tympanic (middle ear) cavity; hence it is also known as the pharyngotympanic tube. It serves to equalize pressure in the middle ear with the atmospheric pressure. It also acts as a conduit for the spread of infection into the middle ear!
Nasopharynx
Tympanic cavity
Pharyngotympanic (auditory) tube

8. OROPHARYNX IN ANTERIOR VIEW
(BOUNDARIES OF OROPHARYNGEAL ISTHMUS)
Soft palate
Palatoglossal arch
Dorsum of tongue
The opening by which the oropharynx communicates with the oral cavity is the OROPHARYNGEAL ISTHMUS. This opening is bounded by the soft palate above, dorsum of the tongue below, and on the sides by the palatoglossal arches.

9. Median glossoepiglottic fold Lateral glossoepiglottic fold
Epiglottis
Median glossoepiglottic fold
Lateral glossoepiglottic fold
Vallecula
Palatopharyngeal arch
Palatine tonsil
Lingual tonsil
Root
Palatoglossal arch
The lateral wall of the oropharaynx is marked by two folds (arches), the palatoglossal arch and the palatopharyngeal arch. These arches are folds of mucosa covering muscles of the same name. Between the arches is the palatine tonsil. (The tonsil has crypts (tubular indentations) which open onto its medial surface).
The post. one-third of the tongue (root) lies in the oropharynx and is rough due to nodules of lymphatic tissue (lingual tonsil).
Note the median and lateral glossoepiglottic folds of mucosa with the vallecula in between. During surgery, an intubation tube can be secured by hooking it into the valleculae.
Body

10. TONSILLAR BED Tonsillar br. of facial a. Superior constrictor
External palatine
(paratonsillar) v.
Glossopharyngeal n. (IX)
Orient: Lateral wall of oropharynx with palatine tonsil and mucosa removed. Point out palatoglossus and palatopharyngeus muscles, and posterior 1/3 of tongue (not labelled).
The palatine tonsil lies in the tonsillar bed, the muscular part of which is formed by the sup. pharyngeal constrictor m. Other structures lying in the tonsillar bed include IX (which is sensory to the tonsil and post. 1/3 of the tongue), the ext. palatine v. (paratonsillar v.) and numerous (five) small tonsillar aa.(including the tonsillar br. of the facial a.) With such a rich blood supply it is not surprising that hemorrhage during tonsillectomy can be severe. Patients may experience a temporary loss of sensation on the post. one-third of the tongue following tonsillectomy due to edema and compression of IX.

11. TONSILLAR BED Superior constrictor Styloid process &
Stylohyoid ligament
The styloid pr. may be very long and extend into the region of the palatine tonsil. This can impinge on the tonsil and cause pain.
Lesser horn
of hyoid bone

12. Peritonsillar Abscess
Note the position of the peritonsillar abscess. It is located just lateral to the palatine tonsil and just medial to the superior constrictor m. If the abscess broke through the superior constrictor m., it would enter the lateral pharyngeal space, and from there could spread into the retropharyngeal space.

13. with fold over internal laryngeal n.
Choanae
NASOPHARYNX
Soft palate
OROPHARYNX
Root of tongue
Orient: The POST. WALL OF THE PHARYNX HAS BEEN SPLIT IN THE MIDLINE AND REFLECTED LATERALLY.
The relationships of the three parts of the pharynx to each other and to the cavities with which the pharynx communicates are well displayed. Note the choanae for communication with the nasal cavity and the aditus (inlet) of the larynx (bounded on either side by the aryepiglottic folds). On either side of the aditus is a blind cul-de-sac, the piriform recess. These recesses act as lateral food channels during swallowing. Just deep to the mucosa of the recess is the internal laryngeal n. This is a very imp. sensory nerve to the upper part of the larynx. It can be damaged when trying to extract a sharp fish bone, etc. which has become lodged in the piriform recess.
Epiglottis
Aryepiglottic fold
LARYNGOPHARYNX
Piriform recess
with fold over internal
laryngeal n.

14. NERVES DEEP TO MUCOSA OF PIRIFORM RECESS
Internal laryngeal n.
Recurrent laryngeal n.
With the mucosa removed, note the internal laryngeal n. in the region of the piriform recess.

15. WALDEYER’S RING Orient:
The pharynx is characterized by a ring of lymphatic tissue (Waldeyer's ring): superiorly the (naso)pharyngeal tonsil, inferiorly the lingual tonsil and laterally the two palatine tonsils. The function of this ring is to produce antibodies to ingested and inspired bacteria.

16. WALL OF PHARYNX Mucous membrane Pharyngobasilar fascia Muscle layer
Buccopharyngeal fascia
1. The WALL OF THE PHARYNX consists of FOUR LAYERS: 1) MUCOSA (innermost) 2) PHARYNGOBASILAR FASCIA
(esp. thick near the base of the skull) 3) MUSCULAR (with inner longitudinal and outer circular parts) and
4) BUCCOPHARYNGEAL FASCIA (outermost).
I will concentrate on the muscular layer.

17. MUSCLES OF PHARYNX

18. THREE PHARYNGEAL CONSTRICTOR MUSCLES
Superior constrictor
Pterygomandibular raphe
Middle constrictor
Inferior constrictor
The OUTER LAYER OF PHARYNGEAL MUSCLES is composed of the THREE CONSTRICTORS. The fibers of the constrictors are circularly arranged with the inf. constrictor overlapping the mid. constrictor, and the mid. constrictor overlapping the sup. constrictor (like three stacked flower pots). The constrictors take their origin from bones and cartilages anteriorly and sweep back to a common insertion into a median raphe posteriorly. Thus, they contribute to the lat. and post. walls of the pharynx but not to the ant. wall.
Esophagus

19. Pterygomandibular raphe
Superior pharyngeal constrictor m.
Middle pharyngeal constrictor m.
The SUP. CONSTRICTOR M. originates from the pterygomandibular raphe and the bone at either end of the raphe (ie, the pterygoid hamulus and the post. end of the mylohyoid line of the mandible). The raphe also serves for part of the origin of the buccinator m.
2. The MID. CONSTRICTOR M. originates from the hyoid bone and the lower end of the stylohyoid lig.
 3. The INF. CONSTRICTOR M. has two parts: 1) THYROPHARYNGEUS (originates from thyroid cartilage) and 2)
CRICOPHARYNGEUS (originates from cricoid cartilage). The cricopharyngeus acts as a sphincter to prevent air
from entering the esophagus (causing "gas"). Clinically the cricopharyngeus is imp. because it may undergo spasm
leading to obstruction of the food channel. As a result an outpocketing of the pharyngeal wall (HYPOPHARYNGEAL
DIVERTICULUM) may develop. Such a diverticulum may become so large that it may interfere with the nutrition of the
individual and have to be treated surgically!
All three constrictor muscles insert into a midline raphe in the posterior wall of the pharynx.
Hyoid bone
Inferior pharyngeal constrictor m.
Zone of sparse muscle fibers
Thyroid cartilage
Cricopharyngeus m.
(part of inferior constrictor m.)
Cricoid cartilage

20. pharyngotympanic tube Styloid process
Cartilaginous part of
pharyngotympanic tube
Styloid process
Stylopharyngeus m.
Salpingopharyngeus m.
Palatopharyngeus m.
Pharyngobasilar fascia
Pharyngeal raphe
Stylopharyngeus m.
Superior constrictor m.
Orient: Posterior wall of pharynx split in midline and reflected laterally on one side.
The INNER LONGITUDINAL LAYER OF PHARYNGEAL MUSCLES is composed of the stylopharyngeus, palatopharyngeus and salpingopharyngeus. The STYLOPHARYNGEUS descends from the styloid pr. and passes between the sup. and mid. constrictor mm. (useful relationship for identifying the constrictor mm. in lab).
The PALATOPHARYNGEUS descends from the palate. The stylo- and palatopharyngeus blend inferiorly and have a common insertion into the thyroid cartilage and wall of the pharynx.
The SALPINGOPHARYNGEUS is a tiny muscle which descends from the cartilage of the auditory tube ("salpinx" means tube) and blends with the palatopharyngeus.
Middle constrictor m.
Longitudinal pharyngeal mm.
Inferior constrictor m.
Posterior border of thyroid cartilage lamina
Cricopharyngeus m.

21. (Mechanism of Swallowing)
Tensor palati m.
Levator palati m.
Salpingopharyngeus m.
Passavant’s ridge
Superior constrictor m.
Palatopharyngeus m.
Stylopharyngeus m.
Mylohyoid m.
Middle constrictor m.
Optional (Can discuss or students could study this slide on their own).
Orient: Median section.
SWALLOWING (DEGLUTITION) can be described in three stages. In the FIRST STAGE, which is voluntary and occurs in the mouth, the bolus of food is pushed back into the oropharynx by the tongue and mylohyoid mm.
The SECOND STAGE is involuntary and occurs in the pharynx. This is a rapid and complex stage. The respiratory passage is closed off both below (at the laryngeal inlet) and above (at the pharyngeal isthmus). The pharyngeal isthmus is closed by pulling the soft palate against the post. pharyngeal wall. The tensor and levator palati mm. move the soft palate while the uppermost fibers of the palatopharyngeus m. (Passavant's ridge) pull the pharyngeal wall forward. The pharynx is then elevated by the three longitudinal muscles (stylo-, palato- and salpingopharyngeus) to receive the bolus. This is followed by the serial contraction of the three constrictors which push the bolus toward the esophagus.
The THIRD STAGE occurs in the esophagus. It is also involuntary and occurs rapidly. Peristaltic action of the esophageal musculature forces the bolus inferiorly toward the stomach.
Optional:
The origin of the mid. constrictor from the hyoid bone and stylohyoid lig. is well illustrated.
Inferior constrictor m.
Cricopharyngeus m.
Circular esophageal m.

22. FOUR GAPS IN THE PHARYNGEAL MUSCULATURE
Levator palati
Superior constrictor
Stylopharyngeus & IX
Middle constrictor
Internal laryngeal n.
& superior laryngeal a.
Various structures pass through gaps in the pharyngeal musculature:
1. Levator palati m. passes through the gap between the base of the skull and the sup. constrictor m.
2. Stylopharyngeus m. and IX pass through the gap between the sup. and mid. constrictor mm.
3. Int. laryngeal n. and sup. laryngeal a. pass through the gap between the mid. and inf. constrictor mm.
4. Rec. laryngeal n. and inf. laryngeal a. pass deep to the inferior border of the inf. constrictor m.
Inferior constrictor
Recurrent laryngeal n.
& inferior laryngeal a.

23. NERVES OF PHARYNX

24. MOTOR INNERVATION OF PHARYNX
Glossopharyngeal n.
(to stylopharyngeus)
Pharyngeal branch of X
(to other pharyngeal mm.) X
The MOTOR INNERVATION TO THE PHARYNGEAL MUSCLES is via IX and X. The STYLOPHARYNGEUS (shown but not labelled) is innervated by a small twig from the glossopharyngeal n. (IX). Note how IX "winds around" the stylopharyngeus on its way to the tongue. ALL OF THE OTHER PHARYNGEAL MM. receive their innervation from the pharyngeal br. of X. (In both cases the functional component is SVE).

25. (Medial view) Trigeminal (V2)
via pharyngeal branch of pterygopalatine ganglion
Glossopharyngeal (IX)
via pharyngeal plexus
via tonsillar branches
taste plus general
sensation via
lingual branches
The SENSORY INNERVATION OF THE PHARYNX is via three cranial nerves. ABOVE THE ORIFICE OF THE AUDITORY TUBE the nerve supply is V2 (GSA). BETWEEN THE AUDITORY TUBE AND LARYNGEAL INLET the innervation is by IX (GVA). BELOW THE LARYNGEAL INLET the innervation is by X (also GVA). There may be some overlap in the regions supplied.
The GAG REFLEX is elicited when the posterior wall of the oropharynx is touched (eg, with a toothbrush). This causes elevation of the soft palate and movement of the tongue. The afferent limb of the reflex is IX (and perhaps X); the efferent limb involves X and XII.
Vagus (X)
via internal laryngeal n.
Trigeminal n. (V)
Glossopharyngeal n. (IX)
Vagus n. (X)
Facial n. (VII)

26. PHARYNGEAL PLEXUS OF NERVES
Pharyngeal br. of IX (GVA)
Pharyngeal br. of X (SVE)
The PHARYNGEAL PLEXUS OF NERVES is a network of fibers located primarily on the mid. constrictor m. It receives
contributions from three sources: 1) pharyngeal br. of IX (GVA, sensory to mucosa of pharynx) 2) pharyngeal br. of
X (SVE, motor to most of the pharyngeal muscles) and 3) pharyngeal br. of sup. cervical sympathetic ganglion
(not shown)(GVE, vasomotor).

27. BLOOD SUPPLY & LYMPHATICS
OF PHARYNX

28. ARTERIAL SUPPLY TO PHARYNX
Ascending pharyngeal a.
Superior constrictor m.
Ascending pharyngeal a.
The ARTERIAL SUPPLY TO THE PHARYNX is from the ascending pharyngeal a. and the sup. and inf. thyroid aa.
Superior thyroid a.
Inferior thyroid a.

29. VENOUS DRAINAGE OF PHARYNX
The PHARYNGEAL PLEXUS OF VV. lies on the post. wall of the pharynx. This plexus drains into the IJV.

30. Retropharyngeal nodes
Jugulodigastric node
Superior deep cervical
nodes
LYMPHATIC DRAINAGE OF THE PHARYNX is to the retropharyngeal and sup. deep cervical nodes. The jugulodigastric node (the uppermost deep cervical node) receives most of the lymph from the palatine tonsil and is therefore sometimes referred to as the tonsillar node.

31. RELATIONSHIPS
OF PHARYNX

32. NEUROVASCULAR RELATIONSHIPSXI IX
XII
Sympathetic trunk
Com. & int. carotid aa.,
IJV, X
1. The last four cranial nerves and the sympathetic trunk are related to the pharynx.
2. IX winds around stylopharyangeus m.
X descends in carotid sheath (look also for sup. laryngeal br. of X)
XI passes into deep surface of SCM.
XII curves inferiorly and anteriorly toward tongue, crossing lateral to both carotid aa. (Note that XII is closely bound to
X at skull base and at first appears to be a branch of X).
3. Sympathetic trunk has been pulled medially in this slide. It lies just posterior to carotid sheath.

33. CRANIOVERTEBRAL JOINTS

34. AXIS (C2): POSTEROSUPERIOR VIEW
Ant. tubercle
Facet for dens
Ant. arch
Lateral mass
Transverse pr.
Tubercle for
transverse lig.
Transverse foramen
Post. arch
Sup. facet for
occipital condyle
Post. tubercle
Groove for vertebral a.
ATLAS (C1): SUPERIOR VIEW
Dens
Post. facet for
transverse lig.
Sup. facet for atlas
Atlas:
a. Atlas is essentially a ring of bone, consisting of two lateral masses connected by ant. and post. arches.
b. Transverse processes project further laterally than other cervical vertebrae (giving mechanical advantage to muscles that attach to it (eg., inf. oblique). Transverse foramen for passage of vertebral a.
c. Ant. tubercle is for attachment of ant. longitudinal lig. and upper end of longus colli m.
d. Atlas has no spine, just a post. tubercle on post. arch.
e. Post. arch has groove for vertebral a.
f. Lateral masses have concave, kidney-shaped facets superiorly for reception of the occipital condyles.
g. Each lateral mass also has a tubercle for attachment of the transverse ligament of the atlas which runs from one lateral mass to the other.
h. Anterior arch has a facet on its posterior aspect for articulation w/ the dens.
2. Axis
a. Strongest of cervical vetebrae.
b. Has two large, flat bearing surfaces, superior articular facets, for articulation w/the atlas above.
c. Dens (odontoid process) represents body of atlas and projects superiorly to articulate with the ant. arch of the atlas. Dens also has a facet on its posterior aspect for the transverse lig. of the atlas.
d. Spinous process of axis is large and bifid.
Body
Interarticular part
Transverse pr.
Inf. articular pr.
Spinous pr.
AXIS (C2): POSTEROSUPERIOR VIEW

35. Atlas and Axis (superior view) Dens Facet for occipital condyle C1 C2
transverse
ligament C3
The joints between the sup. articular facets of the atlas and the occipital condyles are the ATLANTOOCCIPITAL (AO) JOINTS. Together the two joints act as an ELLIPSOID JOINT. They permit flexion and extension of the head, as well as lateral flexion (bending to the side).
There are three ATLANTOAXIAL (AA) JOINTS. The TWO LAT. AA JOINTS are between the inf. articular facets of the atlas and the sup. articular facets of the axis. These are GLIDING JOINTS. The MEDIAN AA JOINT is a PIVOT JOINT. It is formed by the articulation between the dens and the ant. arch of the atlas, and between the dens and the transverse lig. of the atlas . When one rotates the head from side to side (eg, shaking the head "no"), the skull + atlas rotate together around a central stationary pivot --- the dens. C4
Lateral atlanto-axial joints (gliding)
Median atlanto-axial joint (pivot)
Atlanto-occipital Joints (Ellipsoid)
Allow flexion/extension of head (nodding “yes”)
Allow lateral flexion of head

36. ROTATION OF THE HEAD OCCURS AT THE ATLANTO-AXIAL JOINTS

37. Spinous processes and parts of vertebral
arches removed: posterior view
Basilar part of occipital bone
Tectorial membrane
Capsule of AO
joint
Deeper (accessory part) of tectorial membrane
Atlas (C1)
Posterior longitudinal ligament
Capsule of lateral
AA joint
Alar ligaments
Axis (C2)
Capsule of
zygopophysial joint
(C2-C3)
Left side of plate
The POST. LONGITUDINAL LIG. runs along the post. surfaces of the vertebral bodies within the vertebral canal. Its upward continuation (above the axis) is the TECTORIAL MEMBRANE.
Right side of plate
Deep to the tectorial membrane are some imp. ligaments related to the median AA joint. The thick TRANSVERSE LIG. OF THE ATLAS holds the dens against the ant. arch of the atlas. The SUP. & INF. LONGITUDINAL FIBERS pass to the ant. margin of the f. magnum and the body of the axis (resp.). The transverse lig. + the sup. and inf. longitudinal fibers form the CRUCIFORM LIG. The strong ALAR LIGS. pass superolaterally from the dens to the med. aspects of the occipital condyles.
Atlas (C1)
Superior longitudinal band
CRUCIATE
LIGAMENT
Transverse ligament of atlas
Axis(C2)
Inferior longitudinal band
Deeper (accessory part)
of tectorial membrane
Principal part of tectorial membrane
removed: posterior view

38. Apical ligament of dens
Atlas (C1)
Apical ligament of dens
Alar ligament
Facet of dens
(for transverse lig.)
Anterior tubercle of atlas
Alar ligament
Synovial cavities
Axis (C2)
Dens
ON THE LEFT SIDE OF THE PLATE note the ALAR LIGS. These ligs. are also known as "check ligs." because they function to check (restrict) the amount of rotation at the median AA joint. Rupture of an alar ligament results in an increase of ~ 30% in the range of movement to the contralateral side (COA, 5th ed., p.510)
ON THE RIGHT SIDE OF THE PLATE note the TRANSVERSE LIG. OF THE ATLAS. Along with the ant. arch of the atlas,
the transverse lig. forms a fibrous/bony ring surrounding the dens of the axis. This ring rotates around the dens forming
a pivot joint. By keeping the dens against the ant. arch of the atlas, the transverse lig. prevents the dens from post.
displacement which could damage the spinal cord.
Cruciate ligament removed:
posterior view
Transverse ligament
of atlas
Median atlantoaxial joint: superior view

39. CLINICAL CORRELATIONS

40. FRACTURE & DISLOCATION OF THE ATLAS (JEFFERSON OR BURST FRACTURE)
(On left) Note that the lateral masses are wedge-shaped, with the thick sides of the wedges directed laterally. Thus, vertical compressive forces (as would result from striking the bottom of a pool in a diving accident) tend to drive the lateral masses laterally (arrows), fracturing one or both of the bony arches of the atlas. If the force is great enough, the transverse ligament of the atlas will also rupture. This type of fracture is called a Jefferson (or burst) fracture.
2. Coronal section (on right) showing direction of vertical compressive forces and lateral movement of the lateral masses of
the atlas resulting in a Jefferson fracture.

41. FRACTURE & DISLOCATION OF THE ATLAS (JEFFERSON OR BURST FRACTURE)
Note the fractures of both the anterior and posterior arches of the atlas, and the lateral displacement of the lateral masses.
2. A Jefferson fracture in itself does not necessarily result in spinal cord injury, b/c the dimensions of the bony ring actually increase. Spinal cord injury is more likely, however, if the transverse ligament is also ruptured.

42. PREVERTEBRAL MUSCLES

43. Rectus capitis anterior m.
Basilar part
of occipital bone
Longus capitis m. (cut)
Occipital condyle
Jugular process
of occipital bone
Rectus capitis anterior m.
Rectus capitis lateralis m.
Transverse process of atlas
Longus capitis m.
Longus colli m.
Students should study this slide on their own
1. O ,I, F of prevertebral mm.
a. Longus colli m.
O – upper thoracic and lower cervical vertebrae
I - cervical vertebrae (more superiorly) (reaches as high as the ant. tubercle of the atlas)
F – flexes neck
b. Longus capitis m.
O – ant. tubercles of transverse prs. of C3 – C6
I - basilar part of occipital bone
F – flexes head
c. Rectus capitis anterior
O – lateral mass of atlas
d. Rectus capitis lateralis
O - transverse process of atlas
I - jugular process of occipital bone
All of the prevertebral muscles are innervated by the ventral rami of cervical nerves.

44. CERVICAL PART OF
SYMPATHETIC TRUNK

45. Superior cervical ganglion
Internal carotid n.
Superior cervical ganglion
External carotid a. & plexus
Gray rami communicantes
Students should review this material on their own
The CERVICAL PART OF THE SYMPATHETIC TRUNK consists of three (sometimes four) ganglia and the longitudinal fibers interconnecting them. This part of the trunk lies post. to the carotid sheath and ant. to the prevertebral mm. (shown but not labelled). The trunk consists largely of ascending presynaptic fibers, the somata of which lie in the lateral horn of the upper thoracic part of the spinal cord. Synapse occurs in either the sup., mid. or inf. cervical ganglia (sometimes there is a fourth ganglion, the vertebral, between the mid. and inf. ganglia). The inf. ganglion is usually (82%) fused with the first thoracic ganglion to form the cervicothoracic (stellate or star-shaped) ganglion. The ansa subclavia is a nerve which loops around the subclavian a. on each side. It connects the inf. cervical (or stellate) ganglion with the vertebral ganglion (as shown here) or the mid. cervical ganglion. Postsynaptic fibers reach structures in the head and neck by several routes including 1) gray rami communicantes to the cervical spinal nerves and 2) traveling along arteries.
A GRAY RAMUS COMMUNICANS passes to each cervical spinal nerve. This is true even though there are only three or four cervical ganglia but eight cervical nerves. (The presence of only three or four ganglia is due to the embryonic fusion of separate primordia). The gray rami joining C1-C4 arise from the sup. ganglion and are distributed in part via the cervical plexus to smooth muscle and glands in the skin.
3. TRAVELING ALONG THE INT. & EXT. CAROTID AA. & THE VERTEBRAL A. ARE PLEXUSES OF POSTSYNAPTIC
SYMPATHETIC FIBERS. These plexuses use the arteries as "vehicles" to reach involuntary structures (smooth m. and
gls.) in the head and neck. In addition the plexuses supply the arteries themselves (vasomotor).
Middle cervical ganglion
Vertebral ganglion
Vertebral a. & plexus
Cervicothoracic (stellate) ganglion
Ansa subclavia

46. HORNER’S SYNDROME Int. carotid a. & plexus SYMPTOMS:
1. MIOSIS (PARALYSIS OF
DILATOR PUPILLAE M.)
2. PTOSIS (PARALYSIS OF
SUPERIOR TARSAL M.)
3. REDNESS & INCREASED
TEMPERATURE OF SKIN
(VASODILATION)
4. ANHIDROSIS (SWEAT GLS.
CAN’T SECRETE)
Sup. cervical
ganglion
Students should review this material on their own
HORNER'S SYNDROME is a series of signs which occur following a lesion to the cervical part of the sympathetic trunk. These signs include 1) miosis (pupillary constriction) 2) ptosis (drooping upper eyelid) 3) anhidrosis (no sweating) and 4) vasodilation (flushing of facial skin). These signs occur on the same side as the lesion.
Sympathetic trunk
Facial a. & plexus
Ext. carotid a.
& plexus

47. LAB PREVIEW

48. 1. REMOVE ALL MUSCULATURE FROM OCCIPITAL BONE &
POSTERIOR ARCH OF ATLAS.

49. 2. REMOVE WEDGE OF OCCIPITAL BONE

50. 3. REMOVE POST. ARCH OF ATLAS, TRANSECT & REMOVE CERVICAL
SPINAL CORD & ASSOCIATED MENINGES.
4. CUT & REFLECT TECTORIAL MEMBRANE INFERIORLY.
5. CUT ALAR LIGS. & SUP. LONGITUDINAL BAND.
6. DISARTICULATE AO JOINTS W/ HAMMER & CHISEL.
Spinous processes and parts of vertebral
arches removed: posterior view
Basilar part of occipital bone
Tectorial membrane
Capsule of AO
joint
Deeper (accessory part) of tectorial membrane
Atlas (C1)
Posterior longitudinal ligament
Capsule of lateral
AA joint
Alar ligaments
Axis (C2)
Capsule of
zygopophysial joint
(C2-C3)
Atlas (C1)
Superior longitudinal band
CRUCIATE
LIGAMENT
Transverse ligament of atlas
Axis(C2)
Inferior longitudinal band
Deeper (accessory part)
of tectorial membrane
Principal part of tectorial membrane
removed: posterior view

51. 7. CUT PREVERTEBRAL MUSCLES THAT INSERT INTO SKULL.

52. 8. WORK YOUR HANDS INTO RETROPHARYNGEAL SPACE,
AND PULL CERVICAL VISCERA AND HEAD FORWARD AWAY FROM
VERTEBRAL COLUMN.

53. END OF LECTURE