Download The Salivary Glands

630 CHAPTER 11 The Head and Neck
TA B L E 1 1 . 9
Muscles of the Soft Palate
Muscle
Origin
Insertion
Nerve Supply
Action
Tensor veli palatini
Spine of sphenoid,
auditory tube
With muscle of other
side, forms palatine
aponeurosis
Nerve to medial pterygoid
from mandibular nerve
Tenses soft palate
Levator veli palatini
Petrous part of temporal
bone, auditory tube
Palatine aponeurosis
Pharyngeal plexus
Raises soft palate
Palatoglossus
Palatine aponeurosis
Side of tongue
Pharyngeal plexus
Pulls root of tongue
upward and backward,
narrows oropharyngeal
isthmus
Palatopharyngeus
Palatine aponeurosis
Posterior border of
thyroid cartilage
Pharyngeal plexus
Elevates wall of pharynx,
pulls palatopharyngeal
folds medially
Musculus uvulae
Posterior border of hard
palate
Mucous membrane of
uvula
Pharyngeal plexus
Elevates uvula
The Salivary Glands
Parotid Gland
The parotid gland is the largest salivary gland and is composed mostly of serous acini. It lies in a deep hollow below
the external auditory meatus, behind the ramus of the
nasal septum
mandible (Fig. 11.85), and in front of the sternocleidomastoid muscle. The facial nerve divides the gland into
superficial and deep lobes. The parotid duct emerges from
the anterior border of the gland and passes forward over
the lateral surface of the masseter. It enters the vestibule of
the mouth upon a small papilla opposite the upper second
molar tooth (Fig. 11.72).
superior concha
middle
concha
inferior
concha
communication
between nasal
and mouth
cavities
palatal process
of maxilla
mouth
cavity
mouth
cavity
tongue
1
2
3
palatal process
of maxilla
A
primary
palate
palatal
processes
of the
maxilla
1
primary
palate
primary palate
incisive
foramen
future
hard
palate
2
nasal septum
B
nasal
cavity
nasal
cavity
formation of
secondary palate
3
4
soft
palate
uvula
FIGURE 11.82 A. The formation of the palate and the nasal septum (coronal section). B. The different stages in the formation
of the palate.
Basic Anatomy 631
C L I N I C A L
N O T E S
Parotid Duct Injury
A
B
The parotid duct, which is a comparatively superficial structure on the face, may be damaged in injuries to the face or
may be inadvertently cut during surgical operations on the
face. The duct is about 2 in. (5 cm) long and passes forward
across the masseter about a fingerbreadth below the zygomatic arch. It then pierces the buccinator muscle to enter the
mouth opposite the upper second molar tooth.
C L I N I C A L
C
D
N O T E S
Parotid Salivary Gland and Lesions of the Facial
Nerve
The parotid salivary gland consists essentially of superficial
and deep parts, and the important facial nerve lies in the interval between these parts. A benign parotid neoplasm rarely, if
ever, causes facial palsy. A malignant tumor of the parotid is
usually highly invasive and quickly involves the facial nerve,
causing unilateral facial paralysis.
Parotid Gland Infections
E
FIGURE 11.83 Different forms of cleft palate: cleft uvula (A),
cleft soft and hard palate (B), total unilateral cleft palate and
cleft lip (C), total bilateral cleft palate and cleft lip (D), and
bilateral cleft lip and jaw (E).
Nerve Supply
Parasympathetic secretomotor supply arises from the glossopharyngeal nerve. The nerves reach the gland via the
tympanic branch, the lesser petrosal nerve, the otic ganglion, and the auriculotemporal nerve.
The parotid gland may become acutely inflamed as a result of
retrograde bacterial infection from the mouth via the parotid
duct. The gland may also become infected via the bloodstream, as in mumps. In both cases, the gland is swollen; it is
painful because the fascial capsule derived from the investing layer of deep cervical fascia is strong and limits the swelling of the gland. The swollen glenoid process, which extends
medially behind the temporomandibular joint, is responsible
for the pain experienced in acute parotitis when eating.
Frey’s Syndrome
Frey’s syndrome is an interesting complication that sometimes develops after penetrating wounds of the parotid
gland. When the patient eats, beads of perspiration appear
on the skin covering the parotid. This condition is caused
by damage to the auriculotemporal and great auricular
nerves. During the process of healing, the parasympathetic
secretomotor fibers in the auriculotemporal nerve grow
out and join the distal end of the great auricular nerve.
Eventually, these fibers reach the sweat glands in the
facial skin. By this means, a stimulus intended for saliva
production produces sweat secretion instead.
Submandibular Gland
FIGURE 11.84 Cleft hard and soft palate. (Courtesy of R.
Chase.)
The submandibular gland consists of a mixture of serous
and mucous acini. It lies beneath the lower border of the
body of the mandible (Fig. 11.86) and is divided into
superficial and deep parts by the mylohyoid muscle. The
deep part of the gland lies beneath the mucous membrane
of the mouth on the side of the tongue. The submandibular
632 CHAPTER 11 The Head and Neck
temporalis
zygomatic arch
superficial
parotid gland
temporal vein
accessory part of
parotid gland
posterior
parotid duct
auricular vein
external jugular vein
orbicularis oris
angle of mandible
buccinator
sternocleidomastoid
masseter
A
superior constrictor of pharynx
carotid sheath
vagus nerve
internal carotid artery
internal jugular vein
styloglossus
auriculotemporal nerve
glossopharyngeal nerve
accessory nerve
fascial capsule
fibrous capsule
stylomandibular ligament
hypoglossal nerve
stylopharyngeus
styloid process
stylohyoid
division of external
carotid artery
posterior auricular artery
posterior belly
of digastric
medial pterygoid
formation of
retromandibular vein
mastoid process
ramus of mandible
masseter
skin
deep part of parotid gland
facial nerve
sternocleidomastoid
parotid lymph nodes
B
great auricular nerve
superficial part of parotid gland
FIGURE 11.85 Parotid gland and its relations. A. Lateral surface of the gland and the course of the parotid duct. B. Horizontal
section of the parotid gland.
Basic Anatomy 633
deep part of submandibular gland
tongue
submandibular duct
stylohyoid
opening of submandibular duct
central incisor tooth
sublingual gland
mylohyoid
posterior belly of digastric
body of mandible
anterior belly of digastric
A
super ficial part of submandibular gland
fibrous band
mouth cavity
styloglossus
hyoid bone
muscles of tongue
fibrous septum
vestibule
genioglossus
geniohyoid
deep part of submandibular gland
mylohyoid
mylohyoid
super ficial part of submandibular gland
anterior belly of digastric
submandibular duct
inferior alveolar nerve
B buccinator
C
sublingual gland
FIGURE 11.86 A. Submandibular and sublingual salivary glands (lateral view). B. Coronal section through the superficial and
deep parts of the submandibular salivary glands. C. Coronal section (anterior to B) through the sublingual salivary glands and
the ducts of the submandibular salivary glands.
duct emerges from the anterior end of the deep part of the
gland and runs forward beneath the mucous membrane
of the mouth. It opens into the mouth on a small papilla,
which is situated at the side of the frenulum of the tongue
(Fig. 11.72).
Nerve Supply
Parasympathetic secretomotor supply is from the facial
nerve via the chorda tympani, and the submandibular
ganglion. The postganglionic fibers pass directly to the
gland.
C L I N I C A L
N O T E S
Submandibular Salivary Gland: Calculus Formation
The submandibular salivary gland is a common site of calculus formation. This condition is rare in the other salivary
glands. The presence of a tense swelling below the body of
the mandible, which is greatest before or during a meal and
is reduced in size or absent between meals, is diagnostic of
the condition. Examination of the floor of the mouth will reveal
(continued)
634 CHAPTER 11 The Head and Neck
absence of ejection of saliva from the orifice of the duct of the
affected gland. Frequently, the stone can be palpated in the
duct, which lies below the mucous membrane of the floor of
the mouth.
Enlargement of the Submandibular Lymph Nodes
and Swelling of the Submandibular Salivary Gland
The submandibular lymph nodes are commonly enlarged as
a result of a pathologic condition of the scalp, face, maxillary
sinus, or mouth cavity. One of the most common causes of
painful enlargement of these nodes is acute infection of the
teeth. Enlargement of these nodes should not be confused
with pathologic swelling of the submandibular salivary gland.
nasal part
of pharynx
oral part of
pharynx
laryngeal part of
pharynx
Sublingual Gland
The sublingual gland lies beneath the mucous membrane
(sublingual fold) of the floor of the mouth, close to the
frenulum of the tongue (Fig. 11.86). It has both serous and
mucous acini, with the latter predominating. The sublingual ducts (8 to 20 in number) open into the mouth on the
summit of the sublingual fold (Fig. 11.72).
Nerve Supply
Parasympathetic secretomotor supply is from the facial
nerve via the chorda tympani, and the submandibular ganglion. Postganglionic fibers pass directly to the gland.
C L I N I C A L
N O T E S
Sublingual Salivary Gland and Cyst Formation
The sublingual salivary gland, which lies beneath the sublingual fold of the floor of the mouth, opens into the mouth
by numerous small ducts. Blockage of one of these ducts is
believed to be the cause of cysts under the tongue.
The Pharynx
The pharynx is situated behind the nasal cavities, the
mouth, and the larynx (Fig. 11.87) and may be divided into
nasal, oral, and laryngeal parts. The pharynx is funnel
shaped, its upper, wider end lying under the skull and its
lower, narrow end becoming continuous with the esophagus opposite the 6th cervical vertebra. The pharynx has a
musculomembranous wall, which is deficient anteriorly.
Here, it is replaced by the posterior openings into the nose
(choanae), the opening into the mouth, and the inlet of the
larynx. By means of the auditory tube, the mucous membrane is also continuous with that of the tympanic cavity.
Muscles of the Pharynx
The muscles in the wall of the pharynx consist of the
superior, middle, and inferior constrictor muscles
(Fig. 11.80A), whose fibers run in a somewhat circular
FIGURE 11.87 Sagittal section through the nose, mouth,
pharynx, and larynx to show the subdivisions of the pharynx.
direction, and the stylopharyngeus and salpingopharyngeus muscles, whose fibers run in a somewhat longitudinal
direction.
The three constrictor muscles extend around the pharyngeal wall to be inserted into a fibrous band or raphe that
extends from the pharyngeal tubercle on the basilar part
of the occipital bone of the skull down to the esophagus.
The three constrictor muscles overlap each other so that
the middle constrictor lies on the outside of the lower part
of the superior constrictor and the inferior constrictor lies
outside the lower part of the middle constrictor (Fig. 11.88).
The lower part of the inferior constrictor, which arises
from the cricoid cartilage, is called the cricopharyngeus
muscle (Fig. 11.88). The fibers of the cricopharyngeus pass
horizontally around the lowest and narrowest part of the
pharynx and act as a sphincter. Killian’s dehiscence is the
area on the posterior pharyngeal wall between the upper
propulsive part of the inferior constrictor and the lower
sphincteric part, the cricopharyngeus.
The details of the origins, insertions, nerve supply,
and actions of the pharyngeal muscles are summarized in
Table 11.10.
Interior of the Pharynx
The pharynx is divided into three parts: the nasal pharynx,
the oral pharynx, and the laryngeal pharynx.
Nasal Pharynx
This lies above the soft palate and behind the nasal cavities
(Fig. 11.87). In the submucosa of the roof is a collection of
lymphoid tissue called the pharyngeal tonsil (Fig. 11.89).
The pharyngeal isthmus is the opening in the floor between
the soft palate and the posterior pharyngeal wall. On the
lateral wall is the opening of the auditory tube, the elevated
ridge of which is called the tubal elevation (Fig. 11.89).