Download mandibular salivary gland

Head structures II
Lacrimal Apparatus
Lacrimal Apparatus
• the group of structures
that manufacture and
drain away tears
• Lacrimal gland:
– the pink gland lying
on the dorsolateral
aspect of the eyeball
– Gland associated
with 3rd eyelid
• Lacrimal puncta: the
openings of the
lacrimal canaliculi on
the upper and lower
eyelids near the medial
angle (canthus).
• Lacrimal canaliculi: the
small canals from the
lacrimal puncta he
lacrimal sac.
• Lacrimal sac: located
in a fossa in the
lacrimal bone's orbital
face, it marks the
beginning of the
nasolacrimal duct.
• Nasolacrimal duct:
– the duct extending
from the lacrimal sac
to the rostral part of
the nasal cavity, first
traveling in a bony
canal in the lacrimal
and maxillary bones
and then deep to the
nasal mucosa before
opening into the
rostral nasal cavity
Paranasal Sinuses
 The paranasal sinuses are diverticula of the nasal cavity that
excavate the skull bones largely after birth.
 The separation of the inner and outer tables of the bones alters
the conformation of the head.
It is specially striking in pigs and cattle, in which certain sinuses
eventually extend dorsal and even caudal to the cranial cavity.
Paranasal Sinuses
 The sinuses retain their connections with the nasal cavity
 these openings are generally narrow a relatively slow
exchange of air occurs
 The narrowness and locations of the openings make them
prone to blockage when the mucosa is thickened by
inflammation or congestion.
 Not all the sinuses are of equal importance.
The function
 The function of the sinuses is obscure
 Offer some thermal
 Mechanical protection to the orbit and
nasal and cranial cavities
 Enlarge the skull areas available for
muscular attachment without unduly
increasing weight
 Affect the resonance of the voice.
 All species have frontal and maxillary systems
 neither communicating with its contralateral counterpart.
 The frontal system consists of one or more spaces
within the bones at the border between the nasal and
cranial cavities.
 In most species the various frontal compartments
open separately into ethmoidal meatus in the nasal
cavity
 in the horse the frontal sinus communicates with the nasal
cavity indirectly via the caudal maxillary sinus.
The maxillary sinus system occupies the
caudolateral part of the upper jaw, above the
caudal cheek teeth
 In some species it sends extensions,
variously described as separate sinuses or
as diverticula




into the hard palate
the sphenoid bones
the medial aspect of the orbit
the ventral concha.
 In the horse the maxillary sinus is
divided into caudal and rostral parts,
both connected to the middle nasal
meatus
 In the dog the cavity communicates freely
with that of the nose and is known as the
maxillary recess.
EQUINE
 On each side there are frontal, caudal maxillary, and rostral
maxillary sinuses of importance
 sphenopalatine and ethmoidal spaces of less account.
 the frontal sinus communicates with the nasal cavity indirectly
via the caudal maxillary sinus.
 The two maxillary sinuses together occupy a large part of the
upper jaw, where they have a critically important relationship
to the embedded portions of the caudal cheek teeth.
 They share a slit like communication (nasomaxillary opening) with the
middle meatus of the nasal cavity
 The frontal sinus occupies the dorsal part of the skull medial to
the orbit.
 It overlaps both cranial and nasal cavities.
 Since it also occupies the closed part of the dorsal concha, it is more
correctly known as the conchofrontal sinus
BOVINE, OVINE, CAPRINE

The paranasal sinus system is very poorly developed in the young calf,
Even in the mature animal, the maxillary compartment continues to
adjust to extrusion of the cheek teeth.
 The complete set of sinuses is very complicated.
It comprises:
1. Frontal compartments within the bones of the cranial roof and side
walls
2. Platomaxillary complex within the caudal part of the hard palate and
the face, both before and below the orbit
3. Lacrimal sinus within the medial orbital wall;
4. Sphenoidal sinuses that extend past the orbit into the rostral part of
the cranial floor
5. Conchal sinuses within the nasal conchae.
Nasal Conchae
• Project medially from each lateral wall of the
nasal cavity.
– Dorsal conchae
– Ethmoid conchae
– Ventral conchae
• Creates turbulence which increases the
amount of contact between nasal mucosa and
inhaled air
• Function: to filter, heat and moisten air
The superficial muscles move skin and ears, eyelids, nose, and lips to produce facial
expression. The platysma m. (1) runs from the neck to the commissure of the lips. It
retracts the lips to expose teeth; parts of the muscle are missing (asterisks).
Superficial muscles that move the ear may be grouped into rostral (2), lateral (3), and
caudal auricular muscles. An orbicularis oculi m. (4) closes the palpebral fissure.
A levator nasolabialis m. (5) retracts the nose and upper lip. An orbicularis oris m.
is situated within the lips (6).
Muscles of the lips and cheek. The orbicularis oris m. (1) is located within the
wall of the upper lip and the lower lip. The buccinator m. (2) is located within the
wall of the cheek. The levator nasolabialis m. (3) retracts the nose and upper
lip. The orbicularis oculi m. (4) closes the palpebral fissure.
The palpebral fissure (opening) is situated between superior (1) and inferior (2)
palpebrae.
The eyelids meet at medial (3) and lateral (4) palpebral commissures. The lateral
commissure (forceps) has been incised.
Third eyelid (5), has a pigmented edge.
The parotid salivary gland (1) surrounds the external ear canal (2) and sends a
parotid duct (3) toward the vestibule. It empties beside the upper fourth premolar.
The mandibular salivary gland (4) is located where the maxillary v. (5) and linguofacial
v. (6) join to form the external jugular v. (7).
The monostomatic sublingual salivary gland (8) is located just cranial to the
mandibular salivary gland. Notice the mandibular lymph nodes (9) flanking the facial v.
Deep dissection. The temporal m. has been reflected to expose the temporal fossa
(1). The top of the ramus (2) of the mandible has been remove and the ramus has
been reflected laterally to expose vessels and nerves on the surface of the medial
pterygoid m. (3). The zygomatic salivary gland (4) is located ventral to the orbit
which has been incised to expose the eye (5) and extrinsic eye muscles (6).
Muscle of Mastication:
(2) the temporal m; arise from temporal fossa and insert in cronoid p. of mandible
(3) the masseter m. arise from zygomatic arch and insert in masseteric fossa.
(4) the digastricus m. Arise from paracondylar process of occipital bone and insert
in the body (mandible)
Temporal m. (2), the partially reflected masseter m. (3), the mandible (4), and the
digastricus m. (5). Notice the fourth upper premolar and first lower molar teeth
(asterisks).
The zygomatic arch has been removed and the masseter m. (1) has been
reflected. Notice the ramus of the mandible (2) and the temporomandibular
joint (3). Also find the temporal m. (4) and the digastricus m. (5).