الفهرس 
Introduction
The jaw muscles of the common kestrelOnly 14 pages are availabe for public view
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Abstract
The present investigation is concerned with the functional morphology of the jaw apparatus of the Falco tinnunculus and Melopsittacus undulatus, this is performed through the studying of the following points:
I- The jaw skeleton.
A full description of the morphology of the jaw skeleton of Falco tinnunculus and Melopsittacus undulatus which consists of the following four functional and kinematical unites; the upper jaw, the brain case, the bony palate plus the jugal bars and attached quadrates, and the mandible. All these units which form a highly complex integrated mechanical apparatus, was studied by using different techniques, as gross anatomy and SEM.
A. The upper jaw
1) In the common kestrel, the upper jaw is a raptorial bill type. The lateral edges of the rhinotheca carry tooth-like projection this is known as maxillary tomia. While, in the budgerigar, the upper jaw is the psittacid-bill type which carry transverse ridges (filing ridges) on its dorsal surface, as well as, the presence of many sensory papillae which protrude along its lateral edge.
B. The brain case
The brain case of the two bird species is characterized by;
1) In the common kestrel, the brain case exhibits a reduction in kinesis due to the presence of immovable naso-frontal hinge. However, the quadrate can glide antero-posteriorly and vice versa. While, in the budgerigar, the brain case exhibits a high kinesis due to the presence of movable naso-frontal hinge.
2) The brain case of the budgerigar is characterized by the appearance of the suborbital arch which is considered as a parrot-specific structure surrounding the eye.
C. The quadrate bone
The quadrate bone of the two bird species is characterized by;
1) In the common kestrel, the quadrate is robust and has irregularly tetrahedral shape (H-shape), which has two mandibular condyles fitting with the articular facet on the mandible and forming a real diarthrosis joint which is the quadrato-mandibular articulation (Art.qm). Meanwhile, it is articulated to the brain case through otic and squamosal capitulum. In the budgerigar, the quadrate is delicate and has r-shape with single narrow and lateral compressed condyle which fits with the articular facet of the mandible forming uniquely quadrato-mandibular articulation (Art.qm), in addition, it is articulated to the brain case through the otic capitulum.
D. The mandible
The mandible of the two bird species is consisted of double rami, each ramus can be distinguished into three portions; the anterior portion (Rm), the intermediate portion (Pi) and the posterior portion (Pc)
1) In the common kestrel, the mandible carries along its lateral edges, the mandibular tomia (Mt) and contains a medial fossa and two foramens on the intermediate portion of the mandible. The posterior portion of the mandible contains two coronoid processes, as well as, the medial and short lateral process. The posterior portion of the mandible contains a fossa (Quadratic articular fossa, Faq) which is responsible for the articulation with the condyles which protrudes from the mandibular process of the quadrate bone, as well as, it incubates a posterior deep fossa (Fossa caudalis, Fca). While, in the budgerigar, the keratin covers the bony anterior portion of the mandible, and then extends anteriorly to form the broad anterior tip of the mandible without dentale bony support, as well as, carries numerous of sensory papillae like that exist on the upper jaw. The posterior portion of the mandible has just anterior coronoid process and contains shallow quadratic articular fossa (Faq) which runs obliquely from the postero-lateral to the antero-medial direction. That fossa receives the narrow and elongated single condyle of the mandibular process of the quadrate bone.
II) The jaw muscles and Ligaments:
• The jaw muscles of the common kestrel, Falco tinnunculus can be classified into:
1. Adductors of the mandibula.
The adductors of the mandibula comprise of two muscles; muscle adductor mandibulae externus (pars rostralis, pars ventralis and pars profunda), and pseudotemporalis superficialis.
2. Adductors of the mandibula and depressors of maxilla.
The adductor of the mandible and depressor of the maxilla group comprise of four muscles; muscle adductor mandibulae posterior, muscle pseudotemporalis profundus, muscle pterygoideus ventralis (pars lateralis and pars medialis), and muscle pterygoideus dorsalis (pars lateralis and pars medialis).
3. Depressor of the mandibula.
The mandible is depressed by the muscle depressor mandibulae (Dm).
4. Elevator of the maxilla.
The elevator of the maxilla is represented by single muscle, the muscle protractor quadrati.
• The jaw muscles of the budgerigar, Melopsittacus undulatus can be classified into:
1. Adductors of the mandibula.
The adductors of the mandibula comprise of three muscles; muscle adductor mandibulae externus (pars rostralis and pars ventralis), muscle ethmomandibularis and muscle pseudotemporalis superficialis pars lateralis.
2. Adductors of the mandibula and depressors of maxilla.
The adductors of the mandibula and depressors of maxilla group comprise of three muscles; muscle pseudotemporalis profundus, muscle pterygoideus dorsalis and muscle pterygoideus ventralis pars lateralis.
3. Adductor of the mandibula and elevator of maxilla.
The adductor of the mandible and the elevator of the maxilla are represented by the posterior branch of the adductor mandibulae externus muscle which is known as the adductor mandibulae externus pars profunda.
4. Depressors of the mandibula.
The mandible is depressed by two muscles; muscle depressor mandibulae lateralis and muscle depressor mandibulae medialis.
5. Depressors of maxillae.
The maxilla is depressed by two muscles; muscle pterygoideus ventralis pars medialis and muscle retractor palatini.
6. Elevators of the maxilla.
The maxilla is elevated by two muscles; muscle protractor quadrati and muscle pseudotemporalis superficialis pars medialis.
• The ligaments of the common kestrel, Falco tinnunculus include: Lig. Postorbital (Lig.po), Lig. External jugomandibular (Lig.ex.jm), Lig. Internal jugomandibular (Lig.in.jm), Lig. Occipitomandibular (Lig.om), Lig. Quadratomandibular (Lig.qm), and Lig. Mesethmopalatinum (Lig.mp). While the ligaments of the budgerigar, Melopsittacus undulatus include: Lig. Internal jugomandibular (Lig.in.jm), Lig. Occipitomandibular (Lig.om), and Lig. Zygomatic-suborbital (Lig.zs).
III- the roof of mouth
A full description of the roof of the mouth of two bird species; the common kestrel, Falco tinnunuculus and the budgerigar, Melopsittacus undulatus, which is distinguished into two regions; 1- the palate region and 2- the pharyngeal region, was studied from the following points of view, the following parts are described.
1- General morphology of the roof of mouth
a) In the common kestrel, the palate region is relatively twice the length of the upper jaw that incubates longitudinal choana and has one medial and two lateral ridges that bears several longitudinal rows of posteriorly-directed and pointed papillae while posteriorly, the palate flaps to form a pair of distinctive palatine wings. The pharyngeal region is short, relatively half the length of the palate region and incubates a narrow infundibular fissure, as well as, numerous of the orifices of the pharyngeal salivary gland and also bears several rows of posteriorly-directed papillae which are arranged transversely on its posterior margin ”posterior pharyngeal papillae” forming the pharyngeal wing.
b) In the budgerigar, the palate region is twice the length of the upper jaw but shorter than that of the common kestrel and incubates triangular-shaped choana, it demarkated by a semicircular ridge, as well as, The surface of the palate region carries scattered posteriorly-directed papillae and some tuberosities, as well as, many pores of the anterior palatine salivary gland. The pharyngeal region is long and relatively twice the length of the palate region and incubates a narrow oval-shaped infundibular fissure on its most anterior part, as well as, the presence of numerous of scattered papillae spread over the whole surface of the pharyngeal region, associated with the orifices of the pharyngeal salivary gland.
2- The epithelium of the roof of mouth
A full describion of the structure of the epithelia which covers the palate and pharyngeal region of the roof of mouth, was studied by using different techniques, as gross anatomy, SEM and histology;
a) In the common kestrel, the palate region of the roof of mouth is covered with highly desquamate keratinized stratified epithelium that carrying microridges on its surface. The keratinized epithelium forming the papillae that are scattered on the surface of the palate region, as well as, on the posterior margin ”palatine papillae”. The epithelium of the palate region is characterized by the disappearance of the dermal papillae. While, the pharyngeal region is covered by non- keratinized stratified squamous epithelium while the pharyngeal papillae are covered by keratinized epithelium. The epithelium of the pharyngeal region is characterized by the appearance of short and few dermal papillae. The epithelium of the roof of mouth becomes transitional- type at the region of the connection with the upper and lower jaw.
b) In the budgerigar, the whole surface of the roof of mouth is covered with non- keratinized squamous epithelium that carrying microridges, as well as, the appearance of muco-submucosal junctions. The palatine, pharyngeal, and scattered papillae are covered by the keratinized squamous epithelium which is characterized by the disappearance of the dermal papillae.
3- The salivary glands
The salivary glands of the common kestrel, Falco tinnunculus and the budgerigar, Melopsittacus undulatus were studied as a derivative of the epithelium of the roof of mouth and are classified according to their location as following:
A. Anterior palatine salivary gland.
1) The anterior palatine gland of the kestrel is paired and are occupied the antero-medial portion of the palate region underlies the stratified squamous epithelium, while in the budgerigar, it is spread over the antero-ventral surface of the palate region and located lateral to the choana. The anterior palatine gland of each bird species is composed of a compound tubulo-alveolar type and delivers a neutral and acid mucin secretion via one pore in the kestrel, while in the budgerigar, it delivers its secretion via multiple scattered orifices on the epithelial surface of the palate region.
B. Posterior pharyngeal salivary gland.
1) The posterior pharyngeal salivary gland of the two bird species is a compound tubulo-alveolar type which secreted neutral and acidic mucin via multiple scattered orifices on the epithelial surface of the pharyngeal region.
The anterior palatine and posterior pharyngeal salivary gland of the common kestrel give weakly reaction for protein, while in the budgerigar exhibits strong positive reaction.