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The incisive bone is a paired structure composed of body, nasal, palatine and alveolar parts. It joins with the maxilla to form the '''interalveolar margin'''. It also forms the rostral part of the facial section of the skull, the roof of the '''[[Hard Palate|hard palate]]''' and the opening to the nasal cavity. The alveolar process forms conical sockets for the incisor teeth. <br>
The incisive bone is a paired structure composed of body, nasal, palatine and alveolar parts. It joins with the maxilla to form the '''interalveolar margin'''. It also forms the rostral part of the facial section of the skull, the roof of the '''[[Hard Palate|hard palate]]''' and the opening to the nasal cavity. The alveolar process forms conical sockets for the incisor teeth. <br>
=== Palatine Bone (''os palatinum'') ===
=== Palatine Bone (''os palatinum'') ===
The palatine bone is a paired structure between the maxilla, sphenoid and pterygoid bones. It is composed of a horizontal plate (forms part of the [[Hard Palate|hard palate]]), perpendicular plate (forms the dorsal and lateral walls of the nasopharyngeal meatus) and the choanae. The '''nasal crest''' present on the horizontal plate. The '''palatine sinus''' is present on horizontal plate.
The palatine bone is a paired structure between the maxilla, sphenoid and pterygoid bones. It is composed of a horizontal plate (forms part of the [[Hard Palate|hard palate]]), perpendicular plate (forms the dorsal and lateral walls of the nasopharyngeal meatus) and the choanae. The '''nasal crest''' is present on the horizontal plate. The '''palatine sinus''' is present on horizontal plate.
=== Vomer ===
=== Vomer ===
The vomer is unpaired and extends from the choanae of the palatine bone to the floor of the nasal cavity. It attaches to the median nuchal crest and has a '''septal sulcus''' which surrounds nasal cavity.
The vomer is unpaired and extends from the choanae of the palatine bone to the floor of the nasal cavity. It attaches to the median nuchal crest and has a '''septal sulcus''' which surrounds nasal cavity.
The maxilla forms most of the facial part of the skull, including the lateral walls of the face, nasal cavity, [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]] and [[Hard Palate|hard palate]]. It also forms the ventral nasal conchae and articulates with all of the facial bones as it is the largest bone of the face. The maxillary body encloses the '''maxillary sinuses''' and forms the external surface of the face. It also forms the '''facial crest'''. The '''infraorbital foramen''' is palpable. The '''conchal crest''' is on nasal surface where the ventral nasal conchae attaches. The '''lacrimal canal''' opens into the '''lacrimal foramen''' on the nasal surface. The '''pterygopalatine surfaces''' are the caudal part of the maxilla which terminate in the '''maxillary tubercle''' where the '''sphenopalatine, maxillary''' and '''caudal palatine foramen''' are present. The '''alveolar processes''' present are separated by '''interalveolar septa'''. The '''palatine process''' forms the '''[[Hard Palate|hard palate]]''' with the palatine bone. The '''palatine fissure''' is formed at the articulation with the incisive bone. The nasal surface of palatine process forms the '''nasal crest''' and encloses part of the palatine sinuses. The oral surface has numerous palatine foramina present.
The maxilla forms most of the facial part of the skull, including the lateral walls of the face, nasal cavity, [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]] and [[Hard Palate|hard palate]]. It also forms the ventral nasal conchae and articulates with all of the facial bones as it is the largest bone of the face. The maxillary body encloses the '''maxillary sinuses''' and forms the external surface of the face. It also forms the '''facial crest'''. The '''infraorbital foramen''' is palpable. The '''conchal crest''' is on nasal surface where the ventral nasal conchae attaches. The '''lacrimal canal''' opens into the '''lacrimal foramen''' on the nasal surface. The '''pterygopalatine surfaces''' are the caudal part of the maxilla which terminate in the '''maxillary tubercle''' where the '''sphenopalatine, maxillary''' and '''caudal palatine foramen''' are present. The '''alveolar processes''' present are separated by '''interalveolar septa'''. The '''palatine process''' forms the '''[[Hard Palate|hard palate]]''' with the palatine bone. The '''palatine fissure''' is formed at the articulation with the incisive bone. The nasal surface of palatine process forms the '''nasal crest''' and encloses part of the palatine sinuses. The oral surface has numerous palatine foramina present.
=== Mandible (''mandibula'') ===
=== Mandible (''mandibula'') ===
The mandible can be divided into the '''body''' and the '''ramus'''. The body of the mandible supports the incisor teeth (rostrally) and cheek teeth (caudally). The section of the body which does not support any teeth is called the '''interalveolar margin''' or '''diastema'''. The mandibule also contains the '''mandibular canal''' and the '''mental foramen'''. The '''facial notch''' is on the ventral surface where the '''parotid duct''' (in herbivores) and facial vessels run. The '''ramus''' extends from the caudal end of the body dorsally towards the zygomatic arch. The '''masseter muscle''' attaches to the lateral surface at the '''masseteric fossa'''. The '''medial pterygoid''' attaches to the medial surface at the '''pterygoid fossa'''. The angle of the mandible terminates dorsally in the '''condylar process''' and the '''coronoid process''' which are separated by the '''mandibular notch'''. The '''temporal muscle''' inserts onto the '''coronoid head'''. The condylar process articulates with the mandibular process of the skull (see [[Mastication#Jaw_Articulation|here]]).
The mandible can be divided into the '''body''' and the '''ramus'''. The body of the mandible supports the incisor teeth (rostrally) and cheek teeth (caudally). The section of the body which does not support any teeth is called the '''interalveolar margin''' or '''diastema'''. The mandibule also contains the '''mandibular canal''' and the '''mental foramen'''. The '''facial notch''' is on the ventral surface where the facial vessels run. The '''ramus''' extends from the caudal end of the body dorsally towards the zygomatic arch. The '''masseter muscle''' attaches to the lateral surface at the '''masseteric fossa'''. The '''medial pterygoid''' attaches to the medial surface at the '''pterygoid fossa'''. The angle of the mandible terminates dorsally in the '''condylar process''' and the '''coronoid process''' which are separated by the '''mandibular notch'''. The '''temporal muscle''' inserts onto the '''coronoid head'''. The condylar process articulates with the mandibular process of the skull (see [[Mastication#Jaw_Articulation|here]]).
== Major Skull Foramen and Canals ==
== Major Skull Foramen and Canals ==
=Trunk=
=Trunk=
The trunk is in broad terms the body of the animal and is what would remain if the head and limbs were removed. It can be seperated in four parts, the cervical vertebrae, thorax, lumbar region and pelvis. Anatomically these structures are highly distinguishable and each area has a distinctive shape, size and physiological role. The vertebrae within the trunk consist of a body, which encloses the vertebral foramen (through which the spinal cord and meninges run), a spinous process, and a transverse process, as well as articular processes by which they join together. The form of the spinous process varies with respect to species and region.
The trunk is in broad terms the body of the animal and is what would remain if the head and limbs were removed. It can be seperated in four parts, the cervical vertebrae, thorax, lumbar region and pelvis. Anatomically these structures are highly distinguishable and each area has a distinctive shape, size and physiological role. The vertebrae within the trunk consist of a body, which encloses the vertebral foramen (through which the spinal cord and meninges run), a spinous process, and a transverse process, as well as articular processes by which they join together. The form of the spinous process varies with respect to species and region. The table below indicates the type and number of bones found in canines.
[[Image:Spinal landmarks.jpg|center|500px|Spinal Landmarks - Copyright Becky Pocock 2008]]
[[Image:Spinal landmarks.jpg|center|500px|Spinal Landmarks - Copyright Becky Pocock 2008]]
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==Thoracic Vertebrae==
==Thoracic Vertebrae==
Canines and most mammals have thirteen thoracic vertebrae. Thoracic vertebrae articulate with one another and with the ribs using both cartilaginous and synovial joints (see section above). Thoracic vertebrae are generally very similar throughout the length with only small differences occurring gradually between those vertebrae cranially and caudally. Thoracic vertebrae have short bodies with flattened extremities, short transverse processes and prominent spinous processes. Each body has costal facets which have a synovial joint to articulate with the corresponding rib. These costal facets become more basic the further caudal the vertebrae. The spinous processes reach a maximum height only a few vertebrae behind the cervicothoracic junction and then decline gradually towards the lumbar vertebrae. The orientation of spinous processes shifts from slanting in a general caudal direction for the first eight thoracic vertebrae to slanting in a cranio-dorsal direction for the last few caudal vertebrae.
Canines and most mammals have thirteen thoracic vertebrae. Thoracic vertebrae articulate with one another and with the ribs using both cartilaginous and synovial joints. Thoracic vertebrae are generally very similar throughout the length with only small differences occurring gradually between those vertebrae cranially and caudally. Thoracic vertebrae have short bodies with flattened extremities, short transverse processes and prominent spinous processes. Each body has costal facets which have a synovial joint to articulate with the corresponding rib. These costal facets become more basic the further caudal the vertebrae. The spinous processes reach a maximum height only a few vertebrae behind the cervicothoracic junction and then decline gradually towards the lumbar vertebrae. The orientation of spinous processes shifts from slanting in a general caudal direction for the first eight thoracic vertebrae to slanting in a cranio-dorsal direction for the last few caudal vertebrae.
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===Ribs===
===Ribs===
[[File:Dog ribs.JPG|thumb|right|300px|'''Canine ribs & Sternum''' - Kirill Tsukanov, Moscow State University, 12/04/12]]
[[File:Dog ribs.JPG|thumb|right|300px|'''Canine ribs & Sternum''' - Kirill Tsukanov, Moscow State University, 12/04/12]]
The ribs are paired structures that articulate with a two ribs - the corresponding thoracic vertebrae and also partially with the vertebrae directly caudal. It is the caudal vertebrae that has the same numerical designation as the rib. An individual rib is composed of a number of elements. Dorsally the rib has a tubercle, head and neck. The head of the rib is rounded with two facets, each of which represents the surface which articulates with the vertebral body. The area between the two facets is referred to as the ''crest'' and allows the attachment of the intercapital ligament. The tubercle of the dorsal rib can act as a further third articular facet in more caudal ribs with the transverse processes. The main body of the rib is long and curved and the lateral surface of the rib is often flattened. The highest degree of curvature of the rib is just ventral to the dorsal neck of the rib and is known as the ''angle''. The angle allows the attachment of the iliocostalis muscles whilst the cranial and caudal edges of the rib allow attachment of the intercostal muscles. The caudal aspect of the body of the rib also contains a small groove which is designed to afford protection to the neurovascular bundle that runs along the length of each rib. At the ventral third of each rib the bone structure of the rib is replaced with costal cartilage at the costochondral junction. This costal cartilage is more flexible than the bone and progressively ossifies with age. The cartilage is bent in a cranioventral manner before making contact with the sternum which together with the increased flexibility of the cartilage itself provides the thoracic cavity with a wide degree of changes in shape. There are vast differences in the size of rib depending on which number the rib is - the first rib if usually the shortest and articulates with the sternum in a more rigid manner than caudal ribs to act as an anchor on which the other ribs draw for inspiration. Ventrally the cartilaginous element of the rib articulates with the sternum (see section below) in nearly all ribs. The exception are the most caudal ribs in which the cartilaginous ventral element of the rib fails to make contact with the sternum and is referred to as a 'floating' rib.
The ribs are paired structures that articulate with two ribs - the corresponding thoracic vertebrae and also partially with the vertebrae directly caudal. It is the caudal vertebrae that has the same numerical designation as the rib. An individual rib is composed of a number of elements. Dorsally the rib has a tubercle, head and neck. The head of the rib is rounded with two facets, each of which represents the surface which articulates with the vertebral body. The area between the two facets is referred to as the ''crest'' and allows the attachment of the intercapital ligament. The tubercle of the dorsal rib can act as a further third articular facet in more caudal ribs with the transverse processes. The main body of the rib is long and curved and the lateral surface of the rib is often flattened. The highest degree of curvature of the rib is just ventral to the dorsal neck of the rib and is known as the ''angle''. The angle allows the attachment of the iliocostalis muscles whilst the cranial and caudal edges of the rib allow attachment of the intercostal muscles. The caudal aspect of the body of the rib also contains a small groove which is designed to afford protection to the neurovascular bundle that runs along the length of each rib. At the ventral third of each rib the bone structure of the rib is replaced with costal cartilage at the costochondral junction. This costal cartilage is more flexible than the bone and progressively ossifies with age. The cartilage is bent in a cranioventral manner before making contact with the sternum which together with the increased flexibility of the cartilage itself provides the thoracic cavity with a wide degree of changes in shape. There are vast differences in the size of rib depending on which number the rib is - the first rib if usually the shortest and articulates with the sternum in a more rigid manner than caudal ribs to act as an anchor on which the other ribs draw for inspiration. Ventrally the cartilaginous element of the rib articulates with the sternum (see section below) in nearly all ribs. The exception are the most caudal ribs in which the cartilaginous ventral element of the rib fails to make contact with the sternum and is referred to as a 'floating' rib.
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===Sternum===
===Sternum===
The sternum represents the bony structure that runs ventrally along the thoracic cavity and provides attachment for the ribs and an anchor for some of the muscles involved in respiration. The sternum is composed of three elements; the '''manubrium''', the '''body''' and the '''xiphoid'''. The '''manubrium''' in canines is rod-shaped and projects cranially to the first rib and unless the dog is particularly well muscles, it can often be palpated at the region of the ventral neck. The body of the sternum is composed of numerous segments interconnected by the costochondral ventral aspects of the ribs (see section above) via small depressions in the segments. These segments are referred to as ''sternebrae'' and are cartilaginous in young canines and ossify with age. The body of the sternum in dogs is generally cylindrical in shape. The '''xiphoid''' cartilage extends caudally in a similar manner to that of the manubrium cranially. It provides attachents for the most cranial aspects of the abdomen and also for the ''linea alba''.
The sternum represents the bony structure that runs ventrally along the thoracic cavity and provides attachment for the ribs and an anchor for some of the muscles involved in respiration. The sternum is composed of three elements; the '''manubrium''', the '''body''' and the '''xiphoid'''. The '''manubrium''' in canines is rod-shaped and projects cranially to the first rib and unless the dog is particularly well muscled, it can often be palpated at the region of the ventral neck. The body of the sternum is composed of numerous segments interconnected by the costochondral ventral aspects of the ribs (see section above) via small depressions in the segments. These segments are referred to as ''sternebrae'' and are cartilaginous in young canines and ossify with age. The body of the sternum in dogs is generally cylindrical in shape. The '''xiphoid''' cartilage extends caudally in a similar manner to that of the manubrium cranially. It provides attachents for the most cranial aspects of the abdomen and also for the ''linea alba''.
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The acetabulum is contributed to by all of the above bones. The acetabulum is surrounded by an ''acetabular rim'' and the depth of the acetabulum varies depending on breed, shape of pelvis and hip conformation.
The acetabulum is contributed to by all of the above bones. The acetabulum is surrounded by an ''acetabular rim'' and the depth of the acetabulum varies depending on breed, shape of pelvis and hip conformation.
===Pelvic Girdle===
===Pelvic Girdle===
In canines the wings of the ilium are much more oblique conformation when compared to large animals and this allows the muscles of the pelvis floor to be displaced laterally over a wider area when compared to the vertebral column. This increases the efficiency and therefore power of the abdominal muscles which allows a greater degree of flexibility of the vertebral column which is essential for faster locomotion and agility. Canines also have relatively caudal displaced ''ishial tuber'' which increases the leverage of the hamstring muscles onto the hindlimbs providing further efficiency improvements for locomotion.
In canines the wings of the ilium have a much more oblique conformation when compared to large animals and this allows the muscles of the pelvis floor to be displaced laterally over a wider area when compared to the vertebral column. This increases the efficiency and therefore power of the abdominal muscles which allows a greater degree of flexibility of the vertebral column which is essential for faster locomotion and agility. Canines also have relatively caudally displaced ''ishial tuber'' which increase the leverage of the hamstring muscles onto the hindlimbs providing further efficiency improvements for locomotion.
=Forelimb=
=Forelimb=
[[File:Dog fore limb 1.JPG|thumb|centre|350px|Canine Forelimb, Moscow State University Department of Biology, Kirill Tsukanov, 2012]]
[[File:Dog fore limb 1.JPG|thumb|centre|450px|Canine Forelimb, Moscow State University Department of Biology, Kirill Tsukanov, 2012]]
==Proximal Forelimb & Shoulder==
==Proximal Forelimb & Shoulder==
===Scapula===
===Scapula===
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====Tibia & Fibula====
====Tibia & Fibula====
Moving distally the stifle allows articulation between the '''tibia'''. The tibia has intimately related to the fibula which is a much smaller bone that runs parallel to the tibia. The tibia is medial to the fibula and effectively excludes the fibula from articulating with the femur. Proximally the tibia has two condyles to facilitate articulation wioth the femur. These condyles are seperated by a ''caudal popliteal notch'' that allows insertion of the popliteal muscle. The articular surfaces of the tibial condyles correspond to the condyles of the distal femur. The articular surface of the tibia also has small depressions and ridges that allow cruciate ligament attachment within the joint. Slightly distal to the tibial condyles and on the cranial aspect is the large and prominent ''tibial tuberosity'' which is continued distally on the cranial aspect of the tibia via the ''tibial crest'' which gradually reduces distally. Proximally and caudally, the articular surface of the tibia also proves a small facet for articulation with the fibula. The shape of the tibia proximally is triangular in cross-section but distally the tibia becomes more craniocaudally compressed. The distal point of the tibia has an articular surface called the ''cochlea'' which facilitates movement with the ''trochlea'' of the '''talus'''. The cochlea has a central bony prominence which is flanked medially and laterally with grooves. The medial cochlea has a bony salience called the ''medial malleolus''.
Moving distally the stifle allows articulation between the '''tibia'''. The tibia has intimately related to the fibula which is a much smaller bone that runs parallel to the tibia. The tibia is medial to the fibula and effectively excludes the fibula from articulating with the femur. Proximally the tibia has two condyles to facilitate articulation with the femur. These condyles are seperated by a ''caudal popliteal notch'' that allows insertion of the popliteal muscle. The articular surfaces of the tibial condyles correspond to the condyles of the distal femur. The articular surface of the tibia also has small depressions and ridges that allow cruciate ligament attachment within the joint. Slightly distal to the tibial condyles and on the cranial aspect is the large and prominent ''tibial tuberosity'' which is continued distally on the cranial aspect of the tibia via the ''tibial crest'' which gradually reduces distally. Proximally and caudally, the articular surface of the tibia also provides a small facet for articulation with the fibula. The shape of the tibia proximally is triangular in cross-section but distally the tibia becomes more craniocaudally compressed. The distal point of the tibia has an articular surface called the ''cochlea'' which facilitates movement with the ''trochlea'' of the '''talus'''. The cochlea has a central bony prominence which is flanked medially and laterally with grooves. Medially the cochlea has a bony salience called the ''medial malleolus''.
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====Phalanges====
====Phalanges====
The bone anatomy of the hindlimb phalanges is identical to that of the forelimbs and therefore has not been repeated here. For more detailed anatomy of the phalanges, please see the forelimb distal limb section above.
The bone anatomy of the hindlimb phalanges is identical to that of the forelimbs and therefore has not been repeated here. For more detailed anatomy of the phalanges, please see the forelimb distal limb section above.
[[Category:A%26P_Done_CB]]