(3-2) Osteology - The Skull And Thoracic Limb Flashcards
The part of the skeleton within the head is the?
skull
skull protects the?
brain
skull supports many of the?
sense organs
skull forms passages for entry to the?
digestive and respiratory systems
Skull consist of cranial part called?
Braincase
braincase surrounds the?
brain, and the facial part
The skull is a very complex structure made mostly of what bones?
flat bones
All the bones of the skull are connected and fixed in place, except for the?
mandible
The mandible is unique because it’s attached to the skull with what joint?
movable joint( temporomandibular joint )
the bones of the skull are connected by interlocking joints called?
sutures
Suture joints are characterized by what apperance?
saw-toothed or serrated appearance
What is the function of suture?
keeps the bones attached with one another, but allows the cranium to expand and contract while remaining intact
Caudal and Dorsal Walls of skull contains:
- Occipital bone
- Parietal bone
- Interparietal bone
- Frontal bones
Lateral and Ventral Walls of skull contains:
- Temporal bones
- Sphenoid bone
- Ethmoid bone
The rostral wall of the skull contains which bone?
The ethmoid bone (unpaired).
Bone that contains the middle and inner ears
Temporal bone
This bone supports the brain and pituitary gland
Sphenoid bone
This bone presents numerous openings for passage of the olfactory nerves associated with the sense of smell
Ethmoid bone
Facial portion of the skull can be divided into 3 regions:
○ Orbit
○ Nasal
○ Oral
Portion of skull that means circle
Orbit
Orbit is surrounded by portions of what bones?
frontal, lacrimal and zygomatic bones
frontal, lacrimal and zygomatic bones participate in the formation of what arch?
zygomatic arch
zygomatic arch borders what part of the orbit?
ventral and caudal parts of the orbit
the bony arch forming the lateral wall of the orbit.
Zygomatic arch
Zygomatic arch consists of?
zygomatic bone and the zygomatic processes of the temporal bone
the depression in the medial margins of the orbit.
Lacrimal fossa
It collects tears and sends them through the lacrimal canal which opens into the nasal cavity
Lacrimal fossa
the rostral opening of the infraorbital canal, located in the?
maxillary bone
the paired structures lateral to the foramen magnum that articulates with the first cervical vertebra (atlas)
Occipital condyles
the ventral projection near the occipital condyles
Paracondylar (jugular) process
the large opening caudal to the zygomatic arch where the external ear attaches
External acoustic meatus
In life, External acoustic meatus is covered by?
ear drum
- located caudal to the external acoustic meatus
- It is an attachment site for muscles
Mastoid process
the caudal process of the occipital bone
External occipital protuberance
the transverse ridge at the transition from the dorsal to the caudal (nuchal) surfaces of the skull
Nuchal crest
the depression formed by the temporal and parietal bones
Temporal fossa
the rostral bony opening into the nasal cavity
Nasal aperture
extends rostrally from the external occipital protuberance on the midline (absent in ruminants)
Median sagittal crest
The large opening into the cranial cavity for continuity of the spinal cord and brain
Foramen magnum
the smooth bulbous enlargement on the ventral side of the temporal bone housing the middle ear
Tympanic bulla
The area on the zygomatic arch for articulation with the articular process (condyle) of the mandible
Mandibular fossa
the passageway for the optic nerve from the eyeball to the brain
Optic canal
It is rostral to many other foramina that allow passage of other cranial nerves
Optic canal
The two bony openings, at the caudal end of the hard palate, leading from the nasal cavity into the pharynx
Choanae or caudal nares
the horizontal parts of the incisive, palatine and maxillary bones, separating the nasal and oral cavities
Hard palate
the space in the cranium containing the brain, its meninges and blood vessels
Cranial cavity
the depression in the floor of the cranial cavity (sphenoid bone) holding the pituitary gland (hypophysis)
Hypophyseal fossa
the rostral part of the wall of the cranial cavity
Cribriform plate
Cribriform plate has many holes in the ethmoid bone allow the passage of the?
olfactory nerve
the hollow space behind the nose, surrounded by the facial bones
Nasal cavity
What divides the nasal cavity?
nasal septum
What bones are found inside each half of the nasal cavity?
ventral nasal conchae and ethmoturbinate bones
a scroll bone filling the rostral part of the nasal cavity
Ventral nasal concha
the largest nasal turbinate of the ethmoid bone
Dorsal nasal concha
the bone in the caudal nasal cavity
Ethmoid bone
Ethmoid bone has many bony scrolls called?
ethmoturbinates
Right and left nasal passages are separated longitudinally by what bone?
vomer bone and a cartilaginous and bony septum
arise from the lateral walls of the nasal cavity and project into the nasal passages
Scroll-like conchae (turbinate bones)
Covered with highly vascular mucous membrane that helps warm and humidify the inspired air
Conchae
Conchae on the caudal parts of the nasal cavity feature the ? , which contains the nerve cells specialized to detect odors
olfactory epithelium
the cavity (paranasal sinus) within the frontal bone
Frontal sinus
Largest and only mobile bone of the mammalian skull
Mandible
Mandible holds the lower teeth and consists of a right and left half united at the?
mandibular symphysis
the horizontal part bearing the lower incisor, canine, premolar and molar teeth of mandible
Body
the rostral opening of the mandibular canal
Mental foramen
the vertical part of the mandible bearing teeth
Ramus
the smooth process which articulates with the mandibular fossa of the temporal bone to form the temporomandibular joint
Articular (condylar) process
the opening on the medial side of the ramus leading into the mandibular canal
Mandibular foramen
- a bony framework that gives support to the pharynx (throat) and provides attachment to some pharyngeal, laryngeal, and lingual muscles
Hyoid apparatus
the unpaired hyoid bone
Basihyoid
articulates with the base of the skull at the petrus temporal. A paired bone
Stylohyoid
A paired hyoid bone next to stylohyoid and ceratohyoid bone
Epihyoid
A paired hyoid bone next to epihyoid, thyrohyoid and basihyoid bone
Ceratohyoid
articulates with the thyroid cartilage of the larynx. A paired hyoid bone
Thyrohyoid
○ Spine or backbone
○ Protects the spinal cord, supports the head and serves as attachment for the muscles affecting body movements
○ It extends from the skull through the tail and consists of irregular bones - vertebrae
○ The vertebrae are firmly joined by slightly moveable joints
○ All the vertebral joints together allow a great amount of movement
Vertebral column
○ The irregularly-shaped bones making up the spinal column
○ Each group is represented by its first letter followed by the number representing how many are in each section
Vertebrae
Vertebrae are grouped by location into?
cervical (neck) , thoracic (cranial back) ,
lumbar (loin), sacral (croup) and caudal (tail) vertebrae
Canine vertebral formula:
C7 T13 L7 S3 Ca n
The number of each type of vertebrae is constant except the?
caudal ones
What number can be used as a rough estimate of the caudal vertebrae with some dogs having more and some less
Twenty
Common features of a typical vertebra are the?
body, vertebral arch, vertebral foramen and processes
○ The opening between vertebrae formed by caudal and cranial notches of adjacent vertebrae
○ These openings allow passage of the spinal nerves
Intervertebral foramen
the fibrocartilages connecting the bodies of adjacent vertebrae
Intervertebral discs
the space formed by the vertebral arch and the body
Vertebral foramen
of all the vertebrae form the vertebral canal, housing the spinal cord
vertebral foramina
formed in the live animal by all vertebral foramina
Vertebral canal
○ The dorsal part of a vertebra that arises from the body
○ It consists of two upright pedicles forming the walls of the vertebral foramen
○ From the pedicles, two lamina project to the midline and form the roof of the vertebral foramen
Vertebral arch
- the thick, spool-shaped ventral portion of the vertebra
- It is convex cranially and concave caudally to articulate with adjacent vertebrae
Body
The spine and the two transverse processes provide sites for?
muscle attachment
form synovial joints with adjacent vertebrae
4 articular processes (2 cranial; 2 caudal)
Lamina + pedicle = ?
Vertebral arch
the dorsal projection of the vertebral arch
Spinous process or spine
- the lateral extension of the vertebral arch
- they divide the muscles of the back into dorsal (epaxial) and ventral (hypaxial) groups
Transverse process
the four articular process is divided into?
two cranial and two caudal (8’ and 8”)
● The seven vertebrae of the neck in all mammals, characterized by a transverse foramen (except C7)
Cervical Vertebrae
The 7 Cervical Vertebrae of the neck in all mammals, characterized by a transverse foramen except?
C7
cervical vertebrae that are atypical
Atlas & axis
- the spinous process is absent
- articulates with the occipital condyles of the skull cranially and with the axis caudally
Atlas
The body of the axis features a cranial projection called the?
dens
the hole through the transverse process of C1-C6, together forming the transverse canal
Transverse foramen
Transverse foramen is the hole through the transverse process of C1-C6, together forming the?
transverse canal
What is the process of the cervical vertebrae are divided into ventral and dorsal tubercles
Transverse process
large ventral projections of cervical vertebrae which on a radiograph are used as landmarks and often called the “sleds”
Sixth cervical vertebra’s transverse process
This cervical vertebrae has a higher spinous process, an articular facet on the caudal end of its body for the head of the first rib, and no transverse foramen
Seventh cervical vertebra
- the “yes” joint
- formed between the atlas and the occipital bone of the cranium
Atlanto-occipital joint
- the “no” joint
- formed between the atlas and the axis
Atlanto-axial joint
the peg-like cranial process forming a pivot articulation with the atlas, allowing pivotal motion
Dens
the portion of the atlas replacing the body of other vertebrae
Ventral arch
the large lateral masses that are modified transverse processes
Wings
the thoracic vertebra with the most vertically oriented spin
Anticlinal vertebrae
Anticlinal vertebrae in the thoracic vertebra with the most vertically oriented spin, usually the ? in the dog
eleventh (T11)
the two plane surfaces that articulate with a rib’s head
Costal facets/fovea
Located on the caudal and cranial end of the vertebral bodies of most of the thoracic vertebrae
Costal facets/fovea
the plane surface on the transverse process that articulates with the tubercle of the same numbered rib
Transverse costal facet
● The vertebrae of the lumbar (lower back, loin) region
● Characterized by their large size and long plate-like transverse process
● They can be distinguished from the last thoracic vertebrae by their lack of costal facets
Lumbar Vertebrae
This process are found from the midthoracic to the lumbar vertebrae
Accessory processes
● The bone formed by the fusion of the sacral vertebrae
● It articulates with the hip bone forming sacroiliac joint
Sacrum
Sacrum articulates with the hip bones forming what joint?
sacroiliac joint
The portion of the vertebral canal through the sacrum is called?
sacral canal
the openings on the dorsal and ventral surfaces of the bone for passage of spinal nerves
Dorsal and ventral sacral foramina ( foramen )
the lateral parts of the sacrum articulating with the hip bones to form the sacroiliac joint
Wings
Wings is the lateral parts of the sacrum articulating with the hip bones to form what joint?
sacroiliac joint
● The bony cavity formed by the sternum, the ribs, the costal cartilages and the bodies of the thoracic vertebra
Thorax
The thorax encloses and protects the?
thoracic organs
the long, curved bones forming the lateral wall of the thorax
Ribs
These ribs articulate by their costal cartilage with the sternum
True ribs (sternal ribs)
The costal cartilages of ribs unite to form the costal arch, indirectly joining them to the sternum
False ribs (asternal ribs)
These ribs found in the dog and man, end in costal cartilages that do not join to the sternum or other costal cartilage
Floating ribs
articulates with the caudal and cranial costal facets of adjacent thoracic vertebrae and the intervening intervertebral disc
Head of the rib
articulates with the articular facet on the transverse process of the same numbered vertebra
Tubercle of the rib
the bars of hyaline cartilage either connecting the bony rib to the sternum or to the costal arch or ending freely
Costal cartilage
the curved structure formed by the costal cartilages of the false ribs
Costal arch
The unpaired bones forming the floor of the thorax
Sternum or breastbone
the expanded first sternebrae
Manubrium
the last sternebrae which is a thin, horizontal bone capped by the xiphoid cartilage
Xiphoid process
formed by the last cervical vertebra, first pair of ribs and the sternum
Thoracic inlet or cranial thoracic opening
sealed by the diaphragm
Thoracic outlet or caudal thoracic opening
● Made up of the bones of the limbs
Appendicular Skeleton
the bone articulating with the shoulder and the sternum in man to maintain the shoulder in a lateral position
Clavicle (collar bone)
need their thoracic limb under their bodies, so the clavicle is absent or rudimentary
domestic animals
the flat, triangular bone of the shoulder
Scapula (shoulder blade)
The two scapulae make up the
thoracic girdle
the long projection dividing the scapula’s lateral surface and ending as the acromion
Spine of the scapula
the expanded distal end of the spine of the scapula
Acromion
the area cranial to the spine providing attachment for the supraspinatus muscle
Supraspinous fossa
the area caudal to the spine providing attachment for the infraspinatus muscle
Infraspinous fossa
most of the medial (costal) surface of the scapula providing attachment for the subscapular muscle
Subscapular fossa
the shallow cavity of scapula articulating with the head of the humerus to form the shoulder joint
Glenoid cavity
the cartilaginous structure on the dorsal border of the scapula
Scapular cartilage
the process near the cranial aspect of the glenoid cavity, providing attachment for the biceps brachii muscle
Supraglenoid tubercle
the small process on the medial side of the supraglenoid tubercle for the attachment of the coracobrachialis muscle
Coracoid process
the caudal projection of the acromion found only in the cat
Suprahamate process
Suprahamate process is the caudal projection of the acromion found only in the?
cat
The distal end of the spine of scapula can be called the?
acromion or hamate process
the largest bone of the thoracic limb
Humerus (arm or brachial bone)
It articulates proximally with the scapula, forming the
shoulder joint; and distally with the radius and ulna, forming the elbow joint
Humerus (arm or brachial bone)
the sulcus between the greater and lesser tubercles through which the tendon of the biceps brachii muscle runs
Intertubercular (bicipital) groove
the large process craniolateral to the head to which many muscles attach ( humerus )
Greater (lateral, major) tubercle
is a surface feature formed by the greater tubercle ( humerus )
point of the shoulder
the process on the medial side of the head ( humerus )
Lesser (medial, minor) tubercle
the cylindrical part connecting the two ends (epiphyses) of the bone
Body (shaft, diaphysis)
the large tuberosity on the lateral side of the humerus
Deltoid tuberosity
the entire distal extremity of the humerus, including the two articular areas (humeral capitulum and humeral trochlea), and two fossae (three fossae in the cat) and the lateral and medial epicondyles
Humeral condyle
the lateral side of the humeral condyle, giving rise to the extensors of the forearm
Lateral epicondyle
Functionally, Lateral epicondyle is known as the?
extensor epicondyle
The medial-most point of the humeral condyle, functionally known as the flexor epicondyle
Medial epicondyle
Medial epicondyle is the medial-most point of the humeral condyle, functionally known as the?
flexor epicondyle
it provides attachment for the flexor muscles of the forearm
flexor epicondyle
the caudal excavation receiving the proximal end of the ulna on extension of the elbow
Olecranon fossa
the excavation opposite the olecranon fossa receiving the proximal end of the radius on flexion of the elbow
Radial fossa
The cat has a small ? medial to the radial fossa for the medial coronoid process of the ulna on flexion of the elbow
coronoid fossa
the main weight-bearing bone of the forearm, articulating with the humerus and ulna forming the elbow joint and with the carpal bones and ulna forming the antebrachiocarpal joint
Radius
Three distal grooves on Radius cranial surface accommodate?
tendons
the articular surface on the distal end of the radius (trochlea) which articulates with the carpal bones
Carpalarticular surface
distal end of the radius
Styloid process of radius
the long, thin bone serving mainly for muscle attachment and formation of the elbow joint
Ulna
Poximally it articulates with the humerus and radius, distally with the radius and the carpal bones
Ulna
the proximal part of the ulna providing a lever arm for the extensor muscles of the elbow. It forms the points of the elbow
Olecranon
the depression for articulation with the humerus and ending in the anconeal process ( ulna )
Trochlear notch
the proximal end of the trochlear notch which fits in the olecranon fossa of the humerus when the elbow is extended ( ulna )
Anconeal process
the large distal end of the trochanter notch ( ulna )
Medial coronoid process
the pointed, distal end of the ulna
Styloid process of the ulna
the space between the ulna and radius, readily seen in the carnivores and pig.
Interosseous space
○ The distal part of the thoracic limb, consisting of the carpus, metacarpus, phalanges and their associated sesamoid bones
Manus
Manus is distal part of the thoracic limb, consisting of the?
carpus, metacarpus, phalanges and their associated sesamoid bones
Manus is also called ? in the carnivores
forepaw
also the compound joint formed by these bones, or the region between the forearm and metacarpus
carpal bones
○ The two rows of bones forming the carpus
Carpal Bone
Carpal Bones proximal row consists of the?
radial carpal , intermedial carpal , ulnar carpal , and accessory carpal
Carpal Bones distal row, from medial to lateral, consists of?
carpal ones 1-4
the largest carpal bone, medially located
Radial
between the radial and ulnar carpal bones
Intermediate
laterally located bone in the proximal row ( carpal )
Ulnar
projects behind (palmar) carpus, articulating with the ulnar carpal
Accessory
The only carpal bone to which muscles attach (flexor carpi ulnaris and extensor carpi ulnaris )
Accessory
● The region of the manus located between the carpus and digits
Metacarpus
the generalized metacarpus has five bones numbered I-V
from medial to laters
Metacarpal bones
Each bone of metacarpus is composed of:
- base
- head
- shaft
- at least one sesamoid bne
articulating with the carpus
base
articulating with the proximal phalanx of digit
head
connecting the two extremities ( head & base of carpus )
Shaft
Metacarpal bone that is much reduced and bears no weight
Metacarpal I
It is part of the dew claw
Metacarpal I
● The bones corresponding to the fingers and toes of man
Digits
The digits generally consist of?
three phalanges and a number of sesamoid bones
four main weight bearing digits (II-IV)
Carnivore Digits
the 1st digit and the 1st metacarpal bone
Dew claw
Reduced in size having only two phalanges, the proximal and distal, and one proximal sesamoid bone
Dew claw
have double dewclaws
Some dog breeds
the first phalanx divided into the base, body and head
Proximal phalanx
- the second phalanx with the same structure as the proximal phalanx, but shorter.
- not present in the first digit
Middle phalanx
the third phalanx carries the horny claw
Distal phalanx
provides insertion for the deep digital flexor tendon on the palmar side
flexor process
located on the dorsal proximal part of the four main digits provides insertion for the tendons of the common digital extensor muscle
extensor process
the tapered, cone-shaped process covered by the horny claw
Ungual process
the fingernail-like structure covering the ungual process
Horny claw
- the nine small bones at the metacarpophalangeal joint
- two for each main digits and one for the 1st digit
Palmar sesamoid bones
Hyoid apparatus It lies between the right and left portions of the mandible and is attached to the what process of each temporal bone?
styloid process
Each group of vertebrae is represented by its?
First letter followed by the number representing how many are in each section
This cervical vertebrae contains spinous process forms a longitudinal sail on its dorsum
Axis
Characterized by well-developed spinous processes and articular facets for the ribs
Thoracic vertebrae
Space between two adjacent ribs
Intercostal space
Rounded process of humerus articulating with the scapula’s glenoid cavity to form the shoulder joint
Head
Proximal part of radius which articulates with the humerus and ulna
Head
What is the proximal part of the radius which arriculates with humerus?
Fovea capitis
What is the proximal part of the radius which arriculates with ulna?
Capitulum
