The document provides a detailed overview of the skeletal system in dogs, including the axial skeleton (skull, vertebrae, ribs), appendicular skeleton (forelimb and hindlimb), and splanchnic skeleton (os penis). It elaborates on the composition and structure of various bones, joints, and the organization of the thoracic and pelvic girdles, as well as specifics about the limbs. Additionally, it explains the articulation of bones, development of the sternum, and the function of the os penis in male dogs.

2. Content :
+ Axial skeleton
-Skull
-Vertebrae
-Ribs
+ Appendicular skeleton
-Forelimb
-Hindlimb
+ Splanchnic skeleton
-Os penis

3. General view :

5. Skull :
-The skull consist of 3 bones combined with
each other to form the skull.
-The skull consist of cranium , mandible and
hyoid bone.
-The cranium consist of many bones which
combine with each other to form the cranium.
-Those bones are :
Frontal bone-nasal bone-maxillary bone-occipital bone
sphenoid bone-temporal bone-parietal bone
Lacrimal bone-zygomatic bone-incisive bone
Palatine bone-vomer bone-pterygoid bone
Ethmoid bone

7. -The facial crest and facial tuberosity are absent

11. -Only the frontal paranasal sinus is observed
and divided into cranial –middle and caudal
part.
-The maxillary sinus is small and open directly
to the nasal cavity and called maxillary recess.

12. Mandible:
-The mandible consist of body and 2
ramus.
-The 2 halves of the mandible is not
completely fused with each other by the
mandibular symphysis.
-The masseteric fossa is very deep for
the insertion of the masseter muscle.

15. Skull radiology:
Tongue
Hyoid bone

17. Vertebrae:
-The vertebrae is a group of bones which
form the vertebral column in which the spinal
cord is found.
-It is divided into :
Cervical(C)
thoracic(T),lumber(L),sacrum(S),and
caudal(Cd)
-The vertebrae formula is :
C=7
T=13
L=7
S=3
Cd=20-23

18. Cervical vertebrae:
-1st vertebra is called atlas.
-2nd vertebra is called axis
-The last vertebra has articulation surface for 1st rib.

19. Atlas
Axis

21. Radiology:

22. Thoracic vertebrae:
-It is characterised by long spinous process
-The last 3 vertebrae have accessory
processes
-It has articular surface for the rib
articulation

24. A.Vertebral canal; B.Transverse process;
C. Dorsal spinous process;
D.Vertebral
arch; E. Body;
F. Cranial articular process; H. Cranial costal
fovea.

27. Ribs:
Each rib is a curved rod, which at its dorsal end is movably
articulated to the vertebra, and at its ventral end is either
connected with the sternum, or ends freely. In the dog there are
thirteen pairs of ribs, nine pairs of which are directly connected
with the sternum, while the remaining four end freely and are
known as floating ribs. Each rib is obviously divided into two
parts, a dorsal or vertebral part, and a ventral or sternal
part. The vertebral portion, which forms about two-thirds of
the whole rib, is a flattened, regularly curved rod, completely
ossified. Its dorsal end is rounded, forming the head or
capitulum, which articulates with a concave surface furnished
partly by the corresponding vertebra and partly by the vertebra
next in front. The last three or four however articulate with one
vertebra only

28. J. Head;
K.Tuberculum.

29. Articulation between ribs and thoracic
vertebrae

30. Sternum:
This is an elongated cylindrical structure lying in the mid-ventral
wall of the thorax, and is divided into eight segments or
sternebrae. The anterior segment, the presternum (fig. 76, 1)
or manubrium sterni is expanded in front; the next six
segments, which, together form the mesosternum are
elongated, somewhat contracted in the middle and expanded at
the ends. The last segment or xiphisternum (fig. 76, 4) is long
and narrow, and terminates in a flattened expanded plate of
cartilage. The first pair of sternal ribs articulate with the sides of
the presternum, and the remaining pairs between the successive
sternebrae. Between the last sternebra and the xiphisternum
two pairs articulate. Development shows that the sternum is
formed by the union in the middle line of two lateral portions;
this can be well seen in the presternum and xiphisternum of the
puppy, but no traces of this median division remain in the adult
dog.

32. Thoracic cage :
-It is formed :
+Dorsally Thoracic vertebrae
+ventraly Sternum
+Lateraly Ribs
-Thoracic inlet :
+dorsaly 1st thoracic vertebra
+venteraly presternum
+lateraly 1st rib
-Thoracic outlet :
dorsaly  last thoracic vertebra
ventraly  xiphoid process of sternum
lateraly  last rib

34. Lumber vertebrae:

35. B.Transverse process; C. Dorsal
spinous process;
E. Body; F. Cranial articular
process;
G. Caudal articular process.
A.Vertebral canal; B.Transverse process;
C. Dorsal spinous process;
D.Vertebral arch;
E. Body; F. Cranial articular process.

36. Sacral and caudal vertebrae:
sacrum (A)
coccygeal or caudal vertebrae (B).

37. From this dorsal view, notice the attachment of the wings of the sacrum
(C) to the ilium (D).
E is the pelvic symphysis

40. Forelimb:
-Forelimb bones are completely
separated from the axial skeleton due
to the absence of clavicle bone in dog;
while communication occur by
muscules.
-Forelimb bones are:
scapula-humerus-radius and ulna-carpusmetacarpus and phalanges.

42. Scapula:
-Scapula is a flat bone which form
the shoulder girdle.
-The ratio between supraspinous
fossa and infraspinous fossa is 1:1.
-The scapular spine end by wide
trunkated acromion and the
tubular spinae is absent.

44. The articular surface, the glenoid cavity (E) is at the distal end of the bone, and the
.supraspinous fossa (C) is cranial to the spinous process (A), or spine of the scapula
The distal end of the spinous process (A) of the dog has an acromium process (B) .
When we dissect the thoracic limb, we will find that the supraspinatous muscle sits in the
supraspinous fossa (C) and that the infraspinatous muscle sits in the infraspinous fossa (D).
Note that the supraspinatous is above (supra) the spine and the infraspinatous fossa is
below (infra) the spine.
This second image shows the medial aspect eht fo left scapula dionelgarpus eht taht ecitoN .
.(E) ytivac dionelg eht fo tcepsa lainarc eht (arpus) evoba si (F) elcrebut
The small process on the supraglenoid tubercle is the corocoid process (G).
The smooth surface corresponds to where the subscapularis muscle lies, and it is known as
the subscapular fossa (H) (don't worry about these muscle names for now). The roughened
surface is the serrated face (I), and it is where the serratus ventralis muscle attaches

45. Humerus:
-It is a long bone which is called also the brachium-The head of the humerus with the glenoid cavity
of the scapula form the shoulder joint.
-The presence of supratrochlear foramen

47. D=supratrochlear foramen

49. Shoulder joint:

52. Radius and ulna:
In case of dog the radius and ulna is separated
from each other like human , while in farm
domestic animals ( horse, cattle, sheep, goat,
camel ) the radius and ulna is fused.

53. B=Radius C=Ulna

54. Bone A is the radius and bone
B is the ulna. Image 1 is the
cranial view, and because the
olecranon (E) curves medially
and the styloid process (F) of
the ulna is found caudal and
lateral to the distal end of the
radius, we can identify these
bones as the left radius and
ulna. Image 2 is then a view of
the lateral aspect of these
bones.
The proximal extremity of the
radius is the head (C), and the
distal extremity is the trochlea
(D).
The ulna consists of the
olecranon (E) proximally and
the styloid process (F) distally.
Notice that the styloid process
resembles a stylus pen.
The trochlea of the humerus sits
within the trochlear notch
(G).

56. Elbow joint:

58. Carpus , metacarpus and
phalanges:
Carpus is a group of small bone which form the
wrist joint , it is arranged in rows which differ
from species to another .
No. of carpal bone : 7
No. of bones in the proximal row : 4
No. of bones in the distal row : 4

61. Metacarpal bones is a group of long bones
which form the palm in human hand, the number
of these bones differ from species to another.
No. of metacarpal bones : 5
The first one is the shortest while the III and IV is
the longest .

62. Phalanges is a group of 3 bones which form the
fingers ( except in the first finger 2 bones ) , they
are called 1st , 2nd ,3rd .
The 3rd phalange and the distal part of the 2nd
phalange is coverd by claws.

65. Hind limb:
The hind limb which is the lower limb in human is directly connected to the axial
skeleton through the joint between os coxae
and the sacrum
It consist of :
Os coxae – femur – patella – tibia – fibula – tarsus
– metatarsus –and digits

67. Os coxae :
It is the first bone in the hind limb which form the pelvis
The right and left bone fused with each other by the pelvic symphysis
It consist of 3 bones ilium- ischium and
pubis
The gluteal surface is concave ( spoon like)

71. Femur :
It is a long bone which form the thigh
region.
The head of the femur form the hip joint
with the acetabulum of the os coxae .
The caudal surface characterized by 2
rough lines diverge proximally and distally
towards the extremities called linea
Aspera
The present of the supracondyloid facets.

75. Hip joint:
Hip joint is formed of the head of the femur
with the acetabulum of os coxae.

76. Fibula , tibia and patella :
B= tibia
C= fibula
D = Patella

77. The fibula (B) is lateral to
the tibia (A), and the tibial
tuberocity (C) and tibial
crest (D) are on the cranial
aspect of the tibia. This
means that image one is a
cranial view and image two is
a lateral view of the left
tibia and fibula.
The tibial tuberosity is on
the proximal aspect of the
tibia

78. Stifle joint :
Stifle joint is a compound joint which is
formed of 3 bones (distal extremity of femur
– proximal extremity of tibia – patella)

80. Tarsus , metatarsus and
phalanges :
Tarsus

83. The cluster of bones are the tarsal bones (A), which
make up the tarsus, or hock. The tibial-tarsal joint is
the same as your ankle.
The calcaneus (B) is the large tarsal bone that makes
up the heel of man. Unfortunately, I could not get a
good view to show that the calcaneus is in the lateral
portion of the hock.
The metatarsal bones are labelled C.
Remember that at the tarsus, cranial becomes dorsal
(E) and caudal becomes plantar (F), just like when
you plant your foot on the ground.
The phalanges (D) are similar to those in the
thoracic limb.

87. Os penis (baculum) :
Os penis is a bone which is found in the
penis of the dog which help to prevent the
closure of the urethra during intercourse
due to the contraction of the vaginal
muscles of the bitch .

89. A= os penis
B= urethra