Bones of the Forelimb Flashcards
(106 cards)
1
Q
Another name for forepaw?
A
manus
2
Q
Directional term: caudal
A
towards to tail
The caudal direction is toward the tail.
In the limbs, the term caudal is used as a directional term only in those parts of the limb proximal to the carpus or tarsus. At and distal to the carpus or tarsus, this aspect of the limb is described as palmar or plantar, respectively.
3
Q
Directional term: crainial
A
toward the head
The cranial direction is toward the head. When describing structures that are confined to the head region, the directional term used is rostral (a reference to the rostrum, or nose). In the limbs, the term cranial is used as a directional term only in those parts of the limb proximal to the carpus or tarsus. At and distal to the carpus and tarsus, this aspect of the limb is described as dorsal.
4
Q
Directional term: lateral
A
towards the outside, away from the midline
Lateral structures are located away from the midline and toward the sides. Structures that are represented on both sides of midline are said to be bilateral. Those that are located on the same side of midline as a point of reference are said to be ipsilateral to it, whereas those on the opposite side are referred to as contralateral.
5
Q
Directional term: medial ; median
A
towards the midline, away from the outside
Median is a reference to the midline. Implicit in this word is that median structures are unpaired. In the limb, structures described as median are found on the medial side of the limb, generally arrayed longitudinally, close to the limb’s midline.
6
Q
Directional term: distal
A
towards the feet
When limbs are described with reference to their longitudinal axis, proximal is toward the body and distal is toward the extremity (toward the ground).
7
Q
Directional term: proximal
A
towards the trunk
When limbs are described with reference to their longitudinal axis, proximal is toward the body and distal is toward the extremity (toward the ground).
8
Q
Directional term: doral
A
refers to the top side of anatomy; on the back
Dorsal refers to the back (dorsum) of the body; dorsal positions are therefore relatively closer to the back of the body.
For the limbs, dorsal applies to the front aspect of structures distal to and including the carpus or tarsus.
9
Q
Directional term: palmar
A
on the palm/pad side
Palmar is used to describe flexor surfaces of the manus (carpus, metacarpus, and digits). This is the aspect of the manus facing toward the pelvic limb.
10
Q
Review diagraghm of all directional terms:
A
11
Q
On the left limb scapula, identify: caudal angle
A
the angled portion of the scapula toward the tail
The triangular shape of the scapula is oriented with the base dorsal and slightly caudal and the apex ventral and pointed slightly craniad. The base of the triangle is accordingly called the dorsal border, with cranial and caudal angles describing the points at which the margins of the scapula incline ventrad to define the cranial and caudal borders, respectively.
12
Q
On the left limb scapula, identify : caudal border
A
the border of the scapula towards the tail
The triangular shape of the scapula is oriented with the base dorsal and slightly caudal and the apex ventral and pointed slightly craniad. The base of the triangle is accordingly called the dorsal border, with cranial and caudal angles describing the points at which the margins of the scapula incline ventrad to define the cranial and caudal borders, respectively.
13
Q
On the left limb scapula, identify : coraCOID process
A
Two small, indistinct processes in the region of the glenoid cavity are visible on the medial side.
medial side.
Cranially, the coracoid process gives origin to the m. coracobrachialis.
Caudally, the m. teres minor arises from the faint infraglenoid tubercle.
14
Q
On the left limb scapula, identify : cranial angle
A
the angle of scapula towards the tail on the head
The triangular shape of the scapula is oriented with the base dorsal and slightly caudal and the apex ventral and pointed slightly craniad. The base of the triangle is accordingly called the dorsal border, with cranial and caudal angles describing the points at which the margins of the scapula incline ventrad to define the cranial and caudal borders, respectively.
15
Q
On the left limb scapula, identify : cranial border
A
the border of the scapula towards the head
The triangular shape of the scapula is oriented with the base dorsal and slightly caudal and the apex ventral and pointed slightly craniad. The base of the triangle is accordingly called the dorsal border, with cranial and caudal angles describing the points at which the margins of the scapula incline ventrad to define the cranial and caudal borders, respectively.
16
Q
On the left limb scapula, identify : dorsal border
A
the border of the scapula towards the back (dorsal side)
The triangular shape of the scapula is oriented with the base dorsal and slightly caudal and the apex ventral and pointed slightly craniad. The base of the triangle is accordingly called the dorsal border, with cranial and caudal angles describing the points at which the margins of the scapula incline ventrad to define the cranial and caudal borders, respectively.
17
Q
On the left limb scapula, identify : infraglenoid tubercle
A
muscle attachment points in the glenoid cavity (shoulder joint)
Two small, indistinct processes in the region of the glenoid cavity are visible on the medial side.
Cranially, the coracoid process gives origin to the m. coracobrachialis.
Caudally, the m. teres minor arises from the faint infraglenoid tubercle.
18
Q
On the left limb scapula, identify : infraspinatus fossa
A
Muscle attachment points - Divided into 2 parts:
1) infraspinatus cranial - supraspinatus m.
2) infraspinatus caudal - infraspinatus m.
The lateral aspect of the scapula is divided into a supraspinous fossa cranial to and an infraspinous fossa caudal to the scapular spine. In life these flat regions are filled with the mm. supraspinatus et infraspinatus, respectively.
19
Q
On the left limb scapula, identify : scapular neck
A
The most ventral (distal) part of the scapula (the apex of the triangle) is collectively called the ventral angle, and it is modified into an articular surface. The narrowed region proximal to the articulation defines the neck of the scapula, which features an especially deep scapular notch on its cranial aspect.
20
Q
On the left limb scapula, identify : scapular notch
A
The most ventral (distal) part of the scapula (the apex of the triangle) is collectively called the ventral angle, and it is modified into an articular surface. The narrowed region proximal to the articulation defines the neck of the scapula, which features an especially deep scapular notch on its cranial aspect.
21
Q
On the left limb scapula, identify : scapular spine
`
A
The long axis of the scapula is sharply divided on its lateral face into cranial and caudal halves by a perpendicularly oriented scapular spine, which is enlarged at its distal extremity into the acromion. The spine of the scapula provides attachment to the m. trapezius, m. omotransversarius, and the scapular part of the m. deltoideus. The knob-like acromion serves as attachment site for the acromial part of the m. deltoideus.
22
Q
On the left limb scapula, identify : acromion
A
The long axis of the scapula is sharply divided on its lateral face into cranial and caudal halves by a perpendicularly oriented scapular spine, which is enlarged at its distal extremity into the acromion. The spine of the scapula provides attachment to the m. trapezius, m. omotransversarius, and the scapular part of the m. deltoideus. The knob-like acromion serves as attachment site for the acromial part of the m. deltoideus.
23
Q
On the left limb scapula, identify : subscapular fossa
A
The medial face of the scapula is relatively flat, constituting the subscapular fossa to which the m. subscapularis attaches. A roughed region in the dorsal part of the medial scapula is the serrated face, which is the region on which the m. serratus ventralis inserts.
24
Q
On the left limb scapula, identify :
supraglenoid tubercle
A
The concave surface of the ventral angle by which the scapula articulates with the humerus is called the glenoid cavity. The supraglenoid tubercle is a protuberance on the cranial edge of the glenoid cavity and gives origin to the m. biceps brachii.
25
On the left limb scapula, identify :
supraspinatous fossa
## Footnote
The lateral aspect of the scapula is divided into a supraspinous fossa cranial to and an infraspinous fossa caudal to the scapular spine. In life these flat regions are filled with the mm. supraspinatus et infraspinatus, respectively.
26
On the left limb scapula, identify : ventral angle
angle of the scapula along the ventral side
## Footnote
The most ventral (distal) part of the scapula (the apex of the triangle) is collectively called the ventral angle, and it is modified into an articular surface. The narrowed region proximal to the articulation defines the neck of the scapula, which features an especially deep scapular notch on its cranial aspect.
27
On the left humerus, identify : body of the humerus
## Footnote
The body of the humerus possesses a smooth surface that begins on the caudal aspect and spirals to the craniolateral aspect of the bone. This is the brachial groove, against which lies the m. brachialis.
28
On the left humerus, identify :
brachial groove
## Footnote
The body of the humerus possesses a smooth surface that begins on the caudal aspect and spirals to the craniolateral aspect of the bone. This is the brachial groove, against which lies the m. brachialis.
29
On the left humerus, identify : capitulum
## Footnote
The humeral condyle comprises two articular masses and the adjacent processes. The more medial articular surface is the trochlea, which articulates with both the head of the radius and the trochlear notch of the ulna. The capitulum is the smaller, more lateral part of the articular surface, and it articulates with the head of the radius. The capitulum, through its articulation with the radius, represents the primary weight-bearing portion of the distal humerus.
30
On the left humerus, identify : deltoid tuberosity
## Footnote
The crest of the greater tubercle and the tricipital line converge near the middle of the humerus on its lateral aspect in a projection called the deltoid tuberosity. This is the insertional site for the m. deltoideus.
31
On the left humerus, identify :
greater tubercle
## Footnote
The greater tubercle is the large, irregular prominence craniolateral to the humeral head. The mm. supraspinatus et infraspinatus insert on the greater tubercle. The tubercle describes an arc that is continued distad on the cranial aspect of the humerus. This creates the crest of the greater tubercle and provides attachment for the pectoral mm. The greater tubercle is a palpable bony landmark in the living animal, forming what is commonly called the "point of the shoulder."
32
On the left humerus, identify : crest of the greater tubercle
## Footnote
The greater tubercle is the large, irregular prominence craniolateral to the humeral head. The mm. supraspinatus et infraspinatus insert on the greater tubercle. The tubercle describes an arc that is continued distad on the cranial aspect of the humerus. This creates the crest of the greater tubercle and provides attachment for the pectoral mm. The greater tubercle is a palpable bony landmark in the living animal, forming what is commonly called the "point of the shoulder."
33
On the left humerus, identify :
humeral condyle
## Footnote
The humeral condyle comprises two articular masses and the adjacent processes. The more medial articular surface is the trochlea, which articulates with both the head of the radius and the trochlear notch of the ulna. The capitulum is the smaller, more lateral part of the articular surface, and it articulates with the head of the radius. The capitulum, through its articulation with the radius, represents the primary weight-bearing portion of the distal humerus.
34
On the left humerus, identify :
humeral head
## Footnote
The head of the humerus is considerably larger than the complementary area of the glenoid cavity. This fact contributes to the stability of the shoulder joint. The humeral head is also the most common site for development of osteochondrosis in the dog.
35
On the left humerus, identify :
intertubercle groove
## Footnote
A deep intertubercular groove on the cranial aspect of the proximal humerus divides the greater and lesser tubercles. In life, the tendon of origin of the m. biceps brachii lies in the intertubercular groove, where it is invested with an extension of the shoulder joint capsule that serves as a tendon sheath.
36
On the left humerus, identify :
lateral epicondyle
## Footnote
On each side of the condyle are irregular masses, the medial and lateral epicondyles. The lateral epicondyle features a lateral supracondylar crest that passes proximad and caudad from the epicondyle. The** lateral epicondyle **and supracondylar crest give origin to the craniolateral muscles of the antebrachium and the m. anconeus (the extensor group).
37
On the left humerus, identify :
lateral supercondylar crest
## Footnote
On each side of the condyle are irregular masses, the medial and lateral epicondyles. The lateral epicondyle features a lateral supracondylar crest that passes proximad and caudad from the epicondyle. The lateral epicondyle and supracondylar crest give origin to the craniolateral muscles of the antebrachium and the m. anconeus (the extensor group).
38
On the left humerus, identify :
lesser tubercle
## Footnote
The lesser tubercle is an enlargement on the medial aspect of the proximal humerus, just cranial to the humeral head. The m. subscapularis inserts on this tubercle, as does part of the deep pectoral m.
39
On the left humerus, identify :
medial epicondyle
## Footnote
On each side of the condyle are irregular masses, the medial and lateral epicondyles. The medial epicondyle is more massive than the lateral and gives origin to the caudomedial muscles of the antebrachium (the flexor group).
40
On the left humerus, identify :
humeral neck
## Footnote
The humeral head is attached to the body of the humerus by a short, thick neck.
41
On the left humerus, identify :
olecranon fossa
only on the caudal aspect
## Footnote
When viewed from the caudal aspect, a deep olecranon fossa lies between the medial and lateral epicondyles. The anconeal process of the ulna projects into this fossa during extension of the elbow. The bone within the olecranon fossa is usually perforated by the supratrochlear foramen. This aperture represents a diminution of unneeded bone mass and no structures pass through it. The olecranon fossa is open to the radial fossa on the cranial side of the condyle via the supratrochlear foramen.
42
On the left humerus, identify :
radial fossa
## Footnote
When viewed from the caudal aspect, a deep olecranon fossa lies between the medial and lateral epicondyles. The anconeal process of the ulna projects into this fossa during extension of the elbow. The bone within the olecranon fossa is usually perforated by the supratrochlear foramen. This aperture represents a diminution of unneeded bone mass and no structures pass through it.** The olecranon fossa is open to the radial fossa on the cranial side of the condyle via the supratrochlear foramen.**
43
On the left humerus, identify :
supratrochlear foreamen
shown in light green
## Footnote
When viewed from the caudal aspect, a deep olecranon fossa lies between the medial and lateral epicondyles. The anconeal process of the ulna projects into this fossa during extension of the elbow. The bone within the olecranon fossa is usually perforated by the supratrochlear foramen. This aperture represents a diminution of unneeded bone mass and no structures pass through it. The olecranon fossa is open to the radial fossa on the cranial side of the condyle via the supratrochlear foramen.
44
On the left humerus, identify :
teres major tuberosity
## Footnote
Distal to the lesser tubercle on the medial aspect of the body is an indistinct enlargement, the teres major tuberosity, onto which the m. teres major inserts.
45
On the left humerus, identify :
teres minor tuberosity
## Footnote
Near the proximal end of the tricipital line is a very indistinct teres minor tuberosity that represents the site of insertion of the m. teres minor.
46
On the left humerus, identify :
tricipital line
## Footnote
A distinct ridge passes from the caudal part of the greater tubercle distad on the lateral aspect of the humerus. This is the tricipital line,** which marks the edge of the attachment of the lateral head of the m. triceps brachii.**
47
On the left humerus, identify :
trochlea of the humerus
## Footnote
The humeral condyle comprises two articular masses and the adjacent processes. The more medial articular surface is the trochlea, which articulates with both the head of the radius and the trochlear notch of the ulna. The capitulum is the smaller, more lateral part of the articular surface, and it articulates with the head of the radius. The capitulum, through its articulation with the radius, represents the primary weight-bearing portion of the distal humerus.
48
On the left radius, identify :
ulnar notch
## Footnote
The ulnar notch is a small incisure on the lateral aspect of the distal extremity. This articulates with the adjacent ulna.
49
On the left radius, identify :
styloid process
## Footnote
The medial side of the distal radius forms a distinct point called the styloid process. This process participates in the antebrachiocarpal joint and also gives origin to the short medial collateral ligament.
50
On the left radius, identify :
grooves for extensor tendons
## Footnote
The trochlea of the radius is called so because of three extensor grooves on its cranial surface, emphasizing the role of the distal extremity as a "pulley" for the extensor tendons. The most medial of these grooves accepts the tendon of the m. abductor pollicis longus. The middle groove carries the tendon of the m. extensor carpi radialis, and the lateral groove carries the tendon of the common digital extensor m.
51
On the left radius, identify :
trochlea of the radius
## Footnote
The trochlea of the radius is called so because of three extensor grooves on its cranial surface, emphasizing the role of the distal extremity as a "pulley" for the extensor tendons. The most medial of these grooves accepts the tendon of the m. abductor pollicis longus. The middle groove carries the tendon of the m. extensor carpi radialis, and the lateral groove carries the tendon of the common digital extensor m.
52
On the left radius, identify :
fovea capitus
## Footnote
The head of the radius bears two distinct articular surfaces: a concave articular fovea**, the fovea capitis, that articulates with the capitulum of the humerus,** and a caudal articular circumference by which the radius articulates with the radial notch of the ulna. The head is attached to the body of the radius through a short, indistinct neck.
53
On the left radius, identify :
articular cirmcumference
## Footnote
The head of the radius bears two distinct articular surfaces: a concave articular fovea, the fovea capitis, that articulates with the capitulum of the humerus, and a** caudal articular circumference by which the radius articulates with the radial notch of the ulna**. The head is attached to the body of the radius through a short, indistinct neck.
54
On the left radius, identify :
radial head
## Footnote
The radius is divided into a head, a body, and a distal extremity sometimes referred to as the trochlea.
The head of the radius bears two distinct articular surfaces: a concave articular fovea, the fovea capitis, that articulates with the capitulum of the humerus, and a caudal articular circumference by which the radius articulates with the radial notch of the ulna. **The head is attached to the body of the radius through a short, indistinct neck.****
55
On the left radius, identify :
radial neck
## Footnote
The head of the radius is attached to the body through a short, indistinct neck.
Just distal to the neck on the medial aspect of the body is a small enlargement called the radial tuberosity onto which one of the two tendons of the m. biceps brachii inserts.
56
On the left radius, identify :
radial tuberosity
## Footnote
The radius is divided into a head, a body, and a distal extremity sometimes referred to as the trochlea.
The body of the radius is roughly oval in cross-section. Its cranial surface is convex and caudal surface more concave. Just distal to the neck on the medial aspect is a small enlargement called the **radial tuberosity onto which one of the two tendons of the m. biceps brachii inserts.**
57
On the left radius, identify : body
## Footnote
The radius is divided into a head, a body, and a distal extremity sometimes referred to as the trochlea.
The body of the radius is roughly oval in cross-section. Its cranial surface is convex and caudal surface more concave. Just distal to the neck on the medial aspect is a small enlargement called the radial tuberosity onto which one of the two tendons of the m. biceps brachii inserts.
58
On the left ulna, identify : body
## Footnote
The body of the ulna is laterally compressed proximally and tapers into a narrow cylinder distally. The face of the body adjacent to the radius constitutes the interosseous border, to which in life is attached an interosseous ligament uniting these two bones of the antebrachium.
59
On the left ulna, identify : olecranon
## Footnote
The ulna is markedly larger at its proximal extremity than distal. The proximal end is expanded into a robust lever, the olecranon, to which the m. triceps brachii attach. The olecranon forms a prominent, palpable bony landmark, **commonly called the point of the elbow in the living animal.**
60
On the left ulna, identify : radial notch
## Footnote
The distal end of the trochlear notch intersects a second, transversely oriented notch, the radial notch, which articulates with the articular circumference of the radius. The medial and lateral ends of the radial notch form two sharp medial and lateral coronoid processes. Osteochondrosis of the medial coronoid process ("fragmented coronoid process") is a common cause of elbow dysplasia.
61
On the left ulna, identify :
lateral **coraNOID **process
## Footnote
*You are **annoyed** when hitting your funnybone.
COID - Annoyed
## Footnote
The distal end of the trochlear notch intersects a second, transversely oriented notch, the radial notch, which articulates with the articular circumference of the radius. The medial and lateral ends of the radial notch form two sharp medial and lateral coronoid processes. Osteochondrosis of the medial coronoid process ("fragmented coronoid process") is a common cause of elbow dysplasia.
62
On the left ulna, identify :
medial coraNOID process
## Footnote
*You are **annoyed** when hitting your funnybone.
COID - Annoyed
## Footnote
The distal end of the trochlear notch intersects a second, transversely oriented notch, the radial notch, which articulates with the articular circumference of the radius. The medial and lateral ends of the radial notch form two sharp medial and lateral coronoid processes. **Osteochondrosis of the medial coronoid process ("fragmented coronoid process") is a common cause of elbow dysplasia.**
63
On the left ulna, identify :
trochlear notch
## Footnote
The ulna articulates with the trochlea of the humerus via its deep trochlear notch. The most proximal protrusion from the trochlear notch is the anconeal process, which projects into the olecranon fossa of the humerus when the elbow is in extension. In most dogs, the anconeal process forms from a separate ossification center that fuses with the rest of the ulna around four months of age. Failure to fuse is a very common cause of elbow dysplasia.
64
On the left ulna, identify :
anconeal process
## Footnote
The ulna articulates with the trochlea of the humerus via its deep trochlear notch. The most proximal protrusion from the trochlear notch is the anconeal process, which projects into the olecranon fossa of the humerus when the elbow is in extension. In most dogs, **the anconeal process forms from a separate ossification center that fuses with the rest of the ulna around four months of age. Failure to fuse is a very common cause of elbow dysplasia.**
65
On the left ulna, identify :
styloid process
## Footnote
The body of the ulna tapers distad to the styloid process. The styloid process participates in the antebrachiocarpal joint and gives attachment to the short lateral collateral ligament of the carpus.
66
On the left ulna, identify :
medial tuberosity
ONLY seen in medial view
## Footnote
A small elevation, the ulnar tuberosity, can be identified distal and caudal to the medial coronoid process. The ulnar insertion of the m. biceps brachii inserts on this tuberosity.
67
On the left manus, identify :
carpal bones
## Footnote
The carpus of the dog comprises seven short carpal bones arranged in two transverse rows. In conjunction with the bones of the antebrachium and the metacarpus, the carpal bones participate in three transverse joints: antebrachiocarpal, middle carpal, and carpmetacarpal joints. The many articulations between adjacent carpal bones are referred to as intercarpal joints, and although these are capable of some degree of sliding, the primary movement of the carpus in its entirety is flexion-extension, afforded almost entirely by the hinge action of the antebrachiocarpal and middle carpal joints. The carpus, metacarpus and digits together constitute the manus.
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones
68
On the left manus, identify :
1st carpals
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
Note that in the palmar view, the first carpal bone overlies the second carpal bone (see rotatable view).
69
On the left manus, identify :
2nd carpals
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
Note that in the palmar view, the first carpal bone overlies the second carpal bone (see rotatable view).
70
On the left manus, identify : 3rd carpals
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
71
On the left manus, identify :
4th carpals
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
72
On the left manus, identify :
accessory carpal bones
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
The accessory carpal bone lies on the palmerolateral side of the carpus. The mm. ulnaris lateralis et flexor carpi ulnaris insert on the accessory carpal bone.
73
On the left manus, identify :
radial carpal bones
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
74
On the left manus, identify :
ulnar carpal bones
## Footnote
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
75
On the left manus, identify :
digits
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The proximal phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The distal phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
76
On the left manus, identify :
distal phalanges
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The proximal phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The distal phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
77
On the left manus, identify :
middle phalanges
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The proximal phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The distal phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
78
On the left manus, identify :
proximal phalanges
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The proximal phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The distal phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
79
On the left manus, identify :
ungual crests
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The proximal phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The distal phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
80
On the left manus, identify :
ungual processes
It is where the claw attaches
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The proximal phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The distal phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
81
On the left manus, identify :
metacarpals
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
82
On the left manus, identify :
base of metacarpals
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
83
On the left manus, identify :
body of the metacarpals
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
84
On the left manus, identify :
head of metacarpals
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
85
On the left manus, identify :
metacarpal I
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
86
On the left manus, identify :
metacarpal II
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
87
On the left manus, identify :
metacarpal III
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
88
On the left manus, identify :
metacarpal IV
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
89
On the left manus, identify :
metacarpal V
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
90
On the left manus, identify :
palmar sesamoid bones
## Footnote
The metacarpal bones are numbered I – V (first, second, third, fourth, and fifth), with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
91
On the entire thoracic limb, identify :
distal radial joint
## Footnote
The elbow joint is a composite joint formed by the articulations between the condyle of the humerus, the head of the radius, and the proximal end of the ulna. Its movement is confined almost entirely to flexion-extension. A small amount of pronation-supination is afforded by the proximal radioulnar joint formed by the articular circumference of the radius and the radial notch of the ulna. The distal radioulnar joint, between the lateral side of the distal radius and the ulna's styloid process, is capable only of very limited movement, providing instead the distal pivot point for antebrachial pronation-supination.
92
On the entire thoracic limb, identify :
elbow joint
## Footnote
The elbow joint is a composite joint formed by the articulations between the condyle of the humerus, the head of the radius, and the proximal end of the ulna. Its movement is confined almost entirely to flexion-extension. A small amount of pronation-supination is afforded by the proximal radioulnar joint formed by the articular circumference of the radius and the radial notch of the ulna. The distal radioulnar joint, between the lateral side of the distal radius and the ulna's styloid process, is capable only of very limited movement, providing instead the distal pivot point for antebrachial pronation-supination.
93
On the entire thoracic limb, identify :
humerus
## Footnote
The bone of the brachium is the humerus. Its proximal extremity articulates with the scapula at the scapulohumeral (shoulder) joint via the humeral head, which is attached to the body of the humerus by a short, thick neck. The body of the humerus is slightly S-shaped. The entire distal extremity is called the humeral condyle.
94
On the entire thoracic limb, identify :
manus
## Footnote
The manus consists of the carpus, the metacarpal bones, and the phalanges. The canine manus possesses five digits, numbered I through V medial to lateral. Digit I, or the dewclaw, has only two phalanges; each of the four weight-bearing digits is composed of three phalanges.
95
On the entire thoracic limb, identify :
carpus
## Footnote
The carpus of the dog comprises seven short carpal bones arranged in two transverse rows. In conjunction with the bones of the antebrachium and the metacarpus, the carpal bones participate in three transverse joints: antebrachiocarpal, middle carpal, and carpmetacarpal joints. The many articulations between adjacent carpal bones are referred to as intercarpal joints, and although these are capable of some degree of sliding, the primary movement of the carpus in its entirety is flexion-extension, afforded almost entirely by the hinge action of the antebrachiocarpal and middle carpal joints. The carpus, metacarpus and digits together constitute the manus.
The proximal row of carpal bones consists of (from medial to lateral) the radial, ulnar, and accessory carpal bones. The distal row is numbered from medial to lateral: first, second, third and fourth carpal bones.
96
On the entire thoracic limb, identify :
metacarpus
## Footnote
The metacarpal bones are numbered I – V, with I being most medial. These are rod-shaped bones, with I being markedly shorter than the others. Each bone possesses a proximal base, a body, and a distal head. The metacarpophalangeal joint is distinguished by two palmar sesamoid bones, embedded within the tendons of insertion of the mm. interossei.
97
On the entire thoracic limb, identify :
phalanges
## Footnote
The canine forepaw consists of four fully developed, weight-bearing digits and a small, medial first digit ("dewclaw"). With the exception of the dewclaw, each digit comprises three phalanges. The dewclaw possesses only two phalanges. The first phalanx of each digit is the longest. The middle phalanx is similar in shape to the first. The third phalanx is modified by an ungual crest, associated with the tissues that produce the claw. A curved process arises from beneath the crest. This is the ungual process to which the wall of the claw attaches.
98
On the entire thoracic limb, identify :
proximal radioulnar joint
## Footnote
The elbow joint is a composite joint formed by the articulations between the condyle of the humerus, the head of the radius, and the proximal end of the ulna. Its movement is confined almost entirely to flexion-extension. A small amount of pronation-supination is afforded by the proximal radioulnar joint formed by the articular circumference of the radius and the radial notch of the ulna. The distal radioulnar joint, between the lateral side of the distal radius and the ulna's styloid process, is capable only of very limited movement, providing instead the distal pivot point for antebrachial pronation-supination.
99
On the entire thoracic limb, identify :
radius
## Footnote
The radius and ulna are the bones of the antebrachium. They articulate proximally with one another and with the humerus, and distally with each other and the proximal row of carpal bones. The radius is the primary weight-bearing bone of the antebrachium. The canine radius and ulna are capable of a limited amount of pronation and supination, primarily through rotation of their distal extremities.
100
On the entire thoracic limb, identify :
scapula
## Footnote
The scapula is a flat, roughly triangular bone that is the most proximal bone of the thoracic limb. It is attached to the lateral aspect of the thorax through muscular rather than bony connections; this unique sort of articulation is referred to as a synsarcosis.
Distally, the glenoid cavity of the scapula articulates with the humeral head at the scapulohumeral (shoulder) joint.
101
On the entire thoracic limb, identify :
scapulohumeral joint
## Footnote
The glenoid cavity of the scapula articulates with the humeral head at the scapulohumeral (shoulder) joint. This is a spheroidal (ball and socket) joint. In life, the margins of the glenoid cavity are enlarged by the presence of a cartilaginous labrum (glenoid lip), improving the stability of the joint. The joint capsule is capacious in order to accommodate the broad range of motion in this joint. Thickenings of the fibrous joint capsule, glenohumeral ligaments, are present on medial and lateral sides, but these are poorly developed in dogs. Stability of the shoulder joint is primarily achieved by the tendons of mm. supraspinatus, infraspinatus & subscapularis.
102
On the entire thoracic limb, identify :
ulna
## Footnote
The radius and ulna are the bones of the antebrachium. They articulate proximally with one another and with the humerus, and distally with each other and the proximal row of carpal bones. The radius is the primary weight-bearing bone of the antebrachium. The canine radius and ulna are capable of a limited amount of pronation and supination, primarily through rotation of their distal extremities.
103
On the scapulohumeral joint, identify:
humerus
## Footnote
The bone of the brachium is the humerus. Its proximal extremity articulates with the scapula at the scapulohumeral (shoulder) joint via the humeral head, which is attached to the body of the humerus by a short, thick neck. The body of the humerus is slightly S-shaped. The entire distal extremity is called the humeral condyle.
104
On the scapulohumeral joint, identify:
humeral head
## Footnote
The head of the humerus is considerably larger than the complementary area of the glenoid cavity. This fact contributes to the stability of the shoulder joint. The humeral head is also the most common site for development of osteochondrosis in the dog.
105
On the scapulohumeral joint, identify:
## Footnote
The scapula is a flat, roughly triangular bone that is the most proximal bone of the thoracic limb. It is attached to the lateral aspect of the thorax through muscular rather than bony connections; this unique sort of articulation is referred to as a synsarcosis.
Distally, the glenoid cavity of the scapula articulates with the humeral head at the scapulohumeral (shoulder) joint
106
On the scapulohumeral joint, identify:
articular surface of the joint
## Footnote
The glenoid cavity of the scapula articulates with the humeral head at the scapulohumeral (shoulder) joint. This is a spheroidal (ball and socket) joint. In life, the margins of the glenoid cavity are enlarged by the presence of a cartilaginous labrum (glenoid lip), improving the stability of the joint. The joint capsule is capacious in order to accommodate the broad range of motion in this joint. Thickenings of the fibrous joint capsule, glenohumeral ligaments, are present on medial and lateral sides, but these are poorly developed in dogs. Stability of the shoulder joint is primarily achieved by the tendons of mm. supraspinatus, infraspinatus & subscapularis.
