Lab : The Appendicular Skeleton Flashcards
What is the scapula?
the shoulder blade
How is the scapula held in the body?
by muscles, it has no direct attachment to the axial skeleton
what is the large ridge along the lateral aspect of the scapula called?
the spine of the scapula
What bone is typically only found in cats most cranially?
a vestigial clavicle (dogs may/may not have it, completely absent in equine/ox)
Distally from the scapula, what bone is found?
the humerus
where does the humerus and the scapula articulate to form the shoulder joint?
at the head of the humerus
what is the upper arm region also known as?
the brachium
What structure is located medial on the head of the humerus?
the intertubercular groove
what is found in the intertubercular groove?
the tendon of the biceps brachii
In the dog, what is located at the distal end of the humerus?
the supratrochlear notch
what is the lower arm region called?
the antebrachium
which two bones are found in the antebrachium?
the radius and the unla
which bone is the weight bearing bone of the antebachium?
the radius
what structure is located at the proximal end of the radius?
the head of the radius
what bones do the head of the radius articulate with?
the humerus and the unla
what structure is found distally on the radius?
the trochlea
what is found at the trochlea of the radius?
tendons of the extensor muscles
What is the proximal point of the ulna?
the olecranon
what does the olecranon do?
serves as a lever for the triceps muscle to extend the cubital joint
what is the proximal hook-like structure on the ulna?
the trochlear notch
what is the proximal point of the trochlear notch?
the anconeal process
what is the distal tip of the ulna
the styloid process
why can horses and cows not supinate or pronate their antebrachium?
because their radius and ulna are fused together
what is the manus?
the hand (or front foot)
what bones make up the manus?
the carpus, metacarpus, phalanges, and sesamoid bones
What do the bones of the carpus form?
a compound joint
how are the carpal bones arranged?
into two rows; bones in each row differ in number depending on species
in the proximal row of carpal bones, what two bones are found?
the radial and ulnar carpal bones; each associated with either the radius or ulna
How are the distal carpal bones arranged?
in coordination with the digit they associate with
how are digits and metacarpals numbered?
1-5 starting medial and moving laterally
In cats and dogs, what is their first digit?
the dewclaw
where is the dewclaw located?
on the medial aspect of the carpus, higher than other digits; it is not weight bearing
What metacarpals is the horse missing?
the 1st and 5th digits and metacarpals
where are metacarpals 2 and 4 in the horse?
they are vestigial, and typically fuse into the cannon bone forming splint bones
what is the only digit a horse has?
the 3rd digit; which is weight bearing
what does the 3rd metacarpal of a horse form?
the cannon bone
What metacarpals is the cow missing?
1st and 2nd metacarpals
What metacarpals fuse together in the cow?
the 3rd and 4th to fuse the cannon bone
Where is the 5th metacarpal found on the cow?
on the proximal aspect of the lateral cannon bone, typically vestigial
What is found at the distal end of the metacarpal bones?
two small rounded palmar sesamoid bones
what is the function of the palmar sesamoid bones?
to help joints that need extra leverage in order to flex
each digit has how many phalanges?
3
how are they numbered?
the same way metacarpals are, each with a proximal, middle, and distal phalanax
what are the weight bearing digits of dogs and cats?
digits 2-5
what are the weight bearing digits of cows?
digits 3 & 4
what is the weight bearing digit of horses?
digit 3
on dogs and cats, each distal phalanx has a bony point called the
ungual process which connects directly to each claw
on dogs and cats, what is found at the proximal end of the phalanges?
2 small sesamoid bones
what is the most distal phalanx called in cows and horses?
the coffin bone
what do cows and horses have on the palmar aspect of their distal limbs?
proximal and distal sesamoid bones
what are the distal sesamoid limbs called in horses?
the navicular bone
What do the pelvic limbs have that the thoracic limbs lack?
a direct axial skeleton attachment
what is the pelvis called?
os coxae
what does the os coxae articulate with?
the sacral vertebrae
what is the space between the os coxae and the sacral vertebrae?
the pelvic cavity
what bones make up the os coxae?
the ilium, ischium, and pubis
What are the large wing-like projections dorso-lateral on the os coxae
the ilium (or wings of the ilium)
where does the ilium meet the sacrum of the spine?
their medial aspect; the ilium’s articular surface
what is the tip of each ilium?
the tuber coxae
what is the tuber coxae known as in the cow?
the hook
where is the ischium located?
ventro-caudally from the ilium
what is the large hole found medially on the ischium?
the obturator foramen
what is found on the lateral aspect of the ischium?
the acetabulum
what does the acetabulum do?
this is where the pelvis articulates with the femur
what is found on the caudal most aspect of the ischium
the ischiatic tuberosity
what does the ischiatic tuberosity do?
provide muscle attachment for the thigh muscles
what is the most ventral bone of the os coxae?
the pubis
where does the pubis meet and what does it form?
they meet medially and form the pubis symphysis
What part of the femur articulates with the acetabulum?
the head of the femur
what joint does the femur and acetabulum form?
a ball and socket joint
What is found laterally on the proximal femur?
the greater trochanter
what does the greater trochanter allow for?
the surrounding muscles to rotate the femur
Distally on the femoral body is what?
the lateral and medial condyles
what does the cranial surface of these condyles form?
the intercondylar fossa
what does the intercondylar fossa allow for?
the sliding movement of the patella
what is the largest sesamoid bone in the body?
the patella
what does the proximal patella allow for?
attachment of the quadriceps muscles
What is the trochlear tubercle?
the large prominance on the medial aspect of the horse patella
what does the trochlear tubercle do?
allow the horse to lock its stifle in place while standing; also known as the stay apparatus
What bones make up the crus?
the tibia and fibula
what is the ridge on the proximal cranial aspect of the tibia?
the tibial tuberosity
what does the tibial tuberosity allow for?
the patellar ligament to attach; which is a continuation of the quadriceps muscle
Does the fibula bear weight?
No
what does the fibula allow for?
muscle attachments
what is the proximal end of the fibula? the distal end?
head of the fibula; lateral malleolus
What is different about the cows fibula?
it is fused with the tibia and is very short
what is different about the horses fibula?
it is about half the length of the tibia and is fused distally
The proximal row of bones in the tarsus is known as the what?
the calcaneus (lateral) and talus (medial)
what is another name for the tarsus?
the hock
what is the hind foot known as?
the pes
what is missing in the pes of dogs and cats?
the first digit
