forelimb Flashcards
list the bones associated with the shoulder region
scapula
clavicle
list the bone associated with the brachium
humerus
list the bones associated with the antebrachium
radius
ulna
list the bones associated with the carpus
carpal bones
list the bones associated with the metacarpus
metacarpal bones
list the bones associated with the digit
proximal, middle, and distal phalanges
what is the equine equivalent to metacarpal bone?
cannon
what is synsarcosis?
“joint” formed between bone and body through muscle
what is the lateral aspect of the scapula characterized by?
spine
describe scapular cartilage in ungulates
- dorsal aspect of the scapula
- helps increase surface area of the shoulder for muscle attachment
what are the two depressions the spine of the scapula divides and describe them?
supraspinous (above spine) fossa
infraspinous (below spine) fossa
- both filled by muscles
what does the ventral aspect of the scapula have that articulates with the head of the humerus?
glenoid cavity
what is the prominent spinous process at the end of the spine of the scapula is called what and found in which species?
acromion process
all domestic species except horse and pig
what is the clavicle reduced to in domestic species and describe it
brachiocephalicus
- fibrous intersection in the muscle
what joint forms from the head of the humerus to articulate with the glenoid cavity of the scapula
shoulder joint
what are the two processes associated with the head of the humerus?
greater (located laterally) and lesser (located medially) tubercle
what are the greater and lesser tubercle of the humerus separated by?
intertubercular groove
what does the distal extremity of the humerus have?
articular condyle
in domestic species, what is the condyle of the humerus divided into? what does that articulate with?
medial trochlea
- articulates with the ulna and “lateral capitulum” which articulates with the radius
what is the fossa that the groove formed by the trochlea continuing in the caudal aspect? what does it accomodate?
olecranon fossa
- accommodates anconeal process of the ulna
describe the radius
long bone
stronger than the ulna
what process is present on the distal end of the radius on the medial aspect?
medial styloid process
why is pronation and supination not possible in larger domestic species?
because of fusion of the radius and ulna
why is supination and pronation of dogs and cats possible?
radius and ulna bones are separate
what pointed projection does the distal end of the ulna end in?
lateral styloid process
characteristic feature of the ulna is the “______________” that is located on the proximal end of the ulna and is palpable as the “point of the elbow”.
olecranon process
which row of carpal bones articulate with the radius and ulna?
proximal
which row of carpal bones articulate with the metacarpal bones?
distal
how many rows of metacarpals and digits do carnivores typically consist of?
5
how many digits do horses have?
one
how many digits and metacarpals do cattle have?
2 (cloven hooved)
what forms the articulation between the distal portion of the scapula and the proximal portion of the humerus
shoulder joint
what is the articulation between the distal portion of the humerus and the proximal portion of the radius and ulna?
elbow joint
what are the three levels to the carpal joints?
carpal —> metacarpal —-> first phalanx (forms joint)
what are the phalangeal joints between?
proximal and middle, middle and distal phalanges
what is the phalangeal joint between in horses and what is it called?
fetlock joint - between third metacarpal joint (cannon bone) and first phalanx (pastern)
what is the joint between the proximal and middle phalanx?
pastern joint
what is the joint between the middle and distal phalanx (coffin bone)?
coffin joint
describe the brachial plexus
where the muscles of the forelimb are innervated by the nerves
- formed by the last 3 cervical and first two thoracic spinal segments
what do the lateral group of muscles (acting on shoulder joint) include and what nerve are they innervated by?
supra and infraspinatus
- suprascapular nerve
what muscle (acting on shoulder joint) is part of the medial group and what nerve is it innervated by?
subscapularis
- suprascapular nerve
what muscles (acting on shoulder joint) are part of the caudal group and nerve are they innervated by?
deltoideus, tere major, and teres minor
- axillary nerve
what kind of muscles act on the elbow?
flexors and extensors
what do the extensors do (elbow joint), what muscles are included, and what nerve are the muscles innervated by?
fill the area between caudal aspects of the scapula and humerus
- triceps, tensor fasciae antebrachii and anconeus
- radial nerve
what are the primary flexors of the elbow joint and what nerve are they innervated by?
biceps brachii and brachialis
- musculocutaneous nerve
The extensors of the carpus and digits typically arise from the lateral epicondyle of the humerus and include what?
extensor carpi radialis
common digital extensor
lateral digital extensor.
what nerve are the extensors of the carpus and digits innervated by?
radial nerve
action of which extensors (carpus and digits) do not conform to extension?
extensor carpi ulnaris OR the ulnaris lateralis
The flexors of the carpus and digits, typically, arise from the medial epicondyle of the humerus and include what?
flexor carpi ulnarlis
flexor carpi radialis
superficial digital flexor
deep digital flexor
what nerves are the flexors of the carpus and digits innervated by?
median and ulnar nerves
what muscles provide support to the metacarpophalangeal joints?
interosseous muscles
what provides the major blood supply to the forelimb?
axillary artery
in the brachial region, what is the axillary artery called?
brachial artery
what provides most of the blood supply to the distal end of the limbs and is the main trunk of the brachial artery?
median artery
describe how veins work
drain the blood from the tissues in the limbs and run in the opposite direction
describe the flow of veins from distal to proximal
cephalic –> axillary –> subclavian and cranial vena cava –> atrium of heart
The horses have the ability to stand on their legs for a long time and they are endowed with special features to do this. When horses stand, tendons, ligaments and fascial bands in the forelimb help bear most of the weight. Because of this, the horses spare most of the muscles and can stand for prolonged periods of time spending very little energy. What is the feature that enables them to do this?
passive stay apparatus
the forelimb bone supports approximately __% of the body weight in equine
60
what muscles prevent that collapse of the forelimb in horses?
internal tendon of the biceps
long tendon of biceps (lacertus fibrosus)
suspensory apparatus
ligaments
distal ends of superficial and deep digital flexors tendons
