Elbow Joint & Muscles of Proximal Forelimb Flashcards
what does peripheral nervous system supply
supplies the body
cranial nerves –> emerge from brain
spinal nerves –> emerge from spinal cord
what is the afferent pathway
body to brain
sensory fibres (pain, temperature, pressure)
proprioception –> location of limb in space
what is the efferent pathway
brain to body
voluntary movement
how does the nerve supply develop in the embryo
somites in embryo –> blocks of tissue, develop alongside spinal cord, group combines to form each forelimb, drag nerves with them, nerve supply therefore reflects origin
what are spinal nerves and where do they pass
leave spinal cord and pass through intervertebral foramen
paired left and right
what are the branches of spinal nerves that supply the forelimbs
dorsal branches supply dorsal structures
ventral brances from C6, C7, C8, T1, T2 form brachial plexus
what is the brachial plexus
multiple exhanges of fibres –> emerging nerves supply forelimb
how are the fibres of skeletal muscle arranged
parallel bundles
encased in fibrous tissue
what are the origins and insertions of skeletal muscle usually
O: usually proximal
I: usually distal
what are the attachments of skeletal muscle
directly to bone –> rough surface area, bony bumps/tubercles
via aponeurosis (muscle tissue stops but continue on as fibrous tissue) –> sheets, areas of restricted access
via tendons
what are tendons
rope of CT
condensation of fibrous tissue into cords
continuation of muscle as fibrous tissue –> less bulky across joints, small area of attachment
what are the functions of muscle
muscle fibres contract –> muscle belly shorten
points of attachment pulled closer together –> effect depends on origin and insertion
what does action of muscle depend on (2)
- specific joint(s) crossed
- aspect of joint(s) crossed
(a muscle has no effect on a joint if it doesn’t cross it)
what are extrinsic muscles
origin on axial skeleton –> insertion in appendicular skeleton
what movement do extrinsic muscles produce
movement of limb relative to trunk
- protraction (limb moves cranially)
- retraction (limb moves caudally)
- adduction (medually)
- abduction (laterally)
what are intrinsic muscles
original & insertion within appendicular skeleton
movement limited to within lumb (flexion/extension, rotation)
what is flexion and extension
flexion - reduced flexor angle (non-weight bearing position)
extension - increased flexor angle (weight bearing position)
break down what brachiocephalic means
cephalic = head
brachium = arm
what is the origin and insertion of the brachiocephalic muscle
O: cervical vertebrae & skull
I: humerus
where is the brachiocephalic muscle located
cranial to limb
what is the function of the brachiocephalic muscle
forelimb protractor
shoulder extensor (increases angle caudle to the joint and will extend the shoulder)
what is the clavicle
bony remnant in muscle cranial to shoulder
present in cats, absent in dogs
allows differentation on radiographs
what muscle is this

brachiocephalic muscle
what muscle is this

brachiocephalic muscle
what is the latissimus dorsi muscle
latus = broad
dorsi = back
“broadest muscle of the back”
what is the origin and insertion of the latissimus dorsi muscle
O: thoracic vertebrae
I: humerus
where is the latissimus dorsi located
caudal to the limb
what is the function of the latissimus dorsi muscle
forelimb retractor
also propulsion
shoulder flexor (reduces angle)
what muscle is the latissimus dorsi muscle the equal and opposite of
bachiocephalic muscle
what muscle is this

latissimus doris
what muscle is this

latissimus dorsi
what is the origin and insertion of the serratus ventralis muscle
O: thoracic wall (ribs), cervicle vertebrae
I: proximal scapula (medial aspect), (proximal to pivitol point)
where is the serratus ventralis muscle located
between forelimb and trunk
what is the function of serratus ventralis muscle
support weight of trunk between forelimbs
cranial portion –> retractor
caudal portion –> protractor
what muscle is this

serratus ventralis muscle
what is the origin and insertion of the trapezius muscle
O: cervical and thoracic vertebrae
I: proximal scapular spine
how many parts does the trapezius muscle have
2 parts - cranial and caudal
where is the trapezius muscle located
proximal to limb
proximal to pivotal point
what is the function of the trapezius muscle
abduction of the limb (also protraction)
more limited abduction in domestic species –> helps with protraction with serratus ventralis
what muscle is this

trapezius muscle
what muscle is this

trapezius muscle
what muscle is this

trapezius muscle
what is the origin and insertion of the pectoral muscle
O: sternum
I: humerus
what are the two pectoral muscles
deep & superficial groups
where are the pectoral muscles located
medial to limb
distal to pivotal point
what is the function of the pectoral muscles
adduction of the limb
what muscle is this

pectoral muscles
what muscle is this

pectoral muscle
what are the extrinsic forelimb muscles and their functions
- brachiocephalic –> protractor
- latissimus dorsi –> retractor
- serratus ventralis –> both protractor & retractor
- trapezius –> abductor
- pectorals –> adductor
what is nerve supply to the extrinsic forelimb muscles
brachiocephalic –> not brachial plexus
the rest are brachial plexus
what are the components of the elbow joint

- trochlea of humerus
- head of radius
- trochlear notch of ulna
what type of joint is the elbow joint and what does it include
synovial joint
including collateral ligaments (humeral epicondyles to radius and ulna)
what are the palpable landmarks of the elbow joint
medial & lateral epicondyles
olecranon process
how is the elbow joint stabilized
- collateral ligaments
- anconeal process (ulna) –> engaged within olecranon/ulnar fossa (humerus)
what is the movement of the elbow joint
limited to flexion and extension
some rotation possible between radius and ulna
what occurs during elbow dislocation
occurs & replaced flexion
immobilize in extension (flex limb and realign to put back in
what is elbow dysplasia
- combination of development conditions –> osteochondrosis, ununited anconeal process (significant for stability), fragmented medial coronoid process, elbow incongruity (articular surfaces don’t match eachother)
- degenerative joint disease –> classic locations around margins of joint capsule
- capped elbow –> subcutaneous bursa
what is the origin and insertion of the deltoideus muscle
O: spine of scapula (2 heads)
I: lateral aspect of humerus
what is the location of the deltoideus muscle
caudo-lateral aspect of limb
what is the function of the deltoideus muscle
crosses caudal to shoulder joint –> shoulder flexor
what is the nerve supply to the deltoideus muscle
axillary nerve coming from brachial plexus
what muscle is this

deltoideus muscle
what is the origin and insertion of the teres major muscle
O: caudal border of scapula
I: medial humerus
what is the function of the teres major muscle
caudo-medial aspect of limb
what is the function of teres major muscle
crosses caudal to shoulder joint –> shoulder flexor
what is the nerve supply of the teres major muscle
axillary nerve
what muscle is this (lateral)

teres major muscle

what muscle is this

teres major muscle
how many heads does the triceps barchii muscle have
4 heads
what is the origin of the long head of the triceps brachii muscle
O: caudal border scapula
what are the origin of the other heads of the triceps brachii muscle
O: shaft of humerus
what is the insertion of the triceps brachii muscle
I: olecranon process of ulna
what are the functions of the tricpes brachii muscle
crosses caudal to shoulder –> shoulder flexor (the long head)
crosses caudal to elbow –> elbow extensor
what is the nerve supply of triceps brachii
radial nerve (from brachial plexus)
what muscle is this

triceps brachii
what muscle is this

triceps brachii
what muscle is this (lateral and medial aspect)

triceps brachii
what is origin and insertion of the biceps brachii muscle
O: supraglenoid tubercle
I: proximal radius (intrinsic muscle)
what is the location of the biceps brachii muscle
cranio-medial aspect of limb (deep to brachiocephalicus & pectorals)
what is the functions of biceps brachii muscle
crosses cranial to shoulder –> shoulder extensor
crosses cranial to elbow –> elbow flexor
what is the nerve supply to the biceps brachii muscle
musculocutaneous nerve
what muscle is this

biceps brachii muscle
what muscle is this

biceps brachii muscle
what is the tendon of origin of biceps brachii mucsle and how is it held in place and protected
intertubercular groove of humerus
held by transverse ligament
protected by bicipital bursa (extension of shoulder joint capsule)

what is the lacertus fibrosis (insertion, location, function)
fibrous extension of biceps brachii muscle
inserts 3rd metacarpal
crosses dorsal to carpus
carpal extensor –> allows to stand for long periods of time –> part of stay apparatus

what structure is this

intertubercular groove of humerus
yellow - extension of joint capsule
blue - transversr ligament
what structure is this
lacertus fibrosis

what structure is this

lacertus fibrosis
what is the origin and insertion of brachialis muscle
O: humerus
I: radius
what is the location of brachialis
lateral aspect of limb –> wraps around humerus
what is the function of the brachialis muscle
elbow flexor
crosses cranial to elbow joint
what is the nerve supply of brachialis muscle
musculocutaneous nerve
what muscle is this

brachialis muscle

what are the shoulder flexor muscles and the nerves that supply
- latissimus dorsi
- deltoideus –> flexor only
- teres major –> flexor only (axillary nerve)
- triceps brachii –> mult. heads only 1 affects shoulder (radial nerve)
what are the shoulder extensor muscles (cranial aspect)
- brachiocephalicus (cranial direction)
- biceps brachii (musculocutaneous nerve)
name these muscles

- latissimus dorsi
- deltoideus
- teres major
- triceps brachii
- brachiocephalicus
- biceps brachii
what gives shoulder collateral support
supraspinatous
infraspinatous
subscapularis
what causes elbow flexion
- biceps brachii
- brachialis
what causes elbow extension
- triceps (4 heads)
name these muscles

S- supraspinatous
I- infraspinatous
SubS- subscapularis
name these muscles

SubS- subscapularis
- biceps brachii
- triceps
name these muscles

S- supraspinatous
I- infraspinatous
- brachialis
- triceps
what are the extrinsic muscles

A. brachiocephalic
B. latissimus dorsi
C. serratus ventralis
D. trapezius
E. pectorals
identify the features of the elbow joint


what muscle is this

deltoideus muscle
where is the triceps brachii muscle located
caudal aspect of limb
name the muscles of the forelimb


name the muscles


name the muscles
