GA Forelimb Muscles

Origin, Insertion, Action, Innervation

superficial pectoral muscle origin

first 3 sternebrae

superficial pectoral insertion

greater tubercle of the humerus

superficial pectoral action

adduct forelimb when nwb OR prevent abduction when wt-bearing

superficial pectoral innervation

Cranial pectoral nerve

superficial pectoral has how many muscle bodies and what are they

2 muscle bodies

superficial/descending portion, which is superficial to transverse portion and obliquely crosses it

transverse portion which is deep to superficial portion

deep pectoral muscle origin

all the sternebrae/ventral sternum

deep pectoral insertion

lesser tubercle of the humerus

deep pectoral action

adduct limb

when weight-bearing / limb is fixed: pull trunk cranially and extend shoulder

when not weight-bearing on forelimb: draw limb caudally and flex shoulder

deep pectoral innervation

caudal pectoral nerves (C8, T1)

Cleidobrachialis attachments

clavicular insertion and distal third of cranial humerus

cleidocephalicus

clavicular intersection to the neck and head (depending on which portion)

pars cervicalis

part of the cleidocephalicus that attaches to the dorsal midline of the neck

pars mastoidea

part of the cleidocephalicus that attaches to the mastoid process of the skull

brachiocephalicus action

advance the forelimb/extend shoulder joint (non weight bearing)

draw the neck and head to the side (when weight bearing)

brachicephalicus innervation

accessory nerve and ventral branches of cervical spinal nerves

sternocephalicus origin

first stenebra or manubrium

sternocephalicus insertion

mastoid part of the temporal bone and the nuchal crest of the occipital bone

sternocephalicus action

draw the head and neck to the side

sternocephalicus innervation

accessory nerve and ventral branches of cervical spinal nerves

omotransversarius attachments

distal end of the spine of the scapula

the transverse process/wing of the atlas

omotransversarius action

advance the limb

flex the neck laterally

omotransversarius innervation

accessory nerve

trapezius is comprised of how many parts and what are they

2 parts

cervical part

thoracic part

the cervical and thoracic parts of the trapezius are separated by what soft tissue structure

an aponeurosis

trapezius origin

median raphe of the neck and the supraspinous ligament from the level of the 3rd cervical vertebra to the level of the 9th thoracic vertebra

trapezius insertion

spine of the scapula

trapezius action

elevate and abduct forelimb

trapezius innervation

accessory nerve

rhomboideus has how many parts and what are they

3 parts

capital - rhomboideus capitus

cervical - rhomboideus cervicis

thoracic - rhomboideus thoracis

rhomboideus origin

nuchal crest of the occipital bone, median fibrous raphe of the neck, spinous processes of the 1st 7 thoracic vertebrae

rhomboideus insertion

dorsal border and adjacent surfaces of the scapula

rhomboideus action

elevate the forelimb and draw scapula against the trunk

rhomboideus innervation

ventral branches of cervical and thoracic spinal nerves

latissimus dorsi origin

last 7-8 thoracic vertebrae / thoracolumbar fascia

latissimus dorsi insertion

teres major tuberosity of the humerus and the teres major tendon

latissimus dorsi action

draw the free limb caudally, to flex the shoulder joint

latissimus dorsi innervation

thoracodorsal nerve

serratus ventralis cervicis / serratus ventralis thoracis origin

transverse processes of the last 5 cervical vertebrae and first 7 or 8 ribs ventral to their middle

serratus ventralis cervicis and serratus ventralis thoracis insertion

serrated face of the scapula

serratus ventralis cervicis and serratus ventralis thoracis action

support trunk

depress scapula

serratus ventralis cervicis and serratus ventralis thoracis innervation

ventral branches of cervical spinal nerves and the long thoracic nerve (C7)

deltoideus origin

spine and acromial process of the scapula

deltoideus insertion

deltoid tuberosity of the humerus

deltoideus action

flex the shoulder

deltoideus innervation

axillary nerve

infraspinatus origin

infraspinous fossa

infraspinatus insertion

small, circumscribed area on the lateral side of the greater tubercle of the humerus

infraspinatus action

extend OR flex shoulder joint depending on degree of extension or joint position when muscle contracts

abduct shoulder

rotate humerus laterally

prevent medial rotation when wt-bearing

provide lateral stability to the shoulder joint

infraspinatus innervation

suprascapular nerve

teres minor origin

infraglenoid tubercle and distal third of caudal border of the scapula

teres minor insertion

teres minor tuberosity of the humerus

teres minor action

flex shoulder

rotate shoulder laterally

prevent medial rotation when bearing weight

teres minor innervation

axillary nerve

supraspinatus origin

supraspinous fossa

supraspinatus insertion

greater tubercle of the humerus, by a thick tendon

supraspinatus action

extend shoulder

stabilize shoulder

supraspinatus innervation

suprascapular nerve

subscapularis origin

subscapular fossa

subscapularis insertion

lesser tubercle of the humerus

subscapularis action

adduct shoulder

extend shoulder

medially stabilize shoulder

rotate shoulder joint medially and prevent lateral rotation when bearing weight

subscapularis innervation

subscapular nerve

teres major origin

caudal angle and adjacent caudal border of the scapula, and caudal surface of subscapularis

teres major insertion

teres major tuberosity of the humerus

teres major action

flex shoulder

rotate shoulder joint medially

prevent lateral rotation when weight bearing

teres major innervation

axillary nerve

coracobrachialis origin

coracoid process of the scapula

coracobrachialis insertion

crest of the lesser tubercle of the humerus proximal to the teres major tuberosity

coracobrachialis action

adduct, extend, and stabilize shoulder joint

coracobrachialis innervation

musculocutaneous nerve

tensor fasciae antebrachii origin

fascia covering lateral side of latissimus dorsi

tensor fasciae antebrachii insertion

olecranon of the ulna

tensor fasciae antebrachii action

extend elbow joint

tensor fasciae antebrachii innervation

radial nerve

triceps brachii origin (overall)

caudal border of the scapula

long head of triceps brachii insertion

olecranon tuber

long head of triceps brachii action

extend elbow joint

flex shoulder joint

long head of triceps brachii innervation

radial nerve

lateral head of triceps brachii origin

tricipital line of the humerus

lateral head of triceps brachii insertion

olecranon tuber

lateral head of triceps brachii action

extend elbow joint

lateral head of triceps brachii innervation

radial nerve

accessory head of triceps brachii origin

neck of the humerus

accessory head of triceps brachii insertion

olecranon tuber

accessory head of triceps brachii action

extend elbow

accessory head of triceps brachii innervation

radial nerve

medial head of triceps brachii origin

crest of the lesser tubercle near the teres major tuberosity

medial head of triceps brachii insertion

olecranon

medial head of triceps brachii action

extend elbow

medial head of triceps brachii innervation

radial nerve

anconeus origin

lateral supracondylar crest and lateral and medial epicondyles of the humerus

anconeus insertion

lateral surface of the proximal end of the ulna (olecranon)

anconeus action

extend the elbow joint

anconeus innervation

radial nerve

biceps brachii origin

supraglenoid tubercle

biceps brachii insertion

ulnar and radial tuberosities

biceps brachii action

flex elbow

extend shoulder

biceps brachii innervation

musculocutaneous nerve

brachialis origin

proximal third of the lateral surface of the humerus (brachialis groove)

brachialis insertion

ulnar and radial tuberosities

brachialis action

flex elbow