Forelimb Muscles Flashcards
Superficial Pectoral
O = 1st 2 sternebrae and part of 3rd I = whole crest of greater tubercle of humerus A = adduct limb N = cranial pectoral nerves (C7, C8)
Deep Pectoral
O = ventral sternum and fibrous raphe between fellow muscles I = major portion on lesser tubercle of humerus. Aponeurosis onto greater tubercle & crest A = adduct limb & pull trunk in line with extended limb, pull limb back towards trunk N = caudal pectoral nerves (C8, T1)
Brachiocephalicus
Cleidobrachialis, Cleidocephalicus and Cleidomastoideus
Cleidobrachialis
O = distal end, cranial border humerus and significant fascial tie to axilla
I = clavicle
Cleidocephalicus
O = clavicle
I = median raphe of neck, sometimes nuchal crest of occipital bone
cleidomstoideus attaches to mastoid process of temporal bone with sternomastoideus
A = advance limb, extend shoulder, draw head/neck to side N = accessory nerve (Cleidocephalicus), ventral branches of cervical spinal nerves and axillary (cleidobrachialis)
Omotransversarius
O = distal end of scapular spine I = transverse wing of atlas A = draw limb forward, flex neck N = accessory nerve
Trapezius
O = median raphe of neck, from 3rd cervical vertebra to 9th thoracic vertebra (supraspinous ligament) I = scapular spine A = elevate and abduct forelimb N = accessory nerve
Rhomboideus
Capital, cervical & thoracic parts
O = nuchal crest of occipital bone, median fibrous raphe of neck, spinous processes of 1st 3 thoracic vertebrae. Thoracic part from 4th-7th vertebrae I = dorsal border, medial aspect scapula A = elevate forelimb, draw scapula against trunk N = ventral branches of cervical and thoracic nerves
N.b. Lies below trapezius when reflected
Latissimus Dorsi
O = spinous processes of lumbar and last 7-8 thoracic vertebrae I = teres major tuberosity of humerus and teres major tendon A = draw free limb causally (digging), flex shoulder joint N = thoracodorsal nerve (C7, C8, T1)
Serratus Ventralis
O = medial surface scapula (facies serrata) I = transverse processes of last 5 cervical vertebrae and 1/2 way down 1st 7 ribs A = support trunk, depress scapula, move shoulder with respect to limb N = ventral branches of cervical spinal nerves and long thoracic nerve C7
Deltoideus
O = scapular spine and acromium process I = deltoid tuberosity of humerus (lateral aspect) A = flex shoulder N = axillary nerve
Infraspinatus
O = Infraspinous fossa of scapula I = lateral side greater tubercle humerus A = extend and flex shoulder depending on position. Also acts as collateral ligament to shoulder N = suprascapular nerve
Suprascapular originates from C6 of brachial plexus
Teres Minor
O = infraglenoid tubercle and distal 3rd caudal border scapula I = teres minor tuberosity of humerus A = flex shoulder, lateral rotation N = axillary nerve
Lateral capsular muscle
Supraspinatus
O = supraspinous fossa I = greater tubercle of humerus by thick tendon\ A = extension N = suprascapular nerve
Subscapularis
O = subscapular fossa I = lesser tubercle humerus A = extend shoulder, adduct limb N = subscapular nerve
Teres Major
O = caudal angle & adjacent caudal border of scapula, caudal surface of subscapularis I = teres major tuberosity of humerus A = flex shoulder, medially rotate shoulder N = axillary nerve
Coracobrachialis
O = coracoid process of scapula I = medial aspect humerus proximal to trees major tuberosity A = extend, adduct and stabilise shoulder joint N = musculocutaneous nerve
Looks like it wraps round from cranial scapula laterally to medial humerus over the lateral surface of the joint
