Muscles of the Thoracic Limb Flashcards
Osteology, Pectoral Girdle, Shoulder & Elbow Joints
The origin of M. trapezium?
Cervical part: Median fibrous raphe of the neck, up to C3.
Thoracic part: Lig. supraspinale as far as T9.
The insert of M. trapezium?
Cervical part: Spina scapulae, except for a small portion ventrally.
Thoracic part: The dorsal third of the scapular spine.
The function of M. trapezium?
Cervical part: moves the ventral angle of the scapula cranially and advances the limb.
Thoracic part: rotates the scapula caudally and retracts the limb.
Both acting together raise the scapula against the trunk and lift the limb.
The origin of M. latissimus dorsi?
A broad aponeurosis from the superficial thoracolumbar fascia and the lateral surfaces of the last three ribs (11-13).
The insert of M. latissimus dorsi?
Tuberositas teres major and the fascia on the medial surface of the M. triceps brachii Caput longum.
The function of M. latissimus dorsi?
Retraction of the free limb and flexion of the shoulder.
The origin of M. rhomboideus?
Capitis: Lateral edge of the M. rhomboideus cervicis at about the level of C4.
Cervicis: Median fibrous raphe of the neck (as far as C2) and the spinous processes of TI-T3.
Thoracis: Spinous processes of T4-T7
The insert of M. rhomboideus? All parts.
Capitis: Crista nuchae (back of the skull).
Cervicis: Scapula, medially on the dorsal margin.
Thoracis: Scapula, medially on the dorsal margin and a small area laterally, just cranial to the caudal angle.
The function of M. rhomboideus?
Advances or retracts the limb, elevation of the scapula and limb.
The origin of M. brachiocephalicus?
M. cleidocephalicus (Pars cervicalis + Pars mastoidea) + M. cleidobrachialis: Intersectio clavicularis.
The insert of M. brachiocephalicus? All parts.
M. cleidocephalicus:
Pars cervicalis: Crista nuchae and the median fibrous raphe of the neck.
Pars mastoidea: Mastoid process of the temporal bone.
M. cleidobrachialis: Crista humeri.
The function of M. brachiocephalicus?
Unilateral contraction advances the limb
The origin of the M. omotransversarius?
The ventral part of the scapular spine.
The insert of the M. omotransversarius?
Wings of the atlas (transverse process)
The function of the M. omotransversarius?
To advance the limb
What are the types of Mm. pectorales superficiales?
M. pectoralis transvesus + M. pectoralis descendens
The origin of the M. pectoralis descendens?
Manubrium sterni
The insert of the M. pectoralis descendens?
Distal portion of the Crista tuberculi majoris of the humerus
The function of the M. pectoralis descendens?
Protraction, retraction and adduction of the limb
The origin of the M. pectoralis transvesus?
Ventral aspect of the sternum, from the manubrium to the third costal
cartilage.
The insert of the M. pectoralis transvesus?
Distal portion of the Crista tuberculi majoris of the humerus
The function of the M. pectoralis transvesus?
Protraction, retraction and adduction of the limb
The origin of the M. pectoralis profundus?
The sternum, on the ventral midline
The insert of the M. pectoralis profundus?
Tub. minus of the humerus. It also sends a band of muscle and aponeurosis over the proximal M. biceps brachii to insert on cranio-medial aspect of the Tub. majus, and on the proximal portion of the Crista tuberculi majoris. The aponeurosis helps to hold the biceps in position.
The function of the M. pectoralis profundus?
Extension of the shoulder; retraction and adduction of the limb. While running, when the limbs are fixed in extension, bilateral contraction advances the trunk. Since the muscle’s insertion is considerably more dorsal than its origin it slings and supports the trunk between the limbs
The origin of the M. serratus ventralis?
Cervical part: Transverse processes of C3-C7.
Thoracic part: Lateral surfaces of ribs 1-8.
The insert of the M. serratus ventralis?
Facies serrata of the scapula
The function of the M. serratus ventralis?
Suspension of the trunk
The origin of the M. deltoideus?
Pars scapularis: By means of a broad aponeurosis from the spine of the scapula and the underlying M. infraspinatus.
Pars acromialis: Acromion process (scapular spine).
The insert of the M. deltoideus?
Tuberositas deltoidea of the humerus
The function of the M. deltoideus?
Flexion of the shoulder joint
The origin of the M. teres minor?
Tub. infraglenoidale and distal caudal margin of the scapula
The insert of the M. teres minor?
Tuberositas teres minor on the Linea m. tricipitis of the humerus
The function of the M. teres minor?
Flexion of the shoulder joint
The origin of the M. infraspinatus?
Fossa infraspinata of the scapula
The insert of the M. infraspinatus?
Facies m. infraspinati of the humerus
The function of the M. infraspinatus?
Flexion or extension of the shoulder joint; abduction and outward rotation of the humerus. The tendon of insertion stabilizes the shoulder joint by acting as a lateral collateral ligament.
The origin of the M. supraspinatus?
Fossa supraspinata of the scapula
The insert of the M. supraspinatus?
Tub. majus of the humerus
The function of the M. supraspinatus?
Extension and stabilization of the shoulder joint
The origin of the M. coracobrachialis?
Proc. coracoideus of the scapula
The insert of the M. coracobrachialis?
Distal portion of the Crista tuberculi minoris
The function of the M. coracobrachialis?
Adduction and extension of the shoulder joint
The origin of the M. subscapularis?
Fossa subscapularis
The insert of the M. subscapularis?
Tub. minus of the humerus
The function of the M. subscapularis?
Flexion, extension, adduction and stabilization of the shoulder joint
The origin of the M. teres major?
Caudal angle and proximal caudal margin of the scapula
The insert of the M. teres major?
Tuberositas teres major, together with the M. latissimus dorsi and M. cutaneus trunci
The function of the M. teres major?
Flexion of the shoulder joint
The origin of the M. biceps brachii?
Tub. supraglenoidale of the scapula
The insert of the M. biceps brachii?
At the elbow, the tendon of insertion divides into two parts. The stronger part inserts medially on the ulna, just distal to the medial coronoid process. The weaker part inserts on the Tuberositas radii, together with a fleshy insertion of the brachialis muscle.
The function of the M. biceps brachii?
Flexion of the elbow joint; extension and stabilization of the shoulder joint.
The origin of the M. triceps brachii?
Long head: Tub. infraglenoidale and the caudal margin of the scapula.
Lateral head: Linea m. tricipitis of the humerus.
Medial head: Crista tuberculi minoris of the humerus, caudal to the Tuberositas teres major and cranial to the insertion of the M. coracobrachialis.
Accessory head: Caudal surface of the humeral neck.
The insert of the M. triceps brachii?
Olecranon
The function of the M. triceps brachii?
Extension of the elbow joint; the long head is a powerful flexor of the shoulder
The origin of the M. brachialis?
Caudo-lateral surface of the proximal humerus, just distal to the origin of the triceps’ accessory head and caudo-distal to the Tuberositas teres minor.
The insert of the M. brachialis?
The main tendon passes between the two tendons of the biceps and inserts medially on the ulna (immediately distal to the biceps’ ulna insertion). The M. brachialis also has a fleshy insertion, which joins the biceps’ weaker tendon to the Tuberositas radii.
The function of the M. brachialis?
Flexion of the elbow joint
The origin of the M. anconeus?
Lateral epicondyle and supracondylar crest, and the proximo-medial rim of the Fossa olecrani
The insert of the M. anconeus?
Laterally on the Olecranon, just distal to the insertion of the triceps
The function of the M. anconeus?
Extension of the elbow joint; tensing of the elbow joint capsule
