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.