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Shoulder Girdle p121
Lippert ch.9 - Shoulder Girdle (muscles) pages 121-127
Question | Answer |
---|---|
5 primary muscles that move the scapula (aka: muscles of the shoulder girdle) | Trapezius, Levator scapula, Rhomboids, Serratus anterior, Pectoralis minor |
3 parts of the Trapezius muscle | upper, middle, & lower |
Upper Trap: ORIGIN | Occipital bone, nuchal ligament on upper cervical spinous process |
Upper Trap: INSERTION | Outer 1/3 of clavicle, acromion process |
Upper Trap: ACTION | Scapular elevation and upward rotation |
Upper Trap: NERVE | Spinal accessory (CN XI), C3-C4 sensory component |
Upper Trap: line of pull | more UPWARD than inward |
Middle Trap: ORIGIN | spinous processes of C7-T3 |
Middle Trap: INSERTION | Scapular spine |
Middle Trap: ACTION | Scapular retraction |
Middle Trap: NERVE | Spinal accessory (CN XI), C3-C4 sensory component |
Middle Trap: line of pull | INWARD |
Lower Trap: ORIGIN | spinous processes of middle and lower thoracic vertebrae |
Lower Trap: INSERTION | Base of scapular spine |
Lower Trap: ACTION | Scapular depression and upward rotation |
Lower Trap: NERVE | Spinal accessory (CN XI), C3-4 sensory component |
Lower Trap: line of pull | more DOWNWARD than inward |
Levator Scapula: ORIGIN | transverse process of 1st 4 cervical vertebra |
Levator Scapula: INSERTION | Vertebral border of scapula between sup angle and spine |
Levator Scapula: ACTION | Scapular elevation and downward rotation |
Levator Scapula: NERVE | 3rd-4th cervical nerves and dorsal scapular nerve (C5) |
Levator Scapula: line of pull | diagonal, mostly vertical |
Rhomboids: ORIGIN | spinous processes of C7-T5, and nuchal ligament |
Rhomboids: INSERTION | Vertebral border of scapular between spine and inferior angle |
Rhomboids: ACTION | Scapular retraction, elevation, and downward rotation |
Rhomboids: NERVE | Dorsal scapular nerve (C5) |
Rhomboids: line of pull | oblique |
Pectoralis minor: ORIGIN | Anterior surface of ribs 3-5 |
Pectoralis minor: INSERTION | Coracoid process of scapula |
Pectoralis minor: ACTION | Scapular depression, protraction, downward rotation, and tilt |
Pectoralis minor: NERVE | Medial Pectoral (C8, T1) |
Pectoralis minor: line of pull | downward diagonal, pulls top part of scapula forward while the bottom tips "out" |
Serratus Anterior: ORIGIN | lateral surface of upper 8 ribs |
Serratus Anterior: INSERTION | vertebral border of scapula, anterior surface |
Serratus Anterior: ACTION | scapular protraction and upward rotation |
Serratus Anterior: NERVE | Long thoracic (C5,6,7) |
Serratus Anterior: line of pull | nearly horizontal line outward |
What do all 5 shoulder girdle muscles have in common? | all have origins on the trunk |
Of the 3 posterior shoulder girdle muscles, which is the most superficial? | trapezius |
Where is the pectoralis minor located? | anterior side, but deep to pectoralis major |
force couple | muscles pulling in different directions to accomplish the same motion |
What 3 muscles produce a net effect of UPWARD scaplar rotation? | upper trap, lower trap, & serratus anterior |
What 3 muscles produce a net effect of DOWNWARD scaplar rotation? | pectoralis minor, rhomboids, & levator scapula (must also accompany EXTENSION of shoulder joint) |
reversal of muscle action (origin moves toward insertion) | allows some shoulder girdle muscles to assist in other joints (i.e. head & neck) |
Which muscle can assist head and neck extension, side bending/laterally bending to same/ipsilateral side, and rotation to opposite/contralateral side? | upper trap |
Which muscle can assist in elevating the trunk? | lower trap |
Which muscle can move the neck when the scapula is stabilized? | levator scapula |
Which muscle can assist rotating and laterally bending the neck ispilaterally? | levator scapula (assists the splenius cervicis) |