Module 4 Muscles Flashcards
Sternocleidomastoid (SCM) origin and insertion
O: sternal head- top of manubrium
Clavicle head- the medial 1/3rd of the clavicle
I: mastoid process of the temporal bone and the lateral portion of the superior nuchal line of the occiput
Actions of the sternocleidomastoid (SCM)
Actions:
The SCM flexes the neck at the spinal joints
Laterally flexes head and neck to the same side
Rotates the head and neck to the opposite side at the spinal joints
Assist to elevate the ribcage during inhalation
Innervation of the sternocleidomastoid SCM
Innervation: spinal accessory nerve(CN cranial nerve XI (11)), C2-3
Scalene origin and insertion
Anterior:
O:transverse processes of C3-C6
I:first rib
361
Middle scalene:
O:transverse processes of C2-C7
I: first rib
271
Posterior scalene:
O: transverse processes of C6-C7
I: second rib
672
Scalene Innervation
Scalene Innervation : C(3), 4-8
Scalene actions
Anterior:
Flexes the head and neck at the spinal joints (bilaterally)
All fibers:
Laterally flexes the head and neck to the same side at the spinal joints
Elevates the first or second rib during inhalation
Levator Scapulae origin and insertion
Origin: transverse processes of C1-C4
Insertion: medial border of the scapula, between the superior angle and superior portion of the spine of the scapula
Levator Scapulae actions
Elevates and downward rotates the scapula at the scapulothoracic joint
Extend the head and neck bilaterally
laterally flex and rotate the head and the neck to the same side
Levator Scapulae Innervation
Cervical 3,4 and dorsal scapular C4,5
Splenius Capitis origin and insertion “golf tee muscle”
O: inferior 1/2 of the ligamentum nuchae and spinous processes of C7-T4
I: mastoid process and the lateral portion of the superior nuchal line
Splenius Capitis Innervation
Cervical nerves
Splenius Capitis actions
Bilaterally extends the head and neck
Unilaterally rotates the head and neck to the same side
Laterally flexes the head and neck to the same side
Trapezius origin and insertion
O: external occipital protuberance,
the medial portion of the superior nuchal line of the occiput, the ligamentum nuchae, and the spinous processes of C7-T12
I: lateral 1/3 of the clavicle, the acromion process, and the spine of the scapula
Trapezius Innervation
Cranial nerve II C2,3,4 or
Accessory nerve C2,3,4
Trapezius actions
Adducts(retracts) and stabilizes the scapula at the scapulothoracic joint (lower)
Depresses the scapula at the scapulothoracic joint (lower)
Upwardly rotates the scapula at the scaplulothoracic joint (upper/lower)
Elevates the scapula at the scapulothoracic joint (upper)
Laterally flexes the neck and the head (upper)
Extends the neck and head (upper)
Rotates the neck and the head to the opposite side (upper)
Rhomboid major origin and insertion
O: spinous processes of T2-T5
I: medial border of the scapula, between the spine of the scapula and the inferior angle
Rhomboid major Innervation
Dorsal scapular C4,5 nerve
Rhomboid major actions
Adducts (retracts) the scapula at the scapulothoracic joint
Elevate the scapula at the scapulothoracic jt
Downwardly rotate the scapula at the scapulothoracic jt
Rhomboid minor origin and insertion
O: spinous processes of C7-T1
I: upper portion of medial border of scapula, across from the spine of the scapula
Rhomboid MINOR Innervation
Dorsal scapular C4,5 nerve
Rhomboid MINOR actions
Adducts (retracts) the scapula at the scapulothoracic joint
Elevate the scapula at the scapulothoracic jt
Downwardly rotate the scapula at the scapulothoracic joint
