ILS4, TBL 6 TBL7 MSK Back, shoulder and Axilla Flashcards
Trapezius
origin
insertion
action
innervation
Origin - Medial part of nuchal line of the skull, external occipital protuberance, spinous processes of C7 -Th12 vertebrae.
Insertion - Lateral third of the clavicle; acromion and spine of the scapula. Action
ØUpper fibers (a.k.a. descending part) – elevate scapula
ØMiddle fibers (a.k.a. transverse part) – pull scapula medially
ØLower fibers (a.k.a. ascending part) – pull medial border of scapula
downward
Innervation - Cranial nerve XI (accessory nerve), C3 and C4 sensory.
Trapezius movements and exercise
Spinal movements - when the scapulae are stable a co-contraction of both sides can extend the neck.
Exercises
The upper portion can be developed by elevating the shoulders.
Middle fibers are developed by pulling shoulder blades together (i.e. pull bar
horizontally). This adduction also uses the upper/lower fibers.
The lower part can be developed by drawing the shoulder blades downward
while keeping the arms almost straight and stiff (i.e., elevation the torso on
parallel bars).
Latissimus Dorsi
origin
insertion
action
innervation
origin: T7-sacrium, Posterior iliac crest
insertion: Intertubercular (bicipital) groove of the humerus.
Action:
Extends, adducts, and medially rotates the humerus; raises body during climbing.
Innervation - Thoracodorsal nerve.
what exercises can you do with Latissimus Dorsi?
Vertical pulling movements such as pull-downs and pull- ups (including chin-ups).
Horizontal pulling movements such as bent-over row, T-bar row and other rowing exercises.
Levator Scapulae
origin
insertion
action
innervation
origin: C1-C4
insertion: medial border of scapula
Action: Helps stabilize, elevate and inferiorly rotate the scapula.
Innervation: C5 dorsal scapular nerve
Rhomboid minor vs Rhomboid major
origin Minor: C7- T1
Origin Major: T2-T5
insertion: medial border of the scapula
Action:
Both muscles help stabilize, retract, and inferiorly rotate the scapula (adduction of scapula)
Innervation:
Dorsal scapular nerve.
what muscles share the medial border of scapula as the insertion?
Levator Scapulae
and minor and major Rhomboids
what muscles share Innervation:
Dorsal scapular nerve (C5). ?
Levator Scapulae (+ C3 and C4)
and minor and major Rhomboids
what are the superficial back muscles?
Ø1st layer: Trapezius, Latissimus dorsi
Ø2nd layer: Rhomboids minor and major, Levator scapulae
what are the intermediate muscles (extrinsic muscles)
Thin muscles, accessory muscles to respiration.
3rd layer: Serratus posterior (superior and inferior)
which muscle is for inspiration?
Serratus posterior superior
elevates the rib cage and is considered a muscle of inspiration
what muscle is for expiration?
Serratus posterior INFERIOR lowers the ribcage and is considered muscle of expiration
what is the innervation of Serratus posterior (superior and inferior)?
intercostal nerves
Serratus posterior superior
origin
insertion
action
innervation
Located deep to the rhomboid muscles.
Origin: Ligamentum nuchae, spinous processes of C7 - Th2.
Insertion: Second to fifth ribs (muscle fibers run in an inferolateral direction).
Action: Elevates the ribs.
Innervation: Intercostal nerves.
Serratus Posterior Inferior
origin
insertion
action
innervation
Located deep to the latissimus dorsi.
Origin:
Spinous processes of Th11 - L2 or L3.
Insertion:
Lower four ribs (muscle fibers run in a superolateral direction) (9-12)
Action:
Depresses the ribs
Innervation: Intercostal nerves
suboccipital Triangle
boundaries and contents
Boundaries:
ØSuperior-medial – rectus capitis posterior major muscle
ØSuperior- lateral – obliquus capitis superior (superior oblique)
ØInferior – obliquus capitis inferior (inferior oblique)
ØRoof – semispinalis capitis
ØFloor – posterior arch of the atlas (C1) and the posterior atlanto-occipital membrane.
ØContents –vertebral artery, and suboccipital nerve (C1), greater occipital neve (C2)
_____________ compartment deep to the superior part of the posterior cervical region, and deep to the trapezius, sternocleidomastoid, splenius, and semispinalis muscles
suboccpital region
innervates posterior part of the scalp
Scapulohumeral Muscles
intrinsic muscles of the shoulder.
They are the posterior part of the axio-appendicular muscles (muscles
extending from the torso to the upper limb).
ØScapulohumeral muscles extend from the shoulder girdle (mostly scapula) to the humerus.
ØThey are involved in movements of the arm at the shoulder joint.
which muscles stabalize the shoulder joint ( Glenohumeral joint)?
ØDeltoid
Supraspinatus
Infraspinatus
Teres minor
Teres major
ØSubscapularis
Deltoid
origin
insertion
action
innervation
ØOrigin:
Lateral 1/3 of clavicle (like trapezeis), acromion, spine of scapula.
ØInsertion: Deltoid tuberosity on the shaft of the humerus
ØInnervation: axillary nerve
ØAction: Abduction of the arm at shoulder joint; the anterior fibers flex and medially rotate the arm; the posterior fibers extend and laterally rotate the arm.
Teres Major
origin
insertion
action
innervation
ØOrigin: Lower part of the lateral border of the scapula and posterior aspect of inferior angle of scapula.
ØInsertion: bicipital groove of humerus.
ØInnervation: Lower subscapular nerve
action: rotate the arm inward
what are the muscles involved in the rotator cuff?
supraspinatus
origin
insertion
action
innervation
ØOrigin: Supraspinous fossa of the scapula.
ØInsertion: Greater tubercle of the humerus (upper facet).
ØInnervation: Suprascapular nerve C4-C5
ØAction: initiates and assists the deltoid in the abduction of the arm at the shoulder joint. Helps stabilize shoulder joint
ØInitiates the first 15 degrees of arm abduction
infraspinatus
origin
insertion
action
innervation
arterial supply
ØOrigin: Infraspinous fossa of scapula.
ØInsertion: Greater tubercle of the humerus (middle
facet).
ØNote: covers the posterior surface of the rotator cuff
ØInnervation: Suprascapular nerve
ØArterial Supply: Suprascapular and circumflex scapular arteries
ØAction: Helps stabilize the shoulder joint; laterally rotates the arm at the shoulder joint.
