lecture 12 Flashcards
back and shoulder muscles
what are the intrinsic back muscles?
these include muscles that specifically act on the vertebral column, producing its movements and maintaining posture
what are extrinsic back muscles?
these include superficial and intermediate muscles that produce and control limb and respiratory movements
what are the innervations of the intrinsic back muscles?
they are innervated by the posterior rami of spinal nerves
what are the actions of intrinsic back muscle?
these act to maintain posture and control movements of the vertebral column
what are the anatomical locations of the intrinsic back muscle?
these muscles extend from the pelvis to the cranium and are enclosed by a deep fascia that attaches medially to the nuchal ligament, the tips of the spinous processes of the vertebrae, the supraspinous ligaments and the median crest of the sacrum
what is the thoracolumbar fascia and its function?
these constitute the thoracic and lumbar parts of the deep fascia. They extend laterally from the spinous process and form a thin covering over the intrinsic back muscles in the thoracic region and a strong thick covering for muscles in the lumbar region
how are the intrinsic muscles of the back arranged?
superficial, intermediate and deep layer and this is according to their relationship to the surface
what are the superficial layer muscles of the intrinsic back?
splenius muscle broken into splenius cervicis and splenius capitis
what are the intermediate layer muscles of the back? what are they collectively called?
spinalis, longissimus, iliocostalis; erector spinae muscles
what are the deep layer muscles of the back?
semispinalis, rotatores, multifidis
What are the deep muscles of the back collectively called?
transversospinalis
why are the superficial layer muscles of the intrinsic back superficial?
they are thick and flat and lie on the lateral and posterior aspects of the neck, covering the vertical muscles somewhat like a bandage
why are the intermediate layer muscles of the intrinsic back intermediate?
these lie in a groove on each side of the vertebral column between the spinous processes centrally and the angles of the ribs laterally, there are known as the chief extensors of the vertebral column and are divided accordingly into the named groups as mentioned (iliocostalis, longissimus, and spinalis)
why are the deep layer muscles of the intrinsic back deep?
these muscles lie deep to the erector spinae and are obliquely short muscles
what are the two intermediate extrinsic back muscle movements?
remember that the extrinsic back mm move the shoulder and arm and these comprise the trapezius, latissimus dorsi, levator scapulae and the rhomboids collectively referred to as the superficial extrinsic back muscles and then you have the intermediate extrinsic back muscles comprised of the serrates posterior muscles
that are the two intermediate extrinsic back mm and their functions?
the serratus posterior superior and serrates posterior inferior; functions of
Serratus posterior superior, deep to rhomboid mm:
Proximal - lower ligamentum nuchae, C7 – T3
Distal-ribs 2-5
Innervation-intercostal nn
Artery - posterior intercostal aa. 1-4
Action-elevates ribs 2-5
Serratus Posterior Inferior, beneath latissimus dorsi:
Attachments: Prrximal-11 – L3
Distal-o ribs 9-12.
Innervation:-intercostal nn
Artery – lowest posterior intercostal a., subcostal a., first two lumbar aa.
Action- depresses ribs 9-12
*Both may also provide proprioception
what are origin, insertion and pathology due to loss of function (pathology) for the rhomboids?
origin: nuchal ligament and C7-T5 spinous processes
insertion: medial border of the scapula
Action - retracts scapula
Innervation - dorsal scapular nerve (C5)
Artery – dorsal scapular
pathology: scapular retraction and downward rotation of the scapula/glenoid cavity
what are origin, insertion and pathology due to loss of function (pathology) for the levator scapulae?
origin: C1-T4 transverse process
insertion: superior medial border of the scapula
Action – elevates scapula
innervation - dorsal scapular nerve (C5); the upper part of the muscle receives branches of C3 & C4
Artery - dorsal scapular
pathology: lesion of the dorsal scapular nerve with symptoms being a winging of the scapula; also chronic pain
what are origin, insertion and pathology due to loss of function (pathology) for the serratus anterior ?
origin: lateral ribs 1-8
insertion: anterior surface of medial border of the scapula
Action – protracts scapula
innervation - long thoracic nerve (from ventral rami C5-C7)
Artery – lateral thoracic
pathology: damage to the long thoracic nerve leading to functional loss and so you lose function in the axilla symptoms being trouble elevating the arm and unstable shoulder, wing like tilting called scapula alata
what are origin, insertion and pathology due to loss of function (pathology) for the trapezius?
origin: midline occipital protuberance inferior to T-12
insertion: scapular spine
Action
upper fibers - elevate shoulder
middle fibers - retract scapula
lower fibers - depress scapula
Artery -transverse cervical
pathology: A lesion of the accessory nerve may lead to paresis and atrophy of the trapezius. A classic symptom is the inability of abducting the shoulder. The elevation (lifting the arm above 90°) is restricted as well. The shoulder of the affected side is lowered and the medial border of the shoulder blade lies slightly laterally (scapula alata). Injuries of the accessory nerve occur frequently during interventions at the cervical region such as lymph node biopsy or neck dissection, rarely after traumas and skull base tumors.
what four muscles comprise the rotator cuff?
infraspinatus, supraspinatus, subscapularis, teres minor
name the origin, insertion, and major action of the infraspinatus?
origin: infraspinous fossa of scapula
insertion: middle facet of greater tubercle of humerus
major action: laterally rotates the arm
artery: suprascalular nerve
name the origin, insertion, and major action of the supraspinatus?
origin: supraspinous fossa of scapula
insertion: superior facet of greater tubercle of humerus
major action: initiates and assists deltoid in abduction of arms and acts with rotator cuff muscles
artery: suprascapular artery
name the origin, insertion, and major action of the subscapularis?
origin: sub scapular fossa (most anterior surface of scapula)
distal: lesser tubercle of humerus
major action: medially rotate s arm
artery: sub scapular artery
name the origin, insertion, and major action of the teres minor?
origin: middle part of lateral border of the scapula
insertion: inferior facet of greater tubercle of humerus
major action: laterally rotates the arm
artery: subscapular & scapular circumflex
Give the origin, insertion of the following superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff: latissimus dorsi
origin: T7-12 spinous processes, thoracolumbar fascia, iliac crest
insertion: intertubercular groove of humerus
major action: extends, adducts, and medially rotates humerus and raises body toward arms during climbing
artery: thoracodorsal
Give the origin, insertion of the following superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff: deltoid
origin: lateral third of the clavicle; acromion and spine of the scapula
insertion: deltoid tuberosity of the humerus
major action:
clavicular part: flexes and medially rotates arm
acromial part: abducts arm
spinal part: extends and laterally rotates arm
artery: posterior circumflex humeral artery
Give the origin, insertion of the following superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff: teres major
origin: lower 1/3 dorsal surface lateral border of scapula
insertion: medial side of intertubercular groove of humerus
major action:
adducts humerus
internally rotates humerus
extends humerus from flexed position
artery: sub scapular and circumflex scapular
are the following muscles intrinsic or extrinsic?
superficial, deep, intermediate?what do these muscles act on?
rhomboids, levator scapulae, serratus anterior, trapezius
extrinsic; superficial; scapula
what superficial extrinsic muscles back muscles lay posterior axio appendicular muscles connecting the axial skeleton (vertebral column) with the superior appendicular skeleton (pectoral girdle and humerus) and produce and control limb movements?
trapezius, latissimus dorsi, levator scapulae, rhomboids
what superficial extrinsic muscles act on the scapula?
rhomboids, levator scapulae, serratus anterior, trapezius
what are the two intermediate extrinsic back muscles?
serratus posterior superior and the serratus posterior inferior
what are the four muscles that comprise the rotator cuff? and are they intrinsic or extrinsic muscles?
supraspinatus, infraspinatus, subscapularis, teres minor
what are the extrinsic mm? superficial and deep?
superficial: latissimus dorsi, trapezius
deep: levator scapulae, rhomboid major, rhomboid minor
what are the intrinsic mm that originate from the scapula and/or clavicle and attach to the humerus?
deltoid, teres major, rotator cuff muscles
what are the superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff?
latissimus dorsi, deltoid and teres major
what is the triangle of auscultation?
relative thinning of the musculature of the back that can be utilized to listen to respiratory sounds
what are the borders of the triangle of auscultation?
bounded by the trapezius, medial border of scapula and lattisimus dorsi
what do the extrinsic muscles of the back do?
move the shoulder and arm
what do the intrinsic muscle of the back do?
control spine and some neck movement
what does superficial for the back mean?
associated with movements of shoulder
what does intermediate for the back mean?
associated with movements of thorax
what does deep for the back mean?
associated with movements of the vertebral column
