YTTanatomy Flashcards
what is the Sternocleidomastoid
largest & most important anterior neck muscle
what is the origin of the Sternocleidomastoid
dual origins: on the sternum & claviclesuperior occipital line
what is the insertion point of the Sternocleidomastoid
inserts: on the mastiod process & curved
what is the action of the Sternocleidomastoid
actions: when skull is fixed SCM elevates the sternum & clavicle - assists in inspirationwhen htoracic cage is fixed: contraction of SCM causes ipsilateral sidebending and contralateral rotation of the head as well as extension
where does the diaphragm insert?
inserts on its own central tendon
diaphragm - origins?
three major origins, all inserting on the central tendon-sternal origin from the xiphoid process-costal origin - from the deep surfaces of ribs 7-12 and their cartilages-vertebral origin - a ‘right crus’ arising from the bodies of L1-L3 and a ‘left crus’ from the bodies of L1-L2
diaphragm - action?
the diaphragm is the principal muscle of inspiration
Psoas Major - origin
the psoas major arises from the bodies of T12-L5 and from arches of fascia which connect the boney parts of the vertebral bodies but do not attach to the intervertebral disks
Psoas Major - insertion
the psoas major run anterior to the pelvis, posterior to the inguinal ligament and inserts on the lessor trocanter
Psoas Major - action
when the vertebrae are fixed, the psoas flexes the hip and works as a weak adductor and lateral rotatorwhen spine is fixed: straightens the spine (act to erect) the lumbar spine. in unilateral contraction - the unilateral action pulls the spine into a sidebend, flexion and rotation of the side opposite of the contraction
External oblique - O I A
Origin: the external oblique is attached above to the outer surfaces of ribs 5-12 & the ilioinguinal ligament. Insertion: In front & below it ends at the linea alba & inguinal ligamentAction: unilateral contraction of the exteral oblique results in sidebending and contralateral rotation of the spine & ribcageBilateral contraction causes flexion of the trunkfixed pelvis: lowers the ribs - expiratory muscle
Rectus abdominis OIA
O: the crrest and symphysis of the pubusI: the xiphoid process and cartilages of ribs 5-7A: flexor of the trunk (moving the sternum toward the pelvis
Levator scapulae OIA
O: the transverse processes of C1-C4I: superior angle of the scapulaA: elevates the scapula and rotates it downward.When scapula is fixed it acts on the cervical spine (reinforce splenius cervicis)
Rhomboids OIA
O: the spinous process of C7 and T1-T4I: the medial border of the scapulaA: adduct the scapula and rotate it downwardwhen the scapula is fixed they act the contraction of these muscles pulls the vertebrae laterally
Subscapularis OIA
O: the anterior surface of the scapulaI: on the lesser tubercle of the humerusA: principal muscle of medial rotation of the arm
Supraspinatus OIA
O: suprapinous fossa on the posterior scapulaI: highest point on the greater tubercleA:abducts the arm (with the deltoid)
Infraspinatus OIA
O: from the infrespinous fossaI: the greater tubercle (at a point posterinferior to the insertition of the supraspinatus)A;lateral rotation and participates in abduction
what are the Rotator cuff muscles?
four deep muscles: subscapularis, supraspinatus, infraspinatus and teres minorapart from their action of mobilizing the humerus, they play an important role as “active ligaments” in providing mobility to the joint
what do the Rotator cuff muscles do?
apart from their action of mobilizing the humerus, they play an important role as “active ligaments” in providing mobility to the jointsupraspinatus - prevents the humerus from being dislocated/displaced upwardsubscapularis prevents the head of the humerus from gliding backwardthe infraspinatus and teres minor prevent it from being dislocated forward and from gliding forward & backward
Biceps brachii OIA
O: 2 (bi) origins the long head arises from a tubercle about the glenoid cavity of the scapulathe short head starts as a tendon at the coracoid process on the lateral edge of the scapula. the two tendons continue downward & form one tendonI: bicipital tuberosity of the radiusA: the primary elbow flexorI:
Triceps brachii OIA
O: 3 (tri) origins the long head - a tubercle below the glenoid cavity of the scapulathe lateral head - from the lateral posterosuperior shaft of the humerusthe medial head - from the posteroinferior humerusI: singl ebroad insertion by a tendon onto the olecranonA:major elbow extensor
Pectoralis major OIA
O: clavivle head from the anterior, medial clavicle and a sternocostal head from the sternum and costal cartilages 1-6 and rib 7I: the tendon is twisted such that the fibers from the clavicular head insert below those from the sternocoastal head on teh lateral aspect of the bicipital grooveA: ribcage fixed - all the fibers adduct and medially rotate the arm - the “hugging muscle” flexionshoulder fixed: inspiration
Latissimus dorsi OIA
“widest back muscle”O: the scral & iliac crests, thoracolumbar fascia, spinous processes of T7-T12 and the posterior surfaces of the four lower ribsI: the tendon(wraps around the medial side of the humerus, makes a twist &) inserts on the bicipital grooveA: extension, adduction and medial rotation of the arm
Deltoid OIA
three groups of fibers:middle fibers attach to the lateral border of the acromionposterior fibers attache to the spine of the scapulathe anterior fibers attach to the claviclesI: (the three fibers converge) on the lateral surface of the humerusA: contraction of anterior fibers: flexion & medial rotation of armcontraction of middle fibers: abduction of the armcontraction of posterior fibers: extension of the arm
Trapezius OIA
O:occiput, nuchal ligament and spinous processes of the cervical vertebrae and the thoracic vertebrae down to T12I:- the lateral third of the clavicle and acromion (upper fibers)-scapular spine (middle fibers)-a tubercle at the medial end of the scapular spine (lower fibers)A: simultaneous contraction of all the fibers adducts the scapula- upper fibers alone=elevation and upward rotation of the scapula-lower fibers=act in depression and upward rotation of the scapula
Gluteus minimus OIA
O: exteral iliac fossaI:anterior aspect of the greater trochanterA: reinforce those of the anterior part of gluteus mediusIn addition to abduction of the thigh, it assists in flexion and medial rotation
Gluteus medius OIA
O: broad origin on the external iliac fossaI: It’s fibers converge and insert on the lateral aspect of the greater trochanterA: hip fixed: major action=abduction of the hip but can also assist in flexion and extensionfemur fixed: involved in both flexion and extension of the pelvis. Main action is visble when standing on one leg:acts in lateral flexion of the pelvis
Piriformis OIA
O: on the anterior sacrumI: on top of the greater trochanterA: fixed sacrum=laterally rotates, abducts and flexes the femurfixed femur: contributes to extension of the pelvis or medial rotation of the pelvis
Quadricepts femoris - what are the three parts?
massive muscle w/ four bodies which converge into a single quadriceps tendonvastus intermedius- the deepest muscle originates from the upper two thirds of the anterior femoral shaftvastus interedius is covered by vastus lateralis and medialis
rectus femoris OIA
rectus femoris - covers the hip as well as O: anterior inferior iliac spine (& part of the iliumI: the common (quad) tendon (also crosses knee & hip & acts on both joints)A: pelvis fixed= flexes the hip & extends the kneefemur fixed= flexion of the pelvis and extends knee(to stretch hip must be in extention and knee in flexion)
Hamstrings OIA
O: ischium (posterior to the hip bone)I: on the bones of the lower legA:primary actions are extension of the thigh and flexion of the kneethigh fixed= act in extension of the pelvis
Semitendinosus OIA
a hamstring muscle O: located medially (posterior to the semimembranosus) and inserts (via a long thin tendon to the superomedial tibial shaft) on the tibiaA: also acts to medially rotate the knee (with the semitendinosus)
Semimembranosus OIA
a hamstring muscleO: from the ischiumI: inserts on the posteromedial aspect of the tibial condyleA: with the semimembranosus, medially rotates the knee
Biceps femoris OIA
hamstring muscle, two headsO:ischium (posterior to hip bone)I:via common tendon to the head of the fibulaA: also acts in lateral rotation
Adductors OIA
a group of five muscles having their bodies on the medial thighI: on the linea aspera of the femurA:adduction of the hip
Pectinus OIA
an adductor muscleO: runs from the lateral pubis to a line connecting the lesser trochanter to the linea aspera of the femur
Adductor magnus OIA
the largest and strongest of the adductor group - a compund muscleanterior portion originates from the ischiopubic ramus and inserts on the linea asperathe posterior portion originates from the ischial tuberosity and inserts just above the medial femoral condyle.A: also involved in medial rotation of the pelvis when femur is fixed
Tensor fasciae latae OIA
O: anterior iliac crestI: not on a bone but on the fascia lata (aka the iliotibial tract). on a band of strong fibrous tissueA: abducts, flexes and medially rotates the femur. Plays small part in knee extension or lateral rotation of the flexed kneethigh & leg fixed=flexion, lateral flexion or lateral rotation of the pelvis
Gluteus Maximus OIA
O: posterior sacrum and coccyx (as well as the posterolateral iliac fossa)I: the deep layer inserts on the superior linea aspera of the femursuperficial layer inserts on the fascia lataA (deep layer): hip bone fixed=pulls femur backward (hip extension) into lateral rotation and slight adductionfemur fixed= acts in extension of the pelvis and in extension, medial rotation and medial flexion of the pelvisA: superficial layer: acts on the femur by extending, externally rotating and abducting it. works with the tensor facia latae
what is the femur?
thigh bone
what is the humerus?
upper arm bone
what is the tibia?
lower leg bone (along with the fibula)
what is the radius?
the lower arm bone (along with the ulna)
what is the lumbar spine?
vertebrae of the lower spine
what is kyphosis?
forward curvature of the spine
