Lec. 1: Kin of SH Flashcards
Arthrokinematics of the SC jt during RET and PROT
Transverse plane
(clav. is concave on SUP surface, manubrium is convex on SUP surface)
roll and slide occur in same direction
Arthrokinematics of the SC jt during ELEV and depression
Frontal plane
(clav. is convex and manubrium is concave)
roll and slide in opposite directions
CPP, capsule pattern, and typical dislocation of SC jt
CPP: full ELEV
Cap. Pattern: P at extreme ranges, especially horizontal ADD and full humeral ELEV
Dis.: clav. moves anteromedial
ligament that limits elevation and PROTR-RET; serves as the axis for PROTR-RET and ELEV-depression
costcoclavicular
when does ROT occur at the SC jt
terminal humeral ELEV
CPP of AC jt
90-120 degrees ABD
Cap. pattern of AC jt
P at extreme ranges (especially horiz. ADD and full ELEV
typical dislocation of AC jt
clav. moves SUP
scap. PROTR involves ____ rotation and RET involves ____ rotation and occurs around a _____ axis through the ____ jt
MED, LAT, vertical, AC
damage to long thoracic n. or pathological weakness of serratus ANT can cause _____ ______
scapular winging
mvts at the AC jt (3)
-scap. PROTR-RET
-upward tip
-SUP and INF scap. ROT’N
GH JT:
CPP, Cap. pattern, typical dislocation
CPP: full ABD and Ext ROT
Cap. pattern: Ext ROT>ABD>INT ROT
typical dislocation: humerus moves anteroinferior
arthrokinematics at GH jt
convex surface of humerus moves on concave surface of glenoid fossa so roll and glide occur in opposite directions
full ABD at the GH requires ____ humeral ______ or mvt in ______ to avoid the greater tuberosity abutting the superior glenoid rim of the labrum
EXT ROT, scaption
the ST, AC, and SC jts form a ____ _____ _____, meaning that mvt at one invariably causes mvt at the others
closed kinetic chain (CKC)
the ST jt primarily functions to orient the _____ _____ for optimal contact with the ______ ____
glenoid fossa, humeral head
role of the scap
to move in a way that maintains optimal congruency b/w the humeral head and glenoid fossa throughout ROM
lack of co-activation of synergistic mms could cause
muscular fatigue
muscular fatigue can affect _____.
biomechanics
the scap is a ______ link that helps transfer energy from the ______ body to the _____ and _____
kinetic
lower
arms and hands
relationship b/w mvt at the GH and ST jts is described by the ________ _____ and applies to what actions
scapulohumeral rhythm,
ABD, FLEX, and scaption
scapulohumeral rhythm ratio
1:2
every 1 degree of scap motion = 2 degree of humeral motion
the first 30 degrees of humeral ABD occurs where
GH jt
what’s going on in the SH girdle at 30-90 degrees humeral ABD
- Upper and lower traps and serratus ANT cause SUP scap ROT and clav. elevation
- motion is occuring primarily at SC jt b/c coracoclavicular ligs are taut and restrain motion around AC
- clav. ELEV, SUP scap ROT, and AC ELEV occur until costoclavicular lig stops further clav. ELEV (at this point the humerus has ABD ~60 degrees and the scap. has SUP ROT ~ 30degrees)
from 30-90 degrees humeral ABD the axis of ROT of the scap is where
root of the spine of the scap
what’s going on in the SH girdle from 90-165 humeral ABD
-glenoid continues ROT superiorly therefore the coracoid process ROT inferiorly which pulls the coracoclavicular ligs tight and posteriorly ROT the clav 30-50 degrees. The AC jt is then elevated and scap rotates another 30degrees
-humerus has ABD ~110 degrees and scap has rotated ~55 degrees
where is the axis of ROT of the scap in 90-165 degrees of humeral ABD
about the AC jt
what happens to the spine at terminal ABD of humerus
LAT FLEX and ROT
the last 10-15 degrees of SH FLEX or ABD is achieved how
spinal EXT or LAT FLEX
possible causes of restrictions of humeral ABD (4)
-reverse scapulohumeral rhythm
-fused SC
- no EXT humeral ROT
-no clav ROT
prime movers of the SH girdle (6)
deltoid
supraspinatus
traps
lats
pec maj
levator scapulae
synergists of the SH girdle (13)
infraspinatus
teres minor
subscap
rhomboids both
subclavius
long head of biceps
traps
serratus ANT
lats
pecs
supraspinatus
dysfunction of deltoid can cause ____ _____
weak ABD
dysfunction of supraspinatus can cause weak ABD from ___-___ degrees and weak _______ ______ during ABD which can lead to ___ _______
0-30, humeral ELEV, GH impingement
the traps and serratus ANT work together to ____ ____ the scap.
SUP ROT
Dysfunction of the serratus ANT and traps would cause delts to be become actively insufficient at
~60 degrees of ABD
mm that contracts eccentrically to decelerate overhead humeral motion and reduce strain on the rotator cuff
lats
the ___ and _____ ___work together to depress the SH girdle
traps and serratus ANT
When a multi-joint muscle shortens across all joints simultaneously, reducing its ability to generate optimal tension and force.
active insufficiency
When a multi-joint muscle lengthens at all the joints it crosses. This limits the range of motion at each joint as a muscle is typically not long enough to allow full range of motion simultaneously at each joint it crosses.
Passive insufficiency
a SH with ANT instability generally has an _______ serratus ANT which has become ______
overactive, fatigued
SH impingement is typically accompanied by _______ _____ of the serratus ANt
decreased activity
weakness or fatigue of the ____ _____ can cause impingement of the subacromial/deltoid bursae, decrease blood flow to supraspinatus tendon and cause injury by allowing the humerus to move ____
rotator cuff, superiorly
pain in the 60-120 degree range during humeral ABD is likely caused from what
rotator cuff injury
pain at the end range of humeral ABD is likely from
AC injury
which 3 mms provide a resultant mm force vector with a jt-stabilizing rotary component and an INF translatory component during humeral ABD
infraspinatus, teres minor, and subscapularis
what do infraspinatus, teres minor, and subscapularis do during humeral ABD
provide a inferior stabilizing force into glenoid fossa and counteracts the SUP pull of delts during initial stages of ABD which prevents the humeral head from impinging on the coracoacromial arch. Also EXT rotates humerus later in ABD so the greater tuberosity of the humerus clears the SUP glenoid rim (allows greater range of motion)
what does subclavius do (2)
depresses clav and stabilizes the SC jt
what two mms control undesired SUP scapular ROT as teres major pulls the humerus into EXT, MED ROT, and ADD
rhomboids major and minor
what mms provide eccentrically control when traps and serratus ANT are superiorly rotating the scap
rhomboids maj and min
hypertrophy of what tendon is observed with rotator cuff tears
long head of biceps
2 mms that act as synergists for deltoid by eliminating INF scap ROT during flexion and ABD
traps and serratus ANT
pts with SH injuries or whose work has their hands consistently at or above their SHs considering prescribing ______ ______ exercises
scapular stabilizing
ex. plank
