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Sternoclavicular JointProvides major axis
of rotation for movement of clavicle and scapula
Freely permitted frontal and transverse plane motion.
Close pack position is with maximum shoulder elevation
Sternoclavicular Joint
Joint capsule Anterior &
posterior S-C ligaments
Intra-articular disc
Interclavicular ligament
Costoclavicular ligament
Acromioclavicular Joint
Irregular Diarthrodial joint between the acromion process of the scapula and the distal clavicle.
allows limited motions in all three planes.
Rotation occurs during arm elevation
Close-packed position with humerus abducted to 90 degrees
In close- Packed position there is maximum contact between the articulating surfaces and stability is also maximum.
Acromioclavicular Joint
Joint capsule A-C ligaments Intra-articular
disc Coracoclavicul
ar ligaments
Coracoclavicular Joint
A syndesmosis with coracoid process of scapulabound to the inferior clavicle by the Coracoclavicular ligament.
Permits little movement
Glenohumeral JointMost freely moving joint in human bodyGlenoid Labrum composed of:
fibrocartilage rim &Joint capsuleTendon of long head of biceps brachiiGlenohumeral ligaments
Rotator Cuff MusclesMost stable in close-packed position, when the humerus is abducted and laterally rotated.
Glenohumeral Motion
Bony geometry Labrum Capsuloligamen
tous structures Negative intra-
articular pressure
Passive Restraints:
Restraints to External Rotation
00 - SGHL, C-H & subscapularis
450 - SGHL & MGHL
900 - anterior band IGHLC
Dependent on arm position:
Restraints to Internal Rotation
00 - posterior band IGHLC
450 - anterior & posterior band IGHLC
900 - anterior & posterior band IGHLC
Dependent on arm position:
Scapulothoracic JointRegion between the anterior scapula and thoracic wall.
Functions of muscles attaching to scapula:
Contract to stabilize shoulder regionFacilitate movements of the upper extremity through appropriate positioning of the Glenohumeral joint.
Movements of the Shoulder ComplexHumerus movement usually
involves some movement at all three shoulder joints
Positioning further facilitated by motions of spine
Scapulohumeral Rhythm
Scapulohumeral RhythmThe ratio has considerable variation among
individuals but is commonly accepted to be 2:1 (2 of glenohumeral motion to 1 of scapular rotation) overall motion.
During the setting phase (0 to 30 abduction, 0 to 60 flexion), motion is primarily at the glenohumeral joint, whereas the scapula seeks a stable position.
During the mid-range of humeral motion, the scapula has greater motion, approaching a 1:1 ratio with the humerus
later in the range, the glenohumeral joint again dominates the motion
Movements of the Shoulder ComplexMuscles of the ScapulaMuscles of the Glenohumeral Joint
FlexionExtensionAbductionAdduction
Medial and Lateral Rotation of the Humerus
Horizontal Adduction and Abduction at the Glenohumeral Joint
Horizontal Adduction and Abduction at the Glenohumeral Joint
HORIZONTAL ADDUCTION: Anterior to joint:Pectoralis major (both heads), anterior
deltoid, CoracobrachialisAssisted by short head of biceps brachii
HORIZONTAL ABDUCTION: Posterior to joint:Middle and posterior deltoid, infraspinatus,
teres minorAssisted by teres major, Latissimus dorsi
Shoulder joint has to bear most of the weight amongst all other articulations of the shoulder girdle
Shoulder has to provide direct mechanical support
Large leverageMore compressive forces on the
shoulder jointDeltoid produces upward shear forces as
compared to rotator cuff which produces downward shear forces.
Loads on the Shoulder
Loads on the ShoulderArm segment moment arm:
Perpendicular distance between weight vector and shoulder
Large torques from extended moment arms countered by shoulder musclesLoad reduced by half with maximal elbow flexion
Common Shoulder InjuriesDislocationsRotator Cuff Damage
Impingement TheorySubscapular NeuropathyRotational InjuriesEctopic calcification
Hardening of organic tissue through deposit of calcium salts in areas away from the normal sites
Subscapular NeuropathyThe typical patient is a young overhead athlete who
reports vague posterior shoulder pain. Although, the athlete can have painless atropy presenting as supraspinatus and/or infraspinatus weakness, depending on the location of the suprascapular nerve.
Because of the anatomy (see Functional Anatomy), more distal nerve injuries are often relatively painless. In particular, nerve injuries at the spinoglenoid notch that result in selective denervation of the infraspinatus muscle may be painless condition..
Based on anatomic considerations, athletes with more proximal lesions of the suprascapular nerve that affect both the supraspinatus and infraspinatus muscles are more likely to have pain and symptom-limited function.
DislocationsLoose structure of shoulder leads to
extreme mobility = less stabilityIt may be Posterior, Anterior or
inferior dislocationMechanism??////Contact sportsGlenohumeral capsular laxityStrengthening of shoulder
musculature
Elbow ArticulationsHumeroulnar Joint
True elbow jointStrong bony configurationHinge joint
Humeroradial JointSlides along capitulumModified ball and socket jointProvides no ABD or ADD
Proximal Radioulnar JointAnnular ligamentMovementsInterosseous membrane
Loads on the ElbowLarge loads generate by muscles that
cross elbow during forceful pitching/throwingAlso in weight lifting, gymnastics
Extensor moment arm shorter than flexor moment armTricep attachment to ulna closer to elbow joint center than those of the brachialis on ulna an biceps on radius
Moment arm also varies with position of elbow
Wrist and Hand BonesHand
MetacarpalsPhalanges 2-5
ProximalMiddle Distal
Phalange 1 (Thumb) Proximal Distal
Movements of the WristSagittal and frontal plane movementsRotary motionFlexionExtension and HyperextensionRadial DeviationUlnar Deviation
Common Injuries of the Wrist and Hand
Sprains and strains fairly common, due to breaking a fall on hyperextended wrist
Certain injuries characteristic of sport typeMetacarpal fractures and footballUlnar collateral ligament and hockeyWrist fracture and skate/snowboardingWrist in non-dominant hand for golfers
Carpal Tunnel Syndrome
Mallet finger
In medicine, mallet finger, also baseball finger,[1] dropped finger, dolphin finger, "Virgin Finger", "Hannan Finger" and (more generally) extensor tendon injury, is an injury of the extensor digitorum tendon of the fingers at the distal interphalangeal joint (DIP).[2] It results fromhyperflexion of the extensor digitorum tendon, and usually occurs when a ball (such as a softball,basketball, or volleyball), while being caught, hits an outstretched finger and jams it - creating a ruptured or stretched extensor digitorum tendon.