Shoulder
____ is a planar type *synovial joint* between the acromion process of the scapula and lateral clavicle.
*Acromioclavicular (AC) Joint* -AC joint more easily dislocated -intrinsic: *acromioclavicular ligament* (weak, easily torn)
Shoulder separation is dislocation of ______ joint.
*Acromioclavicular (AC) joint* -or tear of AC & Coracoclavicular (CC) ligaments -*AC joint torn first* (weaker) -different grades of AC joint injuries
_____ part of *scapula* articulates with the clavicle.
*Acromion*
__________ is an idiopathic inflammatory condition affecting *glenohumeral joint capsule* with higher prevalence in *females & diabetics*.
*Adhesive Capsulitis* (Frozen Shoulder Syndrome) -inflammation & thickening of glenohumeral joint capsule -severe loss range of motion (ROM) & chronic pain -autoimmune component
Dislocations of *glenohumeral joint* usu result in _____ displacement of humeral head.
*Anterior & Inferior* dislocation -*coracoacromial arch* prevent upward displacement -*axillary nerve* passing thru quadrangular space most likely affected by inferior displacement
Shoulder *ABduction* (away from midline) & *ADduction* (toward midline) occur around ________ axis.
*Anteroposterior Axis*
Fractures of *surgical neck of humerus* endanger _____, most commonly in *elderly pts with osteoporosis*.
*Axillary nerve* -dmg = weaken/paralyze *deltoid muscle* = inability to *ABduct* arm -weaken/paralyze *teres minor muscle*= limited external/lateral rotation
______ nerve (motor) innervates the *deltoid muscle* & *teres minor muscle*.
*Axillary nerve* (C5-C6) off of brachial plexus
Falling onto outstretched arm or directly onto shoulder commonly causes ________ injury.
*Clavicular* (common, esp kids) -fractures: usu at junction between *middle & lateral 1/3* of clavicle Lateral fracture -SCM pulls medial 1/3 upward -Pectoralis major pulls humerus & lateral 1/3 medially -fractured ends overlap
______ connects acromion & coracoid process of scapula, creating *coracoacromial arch* (roof for humeral head).
*Coracoacromial (CA) ligament* -restrict *upward displacement* of joint (most shoulder dislocations are inferior)
_____ is the strongest part of the Acromioclavicular (AC) joint.
*Coracoclavicular (CC) ligament* -anchors clavicle to coracoid process of scapula (indirectly to acromion), helps support AC joint -2 parts: *trapezoid ligament & conoid ligament*
____ muscles are the primary shoulder *ABductors after first 15°*.
*Deltoid muscles* -Anterior: *flexion* -Posterior: *extension*
40yo female presents with right shoulder pain & complaints of limitations in ADL. History of HTN and DM, no recent trauma. ROM testing shows = *limited external & internal rotation*, normal ABduction. What is most likely diagnosis?
*Frozen shoulder* -female, diabetes -defects in *2* different movements
First 30° of humeral elevation is primarily at ____ joint.
*Glenohumeral joint* -in middle range (<120°) = both glenohumeral & scapulothoracic joint movement
______ is a *ball & socket joint* between humeral head & glenoid cavity (fossa), allowing free range of motion for upper limb.
*Glenohumeral joint* Glenoid fossa (of scapilar bone) shallow = -*not as stable, greater mobility*
The 4 Rotator Cuff muscles attach to ______ on the humerus.
*Greater tubercle* (lateral) *Lesser tubercle* (medial) *Intertubercular/bicipital groove* runs between (biceps tendon sits here)
_____ muscles are responsible for *external/lateral rotation* of shoulder.
*Infraspinatous & Teres Minor muscles* -rotator cuff muscles
____ muscle inserts onto *middle facet* of greater tubercle of humerus.
*Infraspinatous muscle*
_____ muscle originates on *infraspinous fossa* (below spine of scapula).
*Infraspinatus muscle*
_____ subscapular nerve provides *motor* innervation to *subscapularis & teres major muscles*.
*Lower subscapular nerve*
_____ nerve innervates the *Teres Major muscle*.
*Lower subscapular nerve* (C5-C6)
_____ subscapular nerve provides *motor* innervation to *latissimus dorsi muscle*.
*Middle subscapular nerve* aka *thoracodorsal nerve*
_______ artery supplies the *Deltoid muscle*.
*Posterior Circumflex Humeral Artery* -Axillary a→ Post Circum Humeral Artery -anastamose with anterior circumflex humeral artery
40yo male presents with right shoulder pain & limitations in ADLs. He is delivery driver for UPS, no recent trauma. ROM = *limit ABduction* What is most likely diagnosis?
*Rotator cuff tear/tendinopathy* -chronic wear/tear with repetitive motions (lifting = arms above horizontal) OR Subacromial bursitis -but need more info to narrow it down
______ is a physiological joint (not true joint because no physical attachments between scapula & ribs).
*Scapulothoracic Joint* -With movements of the shoulder, the scapula glides and rotates on the underlying thoracic wall.
______ Joint involved in: -scapular *elevation/depression* -scapular *protraction/retraction* (reach forward/punch & pull arm back) -scapular *upward/downward rotation*
*Scapulothoracic Joint* -physiologic joint
______ is a *synovial joint* between the clavicle and sternum that connects the upper limb to the axial skeleton.
*Sternoclavicular (SC) Joint* -very strong joint capsule & ligaments (rarely dislocated)
________ lies between deltoid muscle/acromion (scapula) & supraspinatus tendon and *prevents friction as rotator cuff tendons move through subacromial space*.
*Subacromial (Subdeltoid) Bursa* -Subacromial bursitis (cause by impact injury, repetitive strain, impingement)
_____ is a space between acromion of scapula & humeral head. Contains (3) things
*Subacromial space* 1. *Supraspinatus muscle/tendon* 2. *Long head of biceps brachii tendon* 3. Subacromial bursa -impingements within space = *Subacromial Impingement Syndrome* (shoulder pain)
Suprascapulary artery arises from:
*Subclavian a*→Thyrocervical trunk→ Suprascapular A. -supply *supraspinatus, infraspinatus muscles* -contribute to shoulder anastamoses
_____ muscle is responsible for *internal/medial rotation* of shoulder.
*Subscapularis muscle*
_____ muscle originates on *subscapular fossa* (anterior surface of scapula).
*Subscapularis muscle*
____ muscle inserts onto lesser tubercle of humerus.
*Subscapularis muscle* -crosses glenohumeral joint, goes in front of shoulder = internal/medial rotation
_____ muscle is innervated by *upper & lower subscapular nerves*.
*Subscapularis muscle* -rotator cuff muscle
_____ spans across suprascapular notch creating a foramen where *suprascapular nerve/artery* pass through.
*Superior transverse scapular ligament* (STSL) -can be ossified -artery/nerve supplies supraspinatus & infraspinatus muscles
_______ muscles are innervated/supplied by the *suprascapular nerve (C5-6)/artery*.
*Supraspinatus & Infraspinatus muscles* of Rotator Cuff -suprascapular nerve arise from brachial plexus
_____ muscle originates on *supraspinous fossa* (above spine of scapula).
*Supraspinatus muscle*
_____ muscle inserts onto *superior facet* of greater tubercle of humerus.
*Supraspinatus muscle* -pass thru *subacromial space*
______ muscle does the *first 15°* of shoulder *ABduction*.
*Supraspinatus muscle* -rotator cuff muscle
_____tear is the most common rotator cuff tear because it runs thru *subacromial space* (prone to friction injuries)
*Supraspinatus tendon tear* -slide back and forth between acromion (scapula) & head of humerus
Sternoclavicular (SC) joint & Acromioclavicular (AC) joint are _____ joints.
*Synovial joints* -convey biochemical forces between upper limb & axial skeleton
____ muscle inserts into medial lip of intertubercular/bicipital groove (humerus).
*Teres Major muscle*
_____ muscle arises from inferior angle of scapula.
*Teres Major muscle*
______ muscle assists *latissimus dorsi muscle* with extension, internal rotation & ADduction of shoulder.
*Teres Major muscle*
____ muscle inserts onto *inferior facet* greater tubercle of humerus.
*Teres Minor Muscle*
_____ muscle originates on lateral border of scapula below the *infraspinatous muscle*.
*Teres Minor muscle*
Shoulder *Flexion* (forward movement) & *Extension* (backward movement) occur around _____ axis.
*Transverse axis*
_____ subscapular nerve provides *motor* innervation to *subscapularis muscle*.
*Upper subscapular nerve*
*Medial & Lateral Shoulder Rotation* occur around ______ axis.
*Vertical axis*
The anterior, middle & posterior *deltoid muscle* inserts onto ________.
*deltoid tuberosity* on humeral shaft
3 Bones making up Shoulder Joint
-*Clavicle* (only connection between appendicular & axial skeleton) -*Scapula* -*Humerus*
Posterior View of Scapula
-*Spine* -*Medial border* (watch as raise arms, watch for rotation) -*Suprascapular notch* (Suprascapular artery & nerve run here)
Rotator Cuff Muscles (SITS)
-*Supraspinatous* -*Infraspinatous* -*Teres Minor* -*Subscapularis* reinforce *glenohumeral joint*
2 Necks of Humerus
-*Surgical neck* (where amputations done) -*Anatomical neck* (around head of humerus)
Rotator Cuff Tear Causes
-Acute injury (fall) -Chronic wear/tear with repetitive movements (*working with arms above horizontal, lifting etc*) -*Subacromial impingement* (Supraspinatus tendon tear)
6 Shoulder Muscles (pass from scapula to humerus - act on glenohumeral joint)
-Deltoid Muscle -Teres Major Rotator Cuff (SITS) -Supraspinatus -Infraspinatus -Teres Minor -Subscapularis
Quadrangular Space
-Rectangular space allows *axillary nerve* & *posterior circumflex humeral artery* to pass from anterior shoulder toward posterior shoulder -Superior: Teres minor -Inferior: Teres major -Medially: long head of triceps -Lateral: Humerus
4 Shoulder Joints
-Sternoclavicular (SC) Joint -Acromioclavicular (AC) Joint -Glenohumeral Joint -Scapulothoracic Joint
Suprascapular _____ goes ABOVE *superior transverse scapular ligament* in suprascapular notch, while the Suprascapular _____ goes BELOW it.
-Suprascapular *artery* = ABOVE ligament -Suprascapular *nerve* = BELOW ligament *A*rmy OVER bridge *N*avy UNDER bridge
The deltoid muscles originate from same places at trapezius muscles:
-anterior deltoid = *lateral 1/3 of clavicle* -middle deltoid = *acromion* (scapula) -posterior deltoid = *spine of scapula*
3 Subscapular Nerves
-from posterior cord of brachial plexus -Upper, Middle, Lower Subscapular Nerves
Axillary nerve (C5-C6) from Brachial Plexus
-motor to *Deltoid & Teres Minor muscles* -sensory to skin over Deltoid muscle
Scapulothoracic joint movement is imp because ____
-responsible for final range of humeral elevation (after 120°) -without scapular rotation, *acromion block* further upward movement of humerus -painful ABduction past 120° = inflammation to *subacromial space* structures
Scapulohumeral Rhythm
180 Shoulder ABduction -60° rotation due to *scapulothoracic joint* -120° rotation due to *glenohumeral joint* (2:1 ratio, glenohumeral to scapulothoracic)
Scapular Anastamosis
Branches of subclavian a→axillary a→brachial a (1 continuous artery) Branches of Subclavian Artery 1. *Dorsal scapular a.* 2. *Suprascapular a.* (from thyrocervical trunk) Branches of Axillary Artery 3.*Circumflex scapular a.* (from subscapular) -Circumflex humeral a. 4. *Thoracodorsal a.* (from subscapular)
The *middle* deltoid muscle originates from:
acromion (scapula)
The *anterior deltoid muscle* originates from:
lateral 1/3 of clavicle
The *posterior* deltoid muscle originates from:
spine of scapula