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