ANAT Week 2

Which ligament of the radioulnar joint in the wrist goes from the radial styloid process to the scaphoid?

Radial collateral ligament of wrist

What do the scapulohumeral muscles consist of? In broad terms

The rotator cuff muscles and the non rotator cuff muscles

The rotator cuff is comprised of which muscles?

-Subscapularis
-supraspinatus
-infraspinatus,
-teres minor
Remember SITS*

What is the origin of the subscapularis?

Scapula-subscapular fossa, medial 2/3

What is the insertion of the subscapularis?

Humerus-lesser tuberosity

What is the nerve innervation of the subscapularis?

Upper and lower scapular nerves (C5+C6)

What are the actions of the subscapularis?

-Shoulder IR
-Holds head of the humerus in glenoid fossa and depresses it to allow shoulder abduction

What is the origin of the supraspinatus?

Scapula-supraspinous fossa, medial 2/3

What is the most commonly torn rotator cuff muscle?

The supraspinatus

What is the insertion of the supraspinatus?

Humerus-superior facet of greater tuberosity

What is the nerve innervation of the supraspinatus?

Suprascapular nerve (C5)

What are the actions of the supraspinatus?

-Shoulder abduction (initiates)
-Holds the head of the humerus in glenoid fossa

What is the origin of the infraspinatus?

Scapula-infraspinous fossa, medial 2/3

What is the insertion of the infraspinatus?

Humerus-middle facet of greater tuberosity

What is the nerve innervation of the infraspinatus?

suprascapular nerve (C5+C6)

What are the actions of the infraspinatus?

-Shoulder ER
-Holds head of the humerus in glenoid fossa and depresses it to allow shoulder abduction.

What is the origin of the teres minor?

Scapula-lateral border, upper 2/3

What is the insertion of the teres minor?

Humerus-inferior facet of greater tuberosity

What is the nerve innervation of the teres minor?

Axillary nerve (C5+C6)

What are the actions of the teres minor?

-Shoulder ER
-Shoulder adduction
-shoulder extension
-holds head of the humerus in glenoid fossa and depresses it to allow shoulder abduction

What are the nonrotator cuff muscles of the scapulohumeral muscles?

Teres major, deltoid

What is the origin of the teres major?

scapula-lateral border of the scapula, lower 1/3, including oval area and inferior angle.

What is the insertion of the teres major?

Humerus-crest of lesser tuberosity (medial lip of IT groove)

What is the nerve innervation of the teres major?

Lower scapular nerve (C5+C6)

What are the actions of the teres major?

-Shoulder IR
-Adduction
-Extension
-Hyperextension

What are the IT (intertubercular) groove muscles?

-Latissimus dorsi
-Pectoralis major
-Subscapularis
-Teres major

What is the origin of the deltoid?

-clavicle: deltoid tubercle
-scapula: lateral border of acromion -inferior lip of spine to smooth triangular space

What is the insertion of the deltoid?

Humerus-deltoid tuberosity

What is the nerve that innervates the deltoid?

Axillary nerve (C5+C6)

What are the actions of the deltoid?

-anterior deltoid: shoulder flexion, IR, horizontal adduction
-middle deltoid: shoulder abduction
-posterior deltoid: shoulder extension, hyperextension, ER, horizontal abduction

What does the deltopectoral groove contain?

Cephalic vein

Where is the deltopectoral groove? Informative flashcard*

Located between the superlateral aspect of the pectoral region and the deltoid.

What is the insertion of the deltoid?

Humerus-deltoid tuberosity

What is the nerve that innervates the deltoid?

Axillary nerve (C5+C6)

What is the insertion of the supraspinatus?

Humerus-superior facet of greater tuberosity

What allows for shoulder abduction in patients?

The downward glide in glenohumeral joint and sliding of head of the humerus

What are the functions of the rotator cuff muscles?

-holds head of the humerus in glenoid fossa*
-rotation of humerus on long axis
-protection of the shoulder joint by their common muscolotendinous sheath
-stabilizes shoulder joint in every direction except inferiorly*
-acts as an extensible ligament for shoulder motions

What holds the head of the humerus in the glenoid fossa?

The rotator cuff muscles

What direction of the shoulder joint is not stabilized by the rotator cuff muscles?

Inferiorly

What can typically occur with post CVA patients and sports injuries?

Inferior dislocation of the shoulder joint

What acts as an extensible ligament for shoulder motions?

Rotator cuff muscles

What allows for rotation of the humerus along the longs axis?

Rotator cuff muscles

What muscles protect the shoulder joint by their common musculoskeletal sheath?

Rotator cuff muscles

What are common rotator cuff problems?

-rupture of rotator cuff muscles
-calcification of tendons-especially supraspinatus
-subluxation or dislocation-instability inferiorly
a. Superiorly-stabilized by supraspinatus and coracoacromial arch
b. Posteriorly-stabilized by infraspinatus and teres minor
c. Anteriorly-stabilized by subscapularis
d. Inferiorly-no muscles, so subluxation is the easiest

What stabilizes the shoulder joint superiority?

Supraspinatus and coracoacromial arch

What rotator cuff muscle stabilizes the shoulder joint posteriorly?

Infraspinatus and teres minor

What rotator cuff muscle stabilizes the shoulder joint anteriorly?

Subscapularis

What rotator cuff muscle stabilizes the shoulder joint inferiorly?

No muscles, so subluxation is the easiest

Why does subluxation occur easiest inferiorly at the shoulder joint?

Because there are no muscles

What is the pneumonic for the rotator cuff muscles?

S.I.T.S.
Supraspinatus-index finger. This sits on the superior facet of the greater tuberosity of the humerus.
infraspinatus-middle finger. This sits on the middle facet of the greater tuberosity of the humerus.
teres minor-ring finger. This sits on the inferior facet of the greater tuberosity of the greater tuberosity of the humerus.
subscapularis-thumb. This sits on the greater tuberosity of the humerus

What are the quadrangular space borders?

-superior border: inferior margin of teres minor
-inferior border: superior margin of of teres major
-medial border: lateral margin of long head of triceps brachii
-lateral border: surgical neck of humerus

What does the quadrangular space contain?

-axillary nerve
-posterior humeral circumflex artery and vein

Where is the axillary nerve found?

Quadrangular space

Where is the posterior humeral circumflex artery and vein found?

Quadrangular space

What is the superior border of the quadrangular space?

Inferior margin of teres minor

What is the inferior border of the quadrangular space?

Superior margin of teres major

What is the medial border of the quadrangular space?

Lateral margin of long head of triceps brachii

What is the lateral border of the quadrangular space?

Surgical neck of the humerus

What make up the borders of the triangular space?

-superior border: inferior margin of teres minor
-inferior border: superior margin of teres major
-lateral border: medial margin of long head of triceps brachii

What makes up the superior border of the triangular space?

Inferior margin of teres minor

What makes up the inferior border of the triangular space?

Superior margin of teres major

What makes up the lateral border of the triangular space?

Medial margin of long head of triceps brachii

What is found in the triangular space?

-scapular circumflex artery and vein
-sometimes lower subscapular nerve

Where can yo find the scapular circumflex nerve?

Triangular space

Where can the lower subscapular nerve sometimes be found?

Triangular space

What are the borders of the triangular interval?

-superior border: inferior margin of teres major
-medial border: lateral margin of long head of triceps brachii
-lateral border: medial margin of lateral head of triceps brachii

What is the superior border of the triangular interval?

Inferior margin of teres major

What is the medial border of the triangular interval?

Lateral margin of long head of triceps brachii

What is the lateral border of the triangular interval?

Medial margin of lateral head of triceps brachii

What is found in the triangular interval?

-radial nerve
-profunda brachii artery and vein

Where is the radial nerve found?

Triangular interval

Where is the profunda brachiii artery and vein found?

Triangular interval

If you are looking posteriorly at the shoulder, what sits more medially, the quadrangular space, triangular space, or the triangular interval?

Triangular space
*The quadrangular space and the triangular interval sit more laterally. The triangular interval also sits inferior to the quadrangular space.

What sits below the quadrangular space?

Triangular interval

What are the motor nerves and nerve roots of the subscapularis?

Upper + lower subscapular nerves C5+C6

What are the motor nerves and nerve roots of the supraspinatus?

Suprascapular nerve C5

What are the motor nerves and nerve roots of the infraspinatus?

Suprascapular nerve C5+C6

What are the motor nerves and nerve roots of the teres minor?

Axillary nerve C5+C6

What are the motor nerves and nerve roots of the teres major?

Lower subscapular nerve C5+C6

What are the motor nerves and nerve roots of the deltoid?

Axillary nerve C5+C6

What is the action of the subscapularis? Summary page*

Shoulder IR

What is the action of the supraspinatus? Summary page*

Shoulder abduction

What is the action of the infraspinatus? Summary page*

Shoulder ER

What are the actions of the teres minor? Summary page*

Shoulder IR, extension, adduction, hyperextension

What are the actions of the teres major? Summary page*

Shoulder IR, extension, adduction, hyperextension

What are the actions of the deltoid? Summary page*

-Anterior: shoulder flexion, IR, horizontal adduction
-Mid: shoulder abduction
-Post: shoulder extension, hyperextension, ER, horizontal abduction

What are the thoracohumeral muscles?

Pectoralis major

What are the thoracoscapular muscles?

-pectoralis minor
-subclavius

What is the origin of the pectoralis major?

——-clavicular head: clavicle- medial 1/2 superior surface and anterior border
—— head: sternum-lateral 1/2 anterior surface of manubrium/eternal body to rib 7.
-ribs-costal cartilages of all true ribs
-aponeurosis-external oblique abdominals, sometimes a slip from rectus abdominis

What is the insertion of the pectoralis major?

-humerus: crest of greater tuberosity (lateral lip of IT groove)

What are the nerve innervations of the pectoralis major?

-medial and lateral pectoral nerves (C5-T1)

What are the actions of the pectoralis major?

-shoulder adduction
-IR
-horizontal adduction
-pulls trunk up if arms are fixed
-forced inhalation-rib cage elevation

Besides the serratus anterior, what other muscles aide in forced inhalation (rib cage elevation)?

Pectoralis major and pectoralis minor and subclavius

Besides the latissimus dorsi, what other muscle group aides in pulling the trunk upward if the arms are fixed?

Pectoralis major

Where is the cephalic vein?

Deltopectoral groove

What is the origin of the pectoralis minor?

-ribs 3-5 near their costal cartilages and intercostal fascia

What is the insertion of the pectoralis minor?

-scapula-medial border of coracoid process

What is the nerve innervation of the pectoralis minor?

-medial pectoral nerve (C8T1)

What are the actions of the pectoralis minor?

-scapular abduction
-downward rotation
-depression of scapula
-forced inhalation-rib cage elevation

What is the origin of the sublcavius?

-Rib 1:junction of costal cartilage