2.2.3. Posterior Shoulder Flashcards
label the parts of the scapula
- supraspinous process
- infraspinous fossa
- spine
- scapular notch (suprascapular notch
- acromion
- infraglenoid tubercle - origin of of triceps brachii
label the parts of the scapula
- glenoid cavity with the upper portion of the supraglenoid tubercle (bicep brachii attachment) and the lower portion of the (3.) infraglenoid tubercle (tricep brachii attachment)
- neck
- coracoid process
1- head
2- lesser tubercle & its crest (the ridge that is the continuation of the tubercle)
3- greater tubercle & its crest (the ridge that is the continuation of the tubercle)
4- intertubercular sulcus (bicipital groove – where the tendon of the long head
of the biceps runs)
5- anatomic neck (along the capsule of the glenohumeral joint) (GA p 526A)
6- surgical neck (runs across the metaphysis - space between ball portion (epiphysis) and the shaft (diaphysis) that is considered to be part of the growth plate)
1- radial groove (spiral groove for the radial nerve & deep brachial artery)
2- head of humerus
What is the significance of the deltoid tuberosity?
Where the deltoid attaches
- deltoid
- supraspinatus
- infraspinatus
- teres major
- teres minor
- long head of triceps brachii
- lateral head of triceps brachii
Where does the deltoid attach?
Origin: lateral third of clavical
lateral acromion
and inferior edge of spine of scapula
Insertion: the deltoid protuberance of humerus
Where does the supraspinatus attach?
supraspinatus - attaches to the supraspinous fossa of the scapula and the greater tubercle of the humerus
Where does the infraspinatus attach?
infraspinatus - attaches to the infraspinous fossa of the scapula and the greater tubercle of the humerus;
Teres Major Attachments?
Goes from the posterior aspect of the inferior angle of the scapula and inserts at the intertubercular sulcus of the humerus
Action of the teres minor?
laterally rotates the arm and stabilizes the humerus
What are the four SITS muscles?
Supraspinatus
Infraspinatus
Teres Minor
Subscapularis
What do the SITS muscles do?
these four miscles form the musculotendinous rotator cuff; they assist the deltoid in the first 15 degrees of arm abduction
In what posture do patients usually sustain rotator cuff injuries
the most common injuries arise from use above the “horizontal” level (i.e. swimming, throwing, racquet sports, weightlifting)
How does one test a patient for “degenerative tendonitis of the rotator cuff”
ask the patient to lower the fully abducted limb slowly and smoothly; from approximately 90 degrees abduction, the limb will suddenly drop if there is a rotator cuff issue.
Describe the parts of the axillary artery
Part 1 - located between the 1st rib and pectoralis major; enclosed in axillary artery sheath with one branch (superior thoracic artery)
Part 2 - posterior to the pectoralis major, has 2 branches (thoracoacromial and lateral thoracic arteries)
Part 3 - extends from the lateral border of the pectoralis minor to the inferior border of the teres major; has 3 branches (largest - subscapular artery, anterior circumflex humeral and posterior circumflex humeral arteries)
What is the triangular space?
the triangle bounded by the teres major, teres minor, & the long head of the triceps
What is the triangular interval?
between the long & lateral heads of the triceps
What nerve are we worried about with humural fractures of the shaft?
radial nerve as it spirals around the mid-humerus
Where do we find the circumflex artery?
Transits the triangular space
Describe the relationship of the suprascapular a. and n. with the suprascapular (aka superior transverse scapular) ligament.
the artery goes over the ligament; the nerve goes under it
What is the largest branch of the axillary arteries?
Subscapular artery
Saturday night Palsy?
associated with someone who sleeps off a hangover with the back of the arm draped over the edge of the bed or bedrail. They awaken with the so-called “Saturday night palsy.” This palsy manifests itself as a radial nerve loss: inability to raise the wrist - or a “wrist-drop”.
What nerve innvervates the deltoid
innervated by axillary nerve
What does the deltoid do?
It abducts the shoulder, flexes it and extends it.
What innvervates the supraspinatus
innervated by the suprascapular nerve
What does the supraspinatous do?
aBduction of the armand stabilizes the humerus
What innervates the supraspinatus
innervated by suprascapular nerve
What does the infraspinatus do?
It laterally rotates the arm and stabilizes the humerus
Where does the teres major attach
Goes from the posterior aspect of the inferior angleof the scapula. Inserts on the intertubercular sulcus of the humerus
What does the Teres Major do?
teres major - rotates the shoulder joint laterally in combination with the infraspinatus
What innervates the teres major
Innervated by the lower subscapular nerve
Innervation of the teres minor
innervated by axillary nerve
Action of the Teres minor
laterally rotates the arm and stabilizes the humerus
Teres minor attachments
goes from the lateral border of the scapula to the greater tuburcle of the humerus
Triangular space
Borders:
Teres major inferiorly
Long head of the triceps laterally
Medial is teres minor
What makes up the quadrangular space?
Subscapularis & teres minor (superior), teres major (inferior), long head of the triceps (medial), and surgical neck of the humerus (lateral).
What is the Blood Supply of the deltoid
What is the innervation of the deltoid?
deltoid branch of thoraco-acromial artery
posterior circumflex humeral artery
axillary nerve
