Shoulder Anatomy Flashcards
subscapularis origin, insertion, innervation, and action
origin: subscapular fossa
insertion: lesser tuberosity of humerus
nerve supply: upper and lower subscapular nerves
action: medial rotation of humerus
deltoid nerve supply
axillary nerve C5 and C6
Joints of shoulder region
what are the borders of the quadrangular space and what are its contents?
Borders-
medial- long head of triceps
lateral- humeral shaft
superior
contents: axillary and posterior humeral circumflex artery (deep brachial artery)
Features of the glenohumeral joint
Features: • Stability: NOT STABLE: Head of humerus is 3 times larger than glenoid cavity, Capsule is redundant.
Few ligamentous support: (glenoid labrum • coracohumeral)
- Main support: muscles around the joint (ROTATOR CUFF)
- Wide range of movement
What are the borders and contents of triangular interval?
superior border: teres major
lateral border: lateral head of tricep
medial border: long head tricep
contains: radial nerve
deep profunda brachial artery
Nerves of shoulder region
- Axillary nerve (main)
- Radial nerve (beginning)
- Ulna nerve (beginning)
- Median nerve (beginning)
- Musculocutaneous nerve
Bones of shoulder region
- scapula (shoulder blade)
- clavicle (collarbone)
- humerus (upper arm bone)
spaces in shoulder region
quadrangular space
triangular space
triangular interval
suprascapular foramen
infraspinatus origin, insertion, innervation and action
origin: infraspinous fossa
insertion: greater tuberosity of humerus
innervated by suprscapular nerve
action: lateral rotation of humerus
What structure does the axillary arise from, what’s it course, and what does it innervate?
- Terminal branch of the brachial plexus.
- From posterior cord
- From ventral rami of C5 and C6.
- Course: passes posteriorly, through the quadrangular space, inferior to shoulder joint, where it is vulnerable to damage during shoulder dislocations
The branches:
-Muscular branches to the deltoid and teres minor muscles - Articular branch to the shoulder joint. - Upper lateral cutaneous nerve of arm supplies the skin over the superior part of the lateral aspect of the arm.
Explain axillary artery
- continuation of subclavian artery
- divided into 3 by pectoralis minor
What are the borders and contents of the triangular space?
Borders
Superior: lower border of teres minor
Lateral: long head of triceps
Inferior: teres major
Contents: subscapular circumflex artery
Branches of axillary artery
1st part:
-Highest or superior thoracic artery.
2nd part:
-thoracoacromial artery immediately divides into terminal branches. (Clavicular • Acromial • Deltoid • Pectoral)
lateral thoracic artery.
3rd part
subscapular artery
anterior circumflex humeral
posterior circumflex humeral
Some Times Life Seems A Pain
Ligaments of shoulder joint
Ligaments
• Glenohumeral Ligaments
- Superior -Middle -Inferior •
Coraco-acromial Ligament
• Coraco-clavicular Ligaments
-Trapezoid -conoid
- Transverse Humeral Ligament
- Coraco-humeral
- Acromio-clavicular
teres minor origin, insertion, nerve supply, action
origin: lateral border of scapula
insertion: greater tuberosity of humerus
nerve supply: axillary nerve
action: lateral rotation of humerus
deltoid insertion
deltoid tuberosity of humerus
review landmarks of humerus, scapula, and clavicle
humerus: anatomical neck, surgical neck, greater tuberosity, intertubuclar groove between, lesser tuberosity
clavicle: lateral end angle of clavicle, medial aspect
3rd part of axillary artery branch
- subscapular artery.
- anterior circumflex humeral artery
- posterior circumflex humeral artery
3rd part of axillary artery supply
Anteriorly: pectoralis major, medial root of the median nerve
Posteriorly: subscapularis, latissimus dorsi, the teres major, axillary, radial nerves.
• Laterally: coracobrachialis, biceps, humerus, lateral root of the median nerve, musculocutaneous nerves •
Medially: • ulnar nerve, axillary vein, the medial cutaneous nerve of the arm
Blood supply of shoulder region
- Subclavian artery
- Axillary artery- Thoracoacromial artery
- Brachial artery
teres major origin, insertion, innervation, and action
origin: lateral border of scapula
insertion: bicipital groove of humerus
nerve supply: lower subscapular nerve
action: extension, adduction, and medial rotation of humerus
relations of shoulder joint (borders)
anterior
posterior
superior
inferior
anterior: subscapularis, deltoid
posterior: infraspinatus. teres minor
superior: supraspinatus, subacromial bursa, coracoacromial ligament, deltoid muscle
inferior: axillary nerve, posterior cirucumflex artery, long head of triceps, muscle
Explain the 2nd part of axillary artery and what it supplies?
Anteriorly: skin, pectoralis minor, and pectoralis major
Posteriorly: posterior cord of the brachial plexus, subscapularis muscle, shoulder joint
Laterally: lateral cord of the brachial plexus
Medially: The medial cord of the brachial plexus, the axillary vein
What are the 4 muscles of the rotator cuff?
movements of shoulder joint
medial and lateral rotation
extension and flexion
abduction and adduction
circumduction
bursa in shoulder joint (5)
subacriomal bursa: between deltoid, supraspinatus, and capsule
subdeltoid bursa: between deltoid muscle and shoulder joint cavity
subcutaenous acromial bursa: located above the acromion just beneath the skin
subscapularis bursa: between subscapularis tendon and capsule
infraspinatus bursa: between infraspinatus tendon and capsule
glenohumeral joint ligaments- the joint is formed by a group of ligaments that connect the humerus to the glenoid what are these ligaments?
glenohumeral ligaments
superior
middle
inferior
also have glenoid labrum
coracohumeral ligament
(Arterial anastomosis around shoulder region) anastomosis around the shoulder joint are formed by branches of the subclavian and axillary arteries. What are the branches of each? What is the significance?
- Branches from subclavian artery: • Suprascapular artery • Superficial cervical artery
- Branches from axillary artery (3rd part)- • Subscapular artery • Anterior circumflex humeral artery • Posterior circumflex humeral artery
Significant as they provide an alternative route for blood if other route is obstructed
blood supply of shoulder joint
axillary artery- anteriror and posterior circumflex artery (parts of the 3rd part of axillary artery)
Muscles of shoulder region (10)
- Deltoid
- Supraspinatus.
- Infraspinatus. •
Teres minor. •
Teres major. • Subscapularis. • Latissmus dorsi • Trapezius • Levator scapulae • Rhomboids
Rotator cuff disorder?
Which one likely to be injured an why?
impingement, tendonpathy
the supraspinatus, because it passes through acriomion and humeral head, has most force acting on it
supraspinatus origin and insertion
nerve supply and action
origin: supraspinous fossa
insertion: greater tuberosity of humerus
innervated by suprscapular nerve
action: abduction of humerus from 0-15 degrees
deltoid origin
spine of scapula, acromion. lateral 1/3 of clavicle
SACS
(same as insertion of trapezius)
How does rotator cuff get it’s name and what is the problem that may arise?
• Muscles form a tendinous cuff around the shoulder joint covering its- anterior, posterior and superior aspects.
no support on inferior border, disolocates inferiorly and anteriorly
nerve supply to shoulder joint
axillary nerve
suprascapular nerve
deltoid action
anterior fibers flex and medial rotate, medial- abducts, posterior fibers extend and lateral rotate
