Shoulder and Upper Back Flashcards
Delotid. (Location, origin, insertion, innervation and action)
Origin: Acromion; the crest of the spine of the scapula; the lateral one-third of the clavical
Insertion: Deltoid tuberosity of the humerus
Action: Abduction of the arm; flexion and internal rotation via the anterior fibres; external rotation and extension via the posterior fibres
Innervation: Axillary nerve
Serratus Anterior (location, origin, insertion, innervation and action)
Origin: Superior: the 1st and 2nd ribs; intermediate: the 2nd and 3rd ribs; inferior: the 4th and 9th ribs
Insertion: Medial margin of the costal surface of the scapula
Action: Superior external rotation of the scapula draws the scapula internally and forwards; lowers the arm from a raised position; elevation of the ribs.
Innervation: Long thoracic nerve and brachial plexus (C5-C7)
Trapezius (location, origin, insertion, innervation and action)
Origin: Skull, ligamentum nuchae and the spinous processes of C7-T12.
Insertion: Lateral third the clavicle, acromion and the scapula spine.
Innervation: Accessory nerve, C3-C4
Action: Retraction, superior rotation, elevation and depresiion of the scapula
Latissiums Dorsi (location, origin, insertion, innervation and action)
Origin: Inferior angle of the scapula, 9th-12th ribs; spinous processes of T7-T12; thoracolumnar fascia; the posterior one-third of the iliac crest
Insertion: Crest of the lesser tuberoisty of the humers and the intertubercular grove
Action: Extension, adduction and internal rotation of the arm, aids in respiration
Innervation: Thoracodosal nerve
Levator scapulae (location, origin, insertion, innervation and action)
Origin: Transverse process of vertebrae C1-C4
Insertion: Superior angle to the medial border of the scapula
Action: Elevation of the scapula, downward rotation of the scapula
Innervation: Dorsal scapular nerve (C5), C3 and C4
Rhomboids (location, origin, insertion, innervation and action)
Origin: spinous processes of the vertebrae T2-T5
Insertion: Medial margin of the scapula
Action: Retraction and rotation of the scapula
Innervation: Dorsal scapular nerve (C4-5)
Teres major (location, origin, insertion, innervation and action)
Origin: Dorsal surface of the inferior angle of the scapula
Insertion: Crest of the lesser tubercle of the humerus
Action: Adducts at the shoulder and medially rotates the arm.
Innervation: Subscapular nerve
Name the rotator cuff muscles
Subscapularis
Supraspinatus
Infraspinatus
Teres minor
Pneumonic = SITS
Subscapularis (location, origin, insertion, innervation and action)
Origin: Subscapular foss of the scapula
Insertion: Lesser tubercle of the humerus
Innervation: Subscapular nerve
Action: Medially rotates the arm
Supraspinatous (location, origin, insertion, innervation and action)
Origin: Supraspinous fossa of the scapula
Insertion: Greater tubercle of the humerus
Action: Abduction of the arm 0-15o, and assists deltoid for 15-90o
Innervation: Suprascapular nerve
Infraspinatus (location, origin, insertion, innervation and action)
Origin: Infraspinous fossa of the scapula
Insertion: Greater tubercle of the humerus
Action: Laterally rotation of the arm
Innervation: Suprascapular nerve (C4-6)
Teres minor (location, origin, insertion, innervation and action)
Origin: Upper two thirds of the lateral margin of the scapula
Insertion: Greater tubercle of the humerus
Action: External rotation of the arm
Innervation: Axillary nerve
What is the shoulder girdle?
Connects the arm to the axial skeleton. Consists of the clavicle and scapula.
Joints:
Sternoclavicular
Acromioclavicular
Scapulothoracic
Glenohumeral
What are the key landmarks of the scapula?
1 - Supraspinous fossa
2/11 - Coracoid process
3/10 - Acromial process
4 - Infraspinous fossa
9 - Glenoid cavity
Describe the key landmarks of the clavicle
i. Sternal extermity/ facet (articular surface)
ii. Acromial extremity
iii. Costal tuberosity
Describe the key landmarks on the proximal humerus
What is the glenohumeral joint?
The shoulder joint is formed by the articulation of the head of the humerus with the glenoid cavity (or fossa) of the scapula. It is a ball and socket joint allowing for a wide range of movement.
Why is the glenohumeral joint inherently unstable?
The head of the humerus is much larger than the glenoid fossa, giving the joint inherent instability.
What is the function of the glenoid labrum?
To reduce the disproportion in surfaces, the glenoid fossa is deepened by a fibrocartilage rim, called the glenoid labrum
What is the joint capsule? What is its function?
The joint capsule is a fibrous sheath which encloses the structures of the joint. It extends from the anatomical neck of the humerus to the border of the glenoid fossa. The joint capsule is lax, permitting greater mobility (particularly abduction).
What is the synovial membrane and what is its function?
The synovial membrane lines the inner surface of the joint capsule, and produces synovial fluid to reduce friction between the articular surfaces.
What is a synovial bursae and why are they present in the shoulder joint?
To reduce friction in the shoulder joint, several synovial bursae are present. A bursa is a synovial fluid filled sac, which acts as a cushion between tendons and other joint structures.
What is the function of the subacromial bursa and where is it located?
Located inferiorly to the deltoid and acromion, and superiorly to the supraspinatus tendon and the joint capsule. It supports the deltoid and supraspinatus muscles. Inflammation of this bursa is the cause of several shoulder problems.
What is the subscapular bursa and where is it located?
Subscapular – Located between the subscapularis tendon and the scapula. It reduces wear and tear on the tendon during movement at the shoulder joint.
What is the function of the ligamints within the shoulder joint?
Play a key role in stabilising the bony structures. The majority of the ligaments are thickenings of the joint capsule.
Describe the structure and function of the glenohumeral ligaments
Glenohumeral ligaments (superior, middle and inferior) – Consists of three bands, which runs with the joint capsule from the glenoid fossa to the anatomical neck of the humerus. They act to stabilise the anterior aspect of the joint.
Describe the structure and funciton of the coroachohumeral ligament
Coroacohumeral ligament – Attaches the base of the coracoid process to the greater tubercle of the humerus. It supports the superior part of the joint capsule.
What is the transverse humeral ligament and what is its function?
Transverse humeral ligament – Spans the distance between the two tubercles of the humerus. It holds the tendon of the long head of the biceps in the intertubercular groove.
Describe the structure and function of the coracoacromial ligament.
Unlike the other ligaments it is not a thickening of the joint capsule. It runs between the acromion and coracoid process of the scapula, forming the coraco-acromial arch. This structure overlies the shoulder joint, preventing superior displacement of the humeral head.
Which anatomical features are responsible for stabilising the shoulder joint?
Static stabilisers
- Articular anatomy
- Gelnoid labrum
- Capsule
- GH ligaments
- Extra capsular ligaments
- Negative intra articular pressure
Dynamic stabilisers
- Rotator cuff muscles
- Biceps brachii
- Muscles crossing the shoulder
What are the contents of the space between the acromion and the head of the humerus?
Subacromial bursa
Rotator cuff tendons
Capsule
Long head of the biceps
Which muscles are responsible for abduction of the arm?
First 90 degress = GH joint
1-15 = Supraspinatus
15-90 = Deltoid
Over 90 degrees is due to the scapulo-thoracic joint through scapula rotation = upper trapezius and serratus anterior
Which muscles are responsible for adduction of the arm?
Pectoralis major, lat dorsi, teres major.
Which muscles are responsible for flexion of the arm?
Anterior fibres of the deltoid, pectoralis major, coracobrachialis, biceps brachii
Which muscles are responsible for extension of the arm?
Posterior fibres of the deltoid
Lat dorsi
Teres major
Which muscles are responsible for internal rotation of the shoulder?
Subscapularis
Teres major
Pectoralis major
Lattisiumus dorsi
Which muscles are responsible for external rotation of the shoulder?
Infraspinatous
Teres minor
What is the accessory nerve and where is it located?
The accessory nerve is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles.
Describe where to find the posterior circumflex humeral vessels
