Anatomy of shoulder region Flashcards
What is meant by the shoulder girdle?
a set of bones found in the appendicular skeleton connecting the arm on either side
What forms the pectoral girdle?
The clavicle & Scapula
What is the skeleton of the pectoral region?
1) Sternum
- Manubrium
- Body
- Xiphoid process
2) Clavicle
3) Ribs (first rib joint is a fibrous cartilage rest are synovial)
4) Scapula
5) Humerus
Where is the sternoclavicular joint?
Between the sternum and the clavicle
Where is the sternal angle (AKA angle of Luis)?
it is between the body and the manubrium of the sternum, It is the point where the second rib is attached
Where can we find the jugular notch (AKA suprasternal notch)?
It is the V dent above the manubrium
What is the costochondrial junction?
The junction between each rib and the cartilage that attaches it to the sternum
What is the last rib that is attached to the sternum?
7 (8-10 are attached to 7), while 11 and 12 are not attached
Describe the clavicle
- Connects the arm to the body
- The only long bone that lies horizontally in the body
- It is the first bone to ossify in the body (5th week of fetal life)
- Convex from the anterior towards 2/3 to the medial side
- Concave from the posterior
What is the anatomy of the clavicle?
1) 2 Ends (Acromial/lateral/flat end “articulates with the scapula”& sternal/medial/rounded end “articulates with the sternum”)
2) 2 surfaces (smooth superior, rough inferior it has the conoid tubercle (opposite to the acromial extremity) and the costal tuberosity (close to the sternal extremity) which acts as an attachment site for the scapula via the coracoclavicular ligament)
3) 2 borders
What is the role of the clavicle?
It carries the upper arm away from the axial skeleton, thus if there is a fracture the upper arm will fall
Describe the clavicle in more detail
1) 1/3 of the lateral end is concave, and the other 2/3 of the medial end is concave
2) In the inferior surface clavicle we have the costal tuberosity (attachment for the scapula), conoid tubercle (attachment for the scapula), and the trapezoid line (connected to the coracoid process of the scapula)
3) Subclavis groove, connected to the muscle subclavius
What is the cervico-axillary canal
- Forms the apex of the axilla
- It is the passageway which extends between the neck and upper limb where the main vessels passes to and from the upper limb
What are the boundaries of the cervico-axillary canal?
1) Posteriorly: The upper border of the scapula
2) Anteriorly: The clavicle
3) Medially: Outer border of the 1st rib
What are the important structures that go into the canal?
1) Subclavical artery
2) Subclavical vein
3) Nerves (brachial plexus)
-any fracture in the bone surrounding the canal will be dangerous because it contains arteries veins and nerves
Describe the scapula
It is a flat triangular structure that lies posterolateral to the thoracic cage
What are the features of the scapula?
1) 2 surfaces:
- Anterior/coastal “as it is related to the ribs”
- Posterior
2) 3 Angles:
- Superior angle
- Inferior angle
- Glenoid fossa laterally
3) 3 borders:
- Lateral border
- Medial Boarder
- Superior border
4) 4 fossae:
- 3 muscular fossae
subscapular (attached to the subscapularis in the anterior surface), supraspinous fossa (attached to the supraspinatus muscle in the posterior surface above the spine), and infraspinous fossa (attached to the infraspinatus muscle) - 1 Articular fossa (glenoid fossa, attaches to the humerus which forms the glenohumeral joint “shoulder joint”)
5) 2 processes:
- Acromion
- Coracoid
What is the meaning of a fossa?
rounded oval smooth depression
What is the difference between muscular and articular fossa?
The muscular is attached to muscle and the articular is attached to bones.
Which ligament joins the acromion to the coracoid process?
Coracoacromial ligament
The coracoacromial ligament joins two processes
It joins the acromion to the coracoid process
What joins the clavicle to the coracoid process?
The coracoclavicular ligament
What is the subacromial space?
The free space between the acromion process, coracoacromial ligament, coracoid process, glenoid, and the spine of the scapula
Which structure surrounds the glenoid cavity?
Labrum, covered exteriorly by the joint capsule, which is attached medially to the edge of the glenoid and lateral to the humerus
How does the scapula move?
1) Elevation
2) Depression
3) Protraction
4) Retraction
5) Upward rotation of scapula (making the glenoid face upwards)
6) Downward rotation (glenoid fossa faces downwards)
Describe the scapulothoracic articulation/joint
- It is a physiological and not anatomical joint
- The broad articulation area between the anterior surface of the scapula and the back of the thoracic cage, allowing the gliding movement of the scapula against the thoracic cage
- This is a floating joint that is supported by muscles and ligaments of the thoracic area
- It has a bursa that lubricates the area between the muscles and the ribs
Describe the anatomy of the humerus
1) Head
2) Anatomical neck (Contains epiphyseal cartilage)
3) Greater tubercle
4) Lesser tubercle
5) Intertubercular (bicipital) groove “anterior medial, where tendons attach”
6) Surgical neck (most common site to be injured)
7) Deltoid tuberosity (anterolateral, site of deltoid muscle attachment, helping in the abduction of the humerus until 90-degrees)
8) Radial groove (posteriorly)
How many joints are there in the shoulder region?
4
1) Sternoclavicular joint (The medial joint)
2) Acromioclavicular joint (the lateral joint)
3) Glenohumeral joint “shoulder joint” (the bigger joint)
4) Scapulothoracic joint (the physiological joint)
Describe the anatomy of the sternoclavicular joint
- Joins the clavicle to the sternum
- A saddle synovial joint
1) The clavicle is connected to the 1st rib by the costoclavicular ligament (attached to the costal tuberosity of the clavicle)
2) The sternoclavicular ligaments (both posterior and anterior) connects the clavicle to the sternum
3) The right and left clavicles are connected together via the interclavicular ligament
4) The clavicle is also connected to the cartilage of the 1st rib by a branching of the interclavicular ligament named intra-articular disc
Which ligament crosses the midline and connects both clavicles together?
The interclavicular ligament which is located at the base line of the sternal notch
What are the movements of the sternoclavicular joint?
- It does not move alone, but with the shoulder joint
1) Elevation
2) Depression
3) Protraction
4) Retraction
5) Rotation
6) Posterior rotation
Describe the anatomy acromioclavicular joint
- Connects the clavicle to the acromion from the acromial extremity
What is the coracoclavicular ligament?
It is an extracapsular ligament “accessory ligament”, and has two subtypes:
1) Trapezoid (flat ligament)
2) Conoid (rounded ligament)
Which ligament connects the acromion to the coracoid process?
Coraco-acromial ligament
What type of joint is the shoulder joint?
Synovial ball & socket
What are the articular surfaces of the shoulder joint?
Articular surface of the head of the humerus connected to the glenoid fossa containing a glenoid labrum in the middle
What is the capsule of the shoulder joint?
It is a capsule that covers the exterior layer of the shoulder joint, the thinner it is the more movable it is and the less stable the joint is, it has an opening for the long head of the biceps tendon
Where is the long head of the bicep attached to?
goes through the bicipital groove and passes through the capsule attaching to the glenoid cavity (upper end)
Where does the short head of the biceps attach to?
It attaches to the coracoid
What are the ligaments of the shoulder joint?
Glenohumeral ligaments (GHL):
1) Superior GHL
2) Middle GHL
3) Inferior GHL
4) Spiral GHL
Which muscles forms the rotator cuff muscles?
1) Supraspinatus (passes above the joint)
2) Infraspinatus (passes posterior to the capsule)
3) Teres minor (posterior)
4) Subscapularis (anteriorly)
Which structure covers the glenoid cavity?
Glenoid labrum
Which structure connects the glenoid cavity to the glenohumeral ligament?
Bicep brachii tendon
which structure separates the long head of the biceps from the head of the humerus?
Subacromial bursa
Which structure separates the supraspinatus from the head of the humerus?
Glenohumeral joint capsule
which structure separates the deltoid from the rotator cuff muscles
Subdeltoid bursa
What is meant by shoulder impingement?
It is the compression of the supraspinatus due to the muscle hypertrophy
- To treat it you need to cut the coracoacromial ligament to relieve the compression
What are the movements of the shoulder joint?
1) Flexion
2) Extension
3) Hyperextension
4) abduction
5) Adduction
6) Circumduction
7) Lateral rotation
8) Medial rotation
9) Horizontal adduction
10) Horizontal abduction
What are the muscles of the shoulder girdle that are attached to the shoulder from the axial skeleton?
1) Serratus anterior
2) Upper trapezius
3) Middle trapezius
4) Lower trapezius
5) Rhomboideus major and minor
6) pectoralis minor
7) Levator scapula
What are the muscles of the shoulder girdle that are attached to the humerus from the shoulder?
1) Deltoid
2) Rotator cuff muscles (supraspinatus, infraspinatus, subscapularis, teres minor)
3) Teres major
4) Coracobrachialis
5) Bicep brachii (long head)
6) Triceps brachii (long head)
What are the muscles of the shoulder girdle that are attached to the humerus from the axial skeleton?
1) Pectoralis major
2) Latissimus dorsi
What is the movement of the deltoid muscles?
Abduction of shoulder joint from 15-90 degrees
Which vein moves through the deltopectoral groove?
Cephalic vein
Which muscles abducts the hand from 0-15 degrees?
Supraspinatus muscle
Which muscle abducts the arm from 15-90 degrees?
Deltoid muscles
Which muscles abducts the hand >90 egrees?
1) Trapezius
2) Serratus anterior
- Both humerus & scapula rotate as one mass
