Lecture 2: The Pectoral Girdle and Shoulder Flashcards
what are the 4 anatomical regions of the upper limb?
Shoulder (pectoral)
Arm
Forearm
Hand
What are the 3 large joints in the upper limb?
shoulder, elbow, wrist
Where are the 3 neurovascular regions (spaces)?
Axilla (armpit)
Cubital fossa (anterior to the elbow)
Carpal tunnel (anterior wrist / hand)
Which is the most commonly dislocated joint in the body?
Shoulder joint.
what bones make up the pectoral girdle?
the clavicle ( = collar bone)
the scapula ( = shoulder blade)
Where does the pectoral girdle connect to?
Connects your upper limb to your thorax (or axial skeleton)
the clavicle is attached to your sternum (the sternoclavicular joint)
the scapula is anchored to the posterior chest wall by muscles and soft tissues
What is the glenoid fossa (Glenohumeral joint) ?
The proximal part of the humerus (the ‘head’) articulates with a socket on the scapula called the glenoid fossa = glenohumeral joint
What is the articulation of the shoulder joint?
Ball and socket joint, but the glenoid cavity is shallow
What is the shoulder joint referred to as in terms of fit?
Incongruent = poor fit
- thin and loose capsule
- Compromised stability
What does better stability mean for movement?
Better stability = decreased range of movement
Does the shoulder have good movement?
Yes
What features of the shoulder increase stability of the joint?
: the surrounding muscles, the tendon of biceps brachii, and the glenoid labrum (a rim of cartilage around the edge of the glenoid which deepens the glenoid fossa)
What is protraction of the scapula?
Protraction (forwards) – putting your arm out in front of you (e.g. pushing open a door)
What is retraction of the scapula?
Retraction (backwards) – ‘squaring the shoulders’
What is elevation of the scapula?
Elevation (shrugging your shoulders) and depression
What is rotation of the scapula?
Rotation – this moves the scapula so that the inferior angle is pointed either more medially or more laterally
What is the role of pectoralis major?
Pectoralis major adducts and medially rotates the shoulder
What is the role of pectoralis minor?
Pectoralis minor stabilises the scapula and assists in protraction
Where does the serratus anterior originate?
Ribs 1 - 8
What are the functions of the posterior pectoral girdle muscles?
Connect the axial skeleton to the bones of the pectoral girdle
Move the pectoral girdle (usually in combination with movement at the shoulder)
Are Trapezius and latissimus dorsi deep or superficial?
Trapezius and latissimus dorsi are superficial;
Are levator scapulae and the rhomboids deep or superficial?
levator scapulae and the rhomboids are deep
What is the lat dorsi?
originates from the axial skeleton and inserts directly onto the humerus (adducts, medially rotates, and extends the shoulder)
What is the basic function of deltoid and teres major?
Connect the humerus to the pectoral girdle > move the shoulder
Where is the deltoid located?
Connect the humerus to the pectoral girdle > move the shoulder
What innervates the deltoid?
Innervation: axillary n.
What movement in the deltoid involved in?
Abductor of the shoulder joint, extending and flexing
Where is the teres major located?
from the posterior scapula > inserts on the anterior humerus.
What movement is the teres major involved in?
Medially rotates and adducts the shoulder
Where does the rotator cuff originate from?
Originate from the scapula > insert on the humerus
What starts abduction?
Supraspinatus starts abduction (first ~15o )
Which muscles laterally rotate the shoulder?
Infraspinatus and teres minor laterally rotate the shoulder
What muscles medially rotates the shoulder?
Subscapularis adducts and medially rotates the shoulder
How are the rotator cuff muscles commonly injured?
tendons can be torn or become inflamed. Problems can be acute or chronic
Injury / disease > impaired movement, instability, pain