Shoulder, pectoral and axilla anatomy Flashcards
Name the 4 muscles of the pectoral region.
Pectoralis major
Pectroalis minor
Serratus anterior
Subclavius
What is the most superficial muscle in the pectoral region?
Pectoralis major
What are the functions of the pectoralis major?
Adducts and medially rotates upper limb.
Draws scapula anteroinferiorly.
Flexes the upper limb (clavicular head).
What is the innervation of pectoralis major?
Lateral and medial pectoral nerves.
What muscle lies underneath pectoralis major?
Pectoralis minor.
What is the function of the pectoralis minor?
Stabilises scapula (pulls it anteroinferiorly against thoracic wall).
What is the innervation of the pectorals minor?
Medial pectoral nerve.
What border of the axilla does the serrates anterior form?
Medial border.
What border of the axilla do the pectorals major and minor form?
Anterior border.
What is the function of the serratus anterior?
Rotates the scapula, allowing arm to be raised >90 degrees.
Holds scapula against rib cage.
What is the innervation of the serrates anterior?
Long thoracic nerve.
What is the function of the subclavius?
Anchors and depresses clavicle.
What is the innervation of the subclavius?
Nerve to subclavius.
What does the subclavius afford minor protection to?
The neuromuscular structures underlying the clavicle.
If the long thoracic nerve is damaged, what does this cause?
Winging of the scapula, as the serrates anterior cannot hold the scapula against the rib cage.
What is the most common cause of long thoracic nerve palsy?
Traction injuries (where the upper limb is stretched violently).
What are the actions of the latissimus dorsi?
Extends, adducts and medially rotates the upper limb.
What is the innervation of the latissimus dorsi?
Thoracodorsal nerve.
Which 2 bones articulate to form the sternoclavicular joint?
Sternum and clavicle.
What type of joint is the sternoclavicular joint?
Saddle-type synovial joint.
What provide the majority of the stability of the sternoclavicular joint?
Ligaments (particularly the costoclavicular ligament).
Which movements do the sternoclavicular and acromioclavicular joints aid in?
Pectoral movements.
Which 2 bones articulate to form the acromioclavicular joint?
Clavicle and acromion of the scapula.
What type of joint is the acromioclavicular joint?
A plane type synovial joint.
What provides the majority of stability for the acromioclavicular joint?
Ligaments.