Lecture 22 - Pectorial Girdle and Arm Muscles Flashcards
Shoulder muscles
Connect scapula, clavicle, body wall to the humerus
Move the shoulder joints
Shoulder muscles list
Deltoid
Pectoralis major
Latissimus dorsi
Teres major
Deltoid origin and insertion
Origin:
• Scapula, Clavicle
Insertion:
• Humerus
Deltoid is innervated by the
axillary nerve
Deltoid and function on arm
Deltoid has 3 different fibres, looks like an inverted triangle, located in the upper part of the arm
- Anterior fibres = flex (flexion of the shoulder joint)
- Middle fibres = abduct
- Posterior fibres = extend
Pectoralis major origin and insertion
Origin:
• Clavicle, Sternum, costal cartilages (attaches proximally)
Insertion:
• Humerus (attaches distally to the humerus)
Pectoralis major function
• Flexion, adduction and medial rotation of arm
on anterior surface which is why it does dlextion
Latissimus dorsi origin and insertion
It is quite a light muscle
Origin:
• Spinous processes of the vertebrae, iliac crest, inferior ribs
Insertion:
• Humerus (attaches distally)
Latissimus dorsi function
• Extend, adduct (brings the shoulder joint back to the midline), medially rotate arm
connects to shoulder joint therefore has action on it
Teres major origin and insertion
Origin:
• Inferior angle of scapula
Insertion:
• Humerus
Teres major function
Function:
• Extend, adduct, medially rotate arm
Shoulder muscles from most anterior to most posterior
Pectoralis major
Long tendon of biceps
Latissimus dorsi
Teres major
(MLLM)
Pectorial girldle muscles list
Trapezius
Levator scapulae
Rhomboids
Trapezius origin and insertion
Origin: • Occipital bone Insertion: • Clavicle • Scapula (spine & acromion)
Function on scapula of trapezius
Function on scapula: • Superior fibres = Elevate scapula • Horizontal fibres = Retraction of the scapula • Inferior fibres = Depress the scapula • Rotation
Levator scapulae origin and insertion
Origin:
• Transverse processes of cervical vertebrae
Insertion:
• Superior angle of scapula
Levator scapulae function
• Elevate scapula
Rhomboids
4 sided muscle for retraction, more than one rhomboid (minor and major - names are not examinable)
Rhomboids origin and insertion
Origin:
• Spinous processes of the vertebrae
Insertion:
• Medial border of scapula
Rhomboids function
Function:
• Retract scapula
Number of rotator cuff muscles
4
Rotator cuff muscles list
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
(Teres MAJOR is not a part of the rotator cuff)
General function of rotator cuff muscles
General function:
• To support glenohumeral joint
• All rotate humerus, except for supraspinatus
What do rotator cuff muscles connect?
connects scapula and clavicle to the humerus
SITS stands for what group of muscles and also list the muscles
Rotator cuff muscles
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Rotator cuff muscles that are on the posterior side of the scapula
Supraspinatus
Infraspinatus
Teres minor
Rotator cuff muscles that are on the anterior side of the scapula
Subscapularis
Attachments of rotator cuff muscles
All attach to the greater tubercle of the humerus, except for subscapularis (attaches to the lesser tubercle)
greater tubercle is more lateral
Lesser tubercle is more medial therefore helps more with medial rotaiton
Function of rotator cuff muscles
- Supraspinatus initiates abduction
- Infraspinatus and Teres minor laterally rotate humerus
- Subscapularismedially rotates humerus
Supraspinatus function
Supraspinatus initiates abduction (helps to initiate, only about 10 degrees, deltoids then takes over)
Infraspinatus and Teres minor function
Infraspinatus and Teres minor laterally rotate humerus
Subscapularis function
Subscapularis medially rotates humerus
Rotator cuff impingement
impingement is about tendon
Implications: • Inflammation (Tendinitis, bursitis (inflammation of burse which is a pouch of synovial membrane)) • Swelling & pain • Impairs movement • Possible rupture of tendons • Capsular weakness
Remember:
Tendons and ligaments lack blood vessels (Difficulty healing)
Arm muscles
Biceps brachii, brachialis, coracobrachialis, triceps brachii
Anterior compartment of arm muscles
• Flexors
• Muscle: Biceps brachii,
Brachialis, Coracobrachialis
• Nerve: MusculoCutaneous nerve
Posterior compartment of arm muscles
- Extensors
* Muscle: triceps brachii • Nerve: radial nerve
Nerve of the anterior comparment of arm mucles
Musculocutaneous nerve
Nerve fo the posterior compartment of arm muscles
Radial nerve
______ in anterior comparment of arm muscles
flexors
_______ in posterior compartment of arm muscles
extensors
Muscles of the anterior comparment of the arm
Biceps brachii
Brachialis
Coracobrachialis
Muscles of the posterior compartment of the arm
Triceps brachii
Triceps brachii
Only posterior one
3 headed muscle - long, lateral and medial head (medial head is deep to the long head)
Origin and insertion of triceps brachii
Origin:
• Long head: infraglenoid tubercle of scapula
• Medial head: humerus
• Lateral head: humerus
Insertion:
• Olecranon of ulna (common attachment of all three heads here)
Long head of triceps brachii origin
Long head: infraglenoid tubercle of scapula
Medial head of triceps brachii origin
Medial head: humerus
Lateral head of triceps brachii origin
Lateral head: humerus
Function of triceps brachii
Extend arm and forearm (because posterior)
Long head is the only one that attaches at the shoulder joint and the other 2 attach to the arm
All heads cause = Elbow joint extension
Long head = SJ extension
Biceps brachii
Anterior
2 heads - long and short head
Biceps brachii origin and insertion
Origin:
• Long head: supraglenoid tubercle of scapula
• Short head: coracoid process
Insertion:
• Radial tuberosity
Long head of biceps brachii origin
Long head: supraglenoid tubercle of scapula
Short head of biceps brachii origin
Short head: coracoid process
Biceps brachii function
Function:
• Flex arm & forearm
• Supinate forearm
SJ flexion, EJ flexion, supination of forearm
Bicipital aponeuriosis
Median nerve and brachial artery run under this
Need to extend elbow to feel pulse to move this out of the way
brachial artery goes under this then splits
Coracobrachialis origin and insertion
Origin:
• Coracoid process
Insertion:
• Humerus
Coracobrachialis function
Function:
• Flex arm
• Adduct arm
SJ flexion - doesnt cross EJ so no function
Brachialis origin and insertion
arm to elbow
Origin:
• Humerus
Insertion:
• Coronoid process of Ulna
Brachialis function
• Flex forearm
EJ flexion - does not cross the SJ so no function here
Brachial artery
- Continuation of axillary artery
- Runs on medial forearm
- Divides into radial and ulnary arteries
deep veins match
Arterial supply to the upper limb
Subclavian to axillary to brachial to radial and ulnar artery
Arm veins
- Brachial veins is deep, and run with brachial artery
- Two large superficial veins are cephalic and basilic veins
- The median cubital vein crosses between them
Median cubital vein
cross between the cephalic and basilic veins
Connecting branch between the two
Blood is usually taken from here
Innervation of anterior arm muscles
Musculocutaneous nerve (pierces through coracobrachialis, MC in arm itself is between brachialis and biceps)
MC supplies BBC MusculoCutaneous supplies Biceps, Brachialis, Coracobrachialis
MC supplies BBC
MusculoCutaneous supplies Biceps, Brachialis, Coracobrachialis
Innervation of posterior arm muscles
Radial nerve
