Anatomy - The Chest, Back and Arm Flashcards
Muscles of shoulder girdle (scapula)
Pectoralis minor Serratus anterior Trapezius Rhomboid major and minor Levator scapulae
Pectoralis minor
Small muscle lying deep to pec major
Paasess from coracoid process to ribs 2-5
Pectoralis function
Pulls scapula forward and anterior
Protratot - works with serrtaus anterior
Serratus anterior
Anteriorly, seen as several finger-like projection the attach to the ribs
Passes posteriorly to scapula, holding this bone against the body wall
What does serratus anterior sit between
Subscapularis and chest wall
Innervation of serratus anterior
Long thoracic nerves
Function of serratus anterior
Man protractor
Holds scapula against chest wall preventing wining
Helps with lateral rotation
Trapezius
Large, triangular muscle covering back
Forms superior shape of neck and shoulders
Main lateral rotator of scapula
Innervation of trapezius
Spinal accessory nerve
Rhomboid major
Oblique muscle passion from thoracic vertebrae to medial border of scapula
Rhomboid minor
Oblique muscle passion from thoracic vertebrae to medial border of scapula
Superior to rhomboid major
Function of rhomboid muscles
Retraction
Medial rotation of scapula
Why is rhomboid usually underdeveloped in most most people
Medial rotation of the scapula will be brought about by gravity unless the action is against resistance
Function of levator scapula
Elevation of scapula
Levator scapula
Thin muscle passing from cervical vertebra to superior angle of scapula
Muscles of shoulder joints
Deltoid
Pectoralis major
Latissimus dorsi
Teres major
Deltoid
Forms lateral shape of shoulder
Primary muscle of shoulder abduction (20-90 degrees)
Where does the deltoid attach to the humerus
Deltoid tuberosity
Innervation of deltoid
Axillary nerve
Latissimus dorsi
Large, flat muscle passing from thoracolumbar region to humerus. Trapezius partially overlies this muscle
Attaches to floor of intertuberuclar groove on humerus
Function of latissimus dorsi
Shoulder extension
Pectoralis major
Large muscle on front of chest
Split into clavicular and sternum head
Attachments of pectoralis major
Attaches distal at intertubercular tuberosity
Function of pec major
Shoulder flexor
Teres major
Attaches to medial lip of inter tubercular tuberosity, can cause medial rotation w/ LD and PM
Anterior muscle of Shoulder
Pec major Pec minor Deltoid Trapezius Serratus anterior
Anterior muscles of arm
Biceps brachii
Coracobrachials
Brachialis
Biceps brachii
Most superficial muscle in anterior compartmnet
Coracobarchialis
Lies deep to biceps brachii
Thin muscle passing from coracoid process to humerus
Brachialis
Lies deep to biceps brachii
Flat muscle passing from humerus to ulna
Posterior muscles of shoulder
Lat dorsi
Rhomboid major
Rhomboid minor
Lev scapulae
Posterior muscle of arm
Triceps
Function of rotator cuff
Provide a shunt action, pulling head of humerus in
Supraspinatus in abduction
Initiates first 15/20 degrees
Function of supraspinatus
Abduction
Innervation of supraspinatus
Subscapular nerve
Function of infraspinatus
Lateral rotation
Innervation of infraspinatus
Suprascapular nerve
Function of Teres minor
Lateral rotation
Innervation of Teres minor
Axillary nerve
Function of subscapularis
Medial rotation
Innervation of subscapularis
Upper and lower subscapular nerves
Attachments of biceps brachii
Short head attaches to coracoid process and long head attaches to superior glenoid tubercle - prevents upwards displacement of head of humerus
Attaches to radius at bicipital tuberosity
Function of biceps brachii
Supination of arm
Shoulder flexion
Innervation of biceps brachii
Musculocutaenous nerve
Transverse humeral ligament
Holds biceps brachii tendon in place
Function of triceps
Elbow extension
Brachialis function
Elbow flexor
Innervation of brachialis
Musculocutanoeus nerve
Mechanism of shoulder abduction
Can go to 180 degrees
Supraspinatus pulls out humerus so deltoid has leverage 0-90 degrees
Trapezius and serratus anterior (lower fibres) swing infer angel of scapula laterally allows 90-180 degrees
Pectoralis major - clavicular head
Flexion of shoulder from anatomical position
Pectoralis major - sternum head
Flex from extended position, back to anatomical position
What does Pectoralis major contribute to
Adduction and medial rotation
Lat dorsi and Teres major must work together to cancel out flexion action
Extrinisic shoulder muscles definition
Originate from the torso, and attach to the bones of the shoulder (clavicle, scapula or humerus
Intrinsic shoulder muscles definition
Originate from the scapula and/or clavicle and attach to the humerus.
Upper fibres of trapezius
Elevate scapula and rotate it during abduction
Middle fibres of trapezius
Retract scapula
Lower fibres of trapezius
Pull the scapula inferiorly
Extrinsic shoulder muscles
Trapezius
Lat Dorsi
Lev Scapulae
Rhomboids
Intrinsic shoulder muscle
Deltoid
Teres major
Innervation of extrinsic shoulder muscle
Thoracodorsal nerve except trapezius (accessory nerve)
Anterior fibres of deltoid
Flexion and medial rotation.
Posterior fibres of deltoid
Extension and lateral rotation
Middle fibres of deltoid
The major abductor of the arm
Where are flexors usually found
Anteriorly
Where are extensors usually found
Posteriorly
Motor function of Musculocutaneous nerve (C5 -C7)
Elbow flexion (biceps brachii) Supination
Motor function of axillary nerve (C5, C6)
Shoulder adduction - teres minor and deltoid
Motor function of radial nerve
Extension (forearm, hand, wrist, thumb)
Motor function of ulnar nerve
Wrist flexion
Presentation of lower trunk of the brachial plexus (C8, T1) injury
Claw hand
Hyperextended wrist
LOAF muscles
Lateral two lumbricals
Opponens pollicis
ABductor pollicis brevis
Flexor pollicis brevis