DR 1: Back and Shoulder Flashcards
Superficial muscles of the back function
Attach the pectoral girdle to the trunk
Superficial muscles of back
Levator scapulae
Trapezius
Rhomboids
Latissimus dorsi
Origin of upper fibres of trapezius
external occipital protuberance of skull and spinal processes of cervical vertebrae
insertion of upper fibres of trapexius
clavicle, acromion and spine of scapula
middle fibres of trapezius
origin from spinous processes of lower thoracic vertebrae
insert into spine of scapula
lower fibres of trapezius
origin from spinous processes of lower thoracic vertebrae
insert into spine and scapula
rhomboid muscles
deep to trapezius muscle
major and minor rhomboid muscles
origin from spinous processes of C7 and T1-T5 thoracic vertebrae and insert into medial border of the scapula
Lattisimus dorsi
thoracic region of back
origin: thoracolumbar fascia of back
fibres go upwards, round inferior angle towards
insertion on floor of bicipital groove of humerus
Serratus anterior
on lateral chest wall
originates as a series of individual slips from upper eight ribs
goes between ribs to the scapula
inserts at medial border of scapula
Intermediate back muscles
serratus posterior superior and inferior
these are accessory respiratory muscles which help expand chest during inspiration
Deep intrinsic muscles of back
within groove between spinous processes of vertebrae and angle of ribs
Largest group of deep muscles
Erector spinae
Spinalis, longissiums and iliocostalis
originate from erector spinae aponeurosis
Direction of erector spinae muscles
Run superiorly from erector spinae aponeurosis.
Spinales, most medial erector spinae muscle, inserts into thoracic spinous processes and skull
Longissimus, intermediate part of erector spinae, inserts into the thoracic and cervical transverse processes
iliocostalis is most lateral, and inserts mainly into the ribs
Multifidus
posterior to erector spinae in the lumbar region of the back
runs superiorly, from origin on transverse processes to insertion on spinous processes (of lumbar vertebrae)
Pectoral girdle
bony skeleton supporting upper limb
composed of clavicle and scapula, articulating at acromioclavicular joint
pectoral girdle articulates with trunk at sternoclavicular joint
Sternoclavicular joint
articulation between pectoral girdle and trunk
Scapula bony features
Anteriorly:
Acromion, coracoid, glenoid fossa, suprascapular notch, superior angle, subscapular fossa, inferior angle
Posteriorly:
supraspinous fossa, spine, intraspinous fossa, infraglenoud tubercle, supraglenoid tubercle
Bony features of proximal end of humerus
head of humerus, anatomical neck (above tuberosities), greater tubercle, lesser tubercle, intertubercular sulcus, surgical neck (below tuberosities) deltoid tuberositiy
Glenohumeral joint
shallow articulation between head of humerus and glenoid fossa of scapula
is a synovial ball and socket joint, allows a wide range of movement
Supraspinatus
originates from supraspinous fossa, inserts onto greater tubercle
Infraspinatus
Originates from infraspinous fossa, inserts onto greater tubercle
Teres minor
Originates from posterior of scapula, adjacent to lateral border, attaches to greater tubercle
Subscapularis
Originates from subscapular fossa, inserts into lesser tubercle of humerus
teres major
posterior surface of inferior angle of scapula to medial lip of bicepital groove
Where does the tendon of supraspinatus pass?
through a small space unfer the coracoacromial ligament
this can be impinged by overhead activities such as throwing
Deltoid attachment
origin: scapula and clavicle
insertion: deltoid tuberosity
biceps brachii
origin: long head from supraglenoid tubercle of scapula, short head from coracoid process
both heads insert into radial tuberosity and fascia of forearm via bicipital aponeurosis
triceps brachii
long head from infraglenoid tubercle
lateral head from humerus, superior to radial groove
medial head- humerus, inferior to radial groove
insertion: heads converge into one tendon distally and insert into olecranon
coracobrachialis
origin: coracoid process of scapula
Muscle passes through axilla and attaches to medial side of humeral shaft at deltoid tubercle
pectoralis major
origin: clavicle, sternum, superior six costal cartilages
insertion: bicepital groove’s medial lip
Quadrangular space
formed by teres minor, teres major, shaft of humerus, and long head of triceps brachi
Axilla
formed by an apex, base and four walls
base: skin and subcutaneous tissue which creates the axillary fossa
apex (inlet): clavicle anteriorly, first rib medially, superior border of scapula posteriorly
Axilla muscles
teres major, subscapularis, pectoralis major, latissimus dorsi, serratus anterior, pec minor
Axilla anterior wall
pectoralis major and minor - pectoral nerves
posterior wall of axilla
teres major, latissimus dorsi, subscapularis muscle
supplied by branches from posterior cord of brachial plexus
medial wall of axilla
serratus anterior
long thoracic nerve, from C5-C7 roots of brachial plexus
Lateral wall of axilla
shaft of humerus
Contents of axilla
axillary artery and its branches, axillary vein and its tributaries, lymph vessels and nodes, and brachial plexus
axillary artery formation
continuation of subclavian artery.
Subclavian artery passes through scalene triangle, formed by anterior and middle scalene muscles and first rib, then becomes axillary artery
axillary artery course
passes through axilla towards lower border of teres major to become brachial artery
Parts of the axillary artery
divided into three parts by pec minor muscles.
3rd part:
Anterior and posterior circumflex humeral branches wind around surgical neck of humerus, subscapular artery contributes to shoulder anastamoses
Axillary vein
beside axillary artery
continuation of basilic vein, terminates as subclavian vein at first rib
basilic vein
medial side of arm
cephalic vein
passes through the deltopectoral groove to join axillary vein within the axilla
Trunks of brachial plexus
superior, middle and inferior
pass through scalene triangle within subclavian artery
divisions
anterior and posterior
cords
directly below pectoralis minor muscle
named relative to axillary artery which they sit beside
lateral cord- lateral to artery
medial cord - medial to artery
posterior cord - posterior to artery
terminal branches of brachial plexus
musculocutaneous, ulnar, medial, radial and axillary nerves
supraspinatus
origin: supraspinatus fossa, inserts: anterior facet of greater tubercle of humerus
infraspinatus
origin from infraspinus fossa, inserts to middle facet of greater tubercle of humerus
teres minor
origin from dorsal aspect of lateral border of the scapula, inserts into lowest facet on greater tubercle of humerus
subscapularis
origin from subscapular fossa, inserts to lesser tubercle of the humerus
teres major
origin from inferior angle of scapula, inserts into medial lip of intertubercular sulcus of humerus
deltoid
origin from lateral third of clavicle, acromion and spine of scapula
inserts into deltoid tuberosity of humerus
structures passing through quadrangular space
axillary nerve and posterior circumflex humeral artery
Glenohumeral joint
surrounded by fibrous joint capsule attached to rim of glenoid fossa and to anatomical neck of humerus
capsule strengthened by attachments of rotator cuff muscles which surround the joint on all sides except inferiorly
joint also stabilised by coracoacromial ligament, forms an arch superiorly to joint
glenohumeral ligament stabilise joint anteriorly
shallow glenoid fossa deepened by ring of fibrocartilage known as the glenoid labrum
