muscles of the back and neck Flashcards
Muscles of the first superficial layer of the back (extrinsic muscle)
- trapezius
- latissiums dorsi
Muscles of the second superficial layer of the back (extrinsic muscle)
- levator scapulae
- Rhomboid major and minor
Muscles of the third superficial layer of the back (extrinsic muscle)
- serratus posterior superior
- serratus posterior inferior
trapezius origin/insertion
origin - a line from the occipital bone (base of skull) down to vertebrae T12
insert - scapula
trapezius functions
- upper fibers: elevation of the scapula
- middle fibers: retraction of the scapula and upward rotation of the scapula
- lower fibers: depression of the scapula and upward rotation of the scapula
trapezius innervation
cranial nerve, spinal accessory nerve
latissimus dorsi origin/insertion
- very large origin including the crest (top end) of ilium, the lumbar fascia, the lumbar and lower thoracic vertebral spines (t7-t12) and lower three or four ribs
- insertion on bicipital groove
latissimus dorsi functions
Functions (primary):
- extension
- adduction and medial (internal) rotation of the arm at the glenohumeral joint
functions (secondary):
- bilateral: extension of the back
- unilateral: ipsilateral lateral flexion of the lumbar spine
latissimus dorsi innervations
thoracodorsal nerve (part of the brachial plexus) (c6-c8)
seratus anterior origin/insertion
serrated origin from the lateral aspect of the upper nine ribs
fibres run laterally and then backwards around the ribcage and under the scapula then insert on its medial border
seratus anterior function
pulls the scapula forward (protraction) and rotates the glenoid fossa upwards
seratus anterior innervation
long thoracic nerve of the brachial plexus (c5-c7)
levator scapula origin/insertion
origin from the transverse process of c1-c4
insert on the upper medial border of the scapula
levator scapula function
elevation of the scapula, depress the glenoid fossa
seratus anterior innervation
branches of nerves c3-c5
rhomboids origin/insertion
minor origin- ligamentum nuchace and spinous process of c7 and t1
minor insertion - middle medial border of the scapula
major origin - spinous process t2-t5
major insertion - lower third the medial scapular border
rhomboid function
elevate and retract scapula and aid in depressing the glenoid fossa
rhomboid innervation
dorsal scapular nerve (c5) of the brachial plexus
pectoralis major origin/insertion
two heads - two origins
clavicular head
origin- middle of clavicle
costal head
origin- upper costal cartilage and sternum
both insert on the lateral lip of the bicipital groove
pectorals major function
adducts, flexes and medially rotates the arm
pectorals major innervation
brachial plexus via the medial and lateral pectoral nerves
pectoralis minor origin/insertion
origin- ribs 3-5
insert- coracoid process
pectoralis minor function
stabilize the scapula and pull upward and forward on the rib cage
pectoralis minor innervation
medial pectoral nerve
deltoid origin/insertion
origin- continuous line from the lateral third of the clavicle to the acrominon and the lateral third of the spine of the scapula
insertion - v shaped roughness on the lateral upper humerus called the deltoid tubercle
deltoid function
when all act once it is a powerful abductor of the arm
anterior fibres produce flexion
middle fibres produce abduction
posterior fibers produce extension
deltoid innervation
axillary nerve and teres minor
teres major insertion/origin
origin- lower part of back
insertion- medial lip of the occipital groove
teres major function
extends, adducts, and medially rotates the arm
teres major innervation
lower sub scapular nerve
how many muscles make up the rotator cuff and what are they called
4, subscapularis, supraspinatus, infraspimatus, and teres minor
rotator curd insertion/origin, function
origin- scapula
insertion- humerus
function- dynamic ligaments to help reinforce the shoulder joint
subscapularis origin/insertion
origin- most of anterior surface of scapula
insertion- lesser tubercle of the humerus
subscapularis function
powerful medial rotator and weak adductor
subscapularis innervation
sub scapular nerve
supraspinatus origin/insertion
origin- suprasinous fossa
insertion- top facet of the greater tubercle
supraspinatus function
iniates abduction
supraspinatus innervation
supra scapular nerve
teres minor origin/insertion
origin- lower lateral border
insertion- inferior facet of the greater tubercle
teres minor function
lateral rotator
teres minor innervation
axillary nerve
infraspinatus origin/insertion
origin- infraspinous fossa
insertion- middle facet of the greater tubercle
infraspinatus function
laterally rotates the humerus
infraspinatus innervation
supra scapular nerve
glenohumeral (shoulder) joint classification
synovial, triaxial, ball and socket
glenohumeral (shoulder) joint movement
flexion/extension, abduction/adduction, medial and lateral rotation
glenohumeral (shoulder) joint bones involved
scapula, humerus
glenohumeral (shoulder) joint ligaments
ligaments around joint are weak, except coracohumeral ligament
glenohumeral (shoulder) joint innervation
axillary artery
other joints in the shoulders
scapulo-thoracic joint
what is the sternoclavicular joint
synovial joint between the clavicle and the manubrium (sternum), only joint connecting the upper limbs to the rest of the skeleton
sternoclavicular joint function
range of circumduction
how many ligaments reinforce the sternoclavicular joint
2, medial sternoclavicular ligament, costoclavicular ligament
what is the acromioclavicular joint
articulation of the distal clavicle withe medial facing part of the arcrominon process (on the scapula)
how is the acromioclavicular joint reinforced
coracoclavicular ligament
