ANA 201 Upper Limb (Muscles of the shoulder, clavicle and glenohumeral joint) Flashcards
the upper limb is divided into
shoulder, arm, forearm, and hand
what joint is the upper limb suspended by?
sternoclavicular joint ( an articulation between the sternum and clavicle
what are the significant areas of transition in the upper limb?
axilla, cubital fossa and carpel tunnel
the shoulder consists of the…
pectoral girdle (the scapula and clavicle) which also articulates with the proximal end of the humerus
superficial muscles of the shoulder consist of…
the trapezius and deltoid muscles
the trapezius and deltoid muscles connect the scapula and clavicle to what?
the trapezius and deltoid muscles connect the scapula and clavicle to the trunk and to the arm, respectively
which bone is the only bony attachment between the trunk and the upper limb?
clavicle
what forms the sternoclavicular (SC) joint and where is it located?
sternum and clavicle, where the medial region of the clavicle articulates with the manubrium of the sternum
what forms the acromioclavicular (AC) joint and where is it located?
acromion and clavicle, where the lateral region of the clavicle articulates with the acromion of the scapula
describe the characteristic s-shape of the clavicle
The medial two-thirds of the body (shaft) of the clavicle are convex anteriorly, whereas the lateral third is flattened and concave anteriorly.
These curvatures increases the resilience of the clavicle and give it the appearance of an elongated capital “S.”
the clavicle has no medullary (marrow) cavity - true/false
true
why is the inferior surface of the clavicle rough
The inferior surface of the clavicle is rough because strong ligaments bind it to the 1st rib near its sternal end and suspend the scapula from its acromial end
The greater and lesser tubercles are prominent landmarks on the proximal end of the humerus and serve as attachment sites for the…
four rotator cuff muscles of the glenohumeral joint
The greater tubercle of the humerus is medial in position TRUE/FALSE
FALSE it is lateral in position
What are the 3 facets for muscle tendon attatchment of the greater tubercle of the humerus?
1.the superior facet is for attachment of the supraspinatus muscle;
2.the middle facet is for attachment of infraspinatus;
3.the inferior facet is for attachment of teres minor.
what is the muscle attached to the surface marked by a large smooth impression on the lesser tubercle?
subscapularis muscle
What separates the greater and lesser tubercles?
A deep intertubercular sulcus (bicipital groove) separates the lesser and greater tubercles
why was the bicipital groove given its name?
The tendon of the long head of the biceps brachii passes through this sulcus
Roughening’s on the LATERAL lips of the intertubercular sulcus marks sites for the attachment of
Pectoralis major
Roughening’s on the MEDIAL lips of the intertubercular sulcus marks sites for the attachment of
Teres Major
Roughening’s on the FLOOR of the intertubercular sulcus marks sites for the attachment of
latissimus dorsi muscles
where does the deltoid muscle insert onto the humerus
lateral lip of the intertubercular sulcus, on the deltoid tuberosity
where does the coracobrachialis muscle attach on the humerus?
but on the medial surface of the bone, there is a thin vertical roughening for attachment of the coracobrachialis muscle.
Which site of the humerus commonly fractures?
surgical neck
What is myology?
Myology is the branch of anatomy that studies or describes the function and structures of the muscle
How many skeletal muscles do we have?
More than 600 skeletal muscles
Three principal functions of muscles
(1) movement,
(2) heat production,
(3) body support and maintenance of posture.
What are the basic properties that characterize all muscle tissue?
Irritability
Contractility
Extensibility
Elasticity
What are the 3 basic muscle types?
Skeletal/Straited/Voluntary.
Visceral/Smooth/Involuntary.
Cardiac muscle
What are the 2 muscular parts of the shoulder region?
Thoracoappendicular and scapulohumeral region (glenohumeral)
Which anterior thoracoappendicular muscles move the pectoral girdle?
Pectoralis major, pectoralis minor, subclavius, and serratus anterior
What are the 2 origins of the pectoralis major?
Clavicular head (anterior
surface of medial half of
clavicle)
Sternocostal head (anterior of sternum) and costal cartilages of ribs 1-6
(aponeurosis of external oblique muscles)
Insertion of the pectoralis MAJOR is located…
Lateral lip of intertubercular
sulcus or bicipital groove of the humerus
Insertion of the pectoralis MINOR is located…
Medial border and superior
surface of coracoid process
of scapula
Action of the pectoralis minor
Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall
What is the origin of the pectoralis minor?
3rd to 5th ribs NEAR
their costal cartilages
What is the origin of the subclavius?
Junction of 1st rib and
its costal cartilage
Where is the insertion of the subclavius?
Inferior surface of middle
third of clavicle
Origin of the serratus anterior
External surfaces of lateral
parts of 1st to 8th ribs
Insertion of the Serratus anterior
Anterior surface of medial
border of scapula
Action of Serratus anterior
Protracts scapula and holds
it against thoracic wall;
rotates
Which muscles provide the characteristic contour of the shoulder?
Deltoid and trapezius muscles
the trapezius attaches the scapula and clavicle to the_
Trunk
the deltoid attaches the scapula and clavicle to the_
Humerus
The scapula covers _to_ribs
2nd - 7th ribs
What are the three angles of the scapula?
Lateral
Superior
Inferior
What are the three borders of the scapula?
Superior
Medial
Lateral
What are the two surfaces of the scapula?
Costal/anterior
Posterior
What are the three processes of the scapula?
Acromion
Spine
Coracoid process
The spine divides the convex posterior surface is divided into the
Supraspinous fossa
Infraspinous fossa
Superiorlaterally is a structure that articulates with the head of the humerus to form the shoulder joint
Glenoid cavity
Projecting anterolaterally to the glenoid cavity is the
Coracoid process
The median border is also known as the
Vertebrae border
The median border of the scapula is thick
TRUE OR FALSE
FALSE it is thin, the lateral border of the scapula is thick
What is the thinnest border of the scapula?
Superior border
The fracture of the scapula typically involves the
protruding subcutaneous acromion
What is the name of the notch on the superior border?
Suprascapula notch
The supraspinous fossa allows attachment to which muscle?
Supraspinatous muscle
The infraspinous fossa allows attachment to which muscle?
Infraspinatus
What are the muscles of the posterior thoracoappendicular region of the shoulder?
Trapezius
Deltoid
Levator scapulae
Rhomboid minor
Rhomboid major
Which 3 muscles work with the trapezius (and some anterior muscles) to position the scapula on the trunk?
Levator scapulae
Rhomboid minor
Rhomboid major
What are the muscles of the posterior scapulohumeral region?
Supraspinatus
Infraspinatus
Teres minor
Teres major
Long head of tricep brachii
List the rotator cuff muscles
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Define the glenohumeral joint
The glenohumeral joint is a ball-and-socket type of synovial joint that permits a wide range of movement(it is multiaxial); however, the mobility makes the joint relatively unstable.
What is the articulation of a glenohumeral joint?
the large spherical head of the humerus and the small glenoid cavity of the scapula and the glenoid labrum.
Each of the surfaces is covered by hyaline cartilage.
What is the glenoid labrum and its function?
The glenoid labrum is fibrocartilaginous tissue within the glenoid cavity of the shoulder joint. The purpose of the glenoid labrum is to provide stability and shock absorption within the joint
Discuss the capsule of the glenohumeral joint
CAPSULE; a loose fibrous capsule surrounds the glenohumeral joint and is attached;
1. Medially to the margin of the glenoid cavity.
2. Laterally to the anatomical neck of the humerus.
3. Superiorly, the capsule encroaches on the root of the coracoid process so that the fibrous capsule encloses the proximal attachment of the long head of biceps brachii- supraglenoid tubercle of scapula.
Types of ligaments in the glenohumeral joint?
Glenohumeral ligament (superior, middle, and inferior)
Coracohumeral ligament
transverse humeral ligament
The glenohumeral joint is innervated by
The suprascapular,
Axillary,
Lateral pectoral and
Branches from the posterior cord of brachial plexus.
State Hiltons Law
For every nerve that passes a particular joint, the nerve must give supply to that joint irrespective of the final destination of the nerve
Which nerve passes through the surgical neck of the humerus?
Axillary
What are the movements allowed by the glenohumeral joint?
Flexion-extension
Abduction-adduction
Rotation (medial and lateral) of the humerus
Circumduction
What muscles are involved in the flexion allowed by the glenohumeral joint?
clavicular part of the pectorialis major.
The anterior fibre of deltoid muscle.
Coracobrachialis.
Biceps brachii.Both are synergists.
What are the types of fibrous joints?
Sutures
Syndemoses
Gonphoses
When do sutures form in children?
18 months
Sutures replace_in the development of a child’s skull
Pliable fontanel
What are some types of sutures?
Squamous
Serrate
plane
What are syndesmoses joints held together by?
interosseous ligament
Where can a syndesmoses joint be found?
In the forearm between the distal parts of the radius and ulna and in the leg between the distal parts of the tibia and fibula
Which fibrous joint occurs between teeth and supporting bones of the jaw?
gomphoses
What is the dentoalveolar joint?
where the root of a tooth is attached to the periodontal ligament of the dental alveolus tooth socket of the bone.
What are the types of cartilaginous joints?
Symphyses
Synchondrosis
Example of symphyses joints
pubic symphysis and intervertebral disc.
Example of synchondroses
joints within the ribs joining the sternum, and rib-rib joint.
The glenoid cavity is deepened and expanded peripherally by a fibro-cartilaginous collar, which attaches to the margin of the fossa. This is called
The glenoid labrum
Where does the glenohumeral ligament pass?
between the superomedial margin of the glenoid cavity to the lesser tubercle of the humerus.
Where does the corocohumeral ligament pass?
found superiorly between the base of the coracoid process and the greater tubercle of the humerus.
Where does the transverse ligament pass?
a broad fibrous band that runs obliquely from the greater to the lesser tubercle of the humerus, bridging over the intertubercular groove.
Which ligament turns the intertubercular sulcus into a canal?
The transverse ligament converts the groove into a canal that holds the synovial sheath and tendon of the biceps brachii in place during movements of the glenohumeral joint.
Origin of the levator scapulae
Transverse process of cervical vertebrae C1-C4
Insertion of levator scapulae
Medial border of the scapula between superior angle and the root of the spinous process
Innervation of levator scapulae
Dorsal scapular nerve
Action of levator scapulae
elevation and medial rotation of the scapula
Origin of the Rhomboid minor
Lower end of ligamentum nuchae/nuchal ligament and spinous processes of C7 and TI vertebrae
Insertion of rhomboid minor
posterior surface of the medial border of the scapula at the root of the spine
Innervation of rhomboid minor
dorsal scapular nerve C4. C5
Action of rhomboid minor
retraction and elevation of the scapula
Origin of rhomboid major
Spinous processes of T2-T5 vertebrae and intervening supraspinous ligaments
Insertion of rhomboid major
medial border of the scapula, inferior to the root of the spine to the inferior angle of the scapula
Innervation of the rhomboid major
dorsal scapular nerve C4.C5
Innervation of the rhomboid major
dorsal scapular nerve C4.C5
Action of the rhomboid major
Elevates and retracts the scapula
What are the muscles of the posterior scapulohumeral region?
Teres major
Teres minor
Supraspinatus
Infraspinatus
Which 3 muscles work with trapezius (and with muscles found anteriorly) to position the scapula on the trunk
Rhomboid major
Rhomboid minor
Levator Scapulae
Origin of supraspinatus
Medial two-thirds of the supra-spinous fossa of the scapula and the deep fascia that covers the muscle
Insertion of supraspinatus
Most superior facet on the greater tubercle of the humerus
Innervation of supraspinatus
Suprascapular nerve [C5,C6]
Action of supraspinatus
Rotator cuff muscle; initiation of abduction of arm to 15° at gleno-humeral joint
Origin of infraspinatus
Medial two-thirds of the infra-spinous fossa of the scapula and the deep fascia that covers the muscle
Insertion of infraspinatus
Middle facet on posterior surface of the greater tubercle of the humerus
Innervation of infraspinatus
Suprascapular nerve [C5,C6]
Action of infraspinatus
Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint
Origin of Teres minor
Lateral 1/3 of the lateral margin of the scapula
Insertion of the teres minor
Inferior facet on the posterior surface of the greater tubercle of the humerus
Innervation of teres minor
Axillary nerve [C5,6]
Action of the teres minor
Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint
Origin of teres major
posterior surface of inferior angle of scapula
Insertion of teres major
Medial lip of the intertubercular sulcus on the anterior surface of the humerus
Action of teres major
Medial rotation and extension of the arm at the glenohumeral joint
In what kind of places can you find bursae?
Bursae are located where tendons rub against bone, ligaments, or other tendons and where skin moves over a bony prominence
Bursa around glenohumeral joint
Subscapular bursa
Subacromial/subdeltoid bursa
Bursa around glenohumeral joint
Subscapular bursa
Subacromial/subdeltoid bursa
What type of ligaments are the Glenohumeral and transverse humeral?
Capsular ligaments
The coracohumeral ligament is what type of ligament?
Accessary ligament
What is the role of the transverse humeral ligament
Prevents the displacement of the long head tendon of the biceps brachii muscle, from the sulcus
The role of the coracohumeral ligament
It acts to limit inferior translation and excessive external rotation of the humerus
The role of the glenohumeral ligaments
They have a weak stabilizing function, each acting to limit the maximum amplitude of certain arm movements
What part is the superior border of the trapezius inserted into?
Posterior border of the lateral 1/3 of the clavicle
Where do the middle fibers of the trapezius insert?
The medial margin of the acromion
Where do the inferior fibers of the trapezius insert?
Superior edge of the crest of the scapula spine
Innervation of the trapezius
Cranial nerve XI (accessory nerve)
Action of the superior fibers of the trapezius
Elevates shoulder
Extension of the neck and lateral flexión of the neck
Action of the middle and lower fibers of the trapezius
- Powerful elevator of the scapula;
- rotates the scapula during abduction of humerus above horizontal;
- middle fibers retract scapula;
- lower fibers depress scapula
Action Middle fibers
Retraction of the scapula during adduction
Action of lower fibers of the trapezius
Depress scapula
What is the action of the clavicular head and sternocostal head of the pectoralis major?
Clavicular head: flexion of humerus
Sternocostal head: extension of humerus (but only back to the anatomical position)
What is the action of the pectoralis major (both heads together)?
adduction and medial rotation of the humerus
Innervation of pectoralis major
Lateral and medial
pectoral nerves;
clavicular head (C5 and C6),
sternocostal head (C7, C8, and T1)
Innervation of pectoralis minor
Medial pectoral nerve
(C8 and T1)
Innervation of subclavius
Nerve to subclavius (from upper trunk of brachial plexus)
(C5 and C6)
Action of subclavius
Anchors and depresses
clavicle
The pectoralis minor and subclavius are underneath the pectoralis major TRUE/FALSE
TRUE
Innervation of serratus anterior
Long thoracic nerve
(C5, C6, and C7)
Origin of deltoid muscle
Anterior head: Originates from the anterior border of the lateral 1/3 of the clavicle
Middle head: Originates from the acromion
Posterior head: Originates from the spine of the scapula
Insertion of deltoid muscle
Deltoid tuberosity (3 heads converge as a single tendon)
Action of deltoid muscle
Major abductor of the arm beyond 15 degrees (between 15-100 degrees)
Action of the anterior head of the deltoid muscle
Horizontal flexion
Flexion
Adduction
medial rotation
Action of posterior head of the deltoid muscle
Horizontal extension
Extension
Adduction
Lateral rotation
Action of middle head of the deltoid muscle
Abduction
Innervation of the deltoid muscle
Axillary Nerve C5 C6
Describe the glenohumeral ligament
The glenohumeral ligaments are three fibrous bands.
●Anterosuperiorly found in three locations to form superior, middle, and inferior glenohumeral ligaments, which pass between the superomedial margin of the glenoid cavity to the lesser tubercle of the humerus.
Describe the coracohumeral ligament
The coracohumeral ligament; found superiorly between the base of the coracoid process and the greater tubercle of the humerus.
Describe the transverse humeral ligament
The transverse humeral ligament
a broad fibrous band that runs obliquely from the greater to the lesser tubercle of the humerus, bridging over the intertubercular groove.
●The ligament converts the groove into a canal that holds the synovial sheath and tendon of the biceps brachii in place during movements of the glenohumeral joint.
Which arteries take part in the scapula anastomosis?
Suprascapular artery
deep branch of transverse cervical artery subscapular artery
suprascapular artery (scapula anastomosis)
The suprascapular artery is from the thyrocervical trunk of the first part of the subclavian artery.
Above the suprascapular fossa ( and ligament) to reach the supraspinous fossa, then it curves around the spinoglenoid notch to reach the infraspinous fossa.
deep branch of transverse cervical artery (scapula anastomoses)
The deep branch of the transverse cervical artery which is also a branch of the thyrocervical trunk.
The artery descends along the medial border of the scapula deep to the levator scapulae and rhomboids (sometimes the artery may arise from the third part of the subclavian artery and is known as dorsal scapular artery.
subscapular artery (scapula anastomoses)
The subscapular artery from third part of axillary artery.
Its circumflex scapular branches passes between the two origins of teres minor muscle, enters infraspinous fossa.
Lateral border of scapula
Scapular anastomosis is principally formed between
The first part of the subclavian artery and third part of the axillary artery
Two sites of the scapula anastomoses
Body of the scapula
Around the acromion
Where is the weakest part of the clavicle which is more susceptible to fracture?
The weakest part of the clavicle is the junction of its middle and lateral thirds which makes this point more susceptible to fracture
Describe the scapula
The scapula or shoulder blade is a triangular flat bone that lies at the posterolateral aspect of the thorax where it covers the 2nd-7th ribs
Describe the scapula
The scapula or shoulder blade is a triangular flat bone that lies at the posterolateral aspect of the thorax where it covers the 2nd-7th ribs
