shoulder and arm bony landmarks, muscles, joint/ligaments

subacromial bursa

also known as the subdeltoid bursa, this sizable fluid sac has 2 major section: the lateral portion creates a smooth surface for the acromion and deltoid to glide over the head of the humerus' and rotator cuff tendons and the medial part cushions the coracoacromial ligament from the supraspinatus tendon

sternoclavicular joint

articulation between the sternal end of the clavicle and sternum wedge shaoed and contains a small, impalpable fibrous disc

coracoacromial ligament

attaches the scapula's coracoid process to its acromion along with it this ligament forms the coracoacromial arch across the top of the shoulder and this arch helps to protect the rotator cuff tendons and subacromial bursa from direct trauma by the acromion

intertubercular groove

between the greater and lesser tubercles and is roughlt a pencil's width in diameter w/in the groove lies the tendon of the long head of biceps brachii

pectoralis major

broad, powerful muscle located on the chest; its convergent superficial fibers are accessible --divided into 3 segments (clavicular, sternal, and costal fibers) --the upper and lower fibers perform opposing actions at the shoulder joint-flexion and extension-making it antagonist to itself

latissimus dorsi

broadest muscle of the back; thin, superficial fibers originate at the low back, ascend the side of the trunk, and merge into a thick bundle at the axilla

teres major

called "lat's little helper" because it is a complete synergist with the latissimus dorsi is superficial and located along the scapula's lateral border between the latissimus dorsi and teres minor (rotates the arm medially)

supraspinatus

chunky and located in the supraspinous fossa, deep to the trapezius's upper fibers and the belly runs underneath the acromion and attaches to the humerus's greater tubercle --it assists the deltoid with abduction of the shoulder and is the only muscle of the group not involved in shoulder rotation

coracoclavicular ligament

composed of two smaller ligaments: trapezoid and conoid -both stretch from the coracoid process of the scapula to the inferior surface of the clavicle and together they provide stability for the acromioclavicular join and form a strong bridge between the scapula and clavicle

axilla

cone-shaped area commonly called the armpit and is formed by 4 walls -the lateral wall (biceps brachii and coracobrachialis -the posterior wall (subscapularis and latissimus dorsi) -the anterior wall (pectoralis major) -the medial wall (rib cage and serratus anterior) --important vessels pass through the axillary region (brachial artery and brachial plexus (nerves))

brachial artery

continuation of the axillary artery and runs between the biceps and triceps brachii

subscapularis

deep and located on the scapula's anterior surface sandwiched between the subscapular fossa and serratus anterior muscle --is the only rotator cuff muscle that attaches to the humerus's lesser tubercle and rotates the shoulder medially

lateral border

extends superiorly and laterally from the inferior angle toward the axilla or "armpit" attachment site for teres major and teres minor muscles and since they are thick, not as defined as medial border

infraspinatus

flat, convergent belly and is located in the infraspinous fossa; most of its belly is superficial with a medial portion deep to the trapezius and a lateral portion beneath the deltoid --attaches immediately posterior to the supraspinatus on the greater tubercle and is synergist with the teres minor in lateral rotation of the shoulder --unique, dense quality of the infraspinatus muscle is due to its multipennate fibers and thick superficial fascia

acromion

lateral aspect of the spine of the scapula and located at the top of the shoulder. it has a flat surface and articulates with the clavicle's lateral end attachment site for the deltoid and trapezius acromial angle is a small corner felt along the acromion's lateral/posterior aspect

serratus anterior

lies along the posterior and lateral rib cage; its oblique fibers extend from the ribs underneath the scapula and attach to its medial border --most is deep to the scapula, lattisimus dorsi, or pectoralis major but a portion is below the axilla --this muscles is unique in its ability to abduct the scapula, making it an antagonist to the rhomboids

pectoralis minor

lies next to the rib cage deep to the pectoralis major and its fibers run perpendicular to the pectoralis major fibers from the scapula's coracoid process to the upper ribs --the major vessels serving the arm-the brachial plexus, axillary artery and vein-cross underneath the pectoralis minor, creating the potential for neurovascular compression by this muscle

trapezius

lies superficially along the upper back and neck; the broad, thin fibers blanket the shoulders, attaching to the occiput, lateral clavicle, scapula, and spinous processes of the thoracic vertebrae --can be divided into 3 groups (upper, middle, and lower fibers); upper and lower are antagonists in elevation and depression of the scapula

biceps brachii

lies superficially on the anterior arm and it has a long head and a short head, which merge to form a long, oval belly the tendon of the long head passes through the intertubercular groove of the humerus and this helps to stabilize the tendon as it rises over the top of the shoulder --the distal tendon of the biceps dives into the antecubital space (inner elbow) to attach at the radius, allowing the muscle to be the primary muscle of forearm supination

levator scapula

located along the lateral and posterior sides of the neck; its inferior portion is deep to the upper trapezius; however the levator ascends the lateral side of the neck, its fibers come out from under the trapezius and become superficial --attaches to the transverse processes of the cervical vertebrae and located on the lateral side of the neck all of these protuberances extend laterally at about the same width (except for C-1 process which is broader) --the brachial plexus is a large group of nerves which innervated the arm, exits from the transverse processes of the cervical vertebrae

infraglenoid tubercle

located at the most superior aspect of the latetal border, not distinguishable but a small spot that is an attachment site attachment site for long head of the triceps brachii and lies deep to the teres minor and deltoid muscles

superior angle

located at the superior end of the medial border attachment site for levator scapula and since it is deep to the trapezius muscle jt may nkt be as easy to isolate as the inferior

rhomboid major and minor

located between the scapula and vertebral column --has thin fibers that lie deep to the trapezius and superficial to the erector spinae muscles

axillary lymph nodes

located in the axilla (armpit)

deltoid tuberosity

located on the lateral side of the mid-humeral shaft and is a small, loe bump that serves as an attachment site for the converging fibers of the deltoid muscle

greater tubercle

located on the proximal humerus deep to the deltoid muscle located inferior and lateral to the acromion and shaped like a low mound attachment site for 3 out of 4 rotator cuff muscles-supraspinatus, infraspinatus, teres minor

subscapular fossa

located on yhe scapula's anterior surface next to the ribcage attachment site for the subscapularis and location of the serratus anterior muscle hard to sccess

supraspinous fossa

located superior to the spine of the scapula, small but deep attachment site for the supraspinatus muscle and lies deeo in the basin it is hard to access

subclavius

located underneath the clavicle and its fibers run parallel to the clavicle, deep to the pectoralis major --on 4 legged animals this muscle is large and is important to stabilizing the clavicle and shoulder girdle during locomotion

medial border

long edge of thr scapula that runs parallel to the vertebral column, 5-7in long there are two angles-inferior and superior attachment site for the rhomboids and serratus anterior, deep to the trapezius

coracoid process

of the scapula is a beak like projection found inferior to the shaft of the clavicle and depending on position of scapula, often found in the deltopectoral groove between the deltoid abd pectoralis major fiber

triceps brachii

only muscle located on the posterior arm creating extension at the elbow and shoulder is an antagonist at both these joints to the biceps brachii --has 3 heads (long, lateral, and medial) --long head extends off the infraglenoid tubercle of the scapula weaving between the teres major and minor --lateral head lies superficially beside the deltoid while the medial head lies mostly underneath the long head --all three heads converge into a thick, distal tendon proximal to the elbow

acromioclavicular joint

small articulation betwern the acromion of the scapula and the acromial end of the clavicle anterior and superior surfaces of this thin crevice can be felt smooth and slender

teres minor

small muscle squeezed between the infraspinatus and teres major; its located high the axilla --teres minor and teres major are antagonists in rotation of the humerus

coracobrachialis

small, tubular muscle located in the axilla and is known as the "armpit" muscle; its a secondary flexor and adductor of the shoulder --deep to the pectoralis major and anterior deltoid and lies anterior to the axillary artery and brachial plexus (in anatomical position)

lesser tubercle

smaller than the greater tubercle attachment site for the 4th rotator cuff muscle-subscapularis

clavicle

superficial and lies horizontally across the upper chest and has a gentle "S" shape attachment site for a lot of muscles both ends are superficial and accessible; lateral end is flat and rises slightly highe than the acromiin; medial end is round and is with the sternum

inferior angle

superficial and located at the medial border's lower end

spine of the scapula

superficial ridge just off the top of the shoulder, runs at an oblique angle to the body, spans from acromion to the medial birder attachment site for posterior deltoid and middle and lower fibers of trapezius

rotator cuff tendons

supraspinatus and infraspinatus tendons are situated deep to the acromion while the tendons of the subscapularis and teres minor lie deep to the thick belly of the deltoid --since they lie against the surface of the greater or lesser tubercles of the humerus and cannot be separated from the underlying bone

rotator cuff muscles

supraspinatus, infraspinatus, teres minor, subscapularis

latissimus dorsi and teres major gets called "handcuff muscles" because...

their actions collectively bring the arms into the "arresting" position

deltoid

triangle-shaped deltoid is located on the cap of the shoulder; origin of deltoid curves around the spine of the scapula and clavicle forming a V shape and from this broad origin the fibers converge down the arm to attach at the deltoid tuberosity --can be divided into 3 segments (anterior, middle, posterior) and all 3 abduct the humerus but posterior and anterior are antagonists in flexion/extension and medial/lateral rotation

infraspinous fossa

triangular area inferior to the spine of the scapula and filled with infraspinatus muscle