Lecture 3: The pectoral region and shoulder

General Organization of the Upper Limb

Shoulder girdle

Arm

Forearm

Hand

Shoulder Girdle (pectoral girdle)

between the axial skeleton and shoulder joint

Arm

between the shoulder joint and the elbow joint

Forearm

Between the elbow joint and wrist joint

hand

distal to the wrist joint

Terms Indicating Movement

Flexion

Extension

Adduction

Abduction

circumduction

medial rotation

lateral rotation

supination

pronation

Flexion

Extension

Decreasing the angle in a joint

Increasing the angle in a joint

Adduction

Abduction

Movement closer to the medial plane

Movement away from the midline of the body

Circumduction

circular movement of a limb at the far end

Medial Rotation

Lateral Rotation

Rotation toward the midline

rotation away from the midline

Supination

Pronation

rotational movement, results in the palm facing upward

rotational movement, results in the palm facing downward

Myolog

study of muscles

Muscular Attachments

Origins

Insertions

Origins

Insertions

Usually less mobile and/or on the more proximal of a muscle's attachments

Usually more mobile and/or on the more distal of a muscle's attachments

Pectoral Region; Bones

Scapula

Humerus

Clavicle

Scapula- breakdown

Coracoid process

glenoid cavity

scapular notch

scapular spine

acromion

inferior angle

medial border

Coracoid process

a major point of weight/stress transfer from the arm to the shoulder; it also helps shelter the superior aspect of the shoulder joint

Glenoid Cavity

proximal part of the shoulder joint that receives the humeral head

Scapular notch

crossed by the suprascapular artery and nerve

Scapular Spine

divides back of the scapula into supraspinous and infraspinous fossae

Acromion

"point" of the shoulder' distal end of scapular spine; lateral projection

Inferior angle

bottom point of scapula

Medial Border

Inner edge of the scapula

Humerus; breakdown

head

anatomical neck

surgical neck

greater tubercles

lesser tubercles

intertubercular groove

Shaft

deltoid tuberosity

Head

Enlarged proximal part of the humerus that articulates with the glenoid cavity

Anatomical neck

Base of the head

Surgical Neck

Lower than the Anatomical neck, on the shaft of the bone

Greater Tubercles

sites of attachment for the rotator cuff muscles at the upper end of the humerus

Lesser Tubercles

bony projection site of muscle attachment in the humorous

intertub

groove between the greater and lesser tubercles of the humerus

Shaft

Long, slender portion of a long bone

Deltoid tuberosity

raised area on lateral surface of humerus to which deltoid muscle attaches

Clavicle

a strut that keeps the upper limb from the thorax to allow for maximum mobility

transmits forces from the arm to the axial skeleton

one of the most commonly fractured bones in the body

has 2 joints-

sternoclavicular joint

acromioclavicular joint

Sternoclavicular Joint

Articulation between the clavicle and the sternum

acromioclavicular joint

the joint formed by the acromion of the scapula and the clavicle

Pectoral Region- Ligaments

Coracoclavicular ligament

Acromioclavicular ligament

Coracoacromial Ligament

Coracoclavicular ligament

connects the clavicle to the coracoid process

Acromioclavicular ligament

connects the clavicle to the acromion

Coracoacromial Ligament

connects coracoid process and acromion

Pectoral Region- Muscules

Pectoralis Major

Pectoralis Minor

Serratus Anterior

Pectoralis Major

Origin- medial 1/2 of the clavicle, sternum, ribs 1-6

Insertion- upper anterior humerus/intertubercular groove

Innervation- medial and lateral pectoral nerves

Major Actions- Adduction and medical rotation of the arm

Pectoralis Minor

Origin- ribs 3-5

Insertion- coracoid process of the scapula

Innervation- medial pectoral nerve

Major Actions- stabilizes scapula against thoracic wall; medial rotation of scapula

deep to pectoralis major

Serratus Anterior

Origin- Ribs 1-8

Insertion- medial border of the Scapula

Innervation- Long thoracic nerve

Major Actions- stabilizes scapula against thoracic wall; lateral rotation of scapula beyond 90*

Scapular Winging

occurs when an injury to the long thoracic nerve weakens or paralyzes the serratus anterior muscle, causing the medial border of the scapula to rise away from the rib cage

Shoulder Region- Muscules

Trapezius

Latissimus Dorsi

Levator Scapulae

Rhomboid Major

Rhomboid Minor

Trapezuis

Origin- Occipital bone and C7-T12 vertebral spines

Insertion- lateral 1/3 of the clavicle, acromion, and the Scapular spine

Innervation- Accessory Nerve

Major Actions- Elevates, Depresses, Retracts and rotates the scapula

Latissimus Dorsi

Origin- T7-T12 vertebral spines. iliac crest, inferior ribs

Insertion- intertubercular groove

Innervation- thoracodorsal nerve

Major Actions- Extends,adducts, and medically rotates the humerus

Levator Scapulae

Origin- Vertebrae C1-C4

Insertion- medial scapular border, above the base of the scapular spine

Innervation- dorsal scapular nerve

Major Actions- Elevates and medially rotates the scapula

Rhomboid Major

Origin- upper thoracic spines

Insertion- medial scapular border, below the base of the scapular spine

Innervation- dorsal scapular nerve

Major Actions- retracts and medially rotates scapula

Rhomboid Minor

Origin- vertebrae C7-T1

Insertion- medial scapular border, at the base of the scapular spine

Innervation- dorsal scapular nerve

Major Actions- stabilizes, retracts, and medially rotates scapula