T H E G L E N O H U M E R A L ( G H ) J O I N T

THE SHOULDER JOINT

CLARIFICATION OF TERMS

• Shoulder girdle = scapula and clavicle

• Shoulder joint (glenohumeral joint) = scapula and

humerus

Lippert, p115

OSTEOLOGY OF THE GH JOINT(BONES)

• Scapula

• Glenoid fossa

• Glenoid labrum

• Subscapular fossa

• Infraspinous fossa

• Supraspinous fossa

• Axillary border

• Acromion process

(Vertebral)

(Axillary)

(Axillary)

(Vertebral)

Scapula (Dorsal aspect)

OSTEOLOGY OF THE GH JOINT(BONES)…CONT

• Humerus

• Head

• Surgical neck

• Anatomical neck

• Shaft

• Greater tubercle

• Lesser tubercle

• Deltoid tuberosity

• Bicipital groove

• Bicipital ridges

Intertubercular groove

(Bicepital groove)

(Posterior aspect)

Intertubercular Groove (bicepital groove)

Deltoid Tuberosity

Anatomical Neck

JOINT STRUCTURE OF THE GH JOINT

• Ball and socket joint

• Movement in all three planes (3 degrees of

freedom)

• Articulation between the humeral head of the

humerus and the glenoid fossa of the scapula

• One of the most movable joints in the body and,

consequently, one the _______________ stable.

Lippert, p131

JOINT MOVEMENT OF THE GH JOINT

• Osteokinematics • Flexion

• Extension

• Hyperextension

• Abduction

• Adduction

• Medial rotation (internal rotation)

• Lateral rotation (external rotation)

• Horizontal abduction

• Horizontal adduction

• Circumduction

• Scaption

JOINT MOVEMENT OF THE GH JOINT…CONT

• Arthrokinematics

• Concave-convex rule

• The convex humeral head moves within the concave glenoid

fossa

• The convex joint surface (humeral head) moves in a direction

opposite to the movement of the body segment (humeral shaft)

• Flexion – humeral head glides _____________________

• Abduction – humeral head glides _____________________

• Extension – humeral head glides _____________________

• Adduction – humeral head glides _____________________

• Internal rotation – humeral head glides _____________________

• External rotation – humeral head glides _____________________

Lippert, p132

JOINT MOVEMENT OF THE GH JOINT…CONT

• Arthrokinematics

• The articular surface of the humeral head is greater than that of the glenoid fossa

• If the humeral head simply rotated in the glenoid fossa, it

would run out of articular surface before full abduction

occurred

• So, as abduction occurs, the humeral head rolls across the

glenoid fossa and glides inferiorly (thanks to the rotator cuff)

• Complete abduction can occur only with full external

rotation

SUPPORTING STRUCTURES OF THE GH JOINT

• Rotator cuff • SITS muscles surround humeral head and actively hold it

against the glenoid fossa

• Capsular ligaments • Relatively loose capsule attaches the rim of the glenoid fossa

and anatomic neck of the humerus

• Coracohumeral ligaments • Connects coracoid process and anterior side of greater

tubercle

• Glenoid labrum • A fibrocartilaginous ring that encircles the rim of the glenoid

fossa, deepening the socket and sealing the joint

• Long head of the Biceps • The proximal portion of the tendon wraps around the superior

aspect of the humeral head, providing anterior stability

Mansfield, p58

MYOLOGY OF THE GH JOINT (MUSCLES)

• Deltoid

• Pectoralis major

• Latissimus dorsi

• Teres major

• Supraspinatus

• Infraspinatus

• Teres minor

• Subscapularis

• Coracobrachialis

• Biceps brachii

• Triceps brachii, long head

Deltoid: Anterior

Origin Anterior surface of the lateral

aspect of the clavicle

Insertion Deltoid tuberosity of the humerus

Action Sh flexion, HADD, Sh IR, Sh ABD

Innervation Axillary n.

Anterior

Lippert, p136

Deltoid: Middle

Origin Superior lateral surface

of the acromion

Insertion Deltoid tuberosity of the

humerus

Action Sh ABD, Sh flexion

Innervation Axillary n.

Middle Deltoid

Lippert, p136

Deltoid: Posterior

Origin Spine of the scapula

Insertion Deltoid tuberosity of the

humerus

Action Sh extension, HABD, Sh

ER

Innervation Axillary n.

Lippert, p136

Pectoralis Major

Origin Clavicular portion: anterior

margin of the medial portion of

the clavicle

Sternal portion: lateral margin

of the manubrium and body of

the sternum and cartilage of

the first 6-7 ribs

Insertion Crest of the greater tubercle of

the humerus

Action Clavicular: Sh IR, Sh flexion,

HADD

Sternal: Sh IR, Sh ADD, Sh

extension, Sh depression

Innervation Clavicular: lateral pectoral n.

Sternal: lat & medial pectoral n. Mansfield, p82

Latissimus Dorsi

Origin Thoracolumbar fascia, spinous

processes of lower thoracic and

lumbar vertebrae, posterior iliac

crest, lower 4 ribs and inferior angle

of scapula

Insertion

Floor of intertubercular groove of

humerus

Action Sh ADD, Sh extension, Sh IR, scapular

depression

Innervation Thoracodorsal n.

“tidbit” Necessary for “crutchwalking” and

transfers!

Lippert, p137

Teres Major

Origin Inferior angle of the scapula

Insertion

Crest of the lesser tubercle of the

humerus

Action Sh ADD, Sh extension, Sh IR

Innervation Lower scapular n.

Lippert, p138

SITS

• Supraspinatus

• Infraspinatus

• Teres Minor

• Subscapularis

Supraspinatus

Origin Supraspinatus fossa of the

scapula

Insertion

Greater tubercle of the

humerus

Action Sh ABD, stabilization of the

GH, slight ER

Innervation Suprascapular n.

“Tidbit” One of the rotator cuff

muscles

Lippert, p138

Infraspinatus

Origin Infraspinatus fossa of the

scapula

Insertion

Greater tubercle of the

humerus

Action Sh ER, stabilization of the

GH joint

Innervation Suprascapular n.

“tidbit” One of the rotator cuff

muscles

Lippert, p138

Teres Minor

Origin Posterior lateral

border of the scapula

near the inferior

angle

Insertion

Greater tubercle of

the humerus (inferior

to the infraspinaus)

Action Sh ER, stabilization of

the GH joint

Innervation Axillary n.

Lippert, p139

Subscapularis

Origin Subscapular fossa of the

scapula

Insertion

Lesser tubercle of the

humerus

Action Sh IR, stabilization of the

GH joint

Innervation Upper and lower

subscapular n.

“tidbit” One of the rotator cuff

muscles

Lippert, p140

Coracobrachialis

Origin Coracoid process of the scapula

Insertion Medial aspect of the proximal

shaft of the humerus

Action Sh flexion

Innervation Musculocutaneous n.

Lippert, p140

Biceps Brachii

Origin Long head: supraglenoid tubercle of

glenoid fossa

Short head: coracoid process of the

scapula

Insertion Radial tuberosity of the radius

Action Sh flexion, elbow flexion, forearm

supination

Innervation Musculocutaneous n.

“tidbit” The actions of the biceps brachii are

“perfect” in combination for opening a

bottle of wine. “The Corkscrew effect”

Biceps

Brachii

Mansfield, p78

Long Head of the Triceps Brachii

Origin Infraglenoid tubercle of the

scapula

Insertion Olecranon process of the

ulna

Action Sh extension, elbow

extension

Innervation Radial n.

Mansfield, p80

MYOLOGY OF THE GH JOINT (MUSCLES)…CONT

• Anatomical Relationsips • Muscles that stabilize are deep to muscles that move.

• Therefore, glenohumeral joint muscles are superficial to shoulder girdle muscles

• Deltoid: forms a superficial cap over the anterior, lateral and posterior sides of the shoulder

• Anteriorly, pectoralis major covers most of the superficial chest wall

• Biceps brachii and triceps brachii encompass most of the anterior and posterior arm, respectively

• If the trapezius were removed, you would see the supraspinatus above the scapular spine and in descending order, the infraspinatus, teres minor and teres major below the scapular spine

• The latissimus dorsi covers the lumbar and lower thoracic region of the back

Lippert, p140

MYOLOGY OF THE GH JOINT (MUSCLES)…CONT

• Anatomical Relationsips

Lippert, p140

MYOLOGY OF THE GH JOINT (MUSCLES)…CONT

• Summary of Muscle Action:

Action Muscles

Flexion Anterior deltoid, pectoralis major (clavicular)

Extension Posterior deltoid, lattisimus dorsi, teres major,

pectoralis major (sternal)

Hyperextension Latissimus dorsi, posterior deltoid

Abduction Deltoid, supraspinatus

Adduction Pectoralis major, teres major, latissimus dorsi

Horizontal abduction Posterior deltoid, infraspinatus, teres minor

Horizontal adduction Pectoralis major, anterior deltoid

Lateral rotation Infraspinatus, teres minor, posterior deltoid

Medial rotation Latissimus dorsi, teres major, subscapularis,

pectoralis major, anterior deltoid

(Lippert, p142)

MYOLOGY OF THE GH JOINT (MUSCLES)…CONT

• Summary of Muscle Innervation:

Lippert, p143

Muscle Nerve Segment

Subscapularis Upper and lower subscapular C5, C6

Teres major Lower subscapular C5, C6

Pectoralis major Lateral and medial pectoral C5, C6, C7 & C8, T1

Latissimus dorsi Thoracodorsal C6, C7, C8

Supraspinatus Suprascapular C5, C6

Infraspinatus Suprascapular C5, C6

Deltoid Axillary C5, C6

Teres minor Axillary C5, C6

Coracobrachialis Musculocutaneous C6, C7

Biceps Musculocutaneous C5, C6

triceps radial C7, C8

What upper extremity muscles

can you identify on him?

REFERENCES

• Lippert, L.S. (2011). Clinical Kinesiology and

Anatomy, 5th ed. Philadelphia, PA: F.A. Davis.

• Mansfield, P.J., & Neumann, D.A. (2009). Essentials of

Kinesiology for the Physical Therapist Assistant. St.

Louis, MO: Mosby Elsevier.