Anatomy

Upper Extremity

4 major segments of the upper extremity

Shoulder - consists of pectoral, scapular, and deltoid organs

Arm

Forearm

Hand

The bones of the upper limb (superior appendicular skeleton) are attached to the axial skeleton via _____

Pectoral girdle (clavicle and scapula)

Muscles that support, stabilize, and move the pectoral girdle. These muscles attached to the relatively fixed ribs, sternum, and vertebrae of the axial skeleton

Axioappendicular muscles

A long bone that has no medullary canal (composed of superficial compact bone and central spongy bone)

Shaft is described as a double curve in a horizontal line

Clavicle (collarbone)

Describe the medial and lateral halves of the clavicle

Medial half - convex anteriorly; sternal end articulates with the manubrium of the sternum (Sternoclavicular joint)

Lateral half - concave anteriorly; acromial end articulates with the acromion of the scapula (Acromioclavicular joint)

Differentiate the superior surface and inferior surface of the pectoral girdle

Superior surface - smooth

Inferior surface - rough (strong ligaments bind to the 1st rib near its sternal end and suspend the scapula from its acromial end

Ligaments in inferior surface of the clavicle

Coracoclavicular ligaments - at the acromial end

• Conoid ligament - inserts at the conoid tubercle

• Trapezoid ligament - inserts at the trapezoid line

Groove for subclavius - attachment of subclavius muscle

A triangular flat bone that lies on the posterolateral aspect of the thorax (2nd to 7th ribs)

Scapula

Differentiate the posterior surface, costal surface, and body of scapula

Posterior surface - spine (small supraspinous fossa and large infraspinous fossa)
Costal surface - concave (subscapular fossa)

Body - translucent (thick borders)

Part of the scapula that continues laterally as the flat expanded acromion. It articulates with acromial end of the clavicle forming the acromioclavicular (AC) joint

Spine

Prominence indicating the medial point of attachment of the deltoid

Deltoid tubercle of the scapular spine

Shallow, concave, oval fossa located superolaterallly. It receives and articulates with the head of the humerus at the glenohumeral joint.

Glenoid cavity

Beak-like that projects anterolaterally. Superior to the glenoid cavity. Provides inferior attachments to the coracoclavicular ligaments

Coracoid process

Borders of scapula

Superior
Medial (vertebral)
Lateral (axillary)

Angles of the scapula

Superior - thinnest and shortest (Suprascapular notch)
Inferior
Lateral - thickest (Head and Neck)

Movement of scapula

Elevation/Depression
Protraction/Retraction

Upward rotation/downward rotation

Largest bone in the upper limb

Humerus

2 joints articulated by the humerus

Glenohumeral joint

Elbow joint

Structures of the Proximal Humerus

See attached photo

Structures of the Proximal Humerus

See attchached photo

What provides passage of long head biceps tendon in humerus

Intertubercular (bicipital) groove

Structure of the Shaft of Humerus

Deltoid tuberosity - lateral; location of the deltoid muscle

Radial groove - oblique and posterior; passage of the radial nerve and profunda brachii artery

Structure of the Distal HUmerus

• Distal humerus – widens as the sharp medial and lateral supracondylar (supracondylar) ridges:

  • Medial epicondyle

  • Lateral epicondyle

• These structures provide muscle attachment.

Articulates with the head of the radius

Capitulum (lateral)

Medial, spool-shaped or pulley-like for articulation with the proximal end (trochlear notch) of the ulna

Trochlea

Located anteriorly. It receives the coronoid process of the ulna.

Coronoid Fossa

located anteriorly. It receives the radial head during full elbow flexion.

Radial fossa

Located posteriorly. It receives the olecranon process of the

Olecranon fossa

2 parallel bones of the upper forearm

Ulna

Radius

Pivots around the ulna. Enables forearm supination and pronation

Radius

It is the stabilizing bone of the forearm. It is the medial and longer of the two forearm bones.

Ulna

Structures of the Proximal Ulna

Olecranon process

Coronoid process

Trochlear notch

Ulnar tuberosity

Radial notch

posterior prominent projection of the ulna

Olecranon process

Anterior prominent projection of the ulna

Coronoid process

articulates with the trochlea of the humerus. Formed by the olecranon and coronoid process.

Trochlear notch

located inferior to coronoid process and serves as attachment of the brachialis muscle.

Ulnar tuberosity

located laterally, receives the head of the radius.

Radial notch

Must know structures

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Must know structures

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Part of Ulna that is thick and cylindrical proximally

Shaft

Distal End of the Ulna

Ulnar Head

Ulnar Styloid Process

A small, abrupt enlargement, the disc-like structure at the narrow distal end of ulna

Ulnar head

Small, conical structure of the distal end of ulna

Ulnar styloid process

TRUE OR FALSE: The distal ulna articulates with the wrist bone and participates in joint movement

FALSE

The lateral and shorter of the two forearm bones

Radius

Proximal structures of the radius

Head

Neck

Radial tuberosity

It is the smooth, concave superior aspect. It articulates with the capitulum of the humerus.

Radial Head

It is a constriction of the distal head.

Neck of Radius

It is located medially and it demarcates the proximal aspect to the shaft.

Radial Tuberosity

Distal Structures of Radius

Ulnar notch

Radial styloid process

Dorsal tubercle

Scaphoid fossa

Lunate fossa

it accommodates the ulna

Ulnar notch

located on the lateral aspect of radius bone and increasingly becomes ridge-like.

Radial styloid process

articulates with scaphoid bone.

Scaphoid fossa

articulates with lunate bone.

lunate fossa

projects dorsally. Located in between the shallow grooves for the passage of the tendons of forearm muscles.

Dorsal tubercle

Describe the Shaft cross section of the forearm

The ulna and radius apices are lateral

Rounded, superficially directed base

Acute, deeply directed apex

A thin, fibrous membrane that connects the apices of the forearm bones

Interosseous membrane

It is the only articulation between the upper limb and the axial skeleton

Sternoclavicular joint

Formed by the articulation of the sternal end of the clavicle and manubrium and 1st costal cartilage

Sternoclavicular joint

serves as a shock absorber of the forces transmitted along the clavicle from the upper limb.

Articular disc

Covers the sternoclavicular joint

Joint capsule

reinforces the anterior and posterior capsule.

Anterior and posterior sternoclavicular ligament

reinforces the superior capsule.

Interclavicular ligament

anchors the sternal end of the clavicle to the 1st rib, limiting its elevation.

Costoclavicular ligament

Blood supply of the sternoclavicular joint

Internal thoracic and suprascapular arteries.

Nerve supply of sternoclavicular joint

Medial suprascapular nerve and nerve to subclavius.

Articulation between the head of humerus and glenoid fossa of scapula

ball and socket joint

Glenohumeral joint

Fibrous, membranous structure that deepens the glenoid cavity

Glenoid labrum

loose and fibrous layer that surrounds the GH Joint

Joint capsule of GH joint

Parts of the Joint capsule of the GH joint

Medial - margin of glenoid cavity

Lateral - anatomical neck of humerus

Superiorly - coracoid process

3 ligaments of the shoulder joint (Glenohumeral joint)

Glenohumeral ligaments

Coracohumeral ligament

Transverse humeral ligament

3 fibrous bands that reinforce the anterior aspect of the capsule

Glenohumeral ligament

Glenohumeral ligaments:
Origin:
Insertion:

Origin: Glenoid labrum

Insertion: anatomic neck of humerus

Coracohumeral ligaments:
Origin:
Insertion:

Origin: Base of coracoid process

Insertion: Greater tubercle of humerus

a small ligament that bridges the intertubercular (bicipital) groove of the humerus.
Holds the biceps long head tendon in place

Transverse humeral ligament

Transverse Humeral Ligament

Origin:

Insertion:

Origin: Greater tubercle of humerus

Insertion: Lesser tubercle of humerus

Shoulder Joint (GH Joint) blood supplies:

Anterior and posterior humeral circumflex arteries

Branches of suprascapular arteries

Shoulder Joint (GH Joint) nerve supplies:

Suprascapular nerve

Axillary nerve

Lateral pectoral nerve

Movement of glenohumeral joint

Abduction

Adduction

Flexion

Extension

Lateral rotation

Medial rotation

Tip: GH joint is a ball and socket joint capable of circumduction

Articulation between acromial end of clavicle and acromion of scapula (2–3 cm lateral acromion).

Acromioclavicular joint

sleeve-like, relatively loose fibrous layer but strengthened superiorly by the trapezius muscle fibers.

Joint capsule of the AC joint

What are the two ligaments of the AC joint?

Acromioclavicular ligament

Coracoclavicular ligament (Conoid ligament & Trapezoid ligament)

Fibrous band extending from the acromion to the clavicle that strengthens the AC joint superiorly.

Acromioclavicular ligament

Strong pair of bands that unite the coracoid process of the scapula to the clavicle.

Coracoclavicular ligament

inverted triangle shaped. Attaches to the conoid tubercle of the clavicle.

Conoid ligament

from superior surface of the coracoid process and extends laterally to the trapezoid line on the inferior surface of the clavicle.

Trapezoid ligament

Blood supply of the AC joint

Suprascapular and thoracoacromial arteries

Nerve supple of the AC joint

Lateral pectoral nerves

Axillary nerve

(Suprascapular nerve)

Differentiate the blood and nerve supplies of the gh joint, ac joint, and sc joint.

See attached photo

Joints responsible for the pectoral girdle range of motion (Scapulothoracic rhythm)

Scapulothoraric joint
Glenohumeral joint

Initial 30 degrees abduction

glenohumeral joint

Full elevation - for every 3 degrees

2 degrees from glenohumeral joint

1 degree from scapulothroracic joint

(2:1 ratio)

Clavicle - 60 degree

@180 degree abduction of the arm. What is the angle distribution of the glenohumeral joint and scapulathoracic joint

Glenohumeral joint - 120
Scapulathoracic joint - 60

What are the articulations of the elbow joint?

Trochlea and Trochlear notch (Humeroulnar joint)
Capitulum and Radial Head (Humeroradial joint)

Joint capsule boundaries of the elbow joint

Lateral and medial ends - capitulum and trochlea

Anterior and posterior - coronoid and olecranon fossae (weak)

Sides: collateral ligaments (strong)

Collateral ligament of the humerus

Radial collateral ligament - from lateral epicondyle and inserts to annular ligament

Ulnar collateral ligament - from medial epicondyle and inserts to the coronoid and olecranon fossa

• Anterior band - strongest

• Posterior band - weakest

• Oblique band

Movement of the elbow joint and the associated muscles

Flexion (Brachialis muscle, Biceps brachii muscle, Brachioradialis muscle)

Extension (Triceps brachii muscles, Anconeus muscle)

Blood supply of the elbow joint

Anastomosis arteries (no specific arteries)

Nerve supply of the elbow joint

musculocutaneous nerve

radial nerve

ulnar nerve

Subcutaneous (superficial fascia) vs Deep fascia

Subcutaneous fascia - fat containing

Deep fascia -wraps the muscle and compartmentalization