Antomy Arm

What are the four major bones?

• Humerus shaft

• Distal humerus

• Proximal radius

• Proximal ulna

What are the Compartments of the Arm

• anterior ( flexor) compartment

• posterior (extensor) compartment

What structures separate the anterior and posterior arm compartments?

• Lateral intermuscular septum

• Medial intermuscular septum

• Deep fascia

The humerus shaft has what shape

Triangular, then flattened distally

What are the important landmarks of the humerus shaft?

• Lateral supraepicondylar ridge ( lateral supracondylar ridge)

• Medial supraepicondylar ridge ( medial supracondylar ridge)

• Radial groove

What structures make up the distal humerus?

1 Condyle

• Capitulum

• Trochlea

2 Epicondyles

• Lateral epicondyle

• Medial epicondyle

3 Fossae

• Radial fossa

• Coronoid fossa

• Olecranon fossa

Proximal Radius (forearm)

• Head

• Neck

• Radial tuberosity

What structures make up the proximal ulna?

• Olecranon

• Coronoid process

• Trochlear notch

• Radial notch ( Proximal radio -ulnar joint)

• supinator crest

• ulnar tuberosity

Which structure enters the olecranon fossa during elbow extension?

Olecranon

Which structure enters the coronoid fossa during elbow flexion?

Coronoid process

Which structure enters the radial fossa during elbow flexion?

Radial head

what is Flexor (Anterior) muscles anterior compartment 3 muscles?

1) Biceps brachii

2) Brachialis

3) Coracobrachialis

Is the biceps brachii uniarticular or biarticular?

Biarticular

2 heads

What are the origins of the biceps brachii

• Short head → Coracoid process of scapula

• Long head → Supraglenoid tubercle of scapula

Long head goes through what?

Interbtubucular sulcus

b/c bicep tendon long head goes through this groove so thats why its called biceptial groove

What are the insertions of the biceps brachii?

• Radial tuberosity of radius

• deep fascia for anterior compartment via Bicipital aponeurosis

What nerve innervates the biceps brachii?

Musculocutaneous nerve (C5-C7)

What are the actions of the biceps brachii?

• Flexes shoulder

• Flexes elbow

• Supinates forearm (especially when elbow is flexed and forearm is pronated)

Which muscle lies deep to the biceps brachii?

Brachialis

What is the origin of the brachialis?

Anterior surface of humerus

What is the insertion of the brachialis?

Ulnar tuberosity of ulna

What nerve innervates the brachialis?

Musculocutaneous nerve (C5-C7)

What is the action of the brachialis?

flex elbow

Where is the coracobrachialis located?

Medial side of the humerus

What is the origin of the coracobrachialis?

Coracoid process of scapula

What is the insertion of the coracobrachialis?

Midshaft of humerus (medial side)

What nerve innervates the coracobrachialis?

Musculocutaneous nerve (C5-C7)

What is the action of the coracobrachialis?

flex shoulder

Which muscle is found in the posterior compartment of the arm?

Triceps brachii

How many heads does the triceps brachii have?

Three

• Long head

• Lateral head

• Medial head

Which head of the triceps is biarticular?

Long head

What are the origins of the triceps brachii?

• Long head → Infraglenoid tubercle of scapula

• Lateral head → Humerus shaft superior to radial groove

• Medial head → Humerus shaft inferior to radial groove

What is the insertion of the triceps brachii?

Olecranon of ulna

What nerve innervates the triceps brachii?

Radial nerve (C6-C8; C5 and T1 may contribute)

What are the actions of the triceps brachii?

Long head:

• Extends shoulder

• Adducts shoulder

All heads:

• Extend elbow

What are the four major nerves of the arm?

Anterior

• Musculocutaneous

• Median

• Ulnar

Posterior

• Radial

musculocutaneous nerve originates from what cord?

Lateral cord

Which muscle does the musculocutaneous nerve passes?

Coracobrachialis

What muscles does the musculocutaneous nerve passes between?

• Biceps brachii

• Brachialis

Innervates all muscles in anterior compartment

the median nerve orginates from what 2 cords?

Lateral cord + medial cord

Goes along the brachial artery

Does the median nerve have major branches in the arm?

No major branches

ulnar nerve orginates from what cord?

Medial Cord

goes along the brachial artery more medially

What landmark is associated with the ulnar nerve?

Wraps around medial epicondyle ("funny bone")

What syndrome is associated with ulnar nerve compression?

Cubital tunnel syndrome

Does the ulnar nerve have major branches in the arm?

No major branches same as Median nerve

Radial nerve orginates from which cord?

Posterior cord

the radial nerve runs with what artery in the radial groove?

Profunda brachii artery

Radial nerve innervates what?

triceps brachii

enters arm posteriorly

The brachial artery is a continuation of what artery?

Axillary artery

What are the two arteries of the arm?

• Brachial artery

• Profunda brachii artery

the brachial artery has what boarder?

Inferior border of teres major → elbow joint

What is the major artery in the arm, in the anterior compartment, and is palpable?

Brachial artery

which arteries does the brachial artery divide into?

• Radial artery

• Ulnar artery

What is the largest branch of the brachial artery?

Profunda brachii artery

What compartment does the profunda brachii artery supply?

Posterior compartment of arm

Profunda brachii artery runs with what nerve in the radial groove?

Radial nerve

Profunda brachii artery helps what?

Anastomosis

2 main spaces of posterior Scapula Region

Quadrangular space

Triangular interval

What region is the Quadrangular space in?

Posterior scapular region

What passes through the quadrangular space?

• Axillary nerve ( teres minor and deltiod innverated by axillary nerve)

• Posterior circumflex humeral artery

What region is the Triangular interval in?

posterior region

What passes through the triangular interval?

• Radial nerve

• Profunda brachii artery