Arm and Cubital Fossa Anatomy

50 Question-and-Answer flashcards covering the musculature, innervation, arterial supply, venous drainage, and anatomy of the arm and cubital fossa based on Dr. Karen Samonds' lecture.

What is the anatomical extent of the arm?

The arm extends from the shoulder to the elbow.

How is the musculature of the arm divided?

It is divided into an anterior (flexor) group and a posterior (extensor) group.

At which joint do both the anterior and posterior muscle groups of the arm primarily act?

At the elbow joint.

Besides the elbow joint, what other joint do some arm muscles act upon?

The glenohumeral (shoulder) joint.

What shared characteristics do muscles within a single compartment of the arm generally possess?

They share a developmental history, have a similar function, and share a pattern of innervation.

How many flexor muscles are located in the anterior compartment of the arm?

Three flexor muscles.

What are the three muscles located in the anterior compartment of the arm?

Biceps brachii, brachialis, and coracobrachialis.

Which nerve innervates all three flexor muscles in the anterior compartment of the arm?

The musculocutaneous nerve.

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

Triceps brachii.

Which nerve innervates the triceps brachii muscle?

The radial nerve.

Which muscle is described as essentially a distally placed extension of the triceps brachii?

The anconeus muscle.

What are the functional actions of the coracobrachialis muscle?

Shoulder rotation, flexion, and adduction.

What are the two heads of the biceps brachii muscle?

The long head and the short head.

What actions are performed by the biceps brachii muscle?

Elbow rotation and flexion, shoulder rotation, and supination.

What are the primary actions of the brachialis muscle?

Elbow rotation and flexion.

Does the brachialis muscle participate in forearm supination?

No, it does not perform supination.

How are the ulna and radius positioned relative to each other during supination?

The ulna and radius are parallel (in the anatomical position).

What is the position of the thumb and the relative orientation of the radius and ulna during pronation?

The thumb is medial, and the ulna and radius are crossed.

Where does the biceps brachii insert that enables its supinating action?

It attaches to the radial tuberosity.

Why is the biceps brachii a powerful supinator when the forearm is pronated?

Because its tendon is tucked in during pronation, and the muscle acts to unwind the biceps tendon during flexion.

What are the three heads of the triceps brachii muscle?

The long head, lateral head, and medial head.

What is the primary action of the triceps brachii muscle?

Elbow extension (and elbow rotation).

The brachial artery is a direct continuation of which artery?

The axillary artery.

At what anatomical boundary does the brachial artery begin?

At the inferior border of the teres major muscle.

Where does the brachial artery end?

In the cubital fossa opposite the neck of the radius.

Relative to the bicipital aponeurosis, where does the brachial artery divide into its terminal branches?

Deep to the bicipital aponeurosis.

What are the two terminal branches of the brachial artery?

The radial artery and the ulnar artery.

What are the named branches given off by the brachial artery in the arm?

Deep artery of arm (profunda brachii), superior ulnar collateral artery, and inferior ulnar collateral artery.

What are the two major superficial veins located in the arm?

The cephalic vein and the basilic vein.

What are the deep veins of the arm named?

The brachial veins.

What is the cubital fossa?

A triangular hollow area on the anterior aspect of the elbow.

Who presented this lecture on the arm and cubital fossa?

Dr. Karen Samonds.

Which branch of the profunda brachii artery descends toward the lateral aspect of the elbow joint?

The radial collateral branch.

Which superficial vein connects the cephalic vein to the basilic vein across the cubital fossa?

The median cubital vein.

Which nerve travels alongside the basilic vein in the forearm?

The medial cutaneous nerve of forearm.

Which nerve runs in proximity to the cephalic vein in the forearm?

The lateral cutaneous nerve of forearm.

Which protective fascial structure overlies the brachial artery and median nerve in the cubital fossa?

The bicipital aponeurosis.

Which nerve accompanies the profunda brachii artery around the humerus?

The radial nerve.

From which cord of the brachial plexus does the musculocutaneous nerve originate?

The lateral cord of the brachial plexus.

Which spinal nerve roots supply the musculocutaneous nerve according to the brachial plexus diagram?

$C5$, $C6$, and $C7$ spinal nerves.

From which cord of the brachial plexus does the ulnar nerve originate?

The medial cord of the brachial plexus.

Which anterior compartment muscle lies directly on the lower humerus and acts as a pure elbow flexor?

The brachialis muscle.

Which head of the triceps brachii originates from the scapula and crosses the shoulder joint?

The long head of triceps brachii.

In this cross-sectional diagram of the arm, which nerve innervates the top (orange) anterior compartment and which innervates the bottom (green) posterior compartment?

The musculocutaneous nerve innervates the anterior compartment, and the radial nerve innervates the posterior compartment.

Which muscle of the anterior arm is highlighted in green at the proximal end in this illustration?

Coracobrachialis

In this diagram showing two forearm states, which anatomical position is shown on the left vs. the right?

Supination is depicted on the left (parallel radius and ulna), and pronation is depicted on the right (crossed radius and ulna).

Which muscle on the posterior arm, shown with its long and lateral heads in yellow, is highlighted here?

Triceps brachii

In this superficial anatomical diagram of the cubital fossa, what is the central diagonal vein connecting the cephalic and basilic veins?

The median cubital vein.

In this arterial system diagram of the arm, what major artery branches posteriorly from the brachial artery near teres major?

Profunda brachii artery

Which superficial vein drains the lateral aspect of the forearm and arm?

The cephalic vein.