Upper Extremity: Arm and Cubital Fossa Flashcards
Arm
- Region between shoulder to elbow joint
- 2 compartments separated by intermuscular septa
Anterior Compartment
- Flexors of the elbow (forearm) and shoulder (arm)
- 1 supinator
- Innervated primarily by musculocutaneous nerve
- Muscles
Anterior Compartment Muscles
- Biceps brachii
- Coracobrachialis
- Brachialis
Posterior Compartment
- Extensors of the elbow
- Innervated by radial nerve
- Muscles
Posterior Compartment Muscles
- Triceps brachii
- Aconeus
Biceps Brachii
- 3 joint muscle
- 2 heads, short and long
- No attachment to the humerus
Biceps Brachii Proximal Attachment (Origin)
- Short head: tip of coracoid process (scapula)
- Long head: supraglenoid tubercle (scapula)
Biceps Brachii Distal Attachment (Insertion)
- Tuberosity of radius
- Fascia of medial forearm (via bicipital aponeurosis)
Biceps Brachii Innervation
- Musculocutaneous
Biceps Brachii Function
- Forearm (elbow) flexion
- Arm (shoulder) flexion
- Supination
Brachialis Proximal Attachment (Origin)
- Distal half of anterior humerus
Brachialis Distal attachment (Insertion)
- Coronoid process and ulnar tuberosity
Brachialis Innervation
- Musculocutaneous nerve
- Radial nerve
Brachialis Function
- Flexes forearm (not affected by elbow position)
Coracobrachialis Proximal Attachment (Origin)
- Coracoid process
Coracobrachialis Distal Attachment (Insertion)
- Middle 1/3 of medial humerus
Coracobrachialis Innervation
- Musculocutaneous nerve
- Pierces the muscle belly
Coracobrachialis Function
- Flexes and adducts glenohumeral joint
Triceps Brachii
- 3 heads: long, lateral, medial
Long Head (Triceps Brachii) Proximal Attachment (Origin)
- Infraglenoid tubercle of scapula
Lateral Head (Triceps Brachii) Proximal Attachment (Origin)
- Posterior humerus, superior to radial groove
Medial Head (Triceps Brachii) Proximal Attachment (Origin)
- Posterior humerus, inferior to radial groove
Triceps Brachii (Long, Lateral, and Medial Head) Distal Attachment (Insertion)
- Olecranon
Triceps Brachii (Long, Lateral, and Medial Head) Innervation
- Radial nerve
Triceps Brachii (Long, Lateral, and Medial Head) Function
- Extension of the forearm (elbow)
- Long head can also extend and adduct shoulder joint
Brachial Artery Location
- Continuation of axillary artery
- Begins at inferior edge of teres major
- Descends medial to humerus between biceps and tricep muscles
- Medial to median nerve, orientation switches by the cubital fossa
- Ends at its division into radial and ulnar arteries (cubital fossa)
Brachial Artery Supplies
- Arm muscles
- Elbow
- Humerus
Brachial Artery Branches
- Profunda brachii
- Muscular branches
- Humeral nutrient artery
- Superior ulnar collateral
- Inferior ulnar collateral
Profunda Brachii (Deep Artery of the Arm)
- Middle collateral branch
- Radial collateral branch
- Allows for collateral circulation to elbow
Humeral Nutrient Artery
- Enters humerus through nutrient canal
- Supplies bone
Superior Ulnar Collateral
- Travels with ulnar nerve
- Posterior to medial epicondyle
Inferior Ulnar Collateral
- Passes anterior to medial epicondyle
Brachial Artery at Midhumeral Level
- Measure blood pressure
- Brachial pulse
- Compressed to control bleeding
Musculocutaneous Nerve
- Pierces coracobrachialis
- Supplies anterior compartment and elbow joint
- Becomes lateral cutaneous nerve of forearm
Radial Nerve
- Passes through triangular hiatus to enter posterior arm
(Supplies posterior compartment and elbow joint) - Pierces lateral intermuscular septum to enter anterior compartment
(Located between brachioradialis and brachialis) - Passes anterior to lateral epicondyle
(Divides into deep and superficial branches)
Median Nerve
- Lateral to brachial artery in the upper arm (becomes medial)
- No arm branches, except to elbow joint
Ulnar Nerve
- Travels medial to brachial artery
- Pierces medial intermuscular septum
- Passes posterior to medial epicondyle
- No arm branches, except to elbow joint
Cubital Fossa
- Depression in the anterior elbow region
- Injury to this area can damage brachial artery and/or median nerve
Cubital Fossa Boundaries
- Superior: line through medial and lateral epicondyles
- Medial: pronator teres
- Lateral: brachioradialis
- Floor: brachialis and supinator muscles
- Roof: fascia
Cubital Fossa Content
- Median nerve
- Brachial artery/vein
- Biceps brachii tendon
- Radial and ulnar arteries /veins
- Some sources say radial nerve
Medial to Lateral (Cubital Fossa)
- Median nerve
- Brachial artery/veins
- Biceps brachii tendon
Veinpuncture (Cubital Fossa)
- Veins in the cubital fossa are typically used, especially median cubital vein
- Superficial and accessible
- Poorly performed venipuncture can damage cubital fossa content
Bicipital Aponeurosis
- Provides some protection during veinpuncture in cubital fossa
Mid-Humeral Shaft Fractures
- Can damage deep artery of the arm and/or radial nerve
- Can cause a wrist drop
- Triceps (elbow extension) could be weak but should be present
Supracondylar (Supraepicondylar) Fracture
- Most common elbow fracture in pediatrics
- Distal fragment can be pulled superiorly – limb shortening
- Fragments can damage surrounding neurovasculature (median nerve, brachial artery)
Fracture at Surgical Neck of Humerus Potential Damage
- Axillary nerve
- Posterior circumflex humeral artery
Fracture of Medial Epicondyle of Humerus Potential Damage
- Ulnar nerve
- Ulnar collateral artery
Mid-Shaft of Humerus Fracture Potential Damage
- Radial nerve
- Profunda brachii artery
Supracondylar Humerus Fracture Potential Damage
- Brachial artery
- Median nerve
Bicep Reflex
- Deep tendon reflex
- Upper limb is relaxed, partially extended and pronated
- Tap finger over biceps tendon
- Causes biceps contraction, elbow jerk-like flexion
Bicep Reflex Evaluates
- Musculocutaneous nerve
- C5,6 spinal cord segments
Tricep Reflex Evaluates
- Radial nerve
- C6,C7 spinal cord levels
