Upper limb gross anatomy 2: Axilla, arm and elbow Flashcards
What is the thin sheet of fibrous tissue the connects the radius and ulna called?
Intraosseous membrane
What are the articular surfaces of the bones involved in this joint?
The spool-shaped trochlea and spheroidal capitulum of the humerus articulate with the trochlea notch of the ulna and the slightly concave superior aspect of the head of the radius.
There are therefore humero-ulnar and humero-radial articulations.
What structure prevents hyperextension of the elbow joint?
Olecranon fossa
What structure lies in the deltopectoral groove? Describe its course in the upper limb.
Cephalic vein.
Located in the superficial fascia along the anterolateral surface of biceps brachii. Superiorly passes between the deltoid and pectoralis major muscles (deltopectoral groove) and through the deltopectoral triangle where it empties into the axillary vein.
What is the proximal attachment of pectoralis major?
Clavicular head: anterior surface of medial half of clavicle.
Sternocostal head: anterior surface of sternum, superior 6 costal cartilages and aponeurosis of external oblique.
What is the distal attachment of pectoralis major?
Lateral lip of intertubercular sulcus of humerus.
What are the actions of pectoralis major?
- Adducts and medially rotates humerus.
- Draws scapula anteriorly and inferiorly.
- Acting alone clavicular head flexes humerus and sternocostal head extends it from the flexed position.
What is the nerve supply to pectoralis major?
Lateral and medial pectoral nerves, clavicular head (C5-6) and sternocostal head (C7-8 & T1).
What is the proximal attachment of pectoralis minor?
3rd to 5th ribs near their costal cartilages
What is the distal attachement for pectoralis minor?
Medial border and superior surface of coracoid process of scapula.
What are the actions of pectoralis minor?
Stabilises scapula by drawing it inferiorly and anteriorly against the thoracic wall.
What is the nerve supply to pectoralis minor?
Medial pectoral nerve
What is the proximal attachment of serratus anterior?
External surfaces of lateral parts of the 1st-8th ribs.
What is the distal attachment of serratus anterior?
Anterior surface of medial border of scapula.
What are the actions of serratus anterior?
Protracts scapula and holds it against thoracic wall. Rotates scapula.
What is the nerve supply to serratus anterior?
Long thoracic nerve (C5-7).
What is the proximal attachment of subclavius?
Junction of 1st rib and its costal cartilage.
What is the distal attachment of subclavius?
Inferior surface of middle third of clavicle.
What are the actions of subclavius?
Anchors and depresses the clavicle.
What is the nerve supply to subclavius?
Nerve to subclavius (C5-6).
What are the possible consequences of long thoracic nerve injury?
Paralysis of serratus anterior - medial border of the scapula moves superiorly and posteriorly away from the thoracic wall - winged scapula (when arm is raised).
Upper limb may not may not be able to be abducted above above the horizontal because serratus anterior cannot rotate the glenoid.
What structures form the anterior border of the axilla?
Pectoralis major and minor, pectoral and clavicopectoral fascia.
What structures form the posterior border of the axilla?
Superiorly by scapula and subscapularis and inferiorly by latissimus dorsi and serratus anterior.
What structures form the medial border of the axilla?
Thoracic wall (1st-4th ribs and intercostal muscles) and overlying serratus anterior.
What structures from the lateral border of the axilla?
Narrow, bony wall formed by intertubular sulcus in the humerus.
What terminal branches are formed from the posterior cord of the brachial plexus?
Axillary and radial
What is the root value of the musculocutaneous nerve?
C5,6&7 -> superior trunk -> anterior division -> lateral cord -> musculocutaneous
What is innervated by the musculocutaneous nerve?
Muscles of anterior compartment of arm (coracobrachialis, biceps brachii and brachialis. Skin of lateral aspect of forearm.
What is the root value of the axillary nerve?
C5&6 -> superior trunk -> posterior division -> posterior cord -> axillary nerve
What is innervated by the axillary nerve?
Glenohumeral joint, teres minor and deltoid muscles. Skin of superolateral arm (over inferior part of deltoid).
What is the root value of the median nerve?
C7&6 (lateral root), C8&T1 (medial root) -> middle trunk -> posterior division -> posterior cord -> median nerve
What is innervated by the median nerve?
Anterior compartment of the forearm (except for flexor carpi ulnaris and ulnar half of flexor digitorum profundus) five intrinsic muscles in thenar half of palm and palmar skin.
What is the root value of the radial nerve?
C5&6 anterior rami -> superior trunk -> posterior division -> posterior cord -> radial nerve
What structures are innervated by the radial nerve?
All muscles of posterior compartments of arm and forearm; skin of posterior and inferolateral arm, posterior forearm and dorsum and of hand lateral to axial line of digit 4.
What is the root value of the ulnar nerve?
C8&T1 -> inferior trunk -> anterior division -> medial cord -> ulnar nerve
What structures are innervated by the ulnar nerve?
Flexor carpi ulnaris and ulnar half of flexor digitorum profundus; most intrinsic muscles of hand, skin of hand medial to axial line of digit 4.
What landmarks are used to define the beginning and end of the axillary artery?
Lateral border of 1st rib as a continuation of the subclavian artery, ends at inferior border of teres major.
From where does the basilic vein originate?
From ulnar side of dorsal venous network.
Where does the basilic vein drain?
Into axillary vein.
From where does the cephalic originate?
Radial dorsal venous network of the hand.
Where does the cephalic vein drain to?
Axillary vein
What is the median cubital vein?
Connecting vein between basilic and cephalic.
What is the function of the venae commitantes?
Pair of veins (or more) that closely accompany an artery in such a manner that pulsations of the artery aid venous return.
What is the common nerve supply to biceps brachii, brachialis and coracobrachialis
Musculocutaneous nerve
What artery supplies the anterior compartment of the arm?
Brachial
Describe the course of the brachial of the artery.
Begins as continuation of axillary artery in lower border of teres major. In proximal arm brachial artery lies on medial side; in distal arm it moves laterally midway between lateral epicondyl and and medial epicondyl of humerus. Crosses anterior to elbow where it was medial to tendon biceps brachii.
What is the proximal attachment of biceps brachii?
Short head: coracoid process of scapula.
Long head: supraglenoid tubercle of scapula
What is the distal attachment of biceps brachii?
Radial tuberosity
What are the actions of biceps brachii?
Primary supinator of forearm.
Flexor of arm at elbow (only when supinated) and shoulder.
What is the proximal attachment of brachialis?
Medial and lateral surfaces of humeral shaft.
What is the distal attachment of brachialis?
Tuberosity of ulna (just distal to elbow joint).
What are the actions of brachialis?
Main flexor at the elbow.
What is the proximal attachment of coracobrachialis?
Coracoid process of scapula.
What is the distal attachement of coracobracialis?
Medial side of humeral shaft at level of deltoid muscle.
What are the actions of coracobracialis?
Flexor of arm at shoulder.
Describe the attachments of triceps brachii.
Long head originates from infraglenoid tubercle.
Lateral head originates from humerus SUPERIOR to radial groove.
Medial head originates from humerus INFERIOR to radial groove.
Combine into one muscle -> converge into one tendon which attaches to olecranon of ulna.
What is the nerve supply to triceps?
Radial nerve C6-8
Which two structures run in the spiral groove?
Radial nerve, profunda brachii artery.
What artery supplies the the posterior compartment? Describe its course.
Profunda brachii artery -> enters posterior compartment with radial nerve and together they pass through the spiral groove (check this).
