Flashcards in Upper limb gross anatomy 2: Axilla, arm and elbow Deck (59)
What is the thin sheet of fibrous tissue the connects the radius and ulna called?
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?
What structure lies in the deltopectoral groove? Describe its course in the upper limb.
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