Unit 1: Lecture 13 Flashcards
What three joints make up the elbow complex?
- humeroulnar joint (hinge)
- humeroradial joint (not really a functional joint)
- radioulnar joint (symphasis)
How many degrees of flexion/extension should the elbow have, in a normal person?
Flexion: ~145°
Extension: ~170° w/ females, and ~175° with males
What is the “carrying angle?”
When the elbow is in extension, the forearm abducts a slight amount, but when brought back into flexion, it disappears
Articular capsule in the elbow
- loose, and surrounds elbow complex
- thinner posteriorly, thus most dislocations occur posteriorly
- “thick, tough, yet pliable membrane”
Anconeus
- attaches to articular capsule of elbow and ulna
- pulls capsule out of the way of elbow joint upon active extension of elbow
- assist triceps in extending elbow
Collateral ligaments
- support elbow complex, and may be observed running along either side
- help to strengthen articular capsule medially and laterally
- ulnar collateral ligament of elbow and radial collateral ligament of elbow
Large muscles of arm acting on elbow:
Flexion: biceps brachii and brachialis
Extension: triceps brachii
Brachioradialis (of forearm) also helps with extension
Borders of cubital fossa
Proximal: line joining the epicondyles of humerus
Lateral: brachioradialis
Medial: pronater teres
Apex: juncture of brachioradialis and printer teres
Floor: supinator and brachialis
Roof: skin and superficial fascia
What is found WITHIN the cubital fossa?
- median cubital vein
- tendon of biceps brachia
- brachial artery
- median nerve
- bicipital aponeurosis
Joints of the forearm
Proximal radioulnar Joint
Distal radioulnar joint
Middle radioulnar joint
Proximal radioulnar joint
- formed by the radial head against the radial notch of the ulna
Ligaments of the proximal radioulnar joint
- Annular ligament: encircles and holds radial head agains ulna. Rotation within annular ligament allows rotation around ulna, which produces pronation/supination
- Oblique cord: flattened fibrous cord that extends from lateral border of the ulnar tuberosity to the radial shaft distal to the radial tuberosity. Holds and supports proximal radioulnar joint. TAUGHT/SUPINATION – RELAXED/PRONATION
Distal radioulnar joint
- held together only by an articular capsule that has both anterior/posterior thickenings
- articular capsule is chief uniting structure of DRJ, though pronator quadratus also important in stabilizing during supination
Triangular fibrocartilage
Articular disc contained in distal radioulnar joint which is attached to the styloid process of ulna, and helps to protect the articular surface during movement
Middle radioulnar joint
- supported by interosseus membrane, which attaches parallel shafts of ulna and radius
- Interosseous membrane also serves as an attachment site for some of the deeper muscles of the forearm
Anterior flexor compartment of arm - musculocutaneous nerve
- Biceps brachii
- Brachialis
- Coracobrachialis
Transverse Humeral Ligament
Bridges bicipital groove, securing long head of biceps brachii
Extensor compartment of arm - radial nerve
- Triceps brachii (long, lateral, medial)
Cutaneous nerves branching from Radial Nerve
- Lower lateral Brachial cutaneous nerve
- Posterior brachial cutaneous nerve
Cutaneous nerves branching from Medial Cord
Medial brachial cutaneous nerve
Cutaneous nerves branching from Axillary Nerve
Superior lateral Brachial cutaneous nerve
Cutaneous nerves branching from T2
Intercostobrachial cutaneous nerve
Branches of Brachial Artery
- Muscular branches (supply flexors of arm)
- Profunda brachii (supply extensors of arm)
From where does the brachial plexus initially emerge from muscle?
between the anterior and median scalene muscles. So too does the subclavian artery & subclavian vein (passing anterior to artery)
