Brachium

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Lesson 4

• Brachium

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Brachium - arm

• A. Bony landmarks
• 1. humerus
• a. lateral epicondyle - radial side
• b. medial epicondyle - ulnar side
• 2. ulna
• a. olecranon process elbow
• b. styloid process of ulna - dorsomedial point of
  wrist
• 3. radius
• a. styloid process of radius - lateral point of
  wrist
• 4. Interosseous membrane fibrous connective
  membrane, between radius and ulna

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Cutaneous nerves

• (A)1. Medial brachial cutaneous nerve middle of
  arm - medial side - to skin over olecranon
• (A) 2. Medial antebrachial cutaneous nerve
  appears just inferior to medial brachial nerve on
  medial arm, splits
• a. anterior branch - skin of anteromedial forearm
• b. posterior branch - skin of posteromedial
  forearm
• (A) 3. Lateral antebrachial cutaneous nerve
  continuation of musculocutaneous - appears just
  above inside of elbow, near cephalic vein- to
  skin of lateral anterolateral forearm- also
  has anterior posterior branches
• (P) 4. Superior lateral brachial cutaneous nerve
  - a branch off the axillary nerve- to skin over
  inferior half of deltoid

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Cutaneous nerves

• (P) 5. Posterior brachial cutaneous nerve -
  branches off the radial nerve up in the axilla-
  to skin on dorsal arm inferior to deltoid
• (P) 6. Inferior lateral brachial cutaneous nerve
  superior terminal branch - of radial nerve- a
  small branch 2 inches above lateral epicondyle-
  to skin of lower lateral anterolateral arm
• (P) 7. Posterior antebrachial cutaneous nerve
  inferior terminal branch of radial nerve - large
  - appears just below, posterior to lateral
  epicondyle- to skin on dorsal, lateral forearm
• (P) 8. Superficial radial nerve - lateral
  border, distal forearm, just proximal to wrist-
  from under lateral border of brachioradialis-
  innervates skin on lateral dorsum of hand, thumb,
  proximal 2/3 of 1st 2-3 fingers(lateral side of
  middle or ring finger)
• (A) 9. Posterior cutaneous branch of the ulnar
  nerve - medial border, distal forearm, just
  proximal to wrist- innervates skin on medial
  dorsum of hand, last 2 fingers (medial side of
  ring finger)

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Veins

• 1. cephalic vein lateral (radial side) - all the
  way from wrist to deltopectoral groove, to
  axillary vein
• 2. basilic vein medial (ulnar side) - goes deep,
  joins venae comitantes (deep) brachial artery
• 3. median cubital vein crosses over, connects
  cephalic with basilic - common site for drawing
  blood 
• 4. dorsal venous arch back of hand - often used
  for an IV 

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Arteries

• Brachial artery extension/continuation of
  axillary artery, splits into two terminal
  branches (radial and ulnar)
• Branches
• 1. profunda brachii artery ('deep') largest,
  most superior branch follows radial nerve-
  posterior descending branch (splits into radial
  collateral artery and middle collateral artery)
• 2. two ulnar collateral arteries branch off
  brachial below profunda above elbow - superior
  ulnar collateral mid-arm follows ulnar nerve
  post. to medial epicondyle- inferior ulnar
  collateral from 2 in. proximal to elbow,
  anterior to medial epicondyle

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Artery

• 3. radial artery lateral, anterior to elbow,
  crosses anterior to biceps tendon supinator
  muscle overlapped by brachioradialis muscle
• radial recurrent a branch toward lateral
  epicondyle, anastomoses with profunda branch
• 4. ulnar artery medial, anterior to elbow, goes
  deep to pronator teres muscle 
• anterior ulnar recurrent
• posterior ulnar recurrent
• common interosseous artery - divides into
  anterior and posterior interosseous arteries
  (interosseous recurrent artery -- branch off
  posterior interosseous or common interosseous
  artery)  

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Anastomeses

• Collateral elbow circulation - is created by
  anastomoses between recurrents collaterals
• including radial recurrent ulnar recurrents
  (anterior posterior) ulnar collaterals
  (superior inferior), recurrent interosseous and
  descending branch of profunda brachii

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Coracobrachialis

• ORIGINapex of coracoid process of scapula
• INSERTIONmedial surface of middle of shaft of
  humerus, opposite deltoid tuberosity
• ACTIONflexes and adducts the shoulder
• NERVEmusculocutaneous - C6, 7

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BICEPS BRACHII

• ORIGINshort head apex of coracoid process of
  scapulalong head supraglenoid tubercle of
  scapula (just above the fossa)
• INSERTIONshort, long heads tuberosity of
  radius, and aponeurosis of biceps brachii
  (laterous fibrosus)
• ACTIONFlexes the shoulder joint, and the long
  head may assist abduction if the humerus is
  laterally rotated.With the origin fixed flexes
  the elbow, moving forearm towards the humerus and
  supinates forearmWith insertion fixed flexes
  the elbow joint moving the humerus toward the
  forearm as in pull-up or chinning exercises
• NERVEmusculocutaneous nerve - C5, C6

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BRACHIALIS

• ORIGINhumerus - distal 1/2, anterior surface of
  humerus, and medial and lateral intermuscular
  septa
• INSERTIONulna - coronoid process, ulnar
  tuberosity
• ACTIONWith origin fixed flexes the elbow joint
  moving the forearm toward the humerusWith
  insertion fixed flexes the elbow joint moving
  the humerus toward the forearm as in pull-up or
  chinning exercises. 
• NERVEmusculocutaneous nerve a small branch of
  radial nerve - C5, C6

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TRICEPS

• ORIGIN
• long head scapula - infraglenoid tubercle
• lateral head humerus - lateral and posterior
  surfaces of proximal 1/2 of humerus and lateral
  intermuscular septum
• medial head humerus - distal 2/3 of medial and
  posterior surfaces of humerus below the radial
  groove, and from medial intermuscular septum
• INSERTIONulna - posterior surface olecranon
  process antebrachial fascia
• ACTIONextends the elbow joint long head also
  assist  in abduction and extension of the
  shoulder joint
• NERVEradial nerve - C6, C7, C8, T1

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ANCONEUS

• ORIGINhumerus - lateral epicondyle on posterior
  surface
• INSERTIONulna - olecranon process, on lateral
  side proximal 1/4 of ulna, posterior surface
• ACTIONextends the elbow joint, and may stabilize
  the ulna during pronation and supination 
• NERVEradial nerve - C7, C8, T1