Download Lesson 4 - Maryville University

Lesson 4
Brachium
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
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
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)
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
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
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)
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
Coracobrachialis
• ORIGIN
apex of coracoid process of
scapula
• INSERTION
medial surface of middle of shaft
of humerus, opposite deltoid
tuberosity
• ACTION
flexes and adducts the shoulder
• NERVE
musculocutaneous - C6, 7
BICEPS BRACHII
• ORIGIN
short head: apex of coracoid process of scapula
long head: supraglenoid tubercle of scapula (just
above the fossa)
• INSERTION
short, long heads: tuberosity of radius, and
aponeurosis of biceps brachii (laterous fibrosus)
• ACTION
Flexes 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
forearm
With insertion fixed: flexes the elbow joint moving
the humerus toward the forearm as in pull-up or
chinning exercises
• NERVE
musculocutaneous nerve - C5, C6
BRACHIALIS
• ORIGIN
humerus - distal 1/2, anterior surface of
humerus, and medial and lateral
intermuscular septa
• INSERTION
ulna - coronoid process, ulnar tuberosity
• ACTION
With origin fixed: flexes the elbow joint
moving the forearm toward the humerus
With insertion fixed: flexes the elbow joint
moving the humerus toward the forearm
as in pull-up or chinning exercises.
• NERVE
musculocutaneous nerve + a small
branch of radial nerve - C5, C6
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
• INSERTION
ulna - posterior surface olecranon process;
antebrachial fascia
• ACTION
extends the elbow joint; long head also
assist in abduction and extension of the
shoulder joint
• NERVE
radial nerve - C6, C7, C8, T1
ANCONEUS
• ORIGIN
humerus - lateral epicondyle; on posterior
surface
• INSERTION
ulna - olecranon process, on lateral side; &
proximal 1/4 of ulna, posterior surface
• ACTION
extends the elbow joint, and may stabilize
the ulna during pronation and supination
• NERVE
radial nerve - C7, C8, T1