GA8-10-06
Terms
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- Superior Lateral Cutaneous Nerve
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-branch of axillary nerve
-supplied skin on lateral aspect of arm - Inferior Lateral Cutaneous Nerve
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-branch of radial nerve
-supplies skin on lateral aspect of arm - Medial Cutaneous Nerve
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-direct branch of medial cord of brachial plexus
-supplies skin on medial aspect of arm - Intercostobrachial Nerve
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-branch of T2, lateral cutaneous branch of T2
-runs over to supply some of the skin on the medial side of the arm - Posterior Cutaneous Nerve of Arm
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-supplies a strip of skin down the middle of the posterior aspect of the arm
-a branch of the radial nerve - Cephalic vein
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-one of hte two major superficial veins in arm
-begins in back of wrist in from the dorsal venous arch at posterior aspect of wrist
-begins on radial/thumb side and ascends throughout length of limb
-superficial all the way up to delto-pectoral triange where dives deep to enter axillary vein - Basilic Vein
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-on medial/ulnar side
-begins at medial end of dorsal venous arch and ascends on medial aspect of upper limb
-becomes deep at mid humeral level where it pierces the deep fascia
-unites with deep veins at lower border of teres major - Median Cubital Vein
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-connects cephalic and basilic veins
-commonly used for venapuncture - Where do the superficial lymph vessels accompanying the cephalic vein first drain?
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-deltopectoral group of lymph nodes
-terminate in apical root of axillary nodes - Where do superficial lymph vessels accompanying the basilic vein first drain?
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-cubital nodes
-then ascend to lateral group/humeral axillary nodes - Deep Lymphatic Vessels
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-accompany major deep veins of upper limb
-ultimately end in lateral group of axillary nodes - Where does all the lymph from the upper limb ultimately drain?
- -from axillary nodes into subclavian lymph trunk
- Medial and Lateral Intermuscular septa
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-septa composed of deep fascia that divide the arm into two compartments (anterior and posterior)
-attached along lateral and medial supraepicondylar ridges - What nerve innervates the muscles in the anterior compartment of the arm (upper)?
- Musculocutaneous
- What nerves innervate the anterior aspect of the forearm?
- Median and ulnar
- What nerve innervates the posterior compartment of the arm?
- Radial nerve
- What nerve innervates the posterior compartment of the forearm?
- Radial nerve
- Supraglenoid tubercle
- -origin of long head of biceps
- Infraglenoid tubercle
- -origin of long head of triceps
- What two structures do you find in the radial groove of the humerus?
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-Radial nerve
-deep artery of the arm (profunda brachii_ - Capitulum
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-rounded prominence at distal head of hmerus
-"little head"
-articulates with superior surface of head of radius - Trochlea
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-spool shaped smooth articular area
-articulates with trochlear notch on ulna - What muscle inserts on the tuberosity of the radius?
- -biceps
- Coronoid process
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-located at proximal end of ulna
-insertion point of brachialis muscle - Tuberosity of ulna
- -insertion point of brachialis muscle
- Olecranon Process
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-large process on posterior of ulna
-insertion point for triceps and anconeus - What runs in the distinct groove on the posterior side of the medial epicondylar?
- Ulnar nerve
- Muscles of Anterior Compartment of Arm
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1. Coracobrachialis
2. Biceps brachii - Coracobrachialis
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-origin = coracoid process
-insertion = medial aspect of shaft of humerus
-flexes arm at shoulder
-also adducts arm - Biceps brachii
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*Short head
-more medial of hte two
-comes from coracoid process
*Long head
-arises from supraglenoid tubercle
-runs inside shoulder joint capsule
-common insertion with short head into tuberosity of radius - Bicipital Aponeurosis
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-fibrous extension of biceps tendon
-affords some protection to median nerve and brachial artery which run rather superficially in cubital fossa
-"Grace of God Tendon" - Functions of Biceps
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-short head helps flex shoulder joint
-flexes forearm at elbow joint
-supinates forearm and hand at proximal radioulnar joint - Brachialis Muscle
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-origin = anterior surface of distal half of humerus
-insertion = coronoid process of tuberosity of ulna
-most powerful flexor of forearm at elbow joint and this is all it does - What nerve innervates ALL muscles in the anterior compartment of the arm?
- Musculocutaneous
- What muscle does the musculocutaneous nerve pierce to give off branches to the brachialis and biceps?
- Coracobrachialis
- Muscles of Posterior Compartment of Arm
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1. Triceps brachii
2. Anconeus - Triceps Brachii
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1. Long Head
-comes from infraglenoid tubercle of scapula
-unites with lateral head to form tendon that inserts into olecranon process
-strong extensor of forearm
2. Lateral Head
-arises from posterial surface of humerus just above radial groove
-strong extensor of forearm
-joins with long head to insert on olecranon process
3. Medial Head
-hidden
-arises from posterior aspect of humerus below radial groove and inserts w/ other heads - Anconeus
- -triangular shaped muscle that arises from the lateral epicondyle and inserts into the lateral side of the olecranon and upper 1/4 of ulna
- What nerve supplies the posterior compartment of the arm?
- Radial nerve
- Where would you place your stethoscope to hear a brachial pulse?
- cubital fossa
- Three major branches of brachial artery
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1. deep artery of arm (profunda brachii)
2.inferior ulnar collateral
3.superior ulnar collateral - The deep artery of the arm terminates by dividing into which two arteries?
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1. radial collateral (passes in front of lateral epicondyle)
2. middle collateral (passes behind lateral epicondyle) - What two branches does the brachial artery give off on the medial side of the arm?
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1. superior ulnar collateral
2. inferior ulnar collateral - vena comitantes
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-refers to the veins that accompany deep arteries in the limb
-usually there is a pair of veins, one on either side of the artery, with little cross channels that unite the veins - Where do the brachial and basilic veins unite to form the axillary vein?
- lower border of teres major
- What nerve could be damaged if you fracture the surgical neck of the humerus?
- Axillary
- What nerve could be damaged if you fracture the humerus on the shaft (near radial groove)?
- Radial
- What nerve could be damaged if you fracture the medial epicondyle?
- Ulnar
- What physical effects would be seen if the axillary nerve had been damaged?
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-Loss of use of teres minor and deltiod muscles
-weakness in abduction of arm at shoulder because deltoid is paralyzed
-some upper lateral cutaneous loss as well - What physical effects would you see if the radial nerve had been damaged?
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-weakness of extension but not complete extension failure (medial head of triceps and anconeus are innervated by radial nerve but lateral and long heads of triceps are not)
-all extensor muscles in forearm would be paralyzed
-wrist drop - What physical effects would you see if the ulnar nerve was damaged?
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-cutaneous loss in hand
-paralysis of most intrinsic muscles of hand as well as interossei and 3rd and 4th lunbricals--> CLAW HAND - What type of fracture can lead to damage of median nerve?
- supracondylar fracture
- What physical effects would you see if the median nerve was damaged?
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-major loss of flexion of wrist (median nerve innervates most muscles in the flexor compartment of forearm)
-loss of ability to oppose thumb (median nerve innervates thenar muscles)
-APE HAND
-flattened thenar eminence - Supraepicondylar fractures
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-can involve brachial artery and nerves
-in some cases the brachial artery will be impinged by humerus and cause the artery to spasm - Volkmann's Ischemic Contracture
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-when dead muscle tissue becomes fibrous and leads to a permanent shortening of the muscle so hand and fingers are all drawn into flexion
-most common cause of this arterial spasm is application of a cast that is too tight, not the actual fracture - How long before the blood supply to the forearm is compromised and muscles and nerves necrose?
- about 6 hours
- Detachment of biceps tendon long head from supraglenoid tubercle
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-common in people who do a lot of overhead movement (ex. baseball pitchers)
-muscle belly detaches and forms a large bulge in front of the arm
-commonly seen in older people - Boundaries of Cubital Fossa
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1. Lateral Side = brachioradialis
2. Medially = pronator teres
3. base of triangle = imaginary line through epicondyles of humerus
4. Roof = skin and superficial fascia
5. Floor = brachialis and supinator - Contents of Cubital Fossa
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1. Tendon of biceps which is on its way to insert on radial tuberosity
2. brachial artery which is terminating into radial and ulnar branches
3. median nerve (median to artery)
DEEPER
4. radial nerve - What two structures does the median nerve run between as it leaves the cubital fossa?
- -the two heads of pronator teres
- What problems can arise during venipuncture of cephalic or basilic veins?
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-some cutaneous nerves lie nearby and you could hit them leading to pain or parasthesia in skin of forearm --> Lateral cutaneous nerve of forearm, medial cutaneous nerve of forearm
-pushing too deeply can go through bicipital aponeurosis and hit brachial artery or median nerve - What could happen if you injected a drug into an artery instead of a vein?
- -it could spasm
- Superficial Ulnar Artery
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-unusual anomoly (~3% pop.)
-ulnar artery passes superficial to flexor muscle and can be mistaken for a vein and accidentally injected - What type of joint is the elbow?
- -hinge type synovial
- Hinge Joints
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-allow flexion and extension to occur around transverse axis (lateral to medial_
-one surface is convex and other is concave
-fibrous capsule is weak anteriorly and posteriorly to allow for full extension and flexion
-want strength to be medially and laterally - Radioulnar Joint
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-articulation between head of radius and radial notch of ulna
-proximal and distal joint
-responsible for pronation and supination
-enclosed in same fibrous joint capsule as elbow joint - Collateral Ligaments (Radial and Ulnar)
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-thickening of fibrous ligaments medially and laterally
-strengthens elbow joint medially and laterally
-Radial and Ulnar Collateral - Annular Ligament
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-"ring like"
-surrounds head of radius and attaches to the margins of radial notch of ulna
-holds the head of the radius in place in ulnar notch of radius - Radial Collateral Ligaments
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-run from lateral epicondyle to annular ligament of radius
-strengthens joint to lateral side - Ulnar Collateral Ligament
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-runs from medial epicondyle and attaches to coronoid process and olecranon
-3 parts
1. Anterior Cord-Like Band (strong)
2. Posterior Fan-Like Band (weak)
3. Oblique Band - Synovial Membrane of elbow joint
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-delicate vascular membrane that secretes synovial fluid
-lines fibrous capsule and is reflected off fibrous capsule onto non-articular parts of humerus, ulna, and radius
-stops short of articular cartilage which covers capitulum and trochlear - Muscles that produce major flexion of forearm
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1. brachialis
2. biceps brachii
3. brachioradialis (forearm) - Extensors of Arm
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1. triceps brachii
2. anconeus - supination of forearm
- both bones parallel and palm facing anteriorly
- pronation of forearm
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-radius rotates around its own long axis and that pivoting rotational movement is occurring at proximal and distal radioulnar joints
-forearm rotates and makes palm face posteriorly
-radius lies obliquely across ulna - Muscles that cause pronation and supination of forearm
- biceps
- Student's Elbow
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-inflammation of subcutaneous olecranon bursa
-pressure causes subcutaneous olecranon bursitis - Avulsion of medial epicondyle
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-occurs often in children
-forearm is forcefully abducted (like in a fall)
-risk of damage to ulnar nerve - Dislocation of elbow joint
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-often posteriorly
-distal end of humerus driven through weak anterior part of fibrous capsule
-often damage to ulnar collateral ligament