213: HUMAN FUNCTIONAL ANATOMY:
PRACTICAL CLASS 3: Arm and Thigh
SUPERFICIAL FASCIA
The superficial fascia is the fatty layer under the skin. It is separated from the muscles by the sheet-like deep
fascia. The superficial fascia contains superficial veins and cutaneous nerves.
Superficial veins
In each limb there is a dorsal venous arch on the back of the hand and foot, two large veins begin at the medial
and lateral ends of these arches and most of the other limb veins drain into these.
One travels all the way to the front of the hip or shoulder (great saphenous and cephalic veins); and the other
joins deep veins at the knee or elbow (small saphenous and basilic veins).
The long vein in the lower limb (great saphenous) comes from the medial side of the dorsal venous arch of the
foot, while the long vein in the upper limb (cephalic) comes from the lateral side of its venous arch; can you
explain this reversal?.
Developmentally speaking, what do the two long veins have in common?
Find these veins on the superficial prosections of the upper limb, also look for the cutaneous nerves:
1.
The cephalic vein is accompanied by branches of the radial nerve (eg. Posterior cutaneous nerve of the
forearm)
2.
The basilic vein is accompanied by the medial cutaneous nerve of the forearm (from the medial cord of
the brachial plexus).
Can you see a pattern in these relationships? Can you attribute the terms "dorsal" and "ventral" to the main
veins?.
Find the main veins on superficial prosections of the lower limb, also look for
cutaneous nerves
1.
The great saphenous vein is accompanied by branches of the femoral nerve
(eg. saphenous nerve)
2.
The small saphenous vein is accompanied by branches of the tibial nerve
(eg. Sural nerve)
Can you see a pattern in these relationships? Can you attribute the terms "dorsal" and
"ventral" to these main veins?.
COMPARTMENTS OF THE ARM
In the anterior compartment of the arm identify:
Long head of biceps
Short head of biceps
Coraco-brachialis
Brachialis muscles
Musculocutaneous nerve
Median and ulnar nerves
Which parts of the scapula gives attachment to these “ventral” muscles of the upper limb?
Follow the ulnar and median nerves through the arm to the elbow. Neither of these nerves
give branches in the arm; the median nerve travels with the brachial artery and crosses in
front of the elbow on the medial side. While the ulnar nerve crosses into the posterior
compartment to enter the forearm behind the medial epicondyle of the elbow.
In the posterior compartment of the arm identify:
Long head of triceps
Medial head of triceps
Lateral head of triceps
The radial nerve
Trace the radial nerve and the deep brachial artery through the spiral groove of the humerus. It enters the
anterior compartment above the lateral side of the elbow.
On the lateral side of the elbow identify the brachioradialis muscle; if you gently pull it away from brachialis
you will see the radial nerve, where it crosses the elbow giving off branches to brachioradialis and extensor
carpi radialis longus and brevis.
Draw a cross-section through the arm at the level of the deltoid tuberosity, The diagram should include: The
humerus in the middle, skin and superficial fascia, deep fascia and intermuscular septa forming compartments,
the main muscles, nerves and vessels.
Ant.
Basilic vein
Cephalic vein
Biceps
Brachialis
Coracobrachialis
Brachial artery
Median nerve
Ulnar nerve
Medial
lateral
Deltoid
Triceps
Radial nerve
Deep brachial artery
Post.
Can you add any cutaneous nerves?
SURFACE ANATOMY
Take off your glove and roll up your sleeve. You should be able to feel:
Boney points: acromion, greater tubercle, lesser tubercle, deltoid tuberosity, medial and lateral epicondyles.
Main muscles:
1. In the anterior and posterior compartments
2. Pectoralis major, teres major and latissimus dorsi at the axilla
3. Deltoid
4. Brachioradialis on the lateral side of the elbow
The brachial artery can be identified by its pulsations along the medial aspect of the humerus
Nerves can be felt as rubbery cords but also by the sensations that are evoked by your finger pressure
The radial nerve can be felt below the deltoid tuberosity halfway down the lateral side of the arm (corking spot!)
The median nerve runs with the brachial artery all the way down the medial side of the arm and on the medial
side of the biceps tendon at the elbow.
The ulnar nerve behind the medial epicondyle of the elbow (funny bone)
ELBOW
Osteology
1.
Study the lower end of the humerus and identify the
capitulum, trochlear, medial and lateral epicondyles, radial,
coronoid and olecranon fossae.
2.
On the ulna identify the trochlear and radial notches, and
the olecranon and coronoid processes.
3.
On the radius identify the head, neck and tuberosity.
Fit the ulna onto the humerus and move the joint through its full
range. What is the function of the fossae on the lower end of the
humerus?
Ligaments
The elbow has no extracapsular ligaments, all its ligaments are thickenings of
the joint capsule. The capsule of the elbow joint also includes the
proximal radioulnar joint.
Look at prosections of the elbow joint note where the joint capsule is
thick and tight to forming the medial and lateral collateral ligaments.
See how the capsule is thin and slack in front and behind, and how the
head of the radius can rotate independently on the ulna within the
annular ligament.
Muscles
1.
The elbow is crossed by its main flexors and extensors: brachialis, biceps and triceps (and anconeus).
Mark the attachments of those muscles on the diagrams above.
2.
The elbow is also crossed by muscles mainly concerned with the forearm, wrist and hand:
a.
On the lateral side they are Brachioradialis, supinator and extensors of the wrist and fingers
b.
On the medial side they are Pronator teres and flexors of the wrist and fingers
The cubital fossa is the triangular region in front of the elbow joint. It is bounded by:
1.
The line between the epicondyles
2.
The brachioradialis muscle laterally
3.
The pronator teres muscle medially
It is covered by deep fascia and the bicipital aponeurosis
It contains: biceps tendon, median nerve, brachial artery dividing
into radial and ulna arteries
Outside the covering are the cephalic, basilic and median cubital
veins
COMPARTMENTS OF THE THIGH
Use the prosections to identify the structures in each
compartment of the thigh:
Posterior compartment: semimembranosus, semitendonosus,
long and short heads of biceps femoris, and the
sciatic nerve dividing lower down into the tibial
and common peroneal nerves
Medial compartment: adductors longus, brevis and magnus,
gracilis; and the branches of the obturator nerve and
artery.
Anterior
compartment: the quadriceps, and sartorius
muscles; and branches of the femoral nerve and
artery. Follow the femoral artery to where it passes
through the adductor hiatus to enter the popliteal
fossa behind the knee.
Define a "hamstring muscle"
Which division of the sciatic nerve supplies the hamstring muscles?
Some muscles in the thigh have dual nerve supplies:
1.
Pectineus
nerve and the
2.
Adductor magnus
nerve and the
nerve
3.
Biceps femoris
nerve and the
nerve
Can you explain why?
The “lateral compartment” is represented in the thigh by the iliotibial
tract and the thick lateral intermuscular septum, which helps transmit the
action of gluteus maximus and tensor fasciae latae to the femur. The
muscles of the lateral compartment are located in the gluteal region
Study specimens of the gluteal region, identify the following and add
them to the diagram:
Gluteus maximus
Gluteus medius and minimus
Tensor fascia lata
Sciatic (tibial and common peroneal nerves)
Superior and inferior gluteal nerves and vessels
What muscles are supplied by the superior gluteal nerve?
What muscles are supplied by inferior gluteal nerve?
The 6 lateral rotators are also found in the gluteal region and of these
piriformis, the obturator internus tendon and quadratus femoris are quite easy to find
nerve
Practical anatomy checklist
Osteology
Distal humerus and proximal ends of the radius and ulna
Parts of the bones, ligamentous and muscle attachments
Arthrology
The elbow joint including the proximal radioulnar joint
Muscle compartments including the nerves and vessels
Anterior arm
Posterior arm
Anterior thigh
Medial thigh
Posterior thigh
Regions
Cubital fossa
Gluteal region
Surface anatomy
The arm
Superficial veins
Main veins of both limbs