Notes on anatomy surgical exposure
SHOULDER
Anterior approach: Delto-Pectoral
Interneural plane (axillary and medial and lateral pectoral nerves)
Surface markings:

Coracoid process and oblique incision inferiorly between delotpectoral region
Dangers:
1. Musculocutaneous nerve
a. 2-5cm under coracoid and coracobrachialis medially (do not over retract)
2. Axillary Nerve
a. Length of PIPJ to tip of index finger under Coracoid
3. Brachial Plexus
Waymarkers:



Cephalic vein
o marks plane between deltoid and pectoralis muscles
o Ligate tributaries and mobilise vessel
Tip of Coracoid
o Lateral side of conjoint tendon is “safe side”
o Conjoint tendon made up from SH of biceps and coracobrachialis
Leash of vessels at inferior margin of subscapularis
o Lowest safe margin – brachial plexus below
Important Notes:


Quadrangular space
Bursa
Mackenzie Approach to the Shoulder: for access to proximal humerus, rotator cuff and
subacromial space
Muscle splitting
Surface markings:

5cm vertical incision from acromion down line of arm
Dangers:

Axillary nerve – runs 5-7 cm horizontally distal to acromion
Waymarkers:

Split deltoid in line of fibres – place a suture in apex to prevent split propagation
Page 1 of 13
Notes on anatomy surgical exposure
Important Notes:

Identify axillary nerve before making a 2nd vertical incision distally
Posterior Approach to the Shoulder: glenoid fractures
Interneural plane
Surface markings:


Longitudinal incision along scapular spine
Extending to lateral acromion boarder
Dangers:
1. Axillary nerve - laterally
2. Circumflex Scapular artery - medially
Waymarkers:

Junction between infraspinatus – multipennate muscle covered in fascia
(Suprascapular nerve) and Teres Minor – a unipennate muscle (Posterior division of
axillary nerve)
Important Notes:



Rotator interval – between subscapularis and supraspinatus
Ligaments found in the interval
Subscapular bursa
o Communicates with glenohumeral joint via foramen of Rouviere
o Constantly found between superior and middle glenohumeral ligament
Posterior arthroscopic to the shoulder:
Surface markings:



Lateral inferior corner of the acromium
2cm inferior and medial
Soft area aiming for coracoid
Dangers:
1. Axillary nerve - laterally
2. Circumflex Scapular artery - medially
Important Notes:



Rotator interval – between subscapularis and supraspinatus
Ligaments found in the interval
Subscapular bursa
Page 2 of 13
Notes on anatomy surgical exposure
o Communicates with glenohumeral joint via foramen of Rouviere
o Constantly found between superior and middle glenohumeral ligament
HUMERUS
Anterior approach to the humerus: Upper 2/3 of humerus approach can extend to shoulder
approach between deltoid and pectoralis major
Interneural plane (as Brachialis has dual innervation)
Surface markings:

Lateral side of biceps tendon with arm flexed
Dangers: MUST STICK SUBPERIOSTEALLY TO AVOID
NERVES

Radial nerve laterally – identify before brachialis is
split

Ulnar nerve medially
Waymarkers:

Split Brachialis (lateral 1/3 supplied by radius and medial 2/3 by musculocutaneous)
Important Notes:

Distally radial nerve is found between brachioradialis and Brachialis

Cannot extend distally
Anterolateral approach to the humerus: use for radial nerve exploration distal humerus
Interneural plane
Surface markings:

Lateral to biceps muscle
Dangers:

Radial nerve (and the superficial branch)

Lateral cutaneous nerve of forearm (5cm from
elbow crease)
Waymarkers:


Retract Biceps medially and retract lateral antebrachial cutaneous nerve with it.
Between Brachialis (Radial & musculcutaneous nerve) and Brachioradialis (radial
nerve)
Page 3 of 13
Notes on anatomy surgical exposure


Develop intermuscular plane between these 2 muscles
Brachialis also goes medially with the biceps muscle and tendon
Important Notes:
Posterior Approach to the humerus: for inferior 2/3rds of humerus
Muscle splitting approach
Surface markings:

8 cm distal to the acromion to the olecranon fossa
Dangers:

Radial nerve
o nerve crosses posterior aspect of humerus at 20-21 cm proximal to medial
epicondyle and 14-15 cm proximal to lateral epicondyle
Waymarkers:

split fascia between long and lateral head of triceps

retract lateral head laterally and long head medially

radial nerve found in spiral groove
Important Notes:
Lateral Approach to the humerus: for Holsteine Lewis fracture of distal 1/3 of humus with
radial nerve palsy ideal for exploring
Muscle splitting plane
Surface markings:

Lateral supracondylar ridge between brachioradialis in upper 1/3 and ECRL in lower
1/3
Dangers:

Radial nerve pierces lateral septum between proximal 2/3rds and distal 1/3rd
proximately

PIN distally
Waymarkers:
Page 4 of 13
Notes on anatomy surgical exposure

Muscle plane between triceps (radial nerve) and brachioradialis (radial nerve)

Reflect triceps posteriorly and brachioradialis anteriorly

Deeper common extensor origin and triceps can be elevated
Important Notes:

DISTAL EXTENSION Interneural plane between aconeus (radial) and ECU (PIN)
ELBOW:
Posterolateral or Kockers Approach to the Radial head:
Interneural interval – between aconeus and ECU
Surface markings:

Lateral epicondyle to end of proximal ulna
Dangers:

PIN – keep arm pronated to prevent injury
Waymarkers:

Aconeus (radial nerve) is fan shaped proximately and vertical distally

ECU (PIN)
Important Notes:

PIN is found between the muscle planes of EDC and ECRL interval
Triceps Split
Surface markings:

Start 5cm proximal to olecranon and then curve medially around olecranon to middle
of ulna distally
Dangers:

Ulnar nerve dissected out and protected

Median nerve – stay subperiosteal anteriorly will protect nerve

Radial nerve – runs 14-15cm proximal to lateral epicondyle as is travels from
posterior to anterior compartments in the arm
Waymarkers:
Page 5 of 13
Notes on anatomy surgical exposure

Incise fascia over midline identify ulnar nerve and dissect out

Chevron the olecranon making sure the olecranon is mountain shape

Split with an osteotome to aid anatomical reduction after

Subperiosteal elevation laterally and medially allows access to distal 4th of humerus.
Important Notes:

Distally the ulnar nerve is found between the 2 heads of FCU
FOREARM
Volar Approach: Henry’s approach
Interneural plane
Surface markings:

Radial side of biceps tendon to radial styloid
Dangers:

Lateral antebrachial cutaneous nerve

Radial artery and superficial radial nerve – under brachioradialis
(mobile wad)

PIN – enters supinator via arcade of Frohse – this is the moster
superior and superficial layer of the supinator muscle
Waymarkers:

Develop plane between brachioradialis (radial nerve) and flexor
carpi radialis (median nerve)

Start distal to proximal identify superficial radial nerve under brachioradialis and
ligate branches of radial nerve to aid lateral retraction of BR

Proximately the bursa on the radial aspect of the biceps tendon can be incised to gain
access (the radial artery lies ulnar side of biceps tendon TAN)

Proximal 1/3
o Keep arm supinated to avoid PIN.
o The supinator is seen in the proximal 1/3 and this is incised along its broad
insertion

Middle 1/3
Page 6 of 13
Notes on anatomy surgical exposure
o Pronate to bring into view pronator teres and incise and retract medially

Distal 1/3
o Semi supinate arm and elevate periosteum lateral to FDS and PQ
Important Notes:

Proximately supinator needs to go ulnarly

Middle Pronator teres can be peeled off radius in neutral position

Distally plane is between FRC and Brachioradialis
Dorsal Approach: Thompson’s Approach
Internervous plane
Surface markings:

Lateral epicondyle to listers tubercle – for access to
proximal 1/3 of radius
Dangers:

PIN
Waymarkers:
Superficial dissection

Proximal 1/3 – ECRB (radial N) & EDC (Pin) plane

Distal 1/3 – ECRB and EPL (Pin) plane
Deep dissection

Proximal 1/3 Must identify PIN as it leaves the Supinator muscle belly
o Either dissect nerve out of muscle
o Or Subperiosteally lift supinator off bone to protect nerve

Middle 1/3 Abductor pollicis longus and extensor pollicis brevis muscles are retracted
off bone
Important Notes:

PIN usually injured in retraction though 25% actually are in direct contact with the
proximal radius
Page 7 of 13
Notes on anatomy surgical exposure
HIP:
Lateral Approach: Hardinge or Modified Hardinge
Splits gluteus medius distal to superior gluteal nerve
Surface markings:

Longitudinal incision centred over GT and curving posteriorly
Dangers:

Superior gluteal nerve 4-5cm above tip of GT
Waymarkers:

Skin, subcutaneous tissues down to fascia lata

Take GM off GT and go proximately laterally <4cm for access

Extend incision inferiorly through VL

Gluteus minimus is excised off anterior GT

Expose anterior joint capsule and perform T shaped capsulotomy down to fibrous rim
Important Notes:

Leave sufficient cuff on bone to help reattach GM tendon
Anterolateral Approach: Watson Jones
Inter muscular plane
Surface markings:

15cm incision centred over GT
Dangers:

Femoral vessels
Waymarkers:

Same approach as Modified Hardinge

Find plane between GM and TFL (both superior gluteal nerve)

Develop this interval and externally rotate hip to find origin of vastus lateralis

Detach abductor mechanism
Page 8 of 13
Notes on anatomy surgical exposure

In front of the joint capsule will lie rectus femoris and psoas which may need
elevating and retracting
Anterior Approach: Smith Peterson – Hoyter Modification
Interneural plane
Surface markings:

ASIS to lateral side of patella for 8-10 cm

Incision can be extended proximately underneath line of ilium
Dangers:

Lateral cutaneous femoral nerve
o Passes 10-15 cm laterally to ASIS under inguinal ligament

Femoral nerve
o Medial side of Sartorius muscle (forms lateral wall of femoral triangle)

Ascending branch of lateral femoral circumflex artery
o Ligate to avoid excessive bleeding
Waymarkers:

Identify gap between Sartorius (femoral N) and TFL (Superior gluteal N)

Subcutaneous fat will have lateral cutaneous femoral nerve

Incise fascia on medial side of TFL

Detach origin of TFL to develop plane and identify and ligate lateral femoral
circumflex artery

Deeper identify plane between rectus femoris (femoral N) & gluteus medius
(superior gluteal N)

Detach rectus femoris from attachment and retract medially with psoas, GM can go
laterally to expose capsule

Externally rotate hip also to aid this
Page 9 of 13
Notes on anatomy surgical exposure
Posterior Approach (Moore or Southern)
Inter muscular pane splitting of gluteus maximus (inferior gluteal nerve)
Surface markings:

Posterior curvilinear approach centred over GT

Can mark this out by flexing hip to 900 and draw a straight line in line with the
femur, when the leg straightens it is now curvilinear
Dangers:

Sciatic nerve – can split look around piriformis to see if there is another branch

Inferior gluteal artery – leaves pelvis under piriformis

Perforating branch of profunda femoris – can be cut whilst releasing gluteus maximus
insertion

Anterior to acetabulum are the femoral vessels
Waymarkers:
Superficial

Split fascia in line with incision to visualise vastus lateralis and gluteus fan shaped
incision proximately

Split maximus in line with its fibres
Deep

Internally rotate hip to place tension on short rotators

Detach piriformis and obturator internus 1cm from femoral insertion.
FEMUR
Lateral
None splits vastus lateralis
Surface markings:

Lateral thigh with leg internally rotated 15 degrees
Dangers:

Perforating vessels of profunda femoris artery – bleeding ++
Page 10 of 13
Notes on anatomy surgical exposure
Waymarkers

Fascia lata

Fascial covering to VL

Split VL

Subperiosteal dissection to expose femur
Posterolateral
Interneural plane
Surface markings:

Posterior aspect of femoral condyle up the shaft
Dangers:


Perforating branches of the pronfunda femoris artery
Superior lateral geniculate artery and vein
Waymarkers

Deep fascia of thigh

Feel intermuscular septum go anteriorly between VL (femoral N) & hamstrings
(sciatic N)

Reach the linea aspera
KNEE
Medial para-patella – relative CI is previous lateral para-patella
None
Surface markings:

5cm above superior pole of patella down to tibial tubercle
(either straight or curvilinear)
Dangers:

Superior lateral geniculate artery

Infra-patella branch of saphenous nerve
o Subcutaneous after leaving fascia lata
Page 11 of 13
Notes on anatomy surgical exposure
Waymarkers
Superficial

Deepen dissection between vastus medialis and quads tendon

Medial arthrotomy medial to patella tendon

Excise fat pad
Deep

Reflect patella laterally

If difficult extend incision proximately
ANKLE
Lateral ankle
None
Surface markings:

Centre incision over fracture make long enough to avoid skin tension
Dangers:

Superficial peroneal nerve – 6-10 cm proximal to tip of fibula from posterior to
anterior

Short saphenous vein

Sural nerve runs along posterior aspect of fibula
Waymarkers

Blunt dissection in subcutaneous tissues

Stick to bone and stay subperiosteally when clearing fracture site
Anteromedial ankle
None
Surface markings:

8-10cm incision curving anteriorly centred over anterior 1/3 of malleolus
Dangers:

Saphenous nerve – numbness over medial foot and vein
Page 12 of 13
Notes on anatomy surgical exposure
Waymarkers

Skin flap blunt dissection in subcutaneous tissues

Stick to bone and lift out fracture to expose joint

Longitudinal split to bring screw to bony tip
Posterolateral ankle: - for posterior malleolus fracture size is not necessarily an issue by
note mechanism – if axial or shearing it should be fixed
None
Surface markings:

Begin 12cm proximal to lateral malleoli tip

Half way between tendon and fibula

Curve to posterior fibula and then follow peroneal tendons to 2cm below and anterior
to malleolar tip
Dangers:

Sural nerve half way between Achilles and fibula

Deep are the posterior n/v bundles going posterior to the medial malleolus
Waymarkers

Aim to go between muscle bellies of peroneals either side depending on access

Meat to the heal is FHL
Anterior to ankle:
None inter-tendinous all supplied by deep peroneal nerve
Surface markings:

Lateral to EHL is where the anterior tibial artery and deep
peroneal nerve
Dangers:

Anterior tibial artery

Deep peroneal nerve
Waymarkers

Incise fascia and locate EHL – n/v bundle lateral to this
Page 13 of 13