Anatomy Facts From Previous Pater

·         The maxillary sinus is innervated by branches of V2 - the greater palatine nerve and the branches of the infraorbital nerve.

·         The pterygopalatine fossa is the distribution centre for the main vessels and nerves of the middle third of the face. The greater and deep petrosal nerves join together before entering the pterygo-palatine fossa.

·         A 54-yr old woman complains of pain & burning over the bottom of the forefoot; her symptoms are relieved by going barefoot. Diag – Morton neuroma

·         Line of gravity passes through – Cervical & lumbar vertebrae; behind hip jt & in front of knee & ankle jt

·         All can act as antigravity muscles except – Popliteus

·         Developmentally hymen is – Endodermal in origin

·         Ulnar n innervates 15 of the 20 intrinsic muscles of the hand

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·         Weitbrecht's cartilage=articular disc of acromioclavicular joint.

Weitbrecht's cord= oblique ligament of elbow joint.

Weitbrecht's ligament= oblique ligament of elbow joint.

Weitbrecht's fibers= retinaculum of articular capsule of hip.

Weitbrecht's foramen= an opening in the articular capsule of the shoulder joint, communicating with the subtendinous bursa of the subscapularis muscle

·         1. Eye Of Hand : Median Nerve

2. Labourer's Nerve : Median Nerve

3. Musician's Nerve : Ulnar Nerve

4. Surgeon's Nerve : Axillary Nerve

5. Wandering Nerve : Vagus Nerve

·         FORAMENAE:

1. Foramen of Scarpa - Incisor Foramen in the mouth

2. Foramen of Vesalii - Transmits veins communicating between the Cavernous sinus to Pterygoid Plexus

3. Foramen of Luschka - Openings of the Lateral recesses of fourth Ventricle

4. Stylomastoid Foramen - Transmits Facial Nerve

1. Foramen Caecum - The foramen anterior to the Crista Galli in the base of the Skull.

2. Foramen Caecum - Located at the junction of Ant 2/3 rds and Post 1/3 rd of tongue (in midline)

3. Epiploic Foramen - Communication between Greater and lesser sacs of peritoneal cavity.

4. Foramen of Langer - A foramen in the axillary fascia through which the Axillary tail of Spence (Part of Breast) passes through

5. Foramen of Monro (Interventricular Foramen) - Opening of lateral ventricles into III ventricle.

6. Foramen of Magendie - Median aperture in the Roof of fourth Ventricle.

7. Jugular Foramen Transmits - a. Sigmoid Sinus b. Inferior Petrosal Sinus c. 9th, 10th, 11th cranial Nerves d. Int. jugular vein

8. Foramen Transversarium of 6th Cervical Vertebra Transmits - Vertebral Artery

·         MUSCLE FACTS:

1. Abdominals – Rectus abdominus, external abdominal oblique, and Transverse abdominus

2. Adductors – Magnus, Longus and brevis

3. Adductor magnus – Underneath the hamstrings

4. Biceps brachii – Corkscrew muscle

5. Brachialis – Strongest elbow flexor / Superficial lateral forearm

6. Costals – Internal and External

7. Deltoid – Shoulder pad muscle / Anterior, Lateral and Posterior / Antagonist to itself

8. Diaphragm – Prime mover in inspiration

9. Erector spinae – Spinalis (Medial tract and hugs the spine), Iliocostalis (Lateral tract and hugs the ribs) and Longissimus (Intermediate tract)

10. External intercostals – Superficial

11. Extensor digiti minimi – Tea drinker’s muscle

12. Gluteus maximus – Strongest hip extensor / can be at least one inch thick / most superficial gluteal muscle

13. Gracilis – The gracilis and the femoral shaft form the letter ‘V’

14. Gastrocnemius – Toe dancer’s muscle

15. Gluteals – Maximus, Medius and Minimus

16. Hamstrings – Semitendinosus, Semimembranosus and Biceps femoris

17. Hypothenar eminence – Opponens digiti minimi, Flexor digiti minimi brevis and Abductor digiti minimi

18. Internal abdominus obliques – The fibers go vertical

19. Internal intercostals – Deep

20. Iliopsoas – Group of psoas major, psoas minor and iliacus

21. Latissimus dorsi – Swimmer’s muscle / Widest muscle / Superficial mid back and lower back muscle

22. Lateral six deep rotatores – Piriformis, Gemellus superior, Obturator internus, Gemellus inferior, Obturator externus and Quadratus femoris

23. Longus colli – Longus colli superior oblique, longus colli inferior oblique and longus colli vertical

24. Orbicularis oculi – Winking muscle

25. Orbicularis oris – Kissing muscle

26. Pronators – Pronator quadratus and Pronator teres

27. Peroneus – Longus, Brevis and Tertius

28. Peroneus longus – Sometimes called ‘fibularis longus’ / Along with the peroneus brevis it is affected in an inversion sprain

29. Psoas – Strongest hip flexor / Strongest posture muscle

30. Piriformis – Tightness causes duck like walking

31. Plantaris – Missing in most cadavers

32. Psoas minor – Missing in most cadavers

33. Platysma – Most superficial neck muscle

34. Pectoralis major – Tightness equals rounded shoulders and or constriction of chest wall

35. Pectoralis minor and Scalenes – Neurovascular entrappers

36. Pectineus – Medial to the femoral artery and considered an extension of the iliopsoas muscle

37. Quadratus lumborum – Hip hiker muscle

38. Quadriceps – Vastus lateralis, Vastus medialis, Vastus Intermedius and Rectus femoris

39. Rhomboid minor and major – Minor is on top / Christmas tree muscle

40. Rectus abdominus – Horizontal layer of connective tissue every few inches / Six pack muscle

41. Rectus femoris – Only quad muscle that crosses two joints and has two actions

42. Rotatores longi and Rotatores brevis – Deepest of the transversospinalis group

43. Scalene – Anterior, Medius and Posterior

44. Serratus posterior superior – Helps inhale

45. Serratus posterior inferior – Helps exhale

46. Stapedius – Smallest muscle (In your ear)

47. Sartorius – Tailor’s muscle / Longest muscle

48. Semispinalis – Most superficial of the transversospinalis group / most superficial of the transversospinalis group

49. Semimembranosus – Most medial hamstring

50. Semitendinosus – On top of the semimembranosus

51. Serratus muscles – Anterior, Posterior superior and Posterior inferior

52. Serratus anterior and Triceps – Boxer’s muscle

53. Sternocleidomastoid – Tightness can cause vertigo or torticollis / Only muscle that

move the head and are not connected to the ribs

54. Supraspinatus / Infraspinatus / Teres minor / Subscapularis – SITS muscles or rotator muscles

55. Subscapularis – Frozen shoulder muscle

56. Suboccipitals – Ghost headache muscle / Rectus capitus posterior major, Rectus capitus posterior minor, oblique capitus inferior and oblique capitus superior

57. Thenar eminence – Opponens pollicis, Abductor pollicis brevis and Flexor pollicis brevis

58. Tensor fascia lata – Connects into the iliotibial band

59. Transversospinalis – Semispinalis, Multifidus and Rotator longi, Rotatores brevis

60. Transverse abdominus – Deepest abdominal muscle / Wraps around the internal organs

61. Tibialis anterior – Weakness causes flat foot / Tightness causes high arch / prone to shin splints

62. Triceps surae – Another name for the soleus and gastrocnemius

63. Trapezius – Coat hanger muscle / Superficial mid and upper back muscle / Antagonist to itself

Neck

Flexion of the Neck - Sternocleidomastoid, Splenius Capitis, Splenius Cervicis, and Scalenes

Extension of the Neck - Splenius Capitis, Splenius Cervicis and Scalene

Lateral Flexion of Neck to same side - Sternocleidomastoid, Scalenes

Rotation of Head to Opposite Side - Sternocleidomastoid, Scalenes

Rotation of Head to Same Side - Splenius Capitis, Splenius Cervicis

Ribs

Bilaterally Raises First 2 Ribs - Scalenes

Scapula

Elevation of the Scapula - Upper Trapezius and Levator Scapula

Depression of the Scapula - Pectoralis Minor and Lower Trapezius

Protraction of the Scapula - Pectoralis Minor and Serratus Anterior

Retraction of the Scapula - Middle Trapezius and Rhomboids

Upward rotation of the Scapula - Upper Trapezius, Lower Trapezius, and Serratus Anterior

Downward Rotation of the Scapula - Levator Scapula, Rhomboids, and Pectoralis Minor

Humerus

Flexion of the Humerus - Anterior Deltoid, Pectoralis Major, Coracobrachialis and Biceps

Extension of the Humerus - Latissimus Dorsi, Teres Major, Posterior Deltoid, Infraspinatus, Teres Minor, Triceps and Pectoralis Major

Medial Rotation of the Humerus - Anterior Deltoid, Pectoralis Major, Subscapularis, Teres Major and Latissimus Dorsi

Lateral Rotation of the Humerus - Infraspinatus, Teres Minor, and Posterior Deltoid

Adduction of the Humerus - Pectoralis Major, Coracobrachialis, Latissimus Dorsi and Teres Major

Abduction of the Humerus - Supraspinatus and Middle Deltoid

Horizontal Adduction of the Humerus - Anterior Deltoid and Pectoralis Major

Horizontal Abduction of the Humerus - Posterior Deltoid

Elbow

Flexion of the Elbow - Biceps, Brachialis, Brachioradialis, and Pronator Teres

Extension of the Elbow - Triceps and Anconeus

Forearm

Supination of the Forearm - Biceps and Supinator

Pronation of the forearm - Pronator Teres and Pronator Quadratus

Wrist

Flexion of the Wrist - Flexor Carpi Radialis, Flexor Carpi Ulnaris, and Palmaris Longus

Extension of the Wrist - Extensor Carpi Radialis Longus, Extensor Carpi Radialis Brevis, and Extensor Carpi Ulnaris

Adduction of the Wrist - Extensor Carpi Ulnaris and Flexor Carpi Ulnaris

Abduction of the Wrist - Flexor Carpi Radialis and Extensor Carpi Radialis Longus

Fingers

Flexion of Fingers - Flexor Digiti Minimi and Flexor Digitorum Profundus, Flexor Digitorum and Flexor Digitorum Superficialis

Extension of Fingers - Extensor Digitorum, Extensor Indicis, and Extensor Digiti Minimi

Adduction of Fingers - Palmar Interossei

Abduction of Fingers - Abductor Digiti Minimi, Dorsal Interossei

Thumb

Adduction of Thumb - Adductor Pollicis

Abduction of Thumb - Abductor Pollicis Brevis, Abductor Pollicis Longus

Opposition of Thumb - Opponens Pollicis

Flexion of the Thumb - Flexor Pollicis Longus and Flexor Pollicis Brevis

Extension of Thumb - Extensor Pollicis Brevis and Abductor Pollicis Longus

Trunk

Flexion of Trunk - Rectus Abdominis, External Obliques, Internal Oblique

Lateral Flexion of Trunk - External Obliques, Internal Oblique, Quadratus Lumborum

Supports Compression of Abdominal Contents - Rectus Abdominis, External Obliques, Internal Oblique, Transverse Abdominis

Spine

Extension of Spine - Iliocostalis, Longissimus, Spinalis, Semispinalis, Multifidus

Lateral Flexion of Spine - Iliocostalis, Longissimus, Spinalis

Rotation of Opposite Side - Semispinalis, Multifidus

Hip

Flexion of the Hip - Iliopsoas, Pectineus, TFL, Adductor Brevis, Adductor Longus, Adductor Magnus, Rectus Femoris, and Sartorius

Extension of the Hip - Gluteus Maximus, Biceps Femoris, Semitendinosus, Semimembranosus, and Adductor Magnus

Medial Rotation of the Hip - Gluteus Medius, Gluteus Minimus, TFL, Pectineus, Adductor Longus, Adductor Brevis, and Adductor Magnus

Lateral Rotation of the Hip - Piriformis, Gemellus Superior, Obturator Internus, Gemellus Inferior, Obturator Externus, Quadratus Femoris, Gluteus Maximus, and Sartorius

Adduction of the Hip - Adductor Brevis, Adductor Longus, Adductor Magnus Gracilis, and Pectineus

Abduction of the Hip - Gluteus Medius, Gluteus Minimus, TFL and Sartorius

Raises Hip - Quadratus Lumborum

Knee

Flexion of the Knee - Biceps Femoris, Semitendinosus, Semimembranosus, Sartorius, Gracilis, Gastrocnemius, Plantaris, and Popliteus

Extension of the Knee - Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rector Femoris and TFL

Medial Rotation of the Knee - Semitendinosus, Semimembranosus, Popliteus, Gracilis, and Sartorius

Lateral Rotation of the Knee - Biceps Femoris

Ankle

Dorsiflexion of the Ankle - Tibialis Anterior, Extensor Digitorum Longus, Peroneus Tertius, and Extensor Hallucis Longus

Plantar Flexion of the Ankle - Gastrocnemius, Soleus, Plantaris, Peroneus Longus, Peroneus Brevis, Tibialis Posterior, Flexor Hallucis Longus and Flexor Digitorum Longus

Foot

Inversion of the Foot - Tibialis Anterior and Tibialis Posterior

Eversion of the Foot - Peroneus Tertius, Peroneus Longus and Peroneus Brevis

Toes

Flexion of Toes - Flexor Digitorum Longus, Flexor Digitorum Brevis, Abductor Digiti Minimi

Extension of Toes - Extensor Digitorum Brevis, Extensor Digitorum Longus

Great Toe

Flexion of Great Toe - Flexor Hallucis Longus, Flexor Hallucis Brevis

Extension of Great Toe - Extensor Hallucis Longus

·         *Adductor brevis- only muscle to b supplied by both ant n post divisions of obturator n

·         *gemellus superior- supplied by n. to obturator internus

·         *gemellus inferior- supplied by n. to quadratus femoris

·         *pectoralis major- MC muscle tat is absent congenitally

·         *peroneus brevis- involved in displacement of # fragment in Jones #

·         *quadriceps femoris – MC muscle to atrophy in osteoarthritis

·         *tibialis anterior – MC muscle to undergo complete atrophy in osteoarthritis

·         *latissimus dorsi – actions are remembered as movin the hand to scratch the opp scapula..adduction, extension, medial rotation

·         *rotator cuff- supraspinatus,infraspinatus,subscapularis & teres minor

·         *sartorius- tailors muscle..longest muscle in the body

·         *lumbricals – lateral two are uni pennate supplied by median nerve

·         Medial two are bipennate supplied by ulnar nerve

·         *thenar muscles- all supplied by median nerve except deep head of

·         flexorpollicis brevis supplied by ulnar nerve

·         *abductor pollicis longus & extensor pollicis brevis – involved in

·         deQuervain’s tenosynovitis

·         *teres minor – supplied by axillary.n with pseudo ganglion

·         *palmar interossi - adductors

·         *dorsal interossi – abductors

smallest muscle - piloerector

longest muscle - sartorius

virgins/antirape muscle - gracilis

locking muscle - popliteus

boxer's muscle - serratus anterior

footballer muscle - quadriceps femoris

climbing muscle - lattismi dorsi

rider's muscle - adductors of thigh

swimmer muscle - lattismi dorsi

tailor's muscle - sartorius

The presence of a “popeye” muscle

deformity in the biceps muscle contour indicates

rupture of the long head of the biceps tendon

Honeymoon muscle-gracilsis

toenbey's muscle-tensor tympani

Referred Pain

·         Diaphragmatic pain is frequently felt at the tip of the shoulder, reflecting common nerve root origins in the neck. It usually occurs when there is inflammation of the diaphragmatic pleura, e.g. in basal pneumonia, pleural effusions or malignant disease.

·         The majority of the sensation of pain arising from the stomach, duodenum,jejunum,ileum is poorly localized. In common with other structures of foregut origin, it is referred to the central epigastrium. Pain arising from the region of the gastro-oesophageal junction may involve innervation from the oesophagus and is commonly referred to the lower retrosternal and subxiphoid areas.

·         Pain in the anus is usually felt with a high degree of acuity and is well localized to the perineum and anal canal itself.

·         Pain arising from the parenchyma of the liver is poorly localized. In common with other structures of foregut origin, pain is referred to the central epigastrium. Stretch of or involvement of the liver capsule by inflammatory or neoplastic processes rapidly produces well-localized pain of a 'somatic' nature.

·         In common with other structures of foregut origin, pain from stretch of the common bile duct or gallbladder is referred to the central epigastrium. Involvement of the overlying somatic peritoneum produces pain which is more localized to the right upper quadrant.

·         Pain arising in the pancreas is poorly localized. In common with other foregut structures, the majority of pain arising from the pancreas is referred to the epigastrium. Inflammatory or infiltrative processes arising from the gland rapidly involve the tissues of the retroperitoneum and their supply from somatic nerves, and this is referred to the posterior paravertebral region around the lower thoracic spine.

·         The majority of the sensation of pain arising from the pulp of the spleen is poorly localized. In common with other structures of foregut origin, it is referred to the central epigastrium. Distension of the splenic capsule stretches the parietal layers of the peritoneum and produces pain localized to the posterior left upper quadrant.

·         Excessive distension of the ureter or spasm of its muscle may be caused by a stone (calculus) and provokes severe pain (ureteric colic, which is commonly, but mistakenly, called renal colic). The pain, spasmodic and agonizing, particularly if the obstruction is gradually forced down the ureter by the muscle spasm, is referred to cutaneous areas innervated from spinal segments which supply the ureter, mainly T11-L2. It shoots down and forwards from the loin to the groin and scrotum or labium majus and may extend into the proximal anterior aspect of the thigh by projection to the genitofemoral nerve (L1, 2). The cremaster, which has the same innervation, may reflexly retract the testis.

·         Sensory fibres accompany the sympathetic nerves, and so ovarian pain can be periumbilical. It is often perceived in the right or left iliac fossa due to local inflammation. Ovarian pain can also be perceived on the medial side of the thigh in the cutaneous distribution of the obturator nerve, presumably because the ovary lies close to the obturator nerve in the ovarian fossa, and so any inflammation of the ovary or peritoneum in the ovarian fossa may affect the obturator nerve.

·         Pain from tubal disease is classically described as occurring in the iliac fossa as a result of local peritoneal irritation. As with pain from the ovary, this can sometimes cause discomfort in the distribution of the obturator nerve on the medial aspect of the thigh.

·         Patients with psoas abscesses may have referred pain to the hip, groin, or knee.

 ·         This referred EAR pain can be due to problems in the oral cavity, oropharynx, hypopharynx, or larynx.

IMP Landmarks

         The diaphragma sellae was an important landmark structure in pituitary surgery in the past - extension of a pituitary tumour above it was an indication for a subfrontal approach through a craniotomy. However, a transsphenoidal approach is currently the first preferred option, irrespective of whether there is suprasellar extension.

·         The anterior and posterior commissures are important neuroradiological landmarks. Prior to the introduction of modern imaging techniques the anterior and posterior commissures could be identified by ventriculography. This led to the use of these two landmarks as the markers of the baseline used for stereotaxic surgical procedures. This convention is now universal and the positions of the anterior and posterior commissures are used as the basic reference points for most surgical atlases of brain anatomy. The narrow interventricular foramen is located immediately posterior to the column of the fornix and separates the fornix from the anterior nucleus of the thalamus.

·         The floor of the temporal fossa is formed by the frontal and parietal bones, the greater wing of the sphenoid, and the squamous part of the temporal bones. All four bones meet on each side at an H-shaped junction of sutures termed the pterion. This is an important landmark on the side of the skull because it overlies both the anterior branch of the middle meningeal artery and the lateral (Sylvian) cerebral fissure intracranially (it is also known as the Sylvian point). The pterion corresponds to the site of the anterolateral (sphenoidal) fontanelle on the neonatal skull, which disappears about three months after birth.

·         The retromandibular vein, formed by the union of the maxillary and superficial temporal veins (which enter near the points of exit of the corresponding arteries), is superficial to the external carotid artery. It is invariably of a reasonable size and is an important landmark for the facial nerve.

·         Scalenus anterior forms an important landmark in the root of the neck, because the phrenic nerve passes above it, the subclavian artery below it, and the brachial plexus lies at its lateral border. The clavicle, subclavius, sternocleidomastoid and omohyoid, lateral part of the carotid sheath, transverse cervical, suprascapular and ascending cervical arteries, subclavian vein, prevertebral fascia and phrenic nerve are all anterior to scalenus anterior. Posteriorly are the suprapleural membrane, pleura, roots of the brachial plexus and the subclavian artery: the latter two separate scalenus anterior from scalenus medius.

·         Posteroinferior end of the superior turbinate is the most appropriate anatomic landmark for the identification of the natural ostium of the sphenoid sinus.

·         The pterygomandibular raphe - a tendinous band between buccinator and the superior constrictor - passes downwards and outwards from the hamulus to the posterior end of the mylohyoid line. When the mouth is opened wide, this raphe raises a fold of mucosa that marks internally the posterior boundary of the cheek, and is an important landmark for an inferior alveolar nerve block.

·         Superior petrosal triangle as anatomic landmark for subtemporal middle fossa orientation.

·         Histological studies have shown the radioscapholunate ligament is not a true ligament because it contains neurovascular structures which supply the scapholunate interosseous membrane and is covered by a thick synovial lining. However it a visible landmark inside the wrist joint when undertaking wrist arthroscopy.

·         A triangular zone ,the triangle of Koch is found between the attachment of the septal cusp of the tricuspid valve, the anteromedial margin of the ostium of the coronary sinus, and the round, collagenous, palpable, subendocardial tendon of Todaro. The triangle is a landmark of particular surgical importance, indicating the site of the atrioventricular node and its atrial connections.

·         The pubic tubercle is an important landmark in distinguishing inguinal from femoral hernias; the neck of the hernia is superomedial to it in inguinal hernia, but inferolateral in the femoral form.

·         The main trunk of the inferior mesenteric vein lies either posterior to the duodenojejunal flexure or beneath the adjacent peritoneal fold. The duodenojejunal flexure is a useful landmark to locate the vein radiologically or surgically.

·         The ligament of Treitz is an important landmark in the radiological diagnosis of incomplete rotation and malrotation of the small intestine.

·         The presacral fascia provides an important landmark because extension of rectal tumours through it signifiantly reduces the chance of curative resectional surgery being possible. Dissection in the plane posterior to it may result in bleeding from the presacral veins and, since the adventitia of the veins is partly attached to the posterior surface of the fascia, the haemorrhage may be severe because the veins are unable to contract down properly.

·         The rectosacral fascia, or Waldeyer's fascia, is a thick condensation of endopelvic fascia connecting the presacral fascia to the fascia propria at the level of S4 and extends to the anorectal ring. Waldeyer's fascia is an important surgical landmark, and its division during dissection from an abdominal approach provides entry to the deep retrorectal pelvis.

·         The common peroneal nerve is found emerging posterior to the biceps femoris tendon, which is thus a useful landmark to find the nerve and also to avoid injury to the nerve.

·         Flexor hallucis longus is an important surgical landmark at the ankle: staying lateral to it prevents injury to the neurovascular bundle.

·         The master knot of Henry is the anatomical landmark where the tendon of flexor hallucis longus crosses deep to the tendon of flexor digitorum longus, to reach its medial side in the sole of the foot. The medial plantar nerve can be irritated at the master knot of Henry: this is usually related to jogging.

·         intersegmental pulmonary veins form surgical landmarks; thus, a surgeon can remove a bronchopulmonary segment without seriously disrupting the surrounding lung tissue and major blood vessels.

·         Sacral cornu or horn: formed by the pedicles of the fifth sacral vertebra. It is an important landmark for locating the sacral hiatus.

·         Iliac crests: a horizontal line connecting the crests passes through the spinous process of L4 and the intervertebral disc of L4-5; a useful landmark for a lumbar puncture or epidural block

·         Umbilicus: site that marks the T10 dermatome, lying at the level of the intervertebral disc between L3 and L4

·         The pectoral neurovascular bundle is a good landmark in that it indicates the position of the axillary vein just above and deep (superior and posterior) to the bundle. This neurovascular bundle needs to be preserved during standard axillary dissection.

·         The left crus of the diaphragm is a useful landmark that leads the surgeon to the left inferior phrenic vein.

·         The inferior epigastric artery and vein are branches of the external iliac vessels and are important landmarks for laparoscopic hernia repair.

·         The white line of Toldt represents the fusion of the mesentery with the posterior peritoneum. This subtle peritoneal landmark serves the surgeon as a guide for mobilizing the colon and mesentery from the retroperitoneum.

·         The mesosigmoid is frequently attached to the left pelvic sidewall, producing a small recess in the mesentery known as the intersigmoid fossa. This mesenteric fold is a surgical landmark for the underlying left ureter.

·         The ureters lie on the psoas muscle, pass medially to the sacroiliac joints, and cross the iliac vessels anteriorly. An important anatomic landmark for easy identification of the ureters is at the site where the ureters cross anterior to the iliac vessels. After crossing the iliac vessels, the ureters swing laterally near the ischial spines before passing medially to penetrate the base of the bladder. In males, the vasa deferentia pass anterior to the ureters as they exit the internal inguinal ring. In females, the uterine arteries are closely related to the lower ureters.

·         The three taenia coli converge at the junction of the cecum with the appendix and can be a useful landmark to identify the appendix.

·         Descemet's membrane becomes continuous and uniform, and fuses with the trabecular beams. The fusion site, known as Schwalbe's line, is a gonioscopic landmark that defines the end of Descemet's membrane and the start of the trabecular meshwork.

·         The preaponeurotic fat pockets in the upper eyelid and the precapsulopalpebral fat pockets in the lower eyelid are anterior extensions of extraconal orbital fat. These eyelid fat pockets are surgically important landmarks and help identify a plane immediately anterior to the major eyelid retractors.

·          

·         The thyrohyoid membrane pierced by the superior laryngeal vessels and internal laryngeal nerves, and Laryngocele (external).

·         The orbital septum is pierced above by levator palpebrae superioris and below by the ligament from inferior rectus. The lacrimal, supratrochlear, infratrochlear and supraorbital nerves and vessels pass through the septum from the orbit on the way to the face and scalp.

·         The axillary fascia is pierced by the tail of the breast.

·         Branches of Musculo Cutaneous Nerve to biceps and brachialis leave after the musculocutaneous has pierced coracobrachialis, also pass between biceps and brachialis, the branch to brachialis also supplies the elbow joint.

·         The middle meningeal is the largest of the meningeal arteries. It passes between the roots of the auriculotemporal nerve and may lie lateral to the tensor veli palatini before entering the cranial cavity through the foramen spinosum.

·         The buccal branch of the mandibular nerve passes between the two heads of lateral pterygoid.

·         The mandibular part of maxillary artery passes between the neck of the mandible and the sphenomandibular ligament, parallel with and slightly below the auriculotemporal nerve.

The pterygopalatine part passes between the two heads of lateral pterygoid to reach the pterygomaxillary fissure before it passes into the pterygopalatine fossa.

·         The buccal nerve and maxillary artery passes between the two heads of lateral pterygoid.

·         The middle meningeal artery ascends between the sphenomandibular ligament and lateral pterygoid, passes between the two roots of the auriculotemporal nerve and leaves the infratemporal fossa through the foramen spinosum to enter the cranial cavity medial to the midpoint of the zygomatic bone.

·         The mandibular nerve immediately passes between tensor veli palatini, which is medial, and lateral pterygoid, which is lateral, and gives off a meningeal branch and the nerve to medial pterygoid from its medial side.

·         The auriculotemporal nerve usually has two roots which encircle the middle meningeal artery. It runs back under lateral pterygoid on the surface of tensor veli palatini, passes between the sphenomandibular ligament and the neck of the mandible, and then runs laterally behind the temporomandibular joint related to the upper part of the parotid gland.

·         The inferior alveolar nerve descends behind lateral pterygoid. At the lower border of the muscle the nerve passes between the sphenomandibular ligament and the mandibular ramus and enters the mandibular canal via the mandibular foramen.

·         Sometimes, when the right subclavian artery is the last aortic branch, it passes between the trachea and oesophagus.

·         GlossoPharyngeal Nerve curves forwards on stylopharyngeus and either pierces the lower fibres of the superior pharyngeal constrictor or passes between it and the middle constrictor to be distributed to the tonsil, the mucosae of the pharynx and postsulcal part of the tongue, the vallate papillae, and oral mucous glands.

·         The vagus descends vertically in the neck in the carotid sheath, between the internal jugular 

vein and the internal carotid artery, to the upper border of the thyroid cartilage, and then passes between the vein and the common carotid artery to the root of the neck.

·         The pharyngeal branch of the vagus passes between the external and internal carotid arteries to the upper border of the middle pharyngeal constrictor.

·         Lingual Artery passes between hyoglossus and the middle constrictor of the pharynx to reach the floor of the mouth accompanied by the lingual veins and the glossopharyngeal nerve.

·         Stylopharyngeus is a long slender muscle arises from the medial side of the base of the styloid process, descends along the side of the pharynx and passes between the superior and middle constrictors to spread out beneath the mucous membrane.

·         Posterior interosseous nerve PIN, which passes between the two heads of supinator and enters the extensor compartment of the forearm.

·         At the elbow the ulnar nerve is in a groove on the dorsum of the epicondyle. It enters the forearm between the two heads of flexor carpi ulnaris superficial to the posterior and oblique parts of the ulnar collateral ligament.

·         The median nerve enters the forearm between the two heads of pronator teres and gives off the anterior interosseous nerve, which supplies all the flexor muscles of the forearm apart from flexor carpi ulnaris and the ulnar half of flexor digitorum profundus.

·         The deep palmar arch and the deep branch of the ulnar nerve pass between the two heads of the adductor pollicis.

·         The superior thoracic artery  runs anteromedially above the medial border of pectoralis minor, then passes between it and pectoralis major to gain the thoracic wall.

·         The femoral nerve descends through psoas major and emerges low on its lateral border. It passes between psoas major and iliacus deep to the iliac fascia and runs posterior to the inguinal ligament into the thigh.

·         The inferior gluteal passes between the first and second or second and third sacral anterior spinal nerve rami, then between piriformis and ischiococcygeus.

·         The profunda femoris artery passes between pectineus and adductor longus, then between the latter and adductor brevis, before it descends between adductor longus and adductor magnus.

·         The anterior tibial artery is the terminal branch of the popliteal artery passes between the heads of tibialis posterior and through the oval aperture in the proximal part of the interosseous membrane to reach the extensor region.

·         the mediastinum is the partition between the lungs and includes the mediastinal pleura; however, the term is commonly applied to the region between the two pleural sacs.

·         There are four anatomical landmarks leading to the identification of the trunk of the facial nerve as it leaves the stylomastoid foramen.

1. The cartilaginous external auditory meatus forms a pointer’ at its anterior, inferior border indicating the direction of the nerve trunk.

2. Just deep to the cartilaginous pointer is a reliable bony landmark formed by the curve of the bony external meatus and its abutment with the mastoid process. This forms a palpable groove leading directly to the stylomastoid foramen. Unfortunately this groove is filled with fibrofatty lobules that often mimic the trunk of the facial nerve which can lie as much as 1 cm deep to this landmark.

3. The anterior, superior aspect of the posterior belly of the digastric muscle is inserted just behind the stylomastoid foramen.

4. The styloid process itself can be palpated superficial to the stylomastoid foramen and just superior to it. The nerve is always lateral to this plane and passes obliquely across the styloid process. A branch of the postauricular artery is usually encountered just lateral to the nerve.