Regional anatomy

Two regions:

1. Pre-axial region = Radial side of the limb (lateral)

2. Post-axial region = ulna side (medial)

3. Ventral axial line - separates tissues of arm and forarm into embryological regions of limb

Shoulder > arm > forarm > wrist > hand

Joints - Sternoclavicular joint (Girdle), Gleno-humeral Joint (Girdle), Elbow joint, Wrist Joints, Joints of the hand

Two musculo-fascial compartments

• each has its own muscles, blood supply, venous drain, nerve innervation and lymphatics

The groove is between anterior and middle scalene muscle

• the roots of brachial plexus lie in relation to the scalene muscles

• Nerve root value of brachial plexus are C5 to T1

• Clinical significance is to be able to temporarily block all sensation arising from the upper limb by anaesthetising roots of brachial plexus.

  • Needle inserted halfway between lateral border of sternocleidomastoid muscle and anterior border of trapezius muscle.

Sternoclavicular joint

• Formed by articulation of medial aspect of clavicle with manubrium of sternum

• Classified as plane style synovial joint and has fibrocartilage joint disc

• One of the 4 joints that compose the shoulder complex (pectoral girdle)

Clavicle extends from manubrium of the sternum to acromion

• Its sternal (or medial) end is triangular & articulates with the Sternum at the Sternoclavicular joint

• Its acromial (or lateral) end is flattened & articulates with the Acromion of the Scapula at the acromioclavicular joint

Sternocleidomastoid muscle pulls the medial 2/3 of the clavicle upwards (convex anteriorly) while the trapezius muslce pulls the lateral piece medially (concave anteriorly) .

Axilla is the anatomical space of the armpit (under where arm connects shoulder). It is a pyramid shape, has 4 sides, apex and base.

Axillary sheath - Brachial plexus, axillary artery, axillary vein

Axillary lymph nodes

• Part of axial skeleton

• Acts as a site of attachment of lower limbs > enables locomotion

• Supports vertebral column, spinal cord and attendant CSF

• Suppors upright posture when standing

• In upright position, supports carrying of weight of head, neck, thorax, upper limbs and trunk

• Site for pregnancy

• Houses important viscera - pelvic viscera proper, viscera of abdomen.

PID, UTI, pregnancy, urinary / faecal incontinence, childbirth

• shared - bones

• Female has wider (rounder) pelvic brim, male ha heart shaped.

• Male has acute (triangular) pubic arch, female is slightly rounded (pic)

Urinary system

Lower GI tract

Reproductive system

Parturition (female)

Pelvic floor (pelvic diaphragm)

Musculature of proximal lower limb

• Greater Pelvis (or False Pelvis)

• Pelvic Brim

  • Also known as the Pelvic Inlet

  • True Pelvis (vs Lesser Pelvis)

• Outlet

  • Pelvic Floor

  • Interaction between the Pelvic Floor & Viscera of

    the Urinary Tract & Reproductive Tract

Formed of 3 main bones;

• 2 pelvic bones - left and right, joined anteriorly by pubic symphysis

• 1 sacrum & coccyx - form middle of the posterior border

Direct landmarks

• Supracristal plan (top black line) - L4/L5, safe site for LP

• Anterior superior iliac spine - site for inguinal ligament attachment, used in measurement of limb length

• Anterior inferior iliac spine (top dot)

• posterior superior iliac spine (bottom dot)

• pubic crest (bottom line) - site for suprapubic puncture of urinary bladder

Indirect landmarks

• Greater trochanter - hip joint

Composed of union of 3 bones - the bones unite to form the acetabulum.

They unite by ossification of tri-radiate cartilage of acetabulum.

• Ilium (forms most of the superior part)

• Ischium (forms most of the Posterior portion)

• Pubis (forms most of the anterior portion)

• forms the lowermost aspect of vertebral column

• Fomed from fusion of 5 sacral bones (S1 to S5)

• Form the sacral curvatures of the vertebral column

• Articulates with hip bones via 2 articular surfaces

• The holes are sacral foramen where spinal nerves comes through

• Forms the final segment of the vertebral column

• Formed by process of secondary neurilation

• Composed from the union of 4 coccygeal bones

• Greater (false) pelvis

• Lesse (true) pelvis

• anterior wall

• posterior wall

• 2 lateral walls (L + R)

• Inferior wall (pelvic floor)

• its the continuation of the pelvic body wall

• Major site of attachments of pelvic organs - uterus

• Site of attachments of muscles that move the lower limb - esp thigh

• important anatomical features includes - pelvic bone, ligaments of pelvis, msucles, peritoneum, fascia, anatomical spaces

• Hip bone

• Ligaments - Sacrospinous and sacrotuberous

• Obturator membrane

• anatomical spaces - obtrurator foramen (anteriorly), greater sciatic foramen, lesser sciatic foraemen (posteriorly)

There are a number of palpable bony landmarks of significance

• Iliac crest

• Anterior superior iliac spine (ASIS)

• Pubic tubercle

• Greater Trochanter

• Medial / inferior edge of the patella

• Tibial tuberosity

• Medial malleolus (tibia)

• Lateral malleolus (fibula)

• Navicular

Iliac crest left and right

• they mark the highest anatomical points of LL

• Imaginary line between the two iliac crest > anatomical plan known as supracristal plane (Tuffier’s line)

• Horizonal plan between R and L iliac crest

• Occurs around level of L4 (L3/4 intervertebral disc)

• landmark for:

  • Bifurcation of descending aorta into left and right common iliac arteries

  • safe area for LP, epidural anaesthesia and determining site for aspiration of bone marrow.

Anterior superior iliac spine (ASIS)

• prominence of the ilium - located onthe superior, anterior margin of the pelvis.

McBurney’s point

• On the right side of the abdomen, 1/3 of the distance from ASIS to the umbilicus - corresponds to the location of appendix.

• Used to assess palpation in suspected appendicitis and used for surgery such as appendicetomy

Inguinal ligament is a fibrous inferior border of the anterior abdominal wall. It attach to ASIS (supero-laterally) and pubic tubercle (infero-medially).

• Defines the border between abdomen and lower limb

• anatomical structures that pass (deep):

  • Femoral canal

  • femoral sheath - fascia which encloses femoral artery and veins

  • femoral nerve/artery /vein (lateral to medial)

  • lateral cutaneous nerve of the thigh

  • psoas major/ iliacus / pectineus muscles (floor of the femoral triangle)

  • lymphatics.

Inguinal canal

• runs directly superior and parallel to the inguinal ligament = runs inferior and medial through inferior part of abdominal wall.

• Canal starts at the deep inguinal ring and ends at the superficial inguinal ring.

• Structures that pass through:

  • Male - spermatic cord and testicular artery

  • female - round ligament of the uterus

  • both - ilio-inguinal nerve and genital branch of genitofemoral nerve

Lateral cutaneous nerve of the thigh pass deep into the inguinal ligament. It can be compressed by inguinal ligament > painful numbness of the upper part of the thigh

Femoral hernia

• herinated peritonieal sac protrude through fermoral ring > femoral canal

• This is because th femoral sheath is only closed by extraperitoneal tissue > site of weakness

Inguinal hernia - can be direct or indirect

• Direct - protrude through posterior wall of the inguinal canal

• Indirect - protrude through deep inguinal ring

• It is a lateral bony prominence of LL

• Detects ant changes in direction of the neck of femur relative to the shaft

• indirect landmark for position of the hip joint, capsule and extracapsular ligaments of hip joint.

Most hip dislocations are posterior (90%). This is due to the posterior (ischiofemoral) ligament being the weakest of the 3 ligaments of the joint.

The clinical presentation of a posterior hip dislocation includes:

• Shortened appearance of the affected lower limb

• Flexed position and Internal rotation of limb

Can occur as a result of motor vehicle collision where the hip joint is flexed

Medial malleolus of tibia

lateral malleolus of fibula

• The greater saphenous vein ascends anterior to medial malleoulus

• posterior tibial pulse of posterior tibial artery palpable in tarsal tunnel. it runs posteriorly and inferiorly to medial malleolus.

Tibial tuberosity - inferior border of the patella

• between these bony landmark is where patella tendon is located.

• strike of the tendon > knee jerk reflex

‘Apparent’ = one limb appears shorter than other, not necessarily short

• Posterior dislocation of hip joint in ‘shorter’ limb.

• Congenital cause of hip dislocation in ‘shorter’ limb.

• Hip tilting, for example due to scoliosis.

‘True’ = The limb is actually shorter in distance between ASIS (hip) and medial malleolus (tibia)

• Congenitally shorter lower limb compared to the other limb.

• Fracture of one or more of the long bones of the shorter limb, leading to overlap in the bone fragments.

• Skeletal growth disorders.

• Scoliosis.

True limb length

• Measure the distance of the right and left limbs between anterior superior iliac spine (proximally) and medial malleolus of tibia (distally)

• If the length between R + L not same = true limb length discrepancy

Apparent limb length

• Measures the distance of R and L between umbilicus (proximally) and medial malleolus (distally)

• If the length between R+L not same = aparent limb length discrepancy

Examination:

• Patient lie down supine on their back then elevate the leg straight individually.

• Aims to stretch the sciatic nerve directly - if the nerve is pinched by slipped IV dic > stress > pain

• if stretched within CNS > pull and irritation of spinal meninges in neck > Meningism = Sign of Kernig

Indication:

• Sciatica (lumbar rediculopathy) - spinal roots of sciatic nerve are damaged or injured

• Lumbar slipped disc or herniation

• Inflammed meninges of the spinal cord (meningism)

-> Stiffness of the neck knowns as nuchal rigidity is tested by stretching or raising the neck of a patient in supine position

-> If this stretch result in flexion of the hip and knee = +ve sign for meningism

They all are built from set of specialised standard tissues:

• Skin, superficial and deep connective tissue, membranes that cover and seperate the organs, skeletal muscles, arteries, veins, lymphatics, LN, nerves and blood cells.

Some regions will contain specialised tissues and organs:

e.g abdominal region - liver, kidney, pancreas, heart, lung, muscles, bones, joints, special sense organs

The Upper Limb (neural level)

• Supplied by the brachial plexus of nerves.

• The Spinal Neural Root values of the brachial plexus are C5 to Tl - (not be confused with vertebral levels)

The Lower Limb (neural level)

• Supplied by a combination of 2 nerve plexuses —> Lumbar Plexus and Sacral Plexus

• Neural Root values of the Lumbar plexus L2 to L4 (half)

• Neural Root values of the Sacral Plexus L4 (half) to S4

Defined as ‘Continuous area or expanse which is free, available, or unoccupied’ e.g oral cavity, nasal cavity.

There are 2 classes of anatomical spaces:

• True anatomical space - Occurs normally, demostrable

• Potential space - Do not exist normally, created as a result of pathological development e.g blister, hepato-renal or Pouch of Morrison.

  • Usually liver and kidney are close but bleed or free fluid around them can seperate the visceral organs creating an anatomical space

• Varients of AS - Rectouterine pouch / puch of Douglas

Cavity

• Defined as empty space within a solid object e.g Thoracic, abdominal, pelvic cavities

• Space with defined boundaries, shape, contents, point of entry and exit

Compartment

• separate section / sub-section within a cavity

• Have defined boundaries with connective tissues, independnet, self-sufficient units.

-> Skin

-> Superficial fascia - binds skin to the tissues of the body

-> Deep fascia - Encloses organs, divides muscles into compartments (investing and intermediate layer)

-> Muscles

-> Deepest layer of deep fascia

After the deep fascia, there are 3 layers of muscles lining body wall:

> Abdominal wall: external oblique -> internal oblique -> transversus abdominis

> Thoracic wall: external intercostal -> internal intercostal -> innermost intercostal

> Ribcage: External intercostal -> internal intercostal -> innermost intercostal

Nerves (out-in)

• Epineurium - ensheathes entire nerve

• Perineurium - ensheathes nerve fascicle (collection of axons)

• Endoneurium - ensheathes single axon

Muscles (out - in)

• Individual muscles (multiple fascicles) are enclosed by the epimysium.

• Bundles (fascicles) enclosed by perimysium

• Individual fibres enclosed by endomysium

• Largest organ, part of integumentary system

• Consits of connective and epithelial tissues

Functions:

• Protection e.g. from water loss, Insulation, Temperature regulation, UV, immune defence

• Metabolic - synthesis of vitamin D, protects Vit B and folate

• Sensation, Signalling

Macroscopic

• 2 types - hairy and glaborous (palms / sole)

Microscopic

• Epidermis - Epithelial layer of skin

• Dermis (skin proper) - Superficial connective tissue layer

• Hypodermis/subcutis - Deep connective tissue layer

• Stratum Corneum – top most layer, doesn’t have nucleus / nutrient supply, made of corneocytes (dead keratin)

• Stratum Lucidum - only in thick skin

• Stratum Granulosum - Here keratinocytes produce granules containing enzymes that dissolve phospholipid bilayer

• Stratum Spinosum – has keratinocytes > synthesis keratins > strength of epidermis

• Stratum Basale - Cells here divide and multiply to give rise to more skin cells, where the keratinocyte mitotic activity occurs.

Melanocytes

• found in basal layer, produce melanin > skin pigmentation

Langerhans cells

• Found in S. spinosum, mediates immune reaction (e.g allergic contact dermatitis), present Ag to WBC

Merkel cells

• Oval shaped mechanoreceptor for light touch sensation.

-> Have papillary and reticular layers

-> Tought, fibrous and vascular connective tissue

-> Mostly made of ECM - colagen (T1), elastin

-> Spindle shaped fibroblasts are scattered throughout - produce matrix and fibres

-> Has blood vessels, lymphatics, mast cells and nerves

-> Body consists of 4 basic tissues arranged into layers:

• Skin > superficial fascia > deep fascia > muscles > neurovasculature > visceral organs

-> Fascia = Part of CT that holds substances of body together.

e.g Skin is tethered to body by superficial fascia (contains CT, fat + blood vessels) > fluidity of movements.

Note: superficial fascial plane of thorax is unusual and has additional contents not seen elsewhere - platysma muscle and mammary gland of male and female.

-> Retro-mammary space or sum-mammary space - lymphatics of mammary runs here

-> Mammary gland is invested with loose CT > allows breast tissue development and movement.

-> the gland is NOT attached to deep fascia of the anterior chest wall

-> Lines of cleavages in the skin - its tethered to the body through pre-determined lines of tension.

-> Incisions along this lines > optimal healing with less scarring.

-> If not followed this line > keloid scars

1. Hair follicles

2. Sebaceous glands (sefretes fat into hair shaft)

3. Sweat glands (eccrine, apocrine)

4. Nails

1 & 2 forms Pilosebaceous unit

-> Large sweat gland, most abdundant in axillae, genital and submammary areas

-> ducts open into hair follicles, produce odourless, protein-rich secretions which get digested by cutanous microbes > body odour.

• Psoriasis: abnormal epidermal growth and differentiation > hyperproliferation of basal layer > gross thickening > excess S. cornum cells

• Allergic contact dermatitis: mediated by Langerhans cells & T lymphocytes

• Malignant melanoma: malignant growth of melanocytes

• Vitiligo: Autoimmune destruction of melanocytes > symmetrical localised skin depigmentation.

• Mast cells are cytoplasmic granules containing histamines, they are distributed around dermal blood vessels

• Activated in T1 immediate hypersensitive allergic reaction > histamine release > increased vascular permeability > leakage of plasma > urticaria and angioedema

The intervertebral disc contributes to 25% of the vertebral height

A central region

-> Has nucleus pulposus (remenant of notchord), has high osmotic power (attracts water).

-> Responsible for water retention and size of IVD (this changes within 24 hr cycle > varying height)

A Peripheral region

-> The annulus fibrosis (CT bands arranged in different directions), very resilient

-> Responsible for retention of nucleus pulposus and confers strength to IVD.