ANATOMY LIMBS; Lecture 1 and 2 - Development and Growth of Bone, Overview of Upper/Lower limbs Flashcards
What are the functions of bone?
Support of body shape, system of levers for muscle action, protection of internal organs, site of blood cell formation, mineral storage pool
What are the mechanical properties of bone?
Cable like flexibility and resistance to tension due to collagen and other bone protein framework; pillar-like stiffness and resistance to compression conferred by impregnation of collagen with crystalline mineral (hydroxyapatite - complex calcium hydroxyphosphate)
What are the 2 main types of bone tissue?
Woven (immature) and lamellar (mature) -> woven only found in repairing fractures in adults
What is the femur?
Thigh bone
What are the characteristics of the femur?
Epiphysis (head), metaphysis (in neck), diaphysis (shaft)
How is the lamellar bone arranged?
Outer hard layer of compact lamellar bone (cortical bone) -> inner layer of interlacing struts of lamellar bone (cancellous bone)
What is cancellous bone?
Spongy or trabecular bone which is lamellar NOT woven bone - although irregularly arranged
How is blood supplied to the bones?
What is the periosteum?
Fibrous and cellular layer -> roles in bone growth and repair, vascular and has a good nerve supply
What are the different kinds of bone cells?
When does the bone develop?
Skeleton starts to form at 6 wks of fetal life and growth continues in some bones until 25y
What are the 2 types of ossification?
Intramembranous and Endochondral
What is intramembranous ossification?
In existing vascular and connective tissue, bone matrix (ostein) deposited around collagen, mineralises to form woven bone and remodels to lamellar
What is endochondral ossification?
Within existing fetal cartilage models, cartilage calcifies and chondrocytes die, periosteal osteoclasts cut channels for sprouting vessels, osteoblasts enter with vessels to build bone round them
How does endochondral ossification occur when the bone needs to support large forces whilst growing?
Shaft ossifies first followed by epiphyses -> growth continues by ossification at growing cartilage plate between them, growth cssation when cartilage growth ceases and plate is overrun by ossification
How do these 2 wrists compare?
Child’s wrist (bottom) epiphyses ossify in 2y -> epiphyseal plates remain cartilaginous until growth ceases after puberty
How adaptable is bone?
Can grow without compromising its support function; increases or decreases bulk and density in response to pattern of use; can alter its external and internal shape in response to pattern of use (remodelling), can repair when fractured
What does the bone need when growing and remodelling?
Bone has a large blood supply (cells aren’t far from nutrients/O2), osteocytes maintain matrix but can activate osteoblasts for new bone building, osteoclasts are giant cells specialised for destruction of bone matrix
How does bone diameter growth occur?
Apposition (addition to exterior at periosteum); osteoblasts/clasts create ridges and grooves on bone surface, blood vessels align in grooves, oestoblasts build new osteons round vessels, osteoclasts remove bone from endosteal surface
What are the different types of fractures?
How do fractures heal?
Early fracture healing -> fracture repair phase with woven bone formation -> late fracture repair: reactive cartilage undergoing endochondrial ossification
What occurs if blood Ca levels are high?
Calcitonin released by parafollicular thyroid cells -> breakdown of bone matrix by osteoclasts inhibited; uptake of Ca into bone matrix is promoted
What occurs if Blood Ca levels are low?
Parathyroid Hormone (PTH) released by chief cells of parathyroid gland; osteoclast bone resorption activity promoted; increases Ca2+ re-absorption by the kidneys.
What are the key clinical vascular points relating to the limb?
Pulses, Varicose veins, Deep-vein thrombosis, Superficial veins for injection, lines, harvesting etc, Arteries for access to cardiac vessels, Compartment syndrome
What are the key clinical features (NM and MS) related to limbs?
What is the appendicular skeleton?
Where do the limbs originate from?
Upper limb C5-T1; lower limb L2-S3
What are the compartments of the upper limb?
Forearm = elbow to wrist and arm (technically) = shoulder to elbow
What are the bones present in the upper limb anterior compartments?
True joint = sternoclavicular joint; 2 phalanges in thumb, 3 in other digits
What are the upper limb anterior compartments?
Anterior shoulder (pectoral) girdle, anterior (flexor) arm and anterior (flexor) forearm, palmar compartment of the hand
What are the muscles present in the upper limb anterior compartments?
x
What are the muscles present in the upper limb anterior compartments?
How does the lower limb differ from the upper limb in arrangment of flexors/extensors?
During development the leg twists so the flexors are posterior and the extensors anterior -> also dermatomes have twisted oblique fields
What are the bones of the posterior upper limb compartment?
What are the muscles of the posterior upper limb compartment?
How does arrangement of the pectoral/shoulder girdle aid in movement?
Movement of the shoulder involves both movements of the arm relative to the scapula and the shoulder joint and movements of the scapula relative to the chest wall -> muscles acting on shoulder joint have attachments in neck, ant chest, back and arm
What are the muscles present in the arm and how are they arranged?
NB: Deltoid isn’t present too far down the arm
What are the compartments of the lower limb?
NB: Thigh is between hip and knee joint; leg is between knee and ankle joints
What are the muscles of the anterior lower limb compartment?
What is the arterial supply to the upper limb?
Aorta, Subclavian artery, Axillary artery, Brachial artery (pulse), Deep brachial artery, Ulnar and radial arteries (pulses), Hand arches, Metacarpal and digital arteries
What is the venous drainage of the upper limb?
Superficial and deep systems: Dorsal venous arch (sup.); Cephalic vein and basilic vein (sup.); Venae comitantes (deep); Axillary vein (deep); Subclavian vein; Superior vena cava
What is the place to take blood?
Superficial veins in region of Cubital Fossa -> NB: median cubital vein aren’t always present
What is the arterial supply of the lower limb?
Aorta; Common iliac arteries: Internal iliac artery, External iliac artery, External iliac artery; Femoral artery (pulse): Deep femoral artery; Popliteal artery (pulse): Posterior tibial artery (pulse), Anterior tibial artery (pulse), Peroneal artery, Dorsalis pedis (pulse)
What is the venous drainage of the lower limb?
Deep System: Ant & Post Tibial Venae Comitantes, Popliteal Vein, Femoral Vein, External iliac vein; Superficial system: Venous arches, Long saphenous vein, Short saphenous vein
What is important about the saphenous veins?
Great and Small arise from venous network of dorsum of foot; great SV drains into femoral vein at groin; Small SV drains into popliteal vein at popliteal fossa
What is important about the femoral triangle?
Region of the groin where the femoral artery is accessed e.g. access to the cardiac vessels to carry out angiograms and angioplasty. A pulse can be felt in this area.
What are varicose veins?
Perforating veins connecting sup and deep veins contain a valve which allows flow only from sup to deep, if compromised then blood is pushed to sup veins leading to varicose veins
How are the spinal nerves organised?
How is the brachial plexus organised?
How are the nerves to the lower limb organised?
Femoral supplies ant compartment of thigh; Obturator supplies medial (adductor) compartment on thigh; Sciatic (tibial and common peroneal branches) supply remaining compartments
What is the segmental supply to the upper limb?
What is the segmental supply to the lower limb?
What is the segmental motor supply to the upper limbs?
What is the segmental motor supply to the lower limbs?
What are the dermatomes of the limbs?
What is the segmental vs cutaneous sensory innervation?
What is the segmental sensory supply to the lower limbs?
What is the segmental sensory supply to the upper limbs?
What is there is a lesion of CPN at fibular neck?
Motor - foot drop; Sensory - dorsum of foot at least; Reflex - none; autonomic - minimal
Summarise the anterior compartment of the arm?
What is compartment syndrome?
What are the muscles of the posterior lower limb compartment?
NB: Gluteus maximus is one of the biggest muscles in the body
What are the bones of the posterior lower limb compartment?
Where do the psoas and iliacus muscle arise from?
From the abdomen (psoas from lateral processes of L1-4 and attaches to bump in femur); involved in flexion of the hip if attached to abdomen and pelvis
Where do the nerves supplying the lower limbs arise from?
Lumbosacral plexus (L2-S3)
How are the muscles arranged going down the leg and thigh?
